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Optimization of the ultrasound-assisted extraction of tryptophan and its derivatives from rice (Oryza sativa) grains through a response surface methodology

Journal Article
Setyaningsih, W., Saputro, I.E., Palma, M., Barroso, C.G.
Journal of Cereal Science, 2017, 75: 192-197, DOI: 10.1016/j.jcs.2017.04.006.

ABSTRACT

An analytical ultrasound-assisted extraction (UAE) technique has been optimized and validated for the extraction of tryptophan and its derivatives from rice grains. A Box–Behnken design in conjunction with a response surface methodology based on six factors and three levels was used to evaluate the effects of the studied factors prior to optimizing the UAE conditions. The significant (p < 0.05) response surface models with high coefficients of determination were fitted to the experimental data. The most significant (p < 0.0001) effect is the solvent-to-sample ratio while quadratic effects caused by temperature and solvent-to-sample ratio were of moderate importance (p < 0.05). The optimal UAE conditions were as follows: extraction time of 5 min, ultrasound amplitude of 30%, cycle of 0.7 s−1, extraction temperature of 30 °C, 8% methanol in water as the extraction solvent at pH 3 and a solvent/solid ratio 5:1. The method validation ensured that appropriate values were obtained for the LOD, LOQ, precision and recovery. Furthermore, the method was successfully applied to the analysis of a number of rice samples of different varieties. It was demonstrated that this particular UAE method is an interesting tool for the determination of tryptophan and tryptophan derivatives in rice grain samples.

JCS_02

 

Tryptophan Levels during Grape Ripening: Effects of Cultural Practices

Journal Article
Ruiz-Rodríguez , A., Carrera, C.A., Setyaningsih, W., Barbero, G.F., Ferreiro-González, M., Palma, M., Barroso, C.G.
Molecules, 2017, 22(6), 941: 1-9, DOI:10.3390/molecules22060941

ABSTRACT

Some cultural practices that are carried out during the grape ripening period are associated with vine stress, including leaf removal, grape bunch removal, and vegetable cover crops. Additionally, several nitrogen and sulfur supplements have also been used directly on leaves during the last stage of the ripening period. In the work described here, five different cultural practices and the reference were applied in three replicates in the same vineyard. The evolution of tryptophan levels was evaluated from just after grape veraison until the harvest date. In some cases, certain specific treatments were also evaluated after the regular harvest date. The cultural techniques that involved the application of nitrogen led to higher levels of tryptophan at the harvest day when compared to other cultural techniques. It was also found that the application of nitrogen without sulfur had a faster effect on the level of tryptophan. It was established that a period of around 20 days is needed for the grapes to show clear differences in tryptophan levels after the application of nitrogen.

Molecules

Profile of phenolic compounds in Indonesian rice (Oryza sativa) varieties throughout post-harvest practices

Journal Article
Setyaningsih, W., Hidayah, N., Saputro, I. E., Palma, M., Barroso, C. G
Journal of Food Composition and Analysis, 2016, 54: 55–62, DOI: 10.1016/j.jfca.2016.10.004

Abstract

Apart from being a foremost source of calories for a large part of the world’s population, cultivated rice (Oryza sativa) provides beneficial effects for human health through several bioactive compounds, including phenolics. Therefore, to earn this advantage, it is essential to retain the phenolics through appropriate post-harvest practices. In this paper, the profile of 10 individual phenolic compounds contained by rice grains after drying, dehusking and polishing processes were studied. A number of Indonesian rice cultivars from indica and javanica subspecies were acquired from conventional (IR-64, Umbul-umbul and Pandanwangi) and organic farming (Batang Lembang, Pandanwangi, black- and red-pigmented rice) were studied. Additionally, the effect of polishing degree on individual phenolics content in the grain was also evaluated. The level of phenolics decreased, also their relative values dramatically changed throughout a series of post-harvest processes. Moreover, changes on the composition of phenolic acids and its aldehydes in the grain have been described. p-Coumaric acid reflects the greatest differences on the phenolic composition during the course of post-harvest practices that altered from 48% to 8% portion to the total phenolics in paddies and polished grains, respectively. However, phenolics content in black-pigmented rice appeared to be the most persistent in the rice matrix. Since the profile of individual phenolics has also been evaluated on different polishing degrees (70%, 80%, 90% and 100% bran removal), the distribution of these compounds in the whole grain rice was effectively disclosed. These variations in the compositions and quantities of phenolics revealed the effect of post-harvest practices, varietal differences as their distribution in the grain.

Artikel PHE post harvest

Multiresponse optimization of a UPLC method for the simultaneous determination of tryptophan and 15 tryptophan-derived compounds using a Box-Behnken design with a desirability function

Journal Article
Setyaningsih, W., Saputro, I.E., Carrera, C.A., Palma, M. , Barroso, C.G.
Food Chemistry, 2017, 225: 1-9, DOI: 10.1016/j.foodchem.2016.12.034

Abstract

A Box–Behnken design was used in conjunction with multiresponse optimization based on the desirability function to carry out the simultaneous separation of tryptophan and 15 derivatives by Ultra Performance Liquid Chromatography. The gradient composition of the mobile phase and the flow rate were optimized with respect to the resolution of severely overlapping chromatographic peaks and the total run time. Two different stationary phases were evaluated (hybrid silica and a solid-core-based C18 column). The methods were validated and a suitable sensitivity was found for all compounds in the concentration range 1–100 μg L–1 (R2 > 0.999). High levels of repeatability and intermediate precision (CV less than 0.25% and 1.7% on average for the retention time and the signal area, respectively) were obtained. The new method was applied to the determination tryptophan and its derivatives in black pigmented glutinous and non-glutinous rice grain samples.

Article 2017

Use of multiple response optimization for the separation of tryptophan and 15 related compounds by ultrahigh performance liquid chromatography

Conference Paper
Saputro I.E., Setyaningsih, W., Carrera, C., Palma, M., and Barroso, C.G.
The 14 international Congress on Amino Acids, Peptides and Proteins (Amino Acids 2015), August 37, 2015, Vienna, Austria.

Abstract

A Box Behnken Design (BBD) in conjunction with multiple response optimizations was performed to develop the simultaneous separation of tryptophan and fifteen related compounds in rice grains by Ultrahigh Performance Liquid Chromatography (UPLC) coupled with Photodiode Array (PDA) detector. The gradient compositions of mobile phase (%B start and %B end) and flow rate were optimized with respect to the resolutions of severely overlapping chromatographic peaks between the phenolic compounds in addition to the total analysis time. Furthermore, two different stationary phases were also evaluated (Cortex C18 and BEH C18). A gradient program of only 4 min analysis run using Cortex C18 was found to provide the best resolution for the simultaneous separation of the 16 studied compounds. The method was validated resulting an adequate sensitivity in the range of 1–100 μg L-1 (R2=0.9993-0.9999) with high precisions (CV lower than 2% in average for both repeatability and intermediate precisions). The suitability of the method was checked by application to the analysis of pigmented and non-pigmented rice samples. Tryptophan and several related compounds were identified and quantified in the tested samples.

Effects of Cultivar Practices on Tryptophan Levels during Grape Ripening

Conference Paper
Ruiz-Rodríguez, A., Setyaningsih, W., Carrera, C., Palma, M., and Barroso, C.G.
The 14 international Congress on Amino Acids, Peptides and Proteins (Amino Acids 2015), August 37, 2015, Vienna, Austria.

Abstract

Different cultivar practices have been applied to vine to promote specific components related to final wine flavor. Some of the cultivar practices are related to vine stress, including leaf removal, grape bunch removal and vegetable cover crops. Some nitrogen and sulfur supplements have been also used directly to leaves during the last stage of the ripening period. Main effects of cultivar practices are related to the final composition of organic acids, volatiles components and phenolics. However some effects on amino acids have been also found.

This paper specifically deals with the effects on tryptophan level because of it has strong effects in the evolution of several other related compounds, including auxins and melatonin. Six different cultivar practices were applied in three replicated in the same vineyard. Evolution of tryptophan levels were determined starting just after grape veraison till harvest date. In some cases, some specific treatments were also evaluated after regular harvest.

