팥의 저항전분 생성을 위한 수분-열처리 최적화 및 특성 규명

Abstract

Resistant starch (RS) is a nondigestible carbohydrate that reaches the large intestine without being broken down in the small intestine. It helps lower the glycemic index and reduce the risk of metabolic diseases. RS3, one type of RS, is formed through retrogradation of gelatinized starch. RS3, produced through physical processing, has high stability and potential for industrial applications. Adzuki bean (Vigna angularis) is a starch-rich legume containing high levels of protein, dietary fiber, and vitamin B1. In this study, heat-moisture treatment (HMT) was applied to optimize producing maximum RS content of adzuki bean flour. A Box-Behnken design of response surface methodology (RSM) was used, with heating temperature (110∼130℃), heating time (60∼90 min), and moisture content (15∼25%) as independent variables, and RS content as the dependent variable. RS content ranged from 10.32%w/w to 12.47%w/w depending on treatment conditions. The regression model was statistically significant (R² = 0.939, Adj-R² = 0.828, p < 0.015). The model showed that the optimal HMT condition for producing RS was 121.31℃ for 70.30 min at 22.37% moisture content, with a predicted RS content of 12.26%w/w. This was experimentally validated, yielding an RS content of 12.25 ± 0.17%w/w. Thus, the RS content increased by 3.46%w/w from the original 8.79%w/w in adzuki bean. These results demonstrate that HMT can effectively increase RS content and be optimized through RSM. After HMT, the water-binding capacity of the sample increased compared to the original material, while the amylose content, swelling power, and solubility significantly decreased. X-ray diffraction (XRD) analysis confirmed that the C-type crystalline structure was maintained and crystallinity was enhanced. Scanning electron microscopy (SEM) revealed that the particle surface became denser, with minute cracks observed. Differential scanning calorimetry (DSC) analysis also demonstrated an increase in gelatinization temperature and a decrease in enthalpy. In conclusion, this experiment demonstrated that the starch structure of adzuki beans can be effectively reorganized through HMT alone, enhancing resistant starch content. These findings suggest the potential for increasing the value of domestic adzuki beans and utilizing them as functional food ingredients.