【作者】 陈云辉；

【导师】 李汴生；

【作者基本信息】 华南理工大学 ， 食品科学， 2013， 硕士

【摘要】 本论文针对粽子目前生产中所存在的粽子瓷实程度差异大，蒸煮时间长，能耗大，水分含量难于控制等问题，主要研究了包制密度对粽子蒸煮特性的影响，并在实验室条件下探索一定包制密度下粽子蒸煮与杀菌的优化工艺，再从产品品质和成本的角度验证这种生产优化工艺的可行性，并探究粽子的蒸煮动力学机制。在此基础上，考察了温度、糯米粒度等对粽子食用品质的影响，以获得粽子最佳的食用品质。1、为研究包制密度对粽子蒸煮特性的影响，考察了不同包制密度对粽子蒸煮及产品品质的影响。结果表明：（1）不同包制密度粽子蒸煮过程中的平均水分含量都呈现出先快速增大后逐渐上升最后基本稳定的趋势。（2）粽子的包制密度和蒸煮过程中的水分含量具有负相关性，包制密度越小，水分含量越大。蒸煮结束时各粽子的平均水分含量、粽子熟制时间都与粽子包制密度成线性相关，可通过控制粽子的包制密度来控制粽子产品的水分含量。2、在实验室条件下探索了一定包制密度下粽子蒸煮与杀菌的优化工艺，并验证其可行性，结果表明：（1）粽子在预煮前期水分含量快速增加，而后缓慢上升，粽子预煮30min后，其水分含量基本趋于稳定且中心温度几乎达到最高。（2）预煮后的高温粽子投入冷水中后，粽子的水分含量表现为先迅速增大后平缓上升直至趋于稳定的趋势，浸水12min后，粽子的水分含量达到普通工艺蒸煮90min的水平。（3）正交实验结果表明，三因素对实验指标的影响排序为：预煮时间>冷水浸泡时间>杀菌时间。实验室条件下粽子蒸煮与杀菌最优工艺为：预煮30min，冷水浸泡8min，121℃杀菌保温35min。（4）蒸煮与杀菌优化工艺的生产周期明显缩短（约1h），但产品的理化指标和食用品质与普通工艺无差异，且可通过控制浸泡时间对粽子水分含量进行控制。（5）在实验室条件下的优化工艺的蒸煮杀菌成本低于普通工艺成本，且在最优条件下成本节省144.56元/吨。3、对粽子蒸煮动力学研究表明：（1）粽子的蒸煮速率符合一级动力学反应方程，不同包制密度粽子都含有三个蒸煮速率常数。（2）粽子蒸煮存在三个阶段，其中第一第二阶段粽子的蒸煮速率与粽子包制密度有关，但第三阶段的蒸煮速率与粽子包制密度无关。（3）优化蒸煮工艺含有四个蒸煮速率常数，预煮后的浸水处理致使粽子表面已经糊化的糯米层遇冷收缩，自由水向粽子内部扩散的阻碍减弱，自由水向粽子内部扩散变得容易，从而使得粽子的蒸煮速率常数增加一个。4、研究了温度、糯米粒度对粽子食用品质的影响，且考察了粽子中肥猪肉的蒸煮特性，结果表明：（1）温度对粽子食用品质的影响显著，粽子温度越高，硬度越小，粽子粘弹性随着温度增大呈现出先增大后减小的趋势。（2）不同温度导致粽子的感官品质差异，温度为37℃时，粽子的外观、香味、滋味较优，硬度适中，粘弹性适中，将获得最佳的感官品质。（3）糯米粒度对其制作出的粽子质构特性影响显著，糯米粒度与各质构指标表现出明显的线性规律。随着糯米粒度的减小，粽子的硬度、粘聚性、咀嚼性都随之增大，粽子的粘性（绝对值）、弹性随之减小。（4）设肥猪肉硬度值为y，对应C值为x，对其做回归分析，其回归方程为y=5139e^-0.01x，R²=0.992，可利用此方程，通过肥猪肉的目标硬度值求得对应的C值，从而可推导出某一温度下需要蒸煮的时间。更多还原