Results point out the specific effect of vegetable cover crops and leaves removal to promote higher levels of tryptophan in grapes.

Ultrasound-assisted Extraction (UAE) for Tryptophan and lts Derivatives from Rice (Oryza sativa) grains

Conference Paper
Saputro I.E., Setyaningsih, W., Carrera, C., Palma, M., and Barroso, C.G.
The 14 international Congress on Amino Acids, Peptides and Proteins (Amino Acids 2015), August 37, 2015, Vienna, Austria.

Abstract

Cultivated rice (Oryza sativa) is a global staple food that subsists calories for more than half of the world’s population. Emerging evidence supports that a number of bioactive compounds have been identified in rice including tryptophan and its derivatives (oxitriptan, serotonin, tryptamine and auxin). The development of single optimized extraction of bioactive compounds from plant may complicate due to the structural diversity. A new ultrasound-assisted extraction (UAE) of tryptophan and its derivatives has been optimized and validated.Experiment with a three-level and six-factor Box-Behnken Design (BBD) combined with Response Surface Methodology (RSM) was employed to evaluate the significances of studied factors (solvent composition,temperature, solvent-solid ratio, pH, amplitude and cycle) on the extraction yields. Subsequently, extraction kinetic was studied to confirm satisfactory recovery of the extracted compounds from the matrix. Later, by chromatographic analyses, tryptophan, oxitriptan, serotonin, tryptamine and 3-indole acetic acid (auxin) were identified and quantified in the extracts of rice grains.

A complete validation of the method was performed and presented agreeable linearity (correlation coefficients higher than 0.9998) with high extraction precisions (in average, expressed as CV, repeatability and intermediate precision were lower than 2.0% and 2.6% respectively). The method was successfully applied in the extraction of a number of real samples. Hence, it can be concluded that UAE under optimum conditions can be considered as a powerful tool for the extraction of tryptophan and its derivatives from a wide variety of rice grains.

Optimisation of Ultrasound-assisted Extraction (UAE) for Phenolics from Rice (Oryza sativa) Grains using Box-Behnken Design

Conference Paper
Setyaningsih, W., Saputro, I.E., Palma, M., and Barroso, C.G.
The GDCh Scientific Forum Chemistry (Chemie 2015), August 30-September 2, 2015, Dresden, Germany.

Abstract

Emerging evidence supports that a number of health-promoting substances have been identified in rice (Oryza sativa) including phenolic compounds. The development of single optimized extraction of phenolic compounds from plant may complicate due to the structural diversity as having multiple hydroxyl groups which results the polarities of these compounds vary significantly. Therefore, an optimised extraction method that effectively extracts phenolics from rice is needed prior to the reliable determination of these compounds in the grains.

A new ultrasound-assisted extraction (UAE) of phenolics has been optimized and validated. A three-level, six-factor Box-Behnken design in conjunction with Multi-responses optimisation was employed to evaluate the significances of studied factors (solvent composition, temperature, solvent-solid ratio, pH, amplitude and cycle) on the extraction yields. Subsequently, extraction kinetic was studied to confirm high recovery of phenolics extracted from the matrix. The levels of phenolics were quantified by Ultrahigh Performance Liquid Chromatography coupled with Photo-diode Array detector (UPLC-PDA) in less than 5 min.

The optimal UAE condition was as follows: extraction time 25 min, ultrasound amplitude 47%, cycle 0.4 s-1, extraction temperature 45oC, pH 5.5, extraction solvent 80% MeOH in water and solvent-solid ratio 5:1. A complete validation of the method was performed and presented agreeable linearity (correlation coefficients between 0.998 and 0.999) with high precision (in average, expressed as CV, repeatability and intermediate precision were lower than 3 and 4.5% respectively). The method was successfully applied in the extraction of a number of real samples in order to evaluate the applicability. Hence, it can be concluded that UAE under optimum conditions can be considered as a powerful tool for the determination of phenolic compounds from a wide variety of rice grains.

Multiresponse HS-SPME Optimization Combined with GC×GC-TOFMS for Key-marker Aroma Compounds in Indonesian Aromatic Rice (Oryza sativa)

Conference Paper
Setyaningsih, W., Majchrzak, T., Dymerski, T., Namieśnik, J., Palma, M., Barroso, C. G.
The GDCh Scientific Forum Chemistry (Chemie 2015), August 30-September 2, 2015, Dresden, Germany.

Abstract

The grain aroma is a primary sensory attribute of high-quality rice that contributes a critical impact on consumer preference. Aromatic rice possesses typical volatile compounds released from the grain that discriminates aromatic rice varieties from ordinary ones. These varieties have become more widely appreciated in the current market. Furthermore, recent researches have led to an increase in rice breeding programs focusing on the odour profile to generate high quality aromatic rice cultivars. Therefore, an analytical method for key-marker aroma compounds determination is crucial to facilitate the selection of lines with superior aroma attributes.Using a dynamic HS-SPME system coupled to a GC×GC-TOFMS and multivariate analysis, the aroma chemistry of Indonesian aromatic and non-aromatic rice grains were compared and characterised to define the chemical markers of aroma quality. Sequentially, the analytical method of HS-SPME tandem with GC×GC-TOFMS for the determination of key marker aroma compounds in rice grains were developed and validated. The factors that are most likely to affect the HS-SPME efficiency were evaluated using a 2_III^(5-2) fractional factorial design in conjunction with multi-response optimisation.

Separation of 20 Phenolic Compounds in Rice by Ultrahigh Performance Liquid Chromatography (UPLC)

Conference Paper
Setyaningsih, W., Saputro, I.E., Barbero, G., Palma, M., and Barroso, C.G.
The 18 Scientific Meeting of the Euroanalysis series (EuroAnalysis 2015), September 6-10, 2015, Bordeaux, France

Abstract

A Box Behnken Design (BBD) in conjunction with multiple response optimizations was performed to develop the simultaneous separation of twenty phenolic compounds in rice grains by Ultrahigh Performance Liquid Chromatography (UPLC) coupled with Photodiode Array (PDA) detector. The gradient compositions of mobile phase and flow rate were optimized with respect to the resolutions of severely overlapping chromatographic peaks between the phenolic compounds and the analysis time. Additionally, two different stationary phases were also evaluated (Cortex C18 and BEH C18). A gradient program starts with 6.4% and rises to 32.6% of phase B in 3 minutes at flow rate of 0.6 mL min-1 using Cortex C18 was found to provide the best resolution for the separation of the 20 phenolic compounds. A complete validation of the method was accomplished reaching high precisions in terms of Coefficient of Variation (CV) lower than 2% for both repeatability and intermediate precision. The suitability of the method was checked by application to the analysis of pigmented and non-pigmented rice samples. The variations in the compositions and quantities of phenolics in rice samples analyzed by the developed method disclose the effect of varietal differences. Hence, this particular chromatographic method was demonstrated to be an excellent alternative for a fast and reliable determination of phenolic compounds in a wide range of rice variety.

Comparison of HPLC and UPLC Methods for the Determination of Melatonin in Rice

Conference Paper
Setyaningsih, W., Palma, M., and Barroso, C.G
DOI: 10.13140/RG.2.1.2300.1687. The 11International Students Conference ‘ModernAnalytical Chemistry’, September 22-23, 2015, Prague, Czech Republic

Abstract

This study compares the high performance liquid chromatography (HPLC) and ultrahigh performance liquid chromatography (UPLC) methods for the determination of melatonin in rice extracts. The methods were validated in terms of linearity, precision, limits of detection (LOD) and quantification (LOQ). Repeatability and intermediate precisions expressed as coefficient of variation (CV) were less than 2.5% for HPLC and 1.5% for UPLC. Linear regression models fit perfectly the standard curves with R2 > 0.99 for both methods. The LODs were 1.15 μg L-1 and 0.73 μg L-1 while LOQs were 3.84 and 2.19 μg L-1, for HPLC and UPLC respectively. High efficiency UPLC gradient is feasible and beneficial to substitute the conventional analysis of melatonin in rice grain by HPLC as permitted the analysis run time to be reduced to one six thus consumes less eluents.

