Effects of different storage conditions on the quality of sweet potato leaf pickles

Abstract

Objective: This study aimed to explore the preservation conditions and quality changes of sweet potato leaf sauerkraut fermented by lactic acid bacteria. Methods: After vacuum packaging, the pH value, lactic acid content, nitrite content, colony number, color difference and sensory score of sweet potato leaves were compared under four different kinds of storage conditions, including 25 ℃ at room temperature, 4 ℃ at low temperature, 4 ℃ after pasteurization at 80 ℃-15 min, and 4 ℃ after pasteurization at 85 ℃-10 min. Results: When stored at 25 ℃, the luminance decreased the fastest, and the color became darker at 60 days. The number of yeasts was the most after 30 days at 4 ℃, and the number of lactic acid bacteria was the most after 45 days; After pasteurization for 90 days at 80 ℃-15 min, the number of Escherichia coli was the least, and the sensory score reached the edible threshold. After pasteurization for 75 days at 85 ℃-10 min, the total number of bacteria was the least and the sensory score was qualified; pH value was negatively correlated with nitrite, and positively correlated with L value and sensory score; Lactic acid bacteria were positively correlated with yeast; E. coli and total bacteria, and the sensory score was the largest in the first principal component. Conclusion: After pasteurization at 80 ℃-15 min and storage at 4 ℃, the main microorganisms were lactic acid bacteria, with other indicators met the safety standards, and the sensory quality was stable. This condition is more suitable for the storage of pickled cabbage with lasting for 90 days.

Keywords

• lactobacillus
• fermentation
• sweet potato leaves
• pickles
• preservation quality