Effects of roasting on purple corn flour quality and addition of anthocyanins and their compounds with cyclodextrin on purple corn flour solid drink quality

Purple corn flour (PCF) has broad applications in the food industry. However, unsuitable cooking conditions and anthocyanin contents lead to unfavorable aroma, color, taste, and functionality of PCF and in the corresponding PCF solid drinks. To address such quality issues, the authors examined the effects of roasting on PCF quality and adding purple corncob anthocyanins (PCCA) on PCF solid drink quality, with a focus on how roasting influences anthocyanin content and aroma, and how microencapsulation influences astringency and efficacy. PCF roasted at 175 °C for 4 min had the most intense and well-balanced aroma, a high anthocyanin retention rate, and a high sensory score. After roasting, 49 metabolites were identified, including 13 upregulated and 36 downregulated compounds. Roasting reduced the levels of ethers, organic acids, olefins, alkanes, esters, and aldehydes, while increasing aromatic hydrocarbons, heterocyclic compounds, and ketones, contributing to roasted, cheesy, sweet, and coffee-like aromas. Microcapsules prepared by embedding PCCA in β-CD as the wall material (wall-core ratio: 2:1) effectively eliminated the astringency and reduced the sour taste of the solid beverage. Compared with that of unencapsulated PCCA at 2%, no significant difference was noted in efficacy when the microcapsule content was 10%. The microcapsules formed by β-CD and PCCA exhibited an irregular blocky structure owing to hydrogen bonding. The findings offer valuable insights into PCCA utilization in the food processing industry and development of PCF-based products. • PCF at 175°C for 4min had the highest color acceptance, more intense and harmonious aroma, and no cornstarch or burnt taste. • Compared with raw PCF, 49 different substances were screened in the roasting group, including 13 up-regulated and 36 down-regulated substances. • 2% PCCA improved the color and flavor of PCF solid beverages, increased packing density, improve digestive characteristics, and reduced glycemic index. • Microcapsules of PCCA embedded with β-CD were added to PCF solid drinks, which could effectively eliminate the astringency of solid drinks, reduced the sour taste and improved the overall flavor.