Method for preparing casein from defatted rice bran

Abstract

The invention discloses a method for preparing casein from defatted rice bran. The method comprises the following steps of (1) crushing the defatted rice bran, putting the crushed defatted rice bran into a stirring kettle, adding 0.5% dilute sulfuric acid with amount being 4-6 times of the mass of the crushed defatted rice bran, performing uniform stirring, performing soaking for 8-10 hours, and performing extraction so as to obtain a supernatant; (2) adding water with amount being 2-3 times of the mass of the rice bran to the rice bran, and performing stirring, washing and pressure filtration so as to obtain filter residues; (3) putting the filter residues into a reaction kettle, adding clean water of 50-60 DEG C, which is 4-6 times of the filter residues, dropwise adding sodium hydroxide while stirring until pH is 12-13, performing heat preservation at 50-60 DEG C for 4-6 hours, performing standing for layering, performing extraction so as to obtain a supernatant, performing pressure filtration on lower-layer precipitate, mixing the obtained filtrate and the supernatant so as to obtain mixed fluid, and adding the mixed fluid into the reaction kettle; and (4) heating materials in the reaction kettle to 35-40 DEG C, adding 5% sulfuric acid while stirring until the pH is 4-5, performing standing for layering, performing pressure filtration on lower-layer precipitate, drying products obtained after the pressure filtration at 60-70 DEG C, and crushing the dried products so as to obtain the casein. The casein prepared by the method disclosed by the invention is superior in quality, low in production cost and good in stability during drying, and suitable for being used as timber glue stocks, paper coatings, plastic, paint, polish for tanning industry, diabetic foods and the like.

Description

technical field [0001] The invention relates to the technical field of waste utilization, in particular to a method for preparing casein from defatted rice bran. Background technique [0002] Casein is a phosphoprotein in animal milk. The structural formula is NH 2 RCOOH, odorless, tasteless white to yellow powder, relative density 1.25-1.31. Almost insoluble in water, alcohol and ether. Soluble in dilute lye, alkaline carbonate solution and concentrated acid, and precipitate in weak acid. Hygroscopic, stable when dry, hardens rapidly when wet. Mainly used as food additives, casein glue, cosmetics, leather chemicals, paints, plastics, aluminum foil, safety matches, pigments, coated paper, plywood industry, glazing industry, 2% casein solution is required when protease activity is measured by Folin method. [0003] At present, the production methods of casein mainly include the following two methods: (1) Skim fresh milk, add acid (lactic acid, acetic acid, hydrochloric a...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for preparing casein by using defatted rice bran to solve the problem that the current production method of casein mainly uses milk as raw material, and the price of milk is rising steadily, which leads to the continuous increase of the production cost of casein