方便稀饭的研制及其糊化回生机理研究

【作者】 周坚；

【导师】 吴谋成；

【作者基本信息】 华中农业大学 ， 农产品加工及贮藏工程， 2003， 博士

【摘要】 本课题在探讨大米品质特性的基础上，对方便稀饭的加工工艺和方便稀饭复水性、糊化回生机理研究两方面进行了较系统的研究。试验结果表明： 1．适宜的工艺参数为：将较低直链淀粉含量(＜16％)的粳米，用常法水洗后，以0.2％三聚磷酸钠与0.4％葡萄糖酸-δ-内酯混和溶液于室温浸泡1hr，沥水后投入6倍量沸水中煮制5min，再于90℃恒温水浴加热25min。其间向蒸煮米水中添加0.40％CMC、0.40％蔗糖酯和单甘酯混合物(1：1)、0.10％β-环糊精(均以大米量计)。糊化后再次沥水并添加65U果胶酶(55±1℃，PH5±0.1)、5倍量水浸泡处理90min，沥水后迅速用15℃凉水冲洗至米粒表面无粘性，然后以70％乙醇浸渍5s，微波干燥(480W，25min)制成方便稀饭。本产品具有良好的复水性能，成品复水后清淡、爽口、无硬芯，与普通稀饭相似。用物性测试仪对其品质进行鉴定，结果表明以上工艺是可靠可行的。加入成品总量0.02％的大米香精、0.05％的CMC与琼脂(2：1混合)、5％～10％的马铃薯淀粉进行修饰，成品品质进一步得到显著改善。 2．浸泡处理、酶处理、干燥疗法的不同，直接影响到方便稀饭内部结构，而结构对方便稀饭复水后的吸水均一，复水率，有无回生现象均有很大的影响，它直接影响到方便稀饭的品质、口感等各质量指标，通过SEM观察可为实践研究提供理论依据。 3．糊化回生是由于糊化淀粉在存放过程中，淀粉分子产生自组现象，形成结晶，粘性下降、分子的柔性减弱、透明度下降、溶液中产生凝聚、相分离现象或沉淀凝胶的硬度上升等。通过用动态流变仪，DSC和物性测试仪对不同原料进行测定分析表明，东北粳稻适合做方便稀饭。淀粉的回生与放置时间成正比，而经过常法糊化后的淀粉产品仍有微弱回生现象发生。β—淀粉酶的适度酶解降低了支链淀粉外侧短链的聚合度，显著抑制直链淀粉的重结晶。更多还原

【Abstract】 Based on the exploring of quality properties of rice material, the processing of instant rice soup has been studied. The test indicates that:1. The suitable processing condition is as follows: Rice of low amylose content ( <16%=, after washing , is soaked in the mixed solution of 0. 2% sodium triphosphate and 0. 4% glucopyrone at room temperature for Ihr. Then it is leached, cooked for 5 min in 6 times boiled water immediately, followed by cooking at 90癈 for 25 min, during which mixture of sucrose fatty acid ester and monoglycerid must be added to the cooking water. When the gelatinization is over , the rice is leached and soaked with 5 times 0.05% pectinase(w%) solution for 90 min, then washed with cool water(15癈) immediately until the surface of grain is not sticky. After soaking the grain in 70% ethanol solution for 5 sec. and drying it by microwave oven (450W, 25min), we get the instant rice soup .which possesses good remoistening property and has no rigid core, with insipid and refreshing taste similar to the common rice soup. The test of quality of the product by TA proves that the above process is reasonable and feasible.The quality of the product can be markedly improved by being modified with addition of 0. 2% (on the basis of total weight) rice essence, 0. 05% mix of CMC and agar(2:l), and 5~10% potato starch.2. The difference of the methods for soaking, enzyme treating and drying affects directly the internal structure of the instant rice soup product, which has great effect on even water-adsorbing, remoistening rate and the occurance of retrogradation that influence such quality index as mouthfeel and quality of instant rice soup.The results from SEM observation can provide theoretical supports for pratical study.3. The occurance of retrogradation is due to the self - organizing phenomenon of starch molecules and resulting in crystal formation during storage of gelatinized starch, which causes the reduction of viscosity and transparency, droping of the molecular flexibitity, coagulating ofsolution and phase-seperating or increasing of the hardness of the precipated gel. Analysis of different rice material hy dynamic rheometer, DSC and TA indicates that: the northeast japonica rice is suitable for instant rice soup making; starch retrogradation is proportional to the time and slight retrogradation can still take place in the starch product prepared by common gelatinizing processing.The re-crystallization of amylopectin could be Inhibited effectively by enzyme trealment such as beta-amylase.更多还原