Effect of cold atmospheric surface micro-discharge plasma on the microbial safety and physicochemical property of Chinese yam flour

Abstract

Abstract Cold atmospheric plasma (CAP) as an emerging non-thermal technology holds great potential in food sterilization and biopolymer modification. This study investigated the antifungal effects of CAP against spoilage fungi in Chinese yam flour and its effects on the physicochemical and nutritional properties of Chinese yam flour. The results show that CAP treatment for 5–20 min achieved a microbial reduction of Fusarium moniliforme ranging from 0.56 to 2.40 log10 CFU/g at day 0 and 1.50 to 3.73 log10 CFU/g at day 9. The inactivation efficiency was increased with the CAP treatment time and storage time. For the physicochemical properties, CAP caused surface corrosion and formed aggregations on the surface of flour granules, as well as enhanced the absorption of carboxyl or carbonyl peak at 1730 cm− 1. The swelling power, starch solubility, and pasting viscosity of Chinese yam flour was increased after CAP treatment, while the endothermic enthalpy was decreased possibly due to the disruption of amorphous and crystalline structure of starch granules. A distinct color change was observed in CAP-treated Chinese yam flour, which became more bright and less yellow. The results of nutritional properties demonstrate that CAP caused a redistribution of dietary fiber components from insoluble to soluble fractions and changed the amino acids composition in Chinese yam flour. The SDS-PAGE analysis confirmed that CAP treatment could degrade or depolymerize the macromolecular proteins into small molecular subunits. Thus, CAP can be a promising technology to modify the physicochemical and nutritional properties of Chinese yam flour and ensure its microbial safety.