Physicochemical and sensory properties of purple sweet potato brownies prepared with autoclave–cooling cycle modified flour

Abstract

This study aimed to determine the effect of the type and concentration of modified flour produced through the autoclave–cooling cycle (ACC) process on the physicochemical and sensory properties of purple sweet potato brownies as an alternative to wheat-based products. The research was conducted in two stages, including raw material preparation and analysis, followed by brownie formulation using three types of ACC-modified tuber flours (cassava, purple sweet potato, and suweg) at concentrations of 2%, 4%, and 6% in a randomized block design with a 3 × 3 factorial arrangement. Physicochemical properties, starch content, texture characteristics, FTIR spectra, and sensory attributes were analyzed to evaluate product quality. The results indicated that three autoclave–cooling cycles did not alter the fingerprint region conformation of the starch structure compared with native sweet potato flour. The type and concentration of modified flour showed no significant effect on color, aroma, moisture content, hardness, adhesiveness, and cohesiveness of the brownies (p > 0.05), while significant differences were observed in taste and starch content (p < 0.05). The best formulation was obtained from brownies containing 6% ACC-modified sweet potato flour, achieving the highest overall score (39.37). The selected product contained 16.21% moisture, 1.28% ash, 3.53% protein, 29.42% fat, 49.56% carbohydrate, and 9.06% dietary fiber, meeting general brownie quality standards. These findings demonstrate the potential application of ACC-modified tuber flours as functional ingredients in bakery products, supporting wheat flour substitution and promoting the utilization of local carbohydrate sources for the development of high-fiber and potentially lower-calorie food products.