Study On Preparation Of Deproteinized Rice By Protease And Lactic Acid Bacteria

Rice protein is a high quality vegetable protein, which has important physiologicalfunctions. However, for some special populations who need to control the protein intake,such as patients with chronic kidney disease, the high intake of plant protein may limitthe intake of high-quality animal protein, thereby increasing the risk of malnutrition.Rice is one of the staple foods for most people in the world. If the intake of vegetableprotein can be reduced, patients’ nutrition intake in protein would be got a greatprotection. Therefore, developing a production process for removal of protein rice hascertain economic and social benefits.The protein content of rice used in the experiment was7.28%. Results on theseven commercial protease showed that, considering the removal of rice protein typeand capacity, pepsin and alcalase had an outstanding performance, which was suitablefor industrial production.The optimum extraction process was determined: alcalase was at pH9, dose ofalcalase2%, solid-to-liquid ratio1:12and temperature60℃with two enzymatichydrolysis of18h, the total rate of removal protein was76.64%; pepsin was at pH1.5,dose of enzyme1.5%, solid-to-liquid ratio1:10and temperature40℃with twoenzymatic hydrolysis of20h, the total rate of removal protein was73.18%.The ability ofremoval protein by these two proteases was similar. For the pepsin, the reaction time ofpepsin was shorter and the ability of maintaining the integrity of rice was much better.Rice recovery under the optimal process plan of pepsin was88.47%. Comparedwith raw rice, most of the rice grain remained on the contour complete, but the color ofrice changed whiter and beige partial transparency was lower, the hardness of rice waslower and very easily broken, but rice flavor did not change much. In terms of cookingand eating, deproteinized rice was much easier to cooked, much softer in taste, muchpoorer in chewable but the rice flavor did not change much. In addition, the five lacticacid bacteria used in the experiment destructed the integrity of the grain of rice, andcouldn’t be removed the remaining protein in the rice obviously.