全小麦固体制曲条件优化研究

以米曲霉作为菌种,全小麦作为制曲基料,以成曲的中性和酸性蛋白酶活为评价指标,全面考察了米曲霉曲精种类、原料粗细度、曲料初始水分含量、制曲湿度、培养温度和培养时间对小麦曲蛋白酶活力的影响。研究结果表明:全小麦制曲的最优工艺为焙炒小麦粉碎过20目筛、曲料初始水分含量为51%、培养时间48 h、培养温度32℃,控湿制曲(即0~24 h湿度95%,24~36 h湿度90%,36~40 h湿度80%,40~44 h湿度70%)。最优条件下大曲的中性和酸性蛋白酶活分别高达1583 U/g干重和497 U/g干重,较本课题组此前研究的最优工艺中性和酸性蛋白酶活分别提高了12.75%和4.63%。本文获得的最优小麦曲制曲工艺,可为工业化制备新型小麦呈味基料和调味品提供实验依据。 

Optimization of koji prepared with whole wheat

Koji was prepared with Aspergillus oryzae as fermentation strain,with the whole wheat as raw material.The effects of fermentation parameters on protease activities were fully investigated,including the type of Aspergillus oryzae spores,the thickness of raw material,the initial moisture content of koji,relative humidity,fermentation temperature as well as culture time. The optimal koji-making conditions were as follows:the whole wheat was crushed to 20 mesh,the initial moisture of koji was 51%,the temperature was 32 ℃,and koji was obtained after 48 h under controlled condition(0~24 h,RH95%,24~36 h,RH90%,36~40 h,RH80%,40~44 h,RH70%). Under above conditions,the neutral protease activity and acid protease activity were as high as1583 U/g and 497 U/g,increased by 12.75% and 4.63% respectively compared with the previous study. The optimal koji-making parameters could provide experimental basis for the preparation of novel wheat flavored base material and seasonings on an industrial scale.