Enzymatic hydrolysis improves the encapsulation properties of rice bran protein by increasing retention of anthocyanins in microparticles of grape juice.

There is a growing demand for the food industry to find appealing matrices that display a clean and sustainable label capable of replacing animal proteins in the encapsulation market for natural pigments. Therefore, this study evaluated the impact of enzymatic hydrolysis by Flavourzyme protease on the encapsulation properties of rice bran proteins, aiming to protect anthocyanins in grape juice microparticles. To achieve this, rice bran protein hydrolysates (RPH) with low (5%, LRPH), medium (10%, MRPH), and high (15%, HRPH) degrees of hydrolysis (DH) were used combined with maltodextrin as carrier agents for the microencapsulation of grape juice by spray drying. The feed solutions contained 1 g of carrier agents (CA)/g of soluble solids from the juice (SS) and protein: a 15% CA ratio. Non-hydrolyzed rice protein was used as a carrier agent to obtain a control sample to evaluate the effect of enzymatic hydrolysis on the microencapsulation of grape juice. Protein modification increased the surface activity of the protein and its ability to migrate to the surface of the microparticles, forming a protective film, as observed by X-ray photoelectron spectroscopy. Using HRPH as a carrier agent combined with maltodextrin improved the internal and total anthocyanin retention, antioxidant capacity measured by DPPH and ABTS assays, and powder recovery compared to the control sample, and increased DH reduced particle size and powder stickiness. These particles were more homogeneous, rough, and without cracks. The microencapsulation efficiency was above 70%. All powders exhibited low values of hygroscopicity and degree of caking. Therefore, enzymatic hydrolysis proves to be a promising alternative for improving rice bran protein's encapsulating properties since using RPH as an encapsulating agent conferred greater protection of anthocyanins in microparticles. Moreover, the HRPH sample exhibited the most favorable outcomes overall, indicating its potential for prospective utilization in the market, supported by its elevated Tg.