An investigation into the formation of fumaric acid in apple juice concentrates.

摘要

In this study, apples inoculated with pure cultures of Rhizopus stolonifer, Penicillium expansum and Lactobacillus plantarum were utilized as the raw material to produce apple juice concentrate. Effects of microorganisms and various processing treatments on fumaric acid, lactic acid and patulin contents of apple juice were investigated. R. stolonifer was found to be the agent responsible for production of fumaric acid and lactic acid. L. plantarum also produced some lactic acid, but not as muchas R. stolonifer. L. plantarum caused a significant decrease in L-malic acid content, indicating the occurrence of malolactic fermentation; a small amount of fumaric acid was also formed. P. expansum produced only patulin, and did not affect the fumaric acid and lactic acid contents. Fumaric acid contents of the samples decreased throughout all processing steps, except for evaporation. Fumaric acid contents of the samples increased just after evaporation depending on the heat applied. Patulin and lactic acid contents of the samples also decreased throughout processing. However, L. plantarum caused a significant increase in lactic acid content just