Effects of UV-A irradiation and microbial fermentation on the physicochemical, microstructure and functional properties of okara

• Published in: Food research international Vol. 200; p. 115445
• Main Authors: Lei, Ya-Ting, Meng, Fan-Bing, Jiao, Xiao-Lei, Tang, Yuan-Mou, Wu, Qi-Jun, Li, Yun-Cheng
• Format: Journal Article
• Language: English
• Published: Canada Elsevier Ltd 01.01.2025
• Subjects: antioxidants; Antioxidants - analysis; Antioxidants - chemistry; Benzothiazoles; Biphenyl Compounds; cation exchange capacity; dietary fiber; Dietary Fiber - analysis; economic valuation; electronic nose; Electronic nose sensor; Fermentation; Food Handling - methods; Food Microbiology; food research; Functionality; irradiation; Lactobacillus plantarum - metabolism; Lactobacillus plantarum - radiation effects; lipids; Microbial fermentation; microstructure; mouthfeel; Odorants - analysis; off odors; Okara; Picrates; Plant Proteins; Polysaccharides; Saccharomyces cerevisiae; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae - radiation effects; Solubility; Soluble dietary fiber; Soy Foods - analysis; Soy Foods - microbiology; Sulfonic Acids; total nitrogen; Ultraviolet Rays; UV-A irradiation; water solubility; Electronic nose sensor; IDF; OHC; UVO; SC; WHC; Microbial fermentation; SDF; LFO; TDF; MFO; ULO; WS; Okara; UV; YFO; MUO; LUO; UYO; LAB; YUO; Functionality; UMO; UV-A irradiation; Soluble dietary fiber
• ISSN: 0963-9969; 1873-7145; 1873-7145
• DOI: 10.1016/j.foodres.2024.115445

UV-A irradiation and/or microbial fermentation were used to modify okara. Single and combined treatments increased the soluble dietary fiber (SDF) content. S. cerevisiae fermentation (YUO), L. plantarum fermentation (LUO), and mixed fermentation (MUO) followed by UV-A irradiation significantly reduced the IDF/SDF ratio of okara, decreased the lipid and protein contents and the E-nose sensor values associated with beany odors. The treatment partially destroyed the crystalline, and further enhanced the functional properties. These results demonstrated that the treatment sequence is very important for the functional properties of okara and microbial fermentation followed by UV-A irradiation is most conducive to improve the physicochemical properties and functionalities of okara. [Display omitted] •Yeast/LAB fermentation combined with UV-A irradiation was used to modify okara.•Treatment sequence is important for structural and functional properties of okara.•Microbial fermentation followed UV-A irradiation reduced the IDF/SDF to below 3.•Mixed fermentation followed by UV-A irradiation is the most effective technology. Whole utilization of okara has important economic value, but there are two technical barriers: coarse mouthfeel caused by insoluble dietary fiber (IDF) and undesirable “beany” off-odors. UV-A irradiation and/or microbial fermentation were used to modify okara. The results indicated that single and combined treatments increased the soluble dietary fiber (SDF) content. Saccharomyces cerevisiae fermentation (YUO), Lactiplantibacillus plantarum fermentation (LUO), and mixed fermentation (MUO) followed by UV-A irradiation of okara significantly reduced the IDF/SDF ratio to 2.48, 1.86 and 2.25, respectively. The modifications significantly reduced the lipid and total nitrogen contents and decreased the E-nose sensor values associated with beany odors. The combined treatment of microbial fermentation and UV-A irradiation partially destroyed the crystalline, resulting in a loose and porous surface, further enhanced the functional properties of water holding capacity, water solubility, antioxidant properties and cation exchange capacity. In particular, the DPPH and ABTS scavenging abilities of okara subject to microbial fermentation followed by UV-A irradiation were greater than that of other samples. These results indicate that the treatment sequence is very important for the functional properties of okara and microbial fermentation followed by UV-A irradiation is most conducive to improve the physicochemical properties and functionalities of okara.