酿酒酵母菌剂等温干燥曲线及其存活率干燥动力学  

Dehydration Isotherm and Vitality Kinetics of Dried Saccharomyces cerevisiae

作　　者：梁璋成[1,2,3] 苏昊 陈秉彦 林晓姿 窦芳娇[1,2] 何志刚 LIANG Zhangcheng;SU Hao;CHEN Bingyan;LIN Xiaozi;DOU Fangjiao;HE Zhigang(Institute of Agricultural Engineering Technology,Fujian Academy of Agricultural Sciences,Fuzhou,Fujian 350003,China;Fujian Key Laboratory of Agricultural Products(Food)Processing,Fuzhou,Fujian 350003,China;Key Laboratory of Subtropical Characteristic Fruits,Vegetables and Edible Fungi Processing(Co-construction by Ministry and Province),Ministry of Agriculture and Rural Affairs,Fuzhou,Fujian 350003,China)

机构地区：[1]福建省农业科学院农业工程技术研究所,福建福州350003 [2]福建省农产品(食品)加工重点实验室,福建福州350003 [3]农业农村部亚热带特色果蔬菌加工重点实验室(省部共建),福建福州350003

出　　处：《福建农业学报》2022年第12期1612-1618,共7页Fujian Journal of Agricultural Sciences

基　　金：福建省自然科学基金项目(2021J01501、2020J011373);福建省科技计划公益类专项(2020R1032005、2020R1032008);福建省农业高质量发展超越“5511”协同创新工程项目(XTCXGC2021019-GCS01)。

摘　　要：【目的】为高活力酿酒酵母直投式发酵剂的研发提供理论和技术支持。【方法】以酿酒酵母JH301为研究对象,采用沸腾炉热风干燥技术制备菌剂,研究不同温度下酿酒酵母沸腾炉热风干燥过程水分含量、菌存活率的变化及其相关性,建立酿酒酵母菌剂等温干燥曲线及其存活率干燥动力学模型,并采用核磁共振技术考察酵母菌沸腾炉热风干燥过程水分迁移分布规律。【结果】(1)酿酒酵母菌剂沸腾炉热风干燥过程等温干燥曲线符合Henderson指数函数模型M=a×EXP(b×T),a、b均为与干燥温度W相关的常数。(2)随着干燥过程菌剂水分含量的下降,菌存活率呈先平缓下降后快速下降趋势,存在菌存活率拐点水分阈值。在拐点水分阈值前后,菌存活率干燥动力学模型分别符合模型y前=a前x+b前、y后=a后x+b后,a、b均为与温度(W)相关的常数。y前与y后的交叉点即为菌存活率拐点水分阈值,菌存活率拐点水分阈值与干燥温度呈正相关,菌存活率与细胞结合水的逃逸速率呈负相关。(3)菌存活率拐点水分阈值的最低干燥温度理论值为41.2℃。通过对模型参数预测与验证,适宜的干燥温度为42℃,时间为20 min,菌剂水分含量为(5.24±0.12)%,菌存活率可达(48.24±0.15)%。【结论】通过调控热风干燥过程酿酒酵母结合水的逃逸速率,可提高菌存活率。【Objective】Isotherm of dehydration process and kinetics of survival rate of a dried Saccharomyces cerevisiae product were studied for the development of a highly active yeast product with extended shelf life for vinification.【Method】S.cerevisiae JH301 was used in the fluidized hot air oven dehydration experimentation.Under varied hot air temperatures,the moisture content and survival rate of S.cerevisiae were monitored to construct dehydration isotherms and analyze yeast vitality.Water migration and distribution in the drying yeasts were determined by a nuclear magnetic resonance mothed.【Results】(1)The dehydration isotherm followed the Henderson exponential equation of M=a×EXP(b×T),where a and b were the constants related to the drying temperature(W)as a=-0.31W+81.36 and b=-0.0094W+0.27.(2)The yeast survival rate declined gradually at first,and then,rapidly as the moisture content decreased with time in the process.A water threshold appeared at the inflection point of the yeast survival rate curve.The kinetic equations before the threshold point were y1=a1x+b1,and after the point y2=a2x+b2,where a1=0.014W+0.20,b1=-0.90W+81.64,a2=0.36W-14.04,and b2=-2.77W+159.40.The moisture content at the point where y1and y2intersected,or the water threshold,positively correlated with the processing hot air temperature,while the yeast survival rate negatively correlated with the rate of bounded water evaporated from the yeast cells.(3)A theoretical minimum drying temperature was determined to be 41.2℃.Based on the kinetic model prediction and a follow-up experimental verification,the optimal yeast dehydration was determined to be conducted at 42℃for 20 min.A final moisture content of(5.24±0.12)%with a survival rate of(48.24±0.15)%on the dried yeast product was achieved.【Conclusion】The vitality of the dried S.cerevisiae could be maximized by controlling the evaporation of bounded yeast cellular water in the hot air dehydration process.

关 键 词：酿酒酵母菌剂 菌存活率 水分阈值 沸腾炉热风干燥 水分分布 

分 类 号：TS201[轻工技术与工程—食品科学]