Evaluating quality indexes of frozen vegetables prepared with different cooking oils during 12 months of frozen storage

This study aimed to evaluate the influence of frozen storage time on the nutritional quality of boxed vegetables prepared with different cooking oils prior to freezing. Two types of vegetables, broccoli and Chinese cabbage, prepared with palm oil (PO) and soybean oil (SBO), were analyzed during their 12-month freezing storage (− 20 °C). The results showed that the nutritional quality of the frozen vegetable products was seriously affected during the storage period. During the storage period, some of the nutritional quality indexes, such as the vitamin C and total phenolic (TP) content, strongly deteriorated by 27–56% and 8.1–8.6%, respectively, whereas the nitrite content was increased by 10–14%. Additionally, a slight change was observed in the nitrate content. Concurrently, the oxidative degradation of the extracted cooking oils was also evaluated, and PO showed better oxidative stability than SBO. The peroxide value (PV), acid value (AV), malondialdehyde (MDA), and anisidine value (AnV) in PO increased less than those in SBO after 12 months at − 20 °C, and the PV, AV, MDA and AnV in PO were lower than those in SBO after frozen storage. On the basis of the findings from this study, PO was recommended as the best oil for the preparation of boxed frozen vegetables to reduce adverse effects during long-term storage.