Effect of Cold Plasma Treatment on the Inhibition of Pellicle-Spoilage and the Storage Quality of Low-Salt Paocai, a Traditional Chinese Fermented Vegetable Food

The spoilage and quality deterioration of packaged low-salt paocai products caused by microorganisms has become a technical bottleneck restricting the development of the paocai industry. In order to overcome this problem, this experiment explore the effect of dielectric barrier discharge (DBD) cold plasma treatment on the inhibition of pellicle spoilage and the storage quality of instant low-salt paocai. With this in mind, the microbial population, physicochemical properties, color difference, texture and volatile compounds of paocai samples were investigated. Results showed that DBD cold plasma treatment reduced the total viable count and yeast count by 1.54–3.55 and 2.12–4.21 (lg (CFU/g)), respectively, and completely killed coliform bacteria while allowing the retention of lactic acid bacteria. Moreover, it inhibited the growth of pellicle-forming yeast obviously, thereby effectively controlling the pellicle spoilage of paocai during storage. In terms of physical and chemical properties, DBD cold plasma could inhibit the increase of pH and increase significantly the brittleness, brightness, yellowness and total acid content compared with pasteurized paocai (P < 0.05). Although higher than that in pasteurized paocai, the nitrite content in DBD cold plasma treated paocai was still far lower than the national standard limit, and gradually decreased to 3.13 mg/L as fermentation proceeded. Additionally, the major volatile compounds of paocai changed little within a short time after DBD cold plasma treatment, and DBD cold plasma treatment could inhibit the odor caused by the increase in the content of dimethyl sulfides during storage. Therefore, DBD treatment could effectively control the pellicle spoilage of low-salt paocai during storage while ensuring its quality characteristics.