EFFECTS OF MODIFIED STARCH AND MOISTURE CONTENT ON THE QUALITY OF PURPLE SWEET POTATO MOCHI (Ipomoea batatas L.)

Abstract

Mochi is a traditional Japanese confectionery, favored for its characteristic soft and chewy texture derived from glutinous rice flour. In the context of developing nutritionally enhanced mochi products, purple sweet potato has emerged as a promising ingredient due to its high content of anthocyanins, dietary fiber and natural antioxidants. To identify the optimal processing conditions, the adjustment of ingredient proportionsparticularly the level of modified starch (MS) and mixing moisture content - plays a critical role in influencing the structure, elasticity and sensory attributes of mochi. This study aimed to determine the appropriate ratio of MS and moisture content that would yield the best sensory, color, flavor and textural qualities in purple sweet potato mochi. Experiments were conducted using MS concentrations of 25%, 30%, 35%, 40%, combined with mixing moisture levels of 45%, 50%, 55%, 60%. Results showed that the combination of 35% MS and 55% moisture yielded the most desirable product quality. This was reflected in color values of L* (20.27) and a* (20.63), elasticity (9.54 N/m²), anthocyanin content (178.60 mg/g), vitamin C content (611.6 µg/g), total phenolic content (823.36 µg/g) and antioxidant capacity as measured by DPPH radical scavenging activity (88.34%). Sensory scores were consistently high, ranging from 4.30 to 4.44, with an overall preference rating of 8.22. These findings indicate that mochi produced under these conditions possessed superior quality compared to other tested formulations.