ISC

Stability of 40 phenolic compounds during Ultrasound-assisted Extractions (UAE)

Conference Paper
Setyaningsih, W., Saputro, I.E. Palma, M., and Barroso
DOI: 10.13140/RG.2.1.2955.5281. International Conference on Science and Technology 2015 (ICST2015), November 11-12, 2015, Yogyakarta, Indonesia.

Abstract

Phenolics have been positively associated with many health benefits due to their prominent antioxidant activities. Sample extractions are required prior to chromatographic measurements for the determination of phenolics in matrices. Hence, the aim of this study was to assess the stability of 40 phenolic compounds of different families (benzoic acids, benzoic aldehydes, cinnamic acids, catechins, stilbens and flavonols) under conditions of ultrasound-assisted extraction (UAE). The influence on the stability affected by the working temperature between 10 and 70°C applying ultrasounds for 20 minutes was evaluated. As for precisely pinpointing the trigger for the degradation, the extractions were repeated in light protected experiments and by stirring to check their influences on the stability of phenolics apart from the effects of ultrasounds. Regardless the present of light, all studied phenolics were stable up to 50°C with the exception for kaempferol and some light sensitive compounds such as resveratrol, sinapic acid and p-coumaric acid. By light protected UAE, starting at 60°C there were significant degradations of gallic acid (12%) and rutin (16%) whilst other compounds showed degradation starting at 70 o C i.e. p-coumaric (11%), o-coumaric (12%) and resveratrol (21%).

ICST 02

Profile of Individual Phenolic Compounds in Rice (Oryza sativa) Grains during Cooking Processes

Conference Paper
Setyaningsih, W., Saputro, I.E. Palma, M., and Barroso
DOI: 10.13140/RG.2.1.2431.2401. International Conference on Science and Technology 2015 (ICST2015), November 11-12, 2015, Yogyakarta, Indonesia.

Abstract

On top of being a prominent source of calories for more than half of the world’s population, cultivated rice (Oryza sativa) provides beneficial effects for human health through several bioactive compounds, including phenolics. To earn this advantage, it is essential to assess the profile of these compounds through appropriate cooking practices. In this study, the compositions of 18 individual phenolics contained by different cultivars (pigmented and non-pigmented rice) were evaluated during cooking processes. The level of the studied compounds dramatically decreased throughout a series of cooking processes in addition to the changes on the composition of phenolic acids and their aldehydes in the grain. Substantial losses was occurred particularly due to heating processes starting at 10 minute adjacent to the alteration of the compositions of phenolic compounds. Regardless of rice varieties, the concentration of phenolics decreased severely and remained merely 35 to 55% compared to the initial level in raw grains. This finding confirms that the stability of some phenolic compounds is adversely affected by heat. Additionally, no clear differences were found for the sensitivity of individual phenolics to degradation during the cooking steps, but most of them showed similar trend of degradation.

ICST 01

Ultrasound-assisted extraction of resveratrol from functional foods: Cookies and jams

Journal Article
Guamán-Balcázar, M.C., Setyaningsih, W., Palma, M., Barroso, C.G.
Applied Acoustics, 2016, 103 (B): 207–213, DOI:10.1016/j.apacoust.2015.07.008.

Abstract

Rapid extraction techniques with ultrasonic systems have been established to extract resveratrol from two functional foods, namely cookies and jams. The ultrasound-assisted extraction (UAE) was optimized using a full factorial design with three variables: solvent composition (10–70% and 30–90% methanol in water for cookies and jams, respectively), solvent-to-solid ratio (10:1–40:1), and ultrasonic probe diameter (2 and 7 mm). The extraction kinetics (5–30 min) were studied to confirm the full recovery of resveratrol from the functional foods. The resveratrol was quantified by Ultrahigh Performance Liquid Chromatography with a Fluorescense Detector (UPLC-FD).

The solvent composition was found to have a significant effect on the recovery (< 0.005) for both of the functional foods studied. The optimal UAE conditions were 90% methanol in water, an extraction time of 10 min, an ultrasonic probe with a diameter of 7 mm, and solvent-to-solid ratios of 40:1 and 10:1, respectively, for cookies and jams.

The methods developed in this study show a high precision in terms of Coefficient of Variance (CV), with values of less than 5% for both repeatability and intermediate precision. The applicability of the methods to real samples has been evaluated and it was confirmed that the methods are suitable for the extraction of resveratrol from cookies and jams.

Applied Acoustic 2016 02

Pressurized liquid extraction of phenolic compounds from rice (Oryza sativa) grains

Journal Article
Setyaningsih, W., Saputro, I. E., Palma, M., and Barroso, C. G
Food Chemistry, 2016, 192:452–459, DOI: 10.1016/j.foodchem.2015.06.102.

Abstract

An analytical pressurized liquid extraction (PLE) process has been studied for the extraction of phenolic compounds from rice grains. A fractional factorial design (27−2) with a centre point was used to optimize PLE parameters such as solvent composition (EtOAc in MeOH), extraction temperature, pressure, flushing, static extraction time, solvent-purge and sample weight. Extraction temperature, solvent and static extraction time were found to have a significant effect on the response value. The optimized method was validated for selectivity, linearity, limits of detection and quantification, recovery and precision. The validated method was successfully applied for the analysis of a wide variety of rice grains. Seventeen phenolic compounds were detected in the sample and guaiacol, ellagic acid, vanillic acid and protocatechuic acid were identified as the most abundant compounds. Nonetheless, different species of rice show very varied compound diversity and levels of compounds in their grain compositions.

Food Chem 2016

Optimization of the ultrasound-assisted extraction of melatonin from red rice (Oryza sativa) grains through a response surface methodology

Journal Article
Setyaningsih, W., Duros, E., Palma, M., Barroso, C.G.
Applied Acoustics, 2016, 103 (B): 129–135, DOI: 10.1016/j.apacoust.2015.04.001.

ABSTRACT:

An analytical ultrasound-assisted extraction (UAE) technique has been optimized and validated for the extraction of melatonin from rice grains. A Box–Behnken design in conjunction with a response surface methodology based on six factors and three levels was used to evaluate the effects of the studied factors prior to optimizing the UAE conditions. The significant (p < 0.05) response surface models with high coefficients of determination were fitted to the experimental data. Solvent composition and extraction temperature were found to have very significant effects on the response value (p < 0.005). The optimal UAE conditions were as follows: extraction time of 10 min, ultrasound amplitude of 30%, cycle of 0.2 s−1, extraction temperature of 40 °C, 50% methanol in water as the extraction solvent at pH 3.5 and a solvent/solid ratio 2.5:1. The method validation ensured right values for linearity, LOD, LOQ, precision and recovery. Furthermore, the method was successfully applied in the analysis of a number of rice samples throughout the rice production process. Hence, it was demonstrated that this particular UAE method is an interesting tool for the determination of melatonin in rice grain samples.

Applied Acoustic 2016 01

Determination of melatonin in rice (Oryza sativa) grains by pressurized liquid extraction

Journal Article
Setyaningsih, W., Estiono, I., Barbero, F., Palma, M., Barroso, C.G.
Journal of Agricultural and Food Chemistry, 2015, 63 (4): 1107–1115, DOI: 10.1021/jf505106m

ABSTRACT:

Melatonin provides a number of benefits for human health. The study reported here concerns the optimization, validation, and application of analytical pressurized liquid extraction and high-performance liquid chromatography coupled to a fluorescence detector for the determination of melatonin in rice grains. The factors that are most likely to affect the extraction efficiency were optimized with a 2IV7–2 fractional factorial design. The optimum extraction conditions were achieved by applying 70% EtOAc in MeOH at 200 °C and 200 atm for a static time of 5 min in two cycles with 50% flushing and a 60 s purge to extract a 2.5 g rice sample. The method validation ensured excellent linearity, limit of detection, limit of quantification, precision, and recovery. Furthermore, the method was applied to various rice products composed of polished, whole grain, aromatic, black, black glutinous, red, and parboiled rice. All kinds of pigmented rice grains showed high levels of melatonin (>100 μg kg –1), and the highest levels were found in red rice.