【Abstract】 ZongZi are widely popular with the consumers in the south of the Yangtze River.However, there are some problems of Zongzi with four corners in process including largedifferences in densities, long cooking time, large energy consumption and difficulty ofcontrol and so on. This paper aimed at those above-mentioned problems and explored theoptimized process parameters of cooking and sterilization of ZongZi of certain packagedensities under the laboratory condition. Feasibility of optimized process was verified at theperspective of product qualities and cost. In addition, effects of temperature and particle sizeof glutinous rice on qualities of Zongzi were also studied in this paper to obtain best eatingqualities.1. In order to study the effect of package densities on the cookingcharacteristicsofZongZi,this paper investigated the effect of different package densities onthe cooking of ZongZi and the product quality. Result showed that: in the process ofcooking, the average moisture content of ZongZi with different package densities raisedrapidly at first, then increased gradually, stabilized at last.Ultimate moisture content showeda negative linear correlation with package density. Moisture content of product can becontrolled by changing package density of ZongZi.A linear correlation was also showedbetween cooking time and package density of ZongZi.2. Under the laboratory condition, this paper explored the optimized process ofcooking and sterilization for certain package densities ZongZi and verified feasibility ofoptimized production process at the perspective of product quality and cost. Result showedthat: at the early stage of the processing of pre-cooking, the moisture content of ZongZiincreased rapidly, and thenrose gradually, stabilized at last. After pre-cooking for30min, themoisture content of ZongZi was almost stable and the center temperature of ZongZialmostreached the top. Themoisture content of ZongZi with high temperature after pre-cookingrapidly rose at first, and then increased gradually, stabilized at last after been put into thecold water. After soaking for12min, themoisture content of ZongZi achieved the level ofnormal process cooking for90min.Orthogonal experiment results showed that the order of three factors: the pre-cooking time>soaking time in cold water> sterilizing time. Theoptimized process of cooking and sterilization under the laboratory condition was:pre-cooking for30min, soaking in cold water8min, sterilizing under121℃for35min.Theproduction cycleof the optimized process was shortened significantly (about1h), but thephysicochemical indexes and eating quality were no difference with normal process.Themoisture content of the product with optimized process can be controlled through controlthe soaking time.Finally, we accounted for the cost of theoptimized process. The cost ofoptimized process under the laboratory condition was less than normal process, and wouldsave144.56RMB/ton under the condition of the optimal.3. The cooking kinetic of ZongZi was studied. Results showed that cooking rate ofZongZi accords with the first-order kinetics equation during the cooking process. Threecooking rate constants were observed of all ZongZi with different package densities. Therewere three stages in cooking process of ZongZi. The cooking rate of first and second stageassociated with package density, but the third stage didn’t. What’s more, the fact that therewere three cooking rate constants of normal process as against four of optimized processemphasized the benefits of soaking ZongZi in cold water before cooking.4. This paper investigated the effect of different temperatures and particle sizes ofglutinous rice on texture and sensory qualities of ZongZi. Cooking quality of lard in ZongZiwas also studied. Results showed that temperature had a significant effect on texturequalities of ZongZi. As the temperature raised, hardness of ZongZi decreased. Similarly,temperature had a significant effect on the sensory qualities of ZongZi. When temperaturewas37℃, ZongZi would get the best sensory qualities of good appearance and taste.Meanwhile, particle size of glutinous rice had a great effect on quality and structurecharacteristics of ZongZi. The particle size of glutinous rice showed an obvious linearcorrelation with texture indexes of ZongZi. With the decrease of the particle size ofglutinous rice, hardness, adhesiveness and chewiness of ZongZi increased, but adhesivenessand springiness fell. The smaller the particle size of glutinous rice was, the higher thehardness was. In addition, the relationship between hardness and C value of the lard in ZongZi followed the following formula (x-C value, y-hardness, g): y=5139e-0.01x (R~2=0.992).更多还原