Studies On Anti-staling Of Frozen And Refrigerated Waxy Rice Flour Dough

Waxy rice flour is a kind of Chinese tradational food loved by consumers. A kind of waxy rice flour dough that was good tasting and had a long shelf-life was mainly studied in this paper. The main content is as follow: the basic formula and process of waxy rice flour dough, property of anti-staling of some additives, property of anti-staling storage temperature and the mechanism for waxy rice flour dough.The effects of process condition on propety of waxy rice flour dough were studied. The results showed that mordern method could produce better waxy rice flour doughs than tradational method. The basic formula of waxy rice flour dough was waxy rice flour: rice flour=3:2, sugar 20%, water 65%, and the tempeature for water was 25℃.With single factor experiment, select three additives with better effect to quality of waxy rice flour dough. The three important factors were analyzed by the experiment of response surface analysis. By ridge analysis, the optimal formula was determined: xanthan gum 0.182%,β-cyclodextrin 0.081%, CSL 0.286%.And added additionalβ-amylase 0.025%.Under the four different storage temperatures -18℃, 4℃, 25℃and 37℃, we studied the saling properties of waxy rice flour dough for 5 days of storage. By evaluating the water content, water activity, texture and thermal propeties during storage, -18℃was a better storage temperature for retarding staling of waxy rice flour dough. And then we did a long-term storage experiment under this better temperature, with additional staling parameters: degrees of gelatinazation and integrity, we found that waxy rice flour dough stored at -18℃had a low staling rate. No matter the short-term storage experiment or the long-term storage experiment, addition of additives both could retard the staling of waxy rice flour dough.By analysing the results of measurement of Tg of waxy rice flour dough, we found that additives increased Tg of it, decreased the energy needed for frozen storage. Dextrins were extracted in water from waxy rice flour dough supplemented with exogenous amylases.The dextrins were separated by HPLC. Addingα-amylase orβ-amylase to the dough, produced loaves with different dextrin profiles. Measured staling rates related to the presence of dextrins in a specific size class. Dextrins of a particular size(DP=4) are presumably mainly responsible for the antifirming effect.In order to understand the physico-chemical properties of the staling process of waxy rice flour dough during storage, in particular the role of water in this process, it is necessary to investigate changes in the states of water over a wider spectrum. The two-component model was found to well represent the states of water in the waxy rice flour dough crumb samples using NMR. The results showed that additives could increase the capability of holding water of waxy rice flour dough, reduce water mobility of waxy rice flour dough. T21 increased during the whole frozen storage as the initial structure of waxy rice flour dough was damaged. For T1s, as the microscopic migration of moisture, T11 increased during storage. There was not law of change for T12 and T22.