JAFC

 

Optimisation and validation of the microwave-assisted extraction of phenolic compounds from rice grains

Journal Article
Setyaningsih, W., Saputro, I. E., Palma, M., and Barroso, C. G
Food Chemistry, 2015, 169: 141–149. DOI:10.1016/j.foodchem.2014.07.128

ABSTRACT:

A new microwave-assisted extraction (MAE) method has been investigated for the extraction of phenolic compounds from rice grains. The experimental conditions studied included temperature (125–175 °C), microwave power (500–1000 W), time (5–15 min), solvent (10–90% EtOAc in MeOH) and solvent-to-sample ratio (10:1 to 20:1). The extraction variables were optimised by the response surface methodology. Extraction temperature and solvent were found to have a highly significant effect on the response value (p < 0.0005) and the extraction time also had a significant effect (p < 0.05). The optimised MAE conditions were as follows: extraction temperature 185 °C, microwave power 1000 W, extraction time 20 min, solvent 100% MeOH, and solvent-to-sample ratio 10:1. The developed method had a high precision (in terms of CV: 5.3% for repeatability and 5.5% for intermediate precision). Finally, the new method was applied to real samples in order to investigate the presence of phenolic compounds in a wide variety of rice grains.

Food Chem 2015

 

Study of Glutinous and Non-Glutinous Rice (Oryza Sativa) Varieties on their Antioxidant Compounds

Journal Article
Setyaningsih, W., Hidayah, N., Saputro, I. E, Palma, M., Barroso, C.G.
DOI: 10.15242/IICBE.C0115, International Conference on Plant, Marine and Environmental Sciences (PMES-2015), pp. 27-31

ABSTRACT:

Cultivated rice (Oryza sativa) is a global cereal crop in Southeast Asia. It serves as staple food, thus has a major contribution to the calorie intake. Furthermore, a number of antioxidant substances have been identified in rice including phenolic compounds and melatonin. The concentration and composition of these antioxidant compounds were studied on glutinous and nonglutinous grains for both pigmented and non-pigmented rice varieties. Additionally, several medium-amylose rice grains of three Indonesian varieties (IR64, umbul-umbul and pandan wangi) were also evaluated. Finding indicates that the composition of phenolic compounds are noticeably different between glutinous and nonglutinous rice grains. The level of both melatonin and total phenolics in non-glutinous rice was higher than its glutinous variety. Hence, higher amylose content exhibits relatively higher amount of antioxidant compounds.

PMES

Melatonin Profile during Rice (Oryza Sativa) Production

Journal Article
Setyaningsih, W., Hidayah, N., Saputro, I. E, Palma, M., Barroso, C.G.
DOI: 10.12720/joaat.1.1.60-64, Journal of Advanced Agricultural Technologies, Vol. 1, No. 1, pp. 60-64, June 2014

ABSTRACT:

Rice (Oryza sativa) is the foremost cereal crop in Southeast Asia. It serves as staple food, thus has a major contribution to the calorie intake. In addition, rice contains melatonin which is beneficial for human health. It is, therefore, essential to retain this compound by appropriate rice production processes. Melatonin profile during rice production was monitored for three varieties (IR64, umbul-umbul and pandan wangi) from conventional farming and four varieties (batang lembang, pandan wangi, black and red rice) from organic farming. The effect of polishing degree on melatonin content in rice was also evaluated. Melatonin level decreased throughout rice production and then remained steady at roughly 25-40% in final product. The most influential factor was polishing which led to melatonin losses of up to 50%. The results for organically cultivated varieties were similar. However, melatonin in black rice appeared to be persistent in the matrix during rice production.

JOAAT

Methods of Analysis of Food Components and Additives

Journal Article
Setyaningsih, W., Editor: Semih Ötleş
DOI: 10.1111/jfbc.12061, Journal of Food Biochemistry, 38: 363–364

A new microwave-assisted extraction method for melatonin determination in rice grains

Journal Article
Setyaningsih, W., Palma, M., Barroso, C.G.
Journal of Cereal Science, 2012, 56 (2): 340-346, DOI: 10.1016/j.jcs.2012.02.012.

ABSTRACT:

A new microwave-assisted extraction (MAE) method has been developed for the extraction of melatonin from rice grains. The stability of melatonin under MAE conditions was studied in order to define the working range. The studied analytical conditions for the MAE were temperature (125−175 °C), microwave power (500−1000 W), time (5−15 min), solvent (10−90% EtOAc in MeOH), and ratio of solvent to sample (10:1–20:1). Extraction variables were optimized by Response Surface Methodology (RSM). Extraction temperature was found to have a highly significant effect on the response value (p < 0.0001) and the solvent and quadratic of time also had significant effects (p < 0.1). The optimized MAE conditions were as follows: extraction temperature 195 °C, microwave power 1000 W, extraction time 20 min, solvent 100% MeOH, and ratio of solvent to sample 10:1. The developed method showed high precision (in terms of CV: 4.97% for repeatability and 4.34% for intermediate precision). Finally, the new method was applied to real samples in order to investigate the presence of melatonin in a wide variety of rice grains.

JCS

Profile of Individual Phenolics in Rice (Oryza sativa): Varietal Differences, Compounds Distribution and Composition Changes in the Grains during Rice Production

Conference Paper
Setyaningsih, W., Hidayah, N., Estiono, I., Palma, M., Barroso, C.G.
The 12th Asian Congress of Nutrition (ACN2015), May 13-18, 2015, Yokohama, Japan

Abstract

Cultivated rice (Oryza sativa) is a global staple food that subsists calories for more than half of the world’s population. Emerging evidence supports that a number of health-promoting substances have been identified in rice including phenolic compounds. Hence, individual profile of these compounds is essential to determine in both raw and processed grains. Pressurised Liquid Extraction (PLE) followed by High Performance Liquid Chromatography coupled with Photo-diode Array detector (HPLC-PDA) has been utilised as reliable analytical techniques for the extraction and quantification. Multivariate analyses based on seventeen phenolic compounds clustered the ten tested rice samples according to their species, pigments and grain productions. The level of these compounds was then individually monitored during the course of rice production of Indonesian rice varieties obtained from conventional (IR-64, umbul-umbul and pandan wangi) and organic farming (batang lembang, pandan wangi, black and red pigmented rice). Phenolics content in black pigmented rice appeared to be the most persistent in the matrix during rice production. However, in general, the level of phenolics decreased throughout a series of rice production with the most influential factors were de-husking and polishing. These particular processing steps led to phenolics losses of up to 86% as well as the changes on the composition of phenolic acids and its aldehydes in the grain. Since the profile of individual phenolics has also been evaluated on different polishing degrees (70%, 80%, 90% and 100% bran removal), the distribution of these compounds in the whole grain rice was effectively mapped. These variations in the compositions and quantities of phenolics disclosed the effect of processing steps, varietal differences as well as their distribution in the grain. Hence, the results from this study could help rice producers to optimize levels of these compounds in the final rice product by selecting the right varieties and appropriate production processes.

Study of Glutinous and Non-Glutinous Rice (Oryza Sativa) Varieties on their Antioxidant Compounds

Conference Paper
Setyaningsih, W., Hidayah, N., Estiono, I., Palma, M., Barroso, C.G
International Conference on Plant, Marine and Environmental Sciences (PMES-2015). January 1-2, 2015, Kuala Lumpur, Malaysia.

