Optimization of the extraction and modification of physicochemical properties of protein and fiber in ViciaFaba by ultrasound and enzymatic hydrolysis

In recent years, legumes have been highly considered as a good source of protein, fibers, minerals and other bioactive compounds in order to develop novel foods with improved nutritional properties. There is some evidence that legume consumption reduces the risk of diabetes, cardiovascular disease and some cancers. Vicia faba has about twice protein content as cereals and can be a good alternative to meat and protein-rich ingredients. It should also be noted that the amount of insoluble fiber is higher than soluble fibers in legume. Vicia faba belongs to the Fabaceae family .Vicia faba contains high protein (21-41% dry content of the bean), carbohydrates (51-68% dry content of the bean), fiber (5-5.8%), B-vitamins and minerals. Recently, the protein function of Vicia faba, especially its protein isolate, has been studied on a laboratory scale for use in food products, due to its good ability in hydration, solubility, emulsification, viscosity, and foam and gel formation. Research has also shown that the protein in Vicia faba has better ability to emulsify water and oil and foaming capacity and foam stability compared to bean and pea flour. The structural and functional properties of the protein isolates and concentrates of legumes such as Vicia faba are strongly influenced by their preparation, extraction and drying methods. One of the ways to improve extraction and optimization of protein properties can be ultrasound and an enzymatic controlled hydrolysis. Due to the importance of dietary fiber, various methods have been developed for their decomposition, many of which are very precise and special, some of which have high-purity enzymes and selectively release oligosaccharides and polysaccharides containing dietary fiber. In this  study, the possibility of using ultrasound and limited enzymatic hydrolysis in order to produce value added product and increase the extraction efficiency and improve the functional properties of protein and fiber of Vicia faba, were evaluated.

In this study, ultrasound and enzymatic hydrolysis were used to optimize extraction and modify physicochemical properties of protein and fiber of VaciaFaba. The proteins were affected by ultrasound at 200, 300 and 400 W for 15, 25 and 35 minutes, and the Alcalase enzyme 2.4 LFG at 0.15, 0.3 and 0.45% doses were extracted at 15, 25 and 35 minutes and the design of the treatments was done by Designer Express software. Solubility, oil absorption capacity, emulsification and zeta potential of protein samples were measured. Vicia faba fiber extraction under alkaline conditions was obtained from solutions of 0.0012, 0.012 and 0.12% sodium hydroxide until reaching pH 12, 11 and 10 and Termamy 2x enzyme was used for enzyme hydrolysis. Water retention capacity and rheological properties of Vicia Faba fiber samples were investigated.

The results showed that the use of ultrasound and enzymatic hydrolysis had a positive effect on solubility, oil absorption capacity and emulsion properties of the protein samples. Zeta potential was also negative for all treatments, which indicates that the Vicia faba protein treatment solution contains more negative amino acids than positive-loaded amino acids. Among the fiber samples of the ViciaFaba, a fiber sample with a pH of 10 had the highest water retention capacity and G-level than the other two samples, indicating a more solid and elastic quality. Also, in all fiber samples, increasing cutting speed reduced the viscosity and the samples showed a dilution action with cutting or pseudoplastic.