Evaluation of the Effect of Disinfection Pretreatment and Packaging Method on Chemical and Microbial Properties of Onion Puree During Storage

Consumers are seeking healthy, natural and fresh food matterials requiring minimal energy and time to be prepared. Onions and their products, rank first among edible alliums due to their medicinal properties. The aim of this study was to investigate the effects of disinfection, packaging and storage period on physicochemical properties of onion puree. For this purpose, onion puree were disinfected with different solutions including: (chlorine + citric acid + ascorbic acid), (nisin + citric acid), (acetic acid + menthol), (sodium sulfate + ascorbic acid + citric acid + calcium chloride), (calcium chloride + calcium Ascorbic + citric acid + water (80 ° C) and (control, without pretreatment). The products were then packaged in low density polyethylene in two ways under normal vacuum and conventional atmospheric packaging and stored for 21 days. The total amount of soluble solids (Brix), weight loss of total phenolic compounds, antioxidant activity (%) and microbial test (total microbial count and mold and yeast) were measured on the samples once a week. Statistical analysis of data by factorial experiment in a completely randomized design showed that in all treatments, chemical properties decreased during storage and the total number of live microbes and the total number of mold and yeast increased. The results showed that in onion puree sample, pretreated with calcium chloride (0.5 g / 100 ml) + ascorbic acid (1 g per 100 ml) + citric acid (1 g per 100 ml) at 80 °C, chemical, phenolic compounds, antioxidant properties were preserved and had the lowest rate of microbial growth. Quantitative, qualitative and microbial properties in vacuum packaging were more appropriate than in conventional atmospheric packaging.