Abstract

Cultivated rice (Oryza sativa) is a global cereal crop in Southeast Asia. It serves as staple food, thus has a major contribution to the calorie intake. Furthermore, a number of antioxidant substances have been identified in rice including phenolic compounds and melatonin. The concentration and composition of these antioxidant compounds were studied on glutinous and nonglutinous grains for both pigmented and non-pigmented rice varieties. Additionally, several medium-amylose rice grains of three Indonesian varieties (IR64, umbul-umbul and pandan wangi) were also evaluated. Finding indicates that the composition of phenolic compounds are noticeably different between glutinous and nonglutinous rice grains. The level of both melatonin and total phenolics in non-glutinous rice was higher than its glutinous variety. Hence, higher amylose content exhibits relatively higher amount of antioxidant compounds

Fast Determination of Anthocyanins from Corn (Zea mays) Grains by Ultrasound-assisted Extraction

Conference Paper
Setyaningsih, W., Guamán Balcázar, M.C., Duros, E., Palma, M., and Barroso, C. G
Seminario Internacional Iberoamericanos: Propiedades Nutricionales y Funcionales. November 19-20, 2014, Loja, Ecuador

Abstract

The extraction by means of sonication method, namely ultrasound-assisted extraction (UAE), is a very interesting technique to extract natural compounds from food matrices due to the cavitation effect, which enhances mass transport by disrupting the plant cell walls. Consequently, various factors can affect the extraction process and these have to be optimized in order to extract quantitatively the analytes of interest. In this research, the chemometric approach based on the advantages of the Central Composite Design (CCD) have been successfully applied in the optimization of anthocyanins from corn (Zea mays) grains using sonication.

In conjunction with Response Surface Methodology (RSM), CCD was applied based on six factors and three levels to evaluate the significances of studied factors prior to the optimization of extraction conditions. The effects of solvent composition (25−75% methanol in water), extraction temperature (10−50oC), solvent-solid ratio (2.5:1−5:1), solvent pH (2−7), amplitude (30−70%) and cycle (0.2−0.7 s-1) on the extraction yields were taken into account. Subsequently, extraction kinetic (5−30 min) was studied to confirm the full recovery of phenolic compounds extracted from the matrix. The levels of anthocyanins in the UAE extracts were quantified by High Performance Liquid Chromatography using a Dioda Array Detector (HPLC-DAD) in less than 10 min.

The optimized condition by RSM was then assed for a kinetic study to evaluate the extraction rate. The optimal UAE condition was as follows: extraction time 5 min, ultrasound amplitude 66%, cycle 0.2 s-1, extraction temperature 10oC, 75:25 methanol:water as the extraction solvent at pH 7 and solvent-solid ratio 2.5:1. Complete validation of the method was performed. High recovery and precision were found for the full analytical method. The suitability of the method was checked by application to corn grain cultivars and demonstrated this extraction method to be suitable for the extraction of anthocyanins from corn grain samples.

Rapid ultrasound-assisted extraction (UAE) of melatonin from corn (Zea mays) grains

Conference Paper
Setyaningsih, W., Guamán Balcázar, M.C., Duros, E., Palma, M., and Barroso, C. G
V Congreso Ecuatoriano de Ingeniera en Alimentos y XIV Jornadas de Ciencia y Tecnología en Alimentos. November 25-28, 2014, Quito, Ecuador

Abstract

Corn (Zea mays) is the third most important crop worldwide and might serves as a staple food, especially in the developing countries. Moreover, corn is essential because it contains naturally occurring melatonin [N-acetyl-3-(2-aminoethyl)-5-methoxyindole]. It has a number of important activities that include neurohormone and chronobiotic actions in biological systems. There are good evidences that melatonin provides effective treatments for cardiovascular diseases, sleep disorders and headache. Reliable determination of melatonin in regular food in human diet would help to evaluate its effect. Hence, a suitable extraction method is needed to determine melatonin level in corn grains.

In this research, a new ultrasound-assisted extraction (UAE) of melatonin has been optimized and validated. Central Composite Design (CCD) in conjunction with Response Surface Methodology (RSM) was applied based on six factors and three levels to evaluate the significances of studied factors prior to optimize the UAE conditions. The effects of solvent composition (25−75% methanol in water), extraction temperature (10−50oC), solvent-solid ratio (2.5:1−5:1), solvent pH (2−7), amplitude (30−70%) and cycle (0.2−0.7 s-1) on the extraction yields were taken into account. Subsequently, extraction kinetic (5−30 min) was studied to confirm the full recovery of phenolic compounds extracted from the matrix. The levels of melatonin in the UAE extracts were quantified by Ultrahigh Performance Liquid Chromatography using a fluoresce detection (UPLC-FD) in less than 4 min.

The significant (p<0.05) response surface models with high coefficients of determination values of 0.7096 were fitted for the experimental data. Solvent composition, solvent-sample ratio and quadratic effect of temperature were found to have a greatly significant effect on the response value (p<0.05). The optimal UAE condition was as follows: extraction time 5 min, ultrasound amplitude 45%, cycle 0.7 s-1, extraction temperature 50oC, 70:30 methanol:water as the extraction solvent at pH 6 and solvent-solid ratio 2.5:1. Complete validation of the method was performed. High recovery and high precision were found for the full analytical method.

The validated method was successfully applied to the analysis of phenolics content in four corn cultivars including black, yellow, red and white. Therefore, this particularly rapid ultrasound extraction method was demonstrated to be suitable for the extraction of melatonin from corn grain samples.

Determination of Melatonin in Rice (Oryza sativa) grains: Analytical tools for Developing Melatonin-Rich Rice Products

Conference Paper
Setyaningsih, W., Palma, M., and Barroso, C. G
III Congreso Científico de Investigadores en Formación en Agroalimentación. November 18-19, 2014, Cordoba, Spain

Abstract

As a grain of life, cultivated rice (Oryza sativa) serves as the foremost food for more than half of the world’s population. Moreover, rice is essential because it contains naturally occurring melatonin [N-acetyl-3-(2-aminoethyl)-5-methoxyindole]. Recent research has led to an increase in the production of melatonin in transgenic rice seeds and melatonin-rich rice plants have been successfully generated. Functional rice products have also become more widely appreciated in the current market.

Research into melatonin was started almost a century ago and this has continued to be an active field to the present day, with many results revealing the utility of this compound. Melatonin diminishes neuro-degenerative diseases, such as Parkinson’s and Alzheimer’s diseases, and it also acts as an anticancer agent. Melatonin effects are more interesting if the compound is taken regularly at a specific time. Therefore, it should be better if people can consume melatonin-rich foods regularly instead of taking it as a drug. Rice grains, potential source of melatonin, normally contains low concentration of this compound. Hence, it is of great interest to extract and quantify endogenous levels of melatonin accurately by selecting the most suitable analytical technique.

Recent studies have shown that Microwave-assisted Extraction (MAE), Ultrasound-assisted Extraction (UAE) and Pressurized Liquid Extraction (PLE) are important sample preparation techniques and these approaches have been used to increase the extraction efficiency for various bioactive compounds. However, these advanced extraction methods have not been developed for the extraction of melatonin from rice grain yet. Thus, the methods still need to be optimised and validated to reach reliable extraction methods. As the outcome of the study, the final method could serve as an analytical tool to evaluate the level of melatonin through the production processes of rice from farm to fork.

This research prompted us to compare the performances of various extraction methods for the extraction of melatonin from rice grains including MAE, UAE and PLE, to the best of our knowledge, this kind of study has never been performed. Of the three studied extraction techniques, one may be chosen depending on the necessity and fitness for purpose.

The developed and validated method for the extraction and determination of melatonin in rice grains reported in this study will enable to come up with reliable data on the quantity of melatonin in wide variety of rice grains, which is currently lacking due to unreliable analytical data. The proposed extraction method also provides opportunities to develop advanced techniques in rice processing. Results obtained from this specific study recommended that the rice production processes should be carefully controlled in order to attain a high level of melatonin in rice products by efficient drying and the optimum degree of milling. Additionally, bearing in mind the importance of rice science and technology, it is envisaged that this work will significantly support further studies to improve rice production techniques in the coming decades.

