Study On Low-Calorie Food By Extrusion Technology

Low-calorie extruded food was made from wheat bran, soybean residue and wheat germ by twin-screw extruder in this paper, this product was suitable for diabetic patients, the main conclusions were as follows:1、Through the single-fact experiments it showed that the flavor of product was better when the proportion among wheat bran and soybean residue was5:2, the degree of gelatinization, WAI and WSI was also increased with the increasing of polydextrose, xylitol, maltodextrin, but the improving degree of WAI and WSI was not obvious while the addition was over6%. Considering costs and effects,the best formulation of products based wheat bran as main material,40%soybean residue,6%wheat germ,6%polydextrose,6%xylitol,6%maltodextrin,.The total energy density of product was0.29kcal/g.2、The moisture content of raw material, screw speed and extrusion temperature had a certain effect on the product’s color, degree of gelatinization, WAI and WSI, free amino acid content and the reducing sugar content after hydrolysis of carbohydrates in vitro. When the moisture content of raw material below20%, screw speed was100r/min, extrusion temperature was greater than170℃, the product browning happened, maillard and caramelization intensified. Taken together, moisture content of30%, screw speed of150r/min, extrusion temperature of150℃was taken for the next step to find the optimum parameters.3、Through the central composite design experiments, we found that the sequence of operating parameters on the influence of the products of the reducing sugar content after hydrolysis of carbohydrates in vitro was: extrusion temperature>screw speed>(extrusion temperature x moisture content)> moisture content>(screw speed x moisture content)>(extrusion temperature x screw speed). The results indicate that the optimum parameter were the moisture content of28%, screw speed of140r/min, extrusion temperature of147℃.4、During extrusion,the content of protein, fat, carbohydrate was decreased, and the total energy density of product was also reduced; the rate of hydrolysis of carbohydrates slowed down; WAI was increased significantly, WSI was decreased slightly; free amino acids and each component of it was decreased, the phenylalanine lose of up to58%; the apparent viscosity of food was decreased, the product solution properties was closest to the Newtonian fluid at70℃.