The objective of this study was to optimize the extraction of different isoflavone forms (glycosidic, malonyl-glycosidic, aglycone and total) from defatted cotyledon soy flour using the simplex-centroid experimental design with four solvents of varying polarity (water, acetone, ethanol and acetonitrile). The obtained extracts were then analysed by high-performance liquid chromatography. The profile of the different soy isoflavones forms varied with different extractions solvents. Varying the solvent or mixture used, the extraction of different isoflavones was optimized using the centroid-simplex mixture design. The special cubic model best fitted to the four solvents and its combination for soy isoflavones extraction. For glycosidic isoflavones extraction, the polar ternary mixture (water, acetone and acetonitrile) achieved the best extraction; malonyl-glycosidic forms were better extracted with mixtures of water, acetone and ethanol. Aglycone isoflavones, water and acetone mixture were best extracted and total isoflavones, the best solvents were ternary mixture of water, acetone and ethanol.

No abstract

ABSTRACT. Rice bran is a by-product of rice processing industry, with high levels of phytic acid or phytate. Considering phytic acid antioxidant activity, its various applications and its high concentration in rice bran, this study had the objective of evaluating the antioxidant capacity of purified phytic acid from rice bran using three different methods. Using of 2,4,6-tripyridil-s-triazine or method of FRAP (Ferric Reducing Antioxidant Power), reducing Fe while the rice bran phytic acid showed a maximum inhibitory activity of 40% associated to its chelating capacity and confirm this important antioxidant capacity.

Two statistical mixture designs were used to optimize the proportions of solvents used in both the extraction medium and the reversed liquid chromatographic mobile phase to improve the quality of chromatographic fingerprints of Bauhinia variegata L extracts. For modeling, the number of peaks was used as a measure of fingerprint information. Three mobile phases, each with a chromatographic strength of two, gave good results. A methanol/water (77:23 v/v) mixture resulted in 17 peaks in the chromatographic fingerprint whereas acetonitrile/water (64.5:35.5 v/v) and methanol/acetonitrile/water (35:35:30 v/v/v) mixtures resulted in 18 and 20 peaks, respectively. The corresponding optimum solvent compositions to extract chemical substances for these three mobile phases were ethanol/acetone (25:75 v/v/v) and dichloromethane/acetone (70:30 v/v) mixtures, and pure dichloromethane, respectively. The mixture designs are useful for understanding the influence of different solvents on the strengths of the extraction medium and the mobile phase.

No abstract

Factorial design experiments were executed to determine the effects of plant pattern and density as well as the degree of light availability on the caffeine, chlorogenic acids, lipids, reducing sugars and ash contents of beans and leaves ofCoffea arabicasamples.

No abstract

Phytic acid (PA) or myo-inositol-1,2,3,4,5,6-hexakisphosphoric acid (IP6) can be hydrolyzed into inositol phosphates, such as inositol pentaphosphate (IP5), inositol tetraphosphate (IP4), inositol triphosphate (IP3) and possibly inositol di-and monophosphates (IP2 and IP1) by phytases (enzyme) during grains and seeds storage and fermentation. Chromatographic conditions of mobile phase, sample diluent, column and ionic par, for IP6 determination in defatted rice bran and purified PA from rice bran, were studied in this research. Linearity, repeatability, recovery, and limit of detection (LOD) and limit of quantification (LOQ) of the method were evaluated. The best resolution occurred with the use of both C18 columns (Shim-pack CLC-ODS and Novapak) at a 45 °C oven temperature and mobile phase A (32.50% methanol and 1.45% TBAH) and sample diluent da (32.50% methanol and 1.45% TBAH) and db (32.10% methanol and 1.20% TBAH). The R 2 of calibration curve was 0.9988, confirming the linearity in the PA range of 1.5 to 10 mg mL-1 (r = 0.9993; p < 0.0000). Intra-day repeatability presented relative standard deviations (RSD) of 3.43, 2.37 and 1.88% for 8, 5, and 3 mg mL-1 of PA concentrations, respectively. Inter-day intermediate precision RSD values were 0.93, 1.38, and 3.50% for each PA concentration, 8, 5, and 3 mg mL-1 respectively. RSD values were lower than 4% for both studies, demonstrating adequate repeatability and intermediate precision for the analytical method proposed. A 91% IP6 recovery was obtained and the LOD and LOQ were 0.05 and 0.15 mg mL-1 , respectively. The IP6 content in defatted rice bran and purified PA from rice bran samples were 3.90 and 420 mg 100 g-1 , respectively.