Abstract:Insoluble dietary fiber (IDF) was extracted from wheat bran using the enzymatic method. The effects of dosages of alkaline protease and α-amylase as well as the duration of enzymolysis on the degrees of hydrolysis of protein and starch were investigated. The extraction conditions of IDF were optimized. The structure and physicochemical properties of IDF from wheat bran were studied. At the alkaline protease and α-amylase dosages of 4 000 U/g and 140 U/g, respectively, and the duration of enzymolysis of 2 h for each enzyme, the purity of extracted wheat bran IDF was 82.56%. The structure of wheat bran IDF was characterized by scanning electron microscopy, X-ray diffractometry, and Fourier transform infrared spectroscopy. The particles of extracted wheat bran IDF had holes and cracks on the surface, their crystalline structure was a typical type I cellulose crystalline structure, and the main components of wheat bran IDF were cellulose, lignin, and hemicellulose. The obtained wheat bran IDF showed higher water holding capacity (3.82 g/g), swelling power (2.59 mL/g), and oil holding capacity (1.78 g/g) than wheat bran, suggesting its potential application in flour products, gelled foods, and meat products to improve the stability and sensory qualities of the products. In addition, the nitrite ion clearance ability of wheat bran IDF reached 95.63%, implying its applicability as a functional ingredient in foods for reducing the negative impacts of nitrites on human health. These results provide guidance for improving the added value of wheat bran and for the application of wheat bran IDF in high-quality healthy foods.
