| Summary: | 碩士 === 國立中興大學 === 食品科學系 === 91 === Red bean jelly is one of the traditional legumous snack foods in China, which is popular with consumers. Soaking, cooking, grinding, filtering, rinsing and centrifuging are processes for producing adzuki bean paste, then followed by adding cooking and concentrating with agar and sugar to form adzuki bean jelly. In this study, effects of soaking and cooking processes on adzuki bean were investigated. A three - variable and three-level design method analyzed by response surface methodology was used to determine optimum operating conditions for preparation of adzuki bean paste and adzuki bean jelly. Based on analyses of microstructure and gel properties. The factors that affected the processes and quality of adzuki bean jelly were determined. On the other hand, the adzuki bean powder was also used to evaluate the feasibility of production of adzuki bean jelly. The results were as follows.
Water absorption, volume swelling and percentage of solid loss of adzuki bean steadily increased with the increase of soaking temperature（r2＞0.87）. The high correlation value（r2＞0.92）observed confirmed that the water absorption rate of adzuki bean during soaking is temperature dependent. The soaking temperature and soaking time could be varied and were related. Their relationship can be expressed by the equation: t = 79583 T -1.426 when moisture content was 80 %（Equilibrium moisture content at 70℃）. On the microstructure of cotyledons, pectic substances of the middle lamella were loss during cooking. Protein denatured and compassed starch granules, then adzuki bean paste granules are produced after grinding and separating. When soaking accompanied with cooking, paste production could increased, rupture of cell wall decreased and improve qualities of adzuki bean paste in the end.
In this study, the response surface methodology (RSM) was determined to obtain the optimum process conditions of adzuki bean paste and jelly. By the way of our results, soaking 5 ~ 6 hrs and cooking at temperature 110.5℃ combined with cooking for 45 min would yield an optimum process with best adzuki bean paste products. And the optimum process conditions of adzuki bean jelly was agar concentration 1.2~1.5 %, sugar content 34 ~ 40 % and concentrating time 30 ~ 45 min.
Gel properties and viscoelasticity of adzuki bean jelly are decided by paste, agar and sugar. Intact adzuki bean paste spread on continuous phase which is formed by agar and sugar, and reach the physical strength of cooking and concentrating. Components of adzuki bean jelly could be well mixed and have good quality.
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