Effect of three pretreatment methods on the quality of canned Chinese yam

Abstract

In this paper, the effects of three methods for material pretreatment on the quality of canned Chinese yam were analyzed and compared, which included blanching treatment, vacuum osmotic treatment and atmospheric osmotic treatment with fructose syrup as osmotic solution. The results showed that the blanching treatment group was able to inactive polyphenol oxidase and peroxidase, and thus had better color protection, but the structure of Chinese yam in blanching treatment group was seriously damaged and led to an increased conductivity, and its hardness decreased by 34.80%, while the structures of yam in atmospheric osmosis and vacuum osmosis treatment groups were denser due to the osmosis of sugar solution, the sample would not be significantly browned during the processing time before canning, and the damage to the cell membrane was much lower than vacuum osmotic dehydration. The hardness of Chinese yam in atmospheric osmosis at 5 h and in vacuum osmosis at 3 h, 4 h and 5 h were both higher than that of fresh Chinese yam, but ascorbic acid content decreased significantly. Moreover, the structure of Chinese yam in vacuum osmotic treatment group was more complete, and the sensory score of canned yam was higher than those of atmospheric osmotic treatment group with the same osmotic time and blanching treatment group. Vacuum osmotic dehydration is an effective way to solve the problem of canned soup turbidity and improve the quality of canned Chinese yam.

Keywords

• blanching treatment
• atmospheric osmotictreatment
• vacuum osmotic dehydration
• canned chinese yam
• organizational structure
• polyphenol oxidase
• peroxidase
• hardness