As other products of ready to eat food, little is known about the melatonin concentration in cooked rice. Yet, several differences on its level can be expected as compared to other rice-derived products, notably in relation to the treatment during food processing. It is, therefore, the proposed analytical method was also useful to asses the level of melatonin through a series of treatments. And finally, it is noteworthy that the recommended melatonin-rich rice products, based on the result applying the analytical method, could be chosen instead of the regular ones by the population interested in the properties associated to melatonin, without dramatic changes in their regular diets.

Microwave-assisted Extraction of Resveratrol from Functional Foods: Cookies and Jams

Conference Paper
Guamán Balcázar, M.C., Setyaningsih, W., Palma, M., and Barroso, C. G
Food Analysis Congress: Safety, Quality, Novel Technologies. October 29-30, 2014, Barcelona, Spain

Abstract

Rapid extraction techniques with ultrasonic systems have been established to extract resveratrol from two functional foods, namely cookies and jams. The ultrasound-assisted extraction (UAE) was optimized using a full factorial design with three variables: solvent composition (10–70% and 30–90% methanol in water for cookies and jams, respectively), solvent-to-solid ratio (10:1–40:1), and ultrasonic probe diameter (2 and 7 mm). The extraction kinetics (5–30 min) were studied to confirm the full recovery of resveratrol from the functional foods. The resveratrol was quantified by Ultrahigh Performance Liquid Chromatography with a Fluorescense Detector (UPLC-FD).

The solvent composition was found to have a significant effect on the recovery (p < 0.005) for both of the functional foods studied. The optimal UAE conditions were 90% methanol in water, an extraction time of 10 min, an ultrasonic probe with a diameter of 7 mm, and solvent-to-solid ratios of 40:1 and 10:1, respectively, for cookies and jams.

The methods developed in this study show a high precision in terms of Coefficient of Variance (CV), with values of less than 5% for both repeatability and intermediate precision. The applicability of the methods to real samples has been evaluated and it was confirmed that the methods are suitable for the extraction of resveratrol from cookies and jams.

Fast Determination of Tryptophan and Its Derivatives by UPLC-PDA-FD

Conference Paper
Saputro, I.E., Setyaningsih, W., Palma, M., and Barroso, C. G
Food Analysis Congress: Safety, Quality, Novel Technologies. October 29-30, 2014, Barcelona, Spain.

Abstract

Tryptophan is an essential amino acid that is necessary for the biosynthesis of neurotransmitters including serotonin and melatonin via two biochemical pathways. However, further research into the role of tryptophan and its derivatives in biological systems has been limited as these compounds are mostly diverse in terms of their chemical properties resulting in the need of more than one analytical technique to determine all the derived products. To the best of recent knowledge, this is the first study that demonstrates the simultaneous identification and quantification of tryptophan and its derivatives employing the useful of ultra-high performance liquid chromatography coupled with photodiode-array and fluorescence detection (UPLC-PDA-FD). Seven compounds of tryptophan and its derivatives were effectively separated within 4 min of chromatographic analysis run time. The method was validated resulting an adequate sensitivity in the range of 0.5–20 μg L-1 (R2=0.991-0.999) with high repeatability (CV <3.9% in average) achieving very low limit of detection and quantification (0.67-2.32 μg L-1 and 2.23-7.73 μg L-1 respectively). The suitability of the method was assessed by application to the extract of ten different rice products that confirmed this rapid method to be suitable for fast determination of tryptophan and related compounds.

Optimization of ultrasound-assisted extraction (UAE) of phenolic compounds from corn (Zea mays) grains using response surface methodology

Conference Paper
Setyaningsih, W., Duros, E., Carrera, C., Palma, M., and Barroso, C. G
Food Analysis Congress: Safety, Quality, Novel Technologies. October 29-30, 2014, Barcelona, Spain

Abstract

A new Ultrasound-assisted Extraction (UAE) of phenolic compounds has been optimized and validated. Central Composite Design (CCD) in conjunction with Response Surface Methodology (RSM) was applied based on six factors and three levels to evaluate the significances of studied factors prior to optimize the UAE conditions. The effects of solvent composition (25−75% methanol in water), extraction temperature (10−50oC), solvent-solid ratio (2.5:1−5:1), solvent pH (2−7), amplitude (30−70%) and cycle (0.2−0.7 s-1) on the extraction yields were taken into account. Subsequently, extraction kinetic (5−30 min) was studied to confirm the full recovery of phenolic compounds extracted from the matrix. The levels of phenolics in the UAE extracts were quantified by Ultrahigh Performance Liquid Chromatography using a Photo-diode Array detection (UPLC-PDA) in less than 4 min of analysis run time. A complete validation of the method was performed presenting recoveries between 72 to 111% with high precisions (in average, CV was lower than 5% for both repeatability and intermediate precision). The validated method was successfully applied to the analysis of phenolics content in four corn cultivars including black, yellow, red and white. The proposed method was found to be reliable and is suited for the rapid extraction of phenolics from corn grain.

 

Melatonin Profile during Rice (Oryza sativa) Cooking: Ultimate Step to Develop a Ready to Eat Melatonin-rich Rice Food

Conference Paper
Setyaningsih, W., Palma, M., and Barroso, C. G
Food Analysis Congress: Safety, Quality, Novel Technologies. October 29-30, 2014, Barcelona, Spain

Abstract

Rice (Oryza sativa) is a pivotal staple food providing important contribution to the calorie intake for a large number of world population. Furthermore, rice contains melatonin that is favourable for human health. However, the nutritional properties of rice including melatonin differ in specific classified rice varieties. Additionally, changes in the chemical compositions of rice can also occur during the cooking processes. Hence, the aim of the study described here was to screen a wide range of rice varieties in order to develop melatonin-rich rice products. Afterwards, to evaluate the profile of melatonin during the cooking processes including soaking, boiling and warming. The levels of melatonin on the tested rice samples were decreased up to 80% in average during the course of rice cooking. However, the final levels of cooked rice from melatonin-rich (whole grain) rice were remained high, especially pigmented rice (138 µg Kg-1 in red rice and 95 µg Kg-1 in black rice) which were significantly higher than the regular (6 µg Kg-1 in white polished grain) rice. Hence, these rice varieties could be chosen instead of the regular ones by the population interested in the properties associated to melatonin, without dramatic changes in their regular diets.

Optimization of ultrasound-assisted extraction of melatonin from red rice (Oryza sativa) grain using Response surface methodology

Conference Paper
Setyaningsih, W., Duros, E., Palma, M., and Barroso, C. G
The first International conference on ultrasonic-based applications: from analysis to synthesis (ULTRASONICS-2014). September 15-17, 2014. Costa da Caparica, Portugal.

Abstract

Melatonin (N-acetyl-5-methoxytryptamine) is an indoleamine that is synthesized from the essential amino acid L-tryptophan. It has a number of important activities that include neurohormone and chronobiotic actions in biological systems. There is good evidences that melatonin provides effective treatments for cardiovascular diseases, sleep disorders and headache. Melatonin is a naturally occurring compound that is found in humans, animals, plants and microbes. The presence of melatonin in plants has been identified in a range of species including rice (Oryza sativa). Hence, a suitable extraction method is needed to determine melatonin levels in both rice and rice derived foods.

In this research, a new ultrasound-assisted extraction (UAE) of melatonin has been optimized and validated. Box-Behnken design in conjunction with response surface methodology was used based on six factors and three levels to evaluate the significances of studied factors prior to optimize the UAE condition. The effects of solvent composition (0−50% methanol in water), extraction temperature (10−70oC), solvent-solid ratio (2.5:1−5:1), solvent pH (3−7), amplitude (30−70 %) and cycle (0.2−0.7 s-1) on the extraction yields were taken into account. Subsequently, extraction kinetic (5−30 min) was studied to confirm high recovery of melatonin extracted from the matrix. The levels of melatonin in the UAE extracts were quantified by Ultrahigh Performance Liquid Chromatography using a fluoresce detection (UPLC-FD) in less than 4 min.

