Besides providing dietary fiber, wheat bran is a recognized source of protein and it is considered a very valuable substitute for other protein-rich sources in the food and feed industry. Nonetheless, several factors affect protein bioavailability, including bran's layered structure. Recent two papers of Arte et al (2015) show that bioprocessing enhances protein bioavailability of wheat bran through liberating proteins from the bran matrix and through enhanced solubilisation of proteins.
Enhancing wheat bran protein bioavailability by enzymatic and microbial bioprocessing
The study of Arte et al (2015a) showed bioprocessing methods to influence on the release and protein modification of wheat bran. Bioprocessing in acidic conditions significantly enhanced the solubilization of protein from wheat bran, reaching the highest value in the treatment where the sole endogenous enzymes were activated. Bioprocessing through controlled fermentation allowed a more intense proteolysis and strongly impacted the in vitro digestibility of proteins.
The results of this study offer new possibilities to enhance the bioavailability of wheat bran proteins by bioprocessing.
Enhancing wheat bran protein bioavailability by exogenous enzymes with proteolytic activities
Another study of Arte et al (2015) aimed to liberate and solubilize wheat bran proteins via cell wall degradation using carbohydrate hydrolysing and proteolytic enzymes without causing extensive protein hydrolysis. The study showed that enzymes with solely carbohydrate hydrolyzing activity increased the level of water-soluble pentosan and reducing sugar contents, but did not significantly increase protein solubilization or protein release from the aleurone cells. Enzymes with proteolytic activity significantly increased the solubilization of protein to 58.2% 30 already in 4 h. Significant protein hydrolysis was detected with a high dosage of protease. With optimized protease treatment (3 h, 35 °C, and 550 nkat/g), effective protein solubilization (>48%) without extensive protein hydrolysis (free amino nitrogen content <45 mg/L) was achieved. In conclusion, intensive solubilization of proteins in the subaleurone layer of wheat bran is possible using exogenous enzymes with proteolytic activities.
Arte E., Rizzello CG., Verni M., Nordlund E., Katina K., Coda R. "Impact of Enzymatic and Microbial Bioprocessing on Protein Modification and Nutritional Properties of Wheat Bran". J Agric Food Chem. 2015
Arte E., Katina K., Holopainen U., Nordlund E. " Effect of hydrolyzing enzymes on wheat bran cell wall integrity and protein solubility".Cereal Chemistry 2015.
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