【作者】 潘薇娜；

【导师】 陈卫； 张灏；

【作者基本信息】 江南大学 ， 食品科学与工程， 2005， 硕士

【摘要】 本文主要针对冷冻预油炸食品经微波加热后的脆性问题展开研究,通过筛选特定的配料控制面拖食品内部的水分迁移,以期解决此类食品经微波重制后的脆性问题,开发更多的冷冻预油炸食品,推动我国微波食品工业的发展。 本文首先通过对油炸食品脆性的感官评定值与峰力值的测定和分析,确定了以感官评定为主、仪器分析值为参照的脆性评价方法。以微波重制后的脆性为指标,通过单因素实验系统分析了在面糊涂层中添加持水、成膜或阻水性配料对改善产品脆性的影响,分别试验了大豆蛋白、大豆磷脂、糊精、黄原胶、钙盐和油脂等,同时发现由于大豆蛋白、磷脂和钙盐存在交互作用,钙盐的添加降低了大豆磷脂的作用,通过钙结合大豆蛋白代替大豆蛋白和钙盐,可以有效解决这一问题。通过钙结合大豆蛋白、大豆磷脂、糊精以及黄原胶为主要因素的正交实验,筛选出大豆蛋白、大豆磷脂、糊精为最主要的影响因素,二次响应面进一步优化得到面糊涂层的组成为:钙结合大豆蛋白5.85g(以100g干粉计),大豆磷脂1.85-2.0g,糊精1.85-2.0g,黄原胶1g。 冷冻预油炸食品加工过程中的环境因素对产品脆性也会有较大的影响。待涂层食品的水分含量会影响水分迁移速度和分布,水分活度控制在0.90-0.925之间对脆性保持较为适合。面拖食品油炸后的冷冻速率和冻藏温度对良好脆性的保持也有重要影响,预冻速率控制在0.058℃/S以上,保藏温度在-40℃到-70℃时产品脆性良好,并且保持的时间较长。微波解冻复热的方式对产品脆性也有影响,采用实验型微波工作站对不同输出功率下微波加热过程中的温度进行进行实时测定,结果表明不同部位在微波场中的升温曲线不一样,达到的最高温度也不一致,采用较高功率的加热方式对获得良好产品脆性比较有利。 采用特定配料提高冷冻预油炸面拖食品的脆性可从高分子自由体积理论和面糊涂层的阻隔性来解释。通过DSC测定表明优化配方的面糊体系表现出的玻璃化相变温度(Tg)比对照样提高了27.57℃;多糖、脂质与大豆蛋白形成的复合体系提高了面糊层的阻水性,从而使面拖食品的脆性得到改善。电镜观察结果也表明,优化样的微观结构更加致密平整,空隙较少,因此产品的脆性良好。更多还原

【Abstract】 The frozen fried coated food will lose crispness after microwave heating due to moisture migration from the inner food base to the outer breading. The research was focused on solving the crispness problems and to develop new microwave able products mainly through selecting the suitable formulation of the coating and also changing the process conditions.Firstly to establish a reasonable crispness evaluation system after correlate analyses of sensory test and penetrometry test ,and decided to select sensory test value as the main test index. Then we studied the influence to the crispness of food with different food additives such as soybean protein, soybean phosphatide, dextrin, xanthic gum, CaCl₂, oil and crumb and found all ingredients increased the crispness, but soybean phosphatide and CaCl₂ can not exist at the same time ,so we use Ca-bind soybean protein to replace SPI .Finally we selected the soybean protein, soybean phosphatide, dextrin, xanthic gum as the main effective factors. After the Orthogonal Experiment and Response surface methodology analyses of such factors, we got to know the optimum composition of the coating batter was Ca-bind soybean protein 5.85/100g, soybean phosphatide 1.85-2g/100g, dextrinl.85-2g/100g, Xanthic gum 1g/100g.The research also studied the effect of inner Aw, and frozen storage condition and microwave heating on the crispiness, water content and temperature of products. The results showed that when the freeze rate reached 0.058 ℃/S or more and the storage temp, is lower than -40 ℃ ,it will lead to good crispness. The determination of microwave station showed that for a product of 30g, it shall need the 30S heating of 600w which will contribute to the good texture.The e ffects o f various a dditives on crispness were explained by film theory, free volume theory of food macromolecule. The WVP value o f optimized complex film was 46.6% lower than the parallel protein film. The determination by DSC indicated that the optimized-coating components could evidently improve Tg value of the system. The SEM analyse results showed the optimized coating was firmer and smoother than the basic coating, which contributed to the good water-resistant capacity.更多还原