A Study on Roasting Conditions of Wheat Flour Materials for Ready-Mixed Powders of Western Cuisine Sauces

• Main Authors: Teng-Jen Cheng, 鄭登仁
• Other Authors: Chi-Yue Chang
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/84356314620406309949

碩士 === 大葉大學 === 生物產業科技學系碩士在職專班 === 99 === The theme of this research focuses on roasting conditions of wheat flour materials for ready-mixed powder of western cuisine sauce. The research is divided into two parts. The first part discusses the quality change during the roasting process of flour, and the impact of flour with different roasting time on the appearance of the ready-mixed powder for western cuisine sauces. The second part is to discuss how the different cooling method affects the quality of the wheat flours with different roasting time. By the results of these two parts, it is expected to seek the optimal processing conditions of roasted wheat flour in ready-mixed powder for western cuisine sauce. In the first part, in the curves of moisture content and water activity, it is found the water activities for the turning points of these two curves are 0.32 and 0.40 respectively, which is in the range for the lowest fat oxidation rate. In color change, Hunter L and a values are negatively correlated with the roasting time, while b value is positively correlated. In the pasting characteristics determination, the RVA profiles have no significant variation during the first 30 minutes of roasting. While roasting for 40 and 50 minutes, except the pasting temperature and peak time exhibited a decreasing trend, other viscosity parameters increased. In addition, by analyzing the falling number, it significantly increased when roasted longer for 40 minutes. In the sensory evaluation, the odor change on the roasted wheat flour, flour odor disappeared after roasting for 30 minutes, roasted odor was formed after roasting for 40 minutes. In the sensory evaluation for the finished product, it was found that it was positive for the roasting time with the soup flavor, taste and overall preference. In the second part, using the wheat flour with different roasting time (20, 30, 40 and 50min) and different cooling batch weight (5 and 20 kg/batch), ambient temperature (21 and 31℃) to explore four cooling mode. It is found in cooling rate determination that the batch weight has a more profound effect on cooling rate than the ambient temperature does. In the sample of the flour after 50 min roasting with different cooling methods, the change of the unsaturated fatty acids and lipid content is decreased significantly. At detection on the odor change, in the process of after cooling and storage, the evaluation results show that after 50 min of roasting, all samples have rancid or reversion odor after cooling and storage for 60 days; while bad odor formed in the two samples of no roasting and roasting for 20 min and storage for 60 days. But all samples of roasted flour have little change in the odor after storage for 20 days. By above results, the optimum roasting time is 40min, the quality of the wheat flour thus obtained is more stable and there’s no risk of the formation of rancid odor. In the cooling method, 5 kg/batch and cooling in the room temperature are more economic processing conditions. The expiration date for the semi-finished wheat flour should be less than 20 days. In addition, it is suggested to store in good airtight or packaging to prevent lipid oxidation in wheat flour.