The significant (p<0.05) response surface models with high coefficients of determination values of 0.7245 were fitted for the experimental data. Solvent composition and extraction temperature were found to have a greatly significant effect on the response value (p<0.005). The optimal UAE condition was as follows: extraction time 10 min, ultrasound amplitude 30%, cycle 0.2 s-1, extraction temperature 40oC, 50:50 methanol:water as the extraction solvent at pH 3.5 and solvent-solid ratio 2.5:1. Complete validation of the method was performed. The developed method presented recoveries between 90% and 109% for the target analytes and showed high precision in terms of CV lower than 2.0% for intermediate precision.

 The suitability of the method was checked by application to semi-finished and finished rice products thus could assess the melatonin profile throughout the rice production. Melatonin was determined in two different rice varieties taken at different production processes i.e. drying (dried paddy), hulling (whole grain rice), and polishing (polished rice). Additionally, the effect of cultivation system on the melatonin content in rice was also able to be evaluated by applying the developed method to different rice varieties produced by conventional and organic farming of black and red rice. Hence, this particular ultrasound extraction method was demonstrated to be an excellent alternative for the extraction of melatonin from rice grain samples.

High performance allelopathy of submerged macrophytes possibly based on polyphenol complementarity

Conference Paper
Rojo, C., Rodrigo, M.A.,Carramiñana, M., Setyaningsih, W., Palma, M.
XVII Congreso de la Asociación Ibérica de Limnología. July 6-11, 2014. Santander, Spain

Abstract

Submerged macrophytes play a significant role in stabilising clear water conditions in coastal wetlands, partly due to their interference with microalgal growth via allelopathy. One of our recent studies tested allelopathic effects of several macrophyte species on microalgae. This study was carried out with the charophytes Chara hispida, C. baltica, C. vulgaris and Nitella hyalina, and with the angiosperm Myriophyllum spicatum. A higher inhibitory effect on natural microalgal assemblages was measured when charophyte exudates were present, particularly in the case of C. hispida. When mixed exudates from several populations were used, the inhibitory effects on microalgal growth were even stronger. Thus, it is likely that in aquatic communities macrophytes cause synergistic allelopathic effects on other organisms. Based on our previous results, the hypothesis that arises is whether the polyphenols of different macrophyte species with allelopathic activity are complementary rather than redundant. This fact would explain that diverse macrophyte assemblages exert a greater negative effect on the microalgae growth. To test this hypothesis, tissues of the several macrophyte species cultivated in the laboratory in monocultures were analysed for polyphenols. The analytical procedure consisted of extractions (Solid Phase Extraction Strata X Cartridge), separation (Ultra‐high Performance Liquid Chromatography (UPLC)) and setting ranges and calibration curves of compounds. The polyphenols found in the target macrophytes were: Gallic Acid, Protocatechuic Acid, Protocatechuic Aldehyde, Catechin, pOH-Benzaldehyde, Epicatechin, pCoumaric Acid, Quercetin, Epigallocatechin Gallate, pOHBenzoic Acid, Kaempferol 3-glucoside, Quercetin 3-Glucoside, Quercetin 3-Rhamnoside, Ethyl Caffeate. The number of different polyphenols in macrophytes varied from six in the angiosperm to one in C. baltica. M. spicatum’s polyphenols were mainly of the flavonoid type. Benzenoic polyphenols were the most common in charophytes. A cluster analysis (Gower index and paired group method) of the macrophyte species based on the tissue polyphenol content (quantified as mg compound/Kg DW of plant) was performed. M. spicatum formed a monospecific group separated from charophytes, and Chara species grouped together separately from N. hyalina. Thus, a complementary allelopathic effect might be likely to occur in aquatic systems dominated by dense and diverse stands of submerged vegetation.

Melatonin Profile during Rice (Oryza Sativa) Production

Conference Paper
Setyaningsih, W., Hidayah, N., Estiono, I., Palma, M., Barroso, C.G.
The 4 th International Conference on Asia Agriculture and Animal (ICAAA 2014). June 9-11, 2014. Bangkok, Thailand.

Abstract

Rice (Oryza sativa) is the foremost cereal crop in Southeast Asia. It serves as staple food, thus has a major contribution to the calorie intake. In addition, rice contains melatonin which is beneficial for human health. It is, therefore, essential to retain this compound by appropriate rice production processes. Melatonin profile during rice production was monitored for three varieties (IR64, umbul-umbul and pandan wangi) from conventional farming and four varieties (batang lembang, pandan wangi, black and red rice) from organic farming. The effect of polishing degree on melatonin content in rice was also evaluated. Melatonin level decreased throughout rice production and then remained steady at roughly 25-40% in final product. The most influential factor was polishing which led to melatonin losses of up to 50%. The results for organically cultivated varieties were similar. However, melatonin in black rice appeared to be persistent in the matrix during rice production.

Optimization and method validation of ultrasound-assisted Extraction (UAE) of serotonin and its precursor

Conference Paper
Setyaningsih, W., Carrera, C., Ruiz-Rodriguez, A., Palma, M., Barroso, C. G.
La XIV Reunión del Grupo Regional Andaluz de la Sociedad Española de Química Analítica (GRASEQA 2014). June 26-27, 2014. Baeza, Spain.

Abstract

Serotonin (5-hydroxytryptamine), a neurotransmitter in the central nervous system (CNS), is synthesised from the essential amino acid L-tryptophan by a short metabolic pathway with oxitriptan (5-hydroxytryptophan) and tryptamine as intermediate compounds. Serotonin has an enormous influence over many brain functions i.e. performing an essential role in the modulation of anger, mood, body temperature, and appetite. However, the exogenous serotonin scarcely accesses the CNS via serotonergic pathways from the bloodstream, while its precursor, oxitriptan, grants the access. Therefore, oxitriptan is recognized as dietary supplement source and has been used in clinical treatment since decades for migraine. Oxitriptan has been produced commercially by extraction from plants.

In this research, a new ultrasound-assisted extraction (UAE) of serotonin and its precursor (tryptophan, tryptamine and oxitriptan) has been optimized and validated. Box-Behnken design in conjunction with response surface methodology was used based on six factors and three levels to evaluate the significances of studied factors prior to optimize the UAE condition. The effects of solvent composition (0−50% ethanol in water), extraction temperature (10−70 oC), solvent-solid ratio (10:1−20:1), solvent pH (3−7), amplitude (30−70 %) and cycle (0.2−0.7 s-1) on the extraction yields were taken into account. Subsequently, extraction kinetic (6−18 min) was studied to reach high recovery of serotonin and its precursors extracted from the matrix. The levels of serotonin and its precursors in the UAE extracts were quantified simultaneously by Ultrahigh Performance Liquid Chromatography coupled with fluoresce detector (UPLC-FD) within 3 min of analysis run time.

The significant (p<0.05) response surface models with high coefficients of determination values of 0.78 were fitted for the experimental data. Solvent composition was found to have a greatly significant effect on the response value (p<0.0001) and the extraction temperature also have a significant effect (p <0.05). The optimal UAE condition was as follows: extraction time 6 min, ultrasound amplitude 30%, cycle 0.7 s-1, extraction temperature 40oC, water as the extraction solvent at pH 5 and solvent-solid ratio 20:1. Complete validation of the method was performed. The developed method presented recoveries between 90% and 106% for the target analytes and showed high precision in terms of CV lower than 3.5% for intermediate precision (except serotonin with 10.5%).

The suitability of the method was checked by application to Vitis vinifera L plants grown under controlled conditions, supplied with different doses of nitrogen and collected at different times during the plants growth. Hence, this particular ultrasound extraction method was demonstrated to be an excellent alternative for the extraction of serotonin and its precursors from plant sample.

