Ultrasound-assisted fermentation and microencapsulation of corn gluten meal-rice bran mixture enhance nutritional quality, bioactive stability, and gut delivery.

Corn gluten meal and rice bran mixture (CRM) are major agricultural by-products of food processing. The nutritional quality of fermented CRM (FCRM) was enhanced through ultrasound-assisted fermentation with Aspergillus oryzae AOX and Lactobacillus helveticus LHS. Additionally, polydopamine/chitosan-gum Arabic/FCRM (P-C-FCRM) microcapsules were fabricated under ultrasonic conditions to enhance the stability of bioactive compounds. After ultrasound-assisted fermentation, high-molecular-weight proteins, zein, and fibers in FCRM were significantly degraded, resulting in 3.32-, 1.42-, and 11.87-fold increases in peptides, total free amino acids, and reducing sugars, respectively, while levels of bioactive compounds-including phenolics, flavonoids, and carotenoids-were also markedly elevated. P-C-FCRM achieved 95.47% encapsulation efficiency and exhibited excellent storage stability. In vitro simulated digestion experiments demonstrated that the degradation rate of unencapsulated FCRM was 59.17%, whereas that of P-C-FCRM was 20.31%, enabling the targeted release of P-C-FCRM in the intestine. Furthermore, in vivo experiments were conducted to examine the regulatory effects of P-C-FCRM on the gut microbiota of chicks. In vivo studies demonstrated that P-C-FCRM improved chick growth and gut health by increasing probiotics and short-chain fatty acids. This work introduces a scalable bioprocess integrating ultrasound, microbial fermentation, and microencapsulation, offering a novel strategy for the valorization of agricultural by-products into value-added functional feed products.