Properties of Buckwheat Proteins from the Standpoint of Food Processing

Abstract

Properties of buckwheat proteins were investigated from the standpoint of food processing, and the following results were obtained. The protein content of the 3rd flour (obtained at the final stage of crushing) was around 5 times as high as that of the 1st flour (obtained at the initial stage), and 80% of the former proteins was water-soluble. Physical properties of acid-precipitated protein (APP) from the water extract resembled those of wheat gluten. Especially, a remarkably high viscoelasticity was found in the APP from the 1st flour. The extent of the protein-protein interaction induced by heat treatment of the water extract from the 1st flour was far extensive as compared with that of the water extract from the 3rd flour. Viscosity of the proteins from the 1st flour was higher than that of the proteins from the 3rd flour, e.g., the former APP showed around 10 times higher value than the latter APP. Viscosity of the proteins generally decreased by the addition of NaCl. Intrinsic viscosity of the APP was 10-40 times as high as that of soybean globulin. Taking the above results and the observation by scanning electron micrography into consideration, the relationship between the buckwheat proteins and the formation of buckwheat noodles was discussed.