Properties and kinetics of the in vitro release of anthocyanin-rich microcapsules produced through spray and freeze-drying complex coacervated double emulsions

This study aimed to prepare anthocyanin-rich microcapsules by spray and freeze-drying complex coacervated double emulsion using gelatin-acacia gum (GE-AG) and chitosan-carboxymethylcellulose (CS-CMC) and to investigate their properties and in vitro release kinetics. Microencapsulation efficiency (MEE) of the microcapsules varied from 84.9% to 94.7%. CS-CMS microcapsules showed significantly higher MEEs than those of GE-AG microcapsules. A significant higher MEE and lower moisture content and hygroscopicity was observed in spray-dried double emulsion (SDE) microcapsules. Freeze-dried double emulsion (FDE) microcapsules possessed higher total anthocyanin and total phenolic contents. The best fit for release kinetics was achieved using first-order and Higuchi models for SDE and FDE microcapsules, respectively. Diffusion-controlled release in the simulated gastric fluid was found for SDE microcapsules, while erosion-controlled release in simulated gastric and intestinal fluids predominated for FDE microcapsules. These findings suggest that the microcapsules can be applied for loading anthocyanins as a nutraceutical with controllable release requirement.

Inhibitory effect of quinoa and fenugreek extracts on pancreatic lipase and α-amylase under in vitro traditional conditions or intestinal simulated conditions

Ethanol extracts (EE) from fenugreek and quinoa seeds with different total content of inhibitory compounds (TIC, total saponin plus phenolic) were prepared with and without concentration of TIC (CEE -concentrated EE-, and EE, respectively). Their inhibitory activity on pancreatic lipase and α-amylase was assessed by traditional in vitro methods (with or without orbital shaking), and by simulating intestinal digestion. CEE contained higher contents of TIC than EE, being fenugreek superior to quinoa (p < 0.001). The extracts inhibited enzymes in a dose-dependent manner, CEE extracts being stronger (fenugreek for lipase -p = 0.009-, and quinoa for α-amylase -p < 0.001-). Shaking did not impact the activity. Intestinal conditions worsened the inhibition of lipase, but slightly catalyzed the α-amylase. Longer times of reaction worsened activities. The importance of assessing the inhibitory activity of extracts under simulated intestinal conditions is concluded, being fenugreek more interesting than quinoa, especially against pancreatic lipase.

Effects of germination and high hydrostatic pressure processing on mineral elements, amino acids and antioxidants in vitro bioaccessibility, as well as starch digestibility in brown rice (Oryza sativa L.)

The effects of germination and high hydrostatic pressure (HHP) processing on the in vitro bioaccessibility of mineral elements, amino acids (AAs), antioxidants and starch in brown rice (BR) were investigated. Germinated BR (GBR) was obtained by incubating at 37°C for 36h and then subjected to HHP treatments at 0.1, 100, 300 and 500MPa for 10min. The in vitro bioaccessibility of calcium and copper was increased by 12.59-52.17% and 2.87-23.06% after HHP, respectively, but bioaccessible iron was decreased. In addition, HHP significantly improved individual AAs, particularly indispensable AAs and gama-aminobutyric acid, as well as bioaccessible total antioxidant activities and starch resistance to enzymatic hydrolysis. However, germination greatly increased starch digestibility. Atomic force microscopy characterization suggested an obvious structural change in bran fraction at pressures above 300MPa. These results can help to understand the effects of germination and HHP technologies on nutrients bioaccessibility and develop appropriate processing conditions.