Study On The Modified Starch And Its Application In Quick-frozen Dumplings

As the developing of people’s living standards, people’s diet concept and dietary habits are changing gradually, the purchase criteria for the food are improving as well, and people’s demands on food not only include eating full, but also convenience and nutrition, etc. With the rhythm of life speeding up, food only made by traditional rice food technology already can’t satisfy modern people. While convenient quick-frozen food that keep the original nutrition and quality characteristics at best have got the favor of more and more people, which contributed to the rapid development of the frozen food industry. At present, in the domestic market, common quick-frozen rice food includes rice dumpling, dumpling, rice pudding, wonton, etc. Among them, rice dumpling sales the widest.Rice dumpling is the most favorite traditional food of many people, as it’s meaning is reunion. No matter in festivals or entertaining guests, rice dumpling is essential. Especially in the Lantern Festival, every household would boil rice dumplings to celebrate. Because rice dumpling is made of glutinous rice flour and hand-made is very troublesome, quick-frozen rice dumpling emerged. In the sales market, quick-frozen rice dumplings are raw dumplings, which need to be cooked before eating and takes a lot of trouble. What’s more, there are problems such as rice dumpling cracking, muddy soup and cooked adhesion when boiling. In this subject I mainly utilized modified starch additives to improve the quality of quick-frozen rice dumpling; at the same time, cooked and quick-freezed the rice dumpling, which can relieve the cracking of rice dumpling and it’s quality losses. Finally, microwave heating or boiling water was used to cook before eating, which is time-saving and convenient.At first, this paper discussed processing technology of boiled quick-frozen rice dumpling, and designed single factor experiment to study influences on the quality of quick-frozen rice dumpling by different added water amount and the proportion of rice flour (glutinous rice flour and rice meal), with the extent of losing water after freeze, the extent of breach after freeze, the transparency after cooking again, physical property, color, volatile flavor, sensory evaluation, etc. The results of single factor experiment showed the added water was75%, and the proportion of rice flour was the range of85%-90%.At the same time, the nature (the viscosity, the freeze-thaw stability, the sinking of the condensate and the transparency) of the five different modified starch and the effects of modified starch by adding different modifiers on the quality of rice dumpling was also studied. In addition, modified starch addition and methods to add the modified starch on improving dumpling quality was researched, results showed that the properties of cassava prepaste starch is better than other several kinds of modified starch, and cassava prepastc starch addition was2%, method to add the modified starch was adding modified starch after starch paste in room temperature. Finally, the processing procedure was optimized, and the results of orthogonal experiment showed the optimized process parameters were as follows, the proportion of rice was85%; cassava prepaste starch addition was:1.5%and method to add the modified starch:adding modified starch after starch paste in room temperature.Under optimized process conditions, cooked rice dumplings, and used natural cooling, air cooling, vacuum cooling (0.01Mpa) and composite cooling (natural cooling5min, and then vacuum cooling to room temperature) to cool the cooked dumplings to room temperature (25℃), determined the extent of losing water after freeze, the extent of breach after freeze, the transparency after cooking again, physical property, coulour, volatile flavor, microorganism during storage period finally carries on the sensory evaluation, the results found that:although vacuum cooling used time more shortly and extend the shelf life of products, the biggest quality was declined after cooling; natural cooling and air cooling’ time longer, the product shelf life is short after cooling, but lost water less, the index influence of rice dumpling was low; Composite cooling can set the advantages of both, small impact on the quality of cooked frozen rice dumplings and can prolong the shelf life.Finally, put the boiled quick-frozen rice dumpling under composite cooling under the storage condition at-10℃,-5℃and0℃, and detected rice dumplings’quality and structure, color and luster every two days, in addition, sensory evaluation,and observe the changes in product quality. Based on total number of colonies instruction factor, constructs the dynamic model, got cooked rice dumplings colony total change rate during storage and storage temperature T (K) between the Arrhenius equation is k=138.49×exp(-17164/RT)), and shelf life of boiled quick-frozen dumpling products was130.6,104.5,93.4, and52.7days at-10℃,-5℃,0℃and20℃respectively. Compaired with the actual shelf life, small errors had certain guiding significance for production.