螺杆挤压生产高凝胶强度的低温溶解江蓠属琼脂  

Production of agar with low-temperature solubility and high gel strength from Gracilaria by screw extrusion

作　　者：徐博[1] 张闻修[1] 李春[1] 王玉堂[1] 刘宁[1,2] 

机构地区：[1]东北农业大学食品学院乳品科学教育部重点实验室,哈尔滨150030 [2]国家乳业工程技术研究中心,哈尔滨150086

出　　处：《农业工程学报》2013年第2期280-286,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家十二五科技支撑课题(2011BAD09B0304)

摘　　要：为了获得在60℃低温溶解且凝胶强度高的琼脂粉,以中国产的江蓠琼脂粉为原料,采用双螺杆挤压加工技术予以改性,研究了加工温度、水料比、螺杆转速和模孔直径对琼脂低温溶解性质的影响,并采用Box-Behnken设计及响应面分析法优化其加工工艺参数。结果表明,加工温度对琼脂低温溶解性影响显著;加工温度和水料比对琼脂凝胶强度影响显著,且加工温度和水料比具有互作效应。经优化后,当加工温度为126℃、水料比为0.37mL/g、螺杆转速为150r/min和模孔直径为6mm时,凝胶强度(质量浓度1%)为683.6g/cm2。产品在60℃具有良好的溶解性和凝胶强度,节约了工业生产中溶解琼脂所需的能源,使温度敏感的物质与琼脂的共同应用成为可能,而且满足不同产品对凝胶强度的需求,为工业生产提供参考。Agar is extracted from red seaweed （Rhodophyceae）. It is insoluble in cold water and hydrates. With good characteristics of reversibility of gel and security, agar is widely used in food, bio-engineering, medicine and other fields. Because some foods are sensitive to high temperature, the need for fully hydrate agar by boiling may limit its use in gel applications. It was reported that the agar was mixed with water and other materials such as sugar, locust bean gum, guar gum or other dispersants to improve its solubility. In order to obtain the optimal processing conditions for agar which dissolves at 60℃ with high gel strength, agar from Chinese Gracilaria Lemaneiformis was extruded and processed without adding other substances by a twin screw extruder, then the production was crushed into powder, sieved, sealed and stored. First, processing temperature, liquid to solid ratio, screw revolution speed and nozzle diameter were optimized by single factor experiment for analyzing their influences on the solubility properties at low temperature and gel strength of agar. The process conditions of agar that dissolves at 60℃ with high gel strength were optimized by Box-Behnken design and response surface methodology. Texture analyzer and advanced rheometer were used to determine gel strength and melting-gelling point respectively. The data were analyzed using SPSS 18.0 and Design-Expert 8.0. Finally the physical indexes of agar were determined. The results showed that processing temperature was the most significant factor affecting the solubility properties of agar at low temperature. Because the surface of agar formed porous expanded state at appropriate processing temperature and the particle size of agar after crushing and sieving was moderate, agar with good flowability and dispersibility dissolved at low temperature. Processing temperature and liquid to solid ratio had significantly influence on the gel strength of agar, while screw revolution speed was the least significant factor. Also, processing temperat

关 键 词：温度 挤压 溶解性 琼脂 凝胶强度 

分 类 号：TS202.3[轻工技术与工程—食品科学]