Development of Anthocyanin-Rich Gel Beads from Colored Rice for Encapsulation and In Vitro Gastrointestinal Digestion.

Colored rice anthocyanins are water-soluble natural pigments that can be used as an active ingredient in healthy food and pharmaceutical products. However, anthocyanin utilization is limited because of its instability. This work produced anthocyanin-rich gel beads from colored rice using a modified ionotropic gelation technique for encapsulation, and their efficacy was studied in vitro in the gastrointestinal tract. In total, 15 colored rice samples of three types (whole grain rice, ground rice, and ground germinated rice) were screened to identify the highest anthocyanin content. The anthocyanin content of the whole grain rice was significantly (p < 0.05) higher than it was in the ground and ground germinated rice. The sample with the highest anthocyanin content (1062.7 µg/g) was the black glutinous rice grain from Phrae, chosen based on its anthocyanin-rich crude extract. A new formula using a modified ionotropic gelation technique was prepared for the inclusion of the extract in gel beads. The results indicated that the incorporation of oil and wax significantly increased the encapsulation efficiency of the gel beads (% EE value of 85.43%) and improved the bioavailability of the active ingredient. Moreover, after simulated digestion, the release of anthocyanin and total phenolic content occurred more than five times. Scanning electron microscopy revealed that the surface of the gel beads was smooth. Furthermore, the presence of polyphenols and polysaccharides in the gel beads was confirmed using FTIR. The oil-wax-incorporated, anthocyanin-rich gel beads could be implemented for antioxidant delivery into the gastrointestinal tract to further improve healthy food and nutraceutical products.

Predicting antioxidant activity of wood vinegar using color and spectrophotometric parameters.

Wood vinegar can be produced from many types of raw materials using different pyrolysis methods resulting in potentially different antioxidant activity. Therefore, this study developed a rapid method to predict the antioxidant activity of wood vinegar based on color using the CIELAB system and spectrophotometric parameters. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) exhibited significant correlations with the L* and b* values of the color parameters and the UV absorbance polyphenol index (I280), European Brewing Convention (EBC) and Institute of Brewing (IOB) color units, color intensity and Linner Hue index of the spectrophotometric parameters. As a result, DPPH radical scavenging activity and FRAP could be predicted by measuring color and spectrophotometric parameters. Overall, this study provide a simple, rapid and no chemical reaction involved method to predict antioxidant activity. Furthermore, models with a set of spectrophotometric parameters could be used to predict antioxidant activities. •Whole new method for predicting wood vinegar antioxidant activity was developed.•The method was models developed by using color and spectrophotometric parameters used in beverage industry.•The models were simple, rapid and involved no chemical reaction.