Hacia productos saludables elaborados con arroces ricos en melatonina

Conference Paper
Setyaningsih, W., García, K., Rodríguez, M. C., Palma, M., Barroso, C.G.
1er. Congreso Internacional sobre Innovación y Tendencias en Procesamiento de

Resumen

El arroz (Oryza sativa) es un cereal fundamental para más de la mitad de la población mundial. Como alimento básico es un aporte calórico en la dieta, adicionalmente contiene melatonina, compuesto beneficioso para la salud. En resultados previos, los arroces; integral, negro y rojo poseen mayor nivel de melatonina comparándolos con otras muestras analizadas, por lo que estos fueron seleccionados para iniciar un estudio de desarrollo de nuevos productos con arroces ricos en melatonina. En esta etapa, se analizó el efecto de la cocción sobre el contenido en melatonina, manteniéndose ésta en niveles aun elevados: 138 μg/kg -1 en el arroz rojo, 95 μg/kg -1 en el arroz negro y 22 μg/Kg -1 en el arroz integral; en el arroz blanco apenas alcanzó 6 μg/kg -1 . La evaluación sensorial mediante prueba de calificación hedónica de los atributos globales aspecto, olor, sabor y textura mostró que no hay diferencia en la aceptación entre las 4 variedades de arroz. Mediante encuestas se analizaron otros factores que a priori podrían influir en la aceptabilidad del producto por los consumidores, tales como, la información en el etiquetado del contenido de melatonina y su origen, los mensajes sobre su efecto beneficioso en el metabolismo, y la familiaridad con la marca.

Abstract

Rice (Oryza sativa) is the essential cereal for the livelihoods of more than half of world population. Its function as staple food, makes rice has a major contribution to the calorie intake. Furthermore, rice contains melatonin that is favourable for human health. Whole grain rice (brown, black and red rice) possesses a higher level of melatonin compared to the rest of the tested rice samples. As a result, these types of rice were then developed to produce melatonin-rich rice products. The ready to eat rice in the form of boiled products were still having a relatively high level of melatonin as follows: 138 μg/Kg -1 in red rice, 95 μg/Kg -1 in black rice and 22 μg/Kg -1 in brown rice; while merely remained at 6 μg/Kg -1 in regular boiled white rice. The sensory evaluation test using hedonic rating of global attributes appearance, odor, flavor and texture showed no difference in acceptance between 4 rice varieties. Other factors that could affect the product acceptability by consumers, such as the information on the labeling of melatonin origin and its content, messages about its benefits on metabolism, and brand familiarity were analyzed by surveys.

Determinacion de compuestos fenolicos en arroz mediante extracción assistida por microondas

Conference Paper
Barroso, C.G., Setyaningsih, W., Saputro, I.E., Palma, M.
VII Congreso Ciencia y Technologia de Los Alimentos. June 12-14, 2013. Córdoba, Spain.

Allelopathy of charophytes: does it work?

Conference Paper
Rodrigo, M. A., Segura, M., Setyaningsih, W., Palma, M., Rojo, C.
6 th International Symposium on Extant and Fossil Charophytes. Nov 22 to Dec 2, 2012. Mendoza, Argentina.

Abstract

The allelopathic potential of macrophytes is extremely significant in shallow waterbodies in semiarid areas, such as the Mediterranean, where the shortage of them makes wetlands, lagoon or coastal; ponds essential aquatic ecosystems. It is also known that allelopathic effects of a macrophyte can be species-specific and this, the resistance or vulnerability of phytoplankton to macrophyte in the field will depend on the composition of both. Our goal is to investigate the allelopathic potential of charophytes that have not been studied previously in this sense (C. hispida, C. baltica, C. vulgaris, and N. hyalina) on microalga assemblaga in order to determine what type of charophyte or combination of them promotes clear water conditions through alleopathy.

Formación específica para la mejora de la comunicación en inglés del profesorado de Química Analítica de la UCA

Conference Paper
Barbero, G.F., Bellido, D., Brenes, A.M., Carmona, Y, Castro, R, Cejudo, M.J, Contero, C, Crespo, J, Cubillana, L, Díaz, M, Durán, E, El Moussaoui, N, Espada, E, Galindo, M.D, García, Granado, M.D, Guillén, D.A., Hidalgo, J.C.,Hidalgo, J.L., López M.M., López-López, J.A., Mánuel, M.V., Mendiguchía, Milla, M., Naranjo, I., Natera, R., Palacios, J.M., Pinto, J.J., Rodríguez, M.C., Ruíz, M.J., Sánchez, M., Schwarz, M., Setyaningsih, W.
Innovación Docente en Química (InDoQuím 2012), July 12-13, 2012, Barcelona, Spain

Resumen

La piedra angular del Espacio Europeo de Educación Superior (EEES) descansa en la armonización de los distintos sistemas educativos de la Unión Europea y la dotación de una forma eficaz de intercambio entre todos los estudiantes, así como la concesión de una dimensión y de una agilidad sin precedentes al proceso de cambio emprendido por las Universidades europeas.

Con la reciente entrada en vigor de los nuevos planes de estudios correspondientes a los diferentes Títulos de Grado en la Universidad de Cádiz (UCA), nuestra inserción en el EEES es ya un hecho consolidado. Dicha inserción va acompañada intrínsecamente de un proceso de internacionalización de la universidad: los crecientes convenios de intercambio de estudiantes amplían el número de alumnos que recibimos, aumentando la participación en programas de postgrado internacionales, y de ahí se deriva la necesidad de asegurar también la formación de nuestros alumnos en una competencia transversal básica y común a todos los nuevos Grados como lo es la comunicación en una segunda lengua. En el área científico-tecnológica, la lengua de referencia es el inglés.

No obstante, el proceso de internacionalización de nuestras universidades no afecta única y exclusivamente a los alumnos, sino también, al personal docente. El incremento de estudiantes Erasmus extranjeros en las aulas y en los laboratorios, la docencia en estudios de Grado y Posgrado a nivel internacional, los nuevos programas de bilingüismo en muchas Facultades y Escuelas, etc., obliga al profesorado a tomar conciencia de la necesidad de saber expresarse de forma fluida, tanto oral como escrita, desde el punto de vista técnico y en un lenguaje específico, en un segundo idioma, fundamentalmente, el inglés. La mejora del nivel competencial en dichas habilidades lingüísticas, además, le son útiles a nivel de investigación.

Es por ello que, desde hace cuatro años, llevamos desarrollando en el Departamento de Química Analítica de la UCA varios programas de formación del profesorado con vistas a perfeccionar su nivel competencial en comunicación en lengua inglesa, en el que nos hallábamos algo deficitarios de acuerdo a los autoinformes de competencias realizados. La financiación necesaria para la ejecución de estos programas de formación ha sido concedida a través de los Planes de Desarrollo del Personal Docente e Investigador (PDI) de la UCA y las Convocatorias de Actuaciones Avaladas para la Mejora Docente, Formación del Profesorado y Difusión de Resultados, del Vicerrectorado de Docencia y Formación, a través de su Unidad de Innovación Docente.

An optimization technique of pressurized liquid extraction (PLE) of melatonin from red rice (Oryza sativa) grains

Conference Paper
Setyaningsih, W., Barbero, Gerardo., Palma, M., Barroso, C.G.
La XIII Reunión del Grupo Regional Andaluz de la Sociedad Española de Química Analítica (GRASEQA 2012). June 7-8, 2012. Malaga, Spain.

Abstract

An analytical pressurized liquid extraction (PLE) process has been studied for the extraction of phenolic compounds from rice grains. A fractional factorial design (27−2) with a centre point was used to optimize PLE parameters such as solvent composition (EtOAc in MeOH), extraction temperature, pressure, flushing, static extraction time, solvent-purge and sample weight. Extraction temperature, solvent and static extraction time were found to have a significant effect on the response value. The optimized method was validated for selectivity, linearity, limits of detection and quantification, recovery and precision. The validated method was successfully applied for the analysis of a wide variety of rice grains. Seventeen phenolic compounds were detected in the sample and guaiacol, ellagic acid, vanillic acid and protocatechuic acid were identified as the most abundant compounds. Nonetheless, different species of rice show very varied compound diversity and levels of compounds in their grain compositions.