Optimization of the pulse electric field assisted extraction of black rice grain for antioxidant and sirtuin1 enzyme stimulation activities.

Cyanidin-3-glucoside (C3G) and peonidin-3-glucoside (P3G) in black rice grain (BRG) demonstrate many beneficial health effects, including antioxidant and anti-aging properties. This research aimed to study on pulsed electric field assisted water extraction (PEF-AWE) on BRG using pre-treatment technique, which was determined for enhanced yields of C3G and P3G, antioxidant and sirtuin1 enzyme stimulation activities. The effects of operating parameters for PEF-AWE (intensity of electric field, X1: 3-5 kV/cm, number of pulse, X2: 1000-3000 pulse and BRG/water ratio, X3: 0.1-0.5 g/mL) were determined using regression analysis and optimized PEF-AWE condition using the response surface methodology. Regression models showed the intensity of electric field and BRG/water ratio were the strong influence parameters significantly on C3G (p < 0.01). The results highlighted optimized conditions of PEF-AWE followed by 5 kV/cm, 3000 pulse and 0.5 g/mL leading to achieve higher C3G (92.59 ± 4.79 mg/g) and P3G (4.59 ± 0.27 mg/g) than no pre-treatment by PEF process, approximately 60%. Additionally, PEF extracts of BRG can modulate the ability of surtuin1 enzyme to deacetylate substrate proteins (26.78 ± 0.50 FIR). Thus, PEF-AWE can be applied to produce BRG extract as natural antioxidant compound and functional ingredient.

Antioxidative effect of Assam Tea (Camellia sinesis Var. Assamica) extract on rice bran oil and its application in breakfast cereal.

The objectives of this research were to investigate the antioxidant effect of Assam tea extract (ATE) and whether it is fit to utilise ATE by fortification in rice bran breakfast cereal (RBC). The increasing ATE powder from 0.1 to 0.3mg/g affected to be decreased. The ATE powder at 0.3mg/g was proved to have decreased the hexanal content (0.21µg/ml) and thiobarbituric acid reactive substances (TBARS) (2.56µg/g) within 28days, and provided the highest antioxidant ability (EC50) (2481.44mg/kg). The fortified 0.3mg/g of ATE powder showed that increasing ATE significantly increased the total phenolic content and decreased TBARS and EC50 of breakfast cereal (p<0.05). The suitable amount ATE powder added in RBC was 0.5%. The consumer acceptance (n=200) of final product showed the sensory scores in the range of 6.3-6.8, with the percentages of acceptance and purchase intention at 98.0% and 89.0%, respectively.