Effect of Cold Atmospheric Surface Microdischarge Plasma on the Inactivation of Fusarium moniliforme and Physicochemical Properties of Chinese Yam Flour

Cold atmospheric plasma (CAP) as an emerging nonthermal technology holds great potential in food sterilization and biopolymer modification. The antibacterial effect of CAP on spoilage fungi and its effects on physicochemical and nutritional properties in yam flour were both studied. The results show that CAP treatment for 5-20 min achieved a microbial reduction of Fusarium moniliforme ranging from 0.56 to 2.40 log(10) CFU/g at day 0 and 1.50 to 3.73 log(10) 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 were increased after CAP treatment, while the endothermic enthalpy was decreased possibly due to the disruption of the 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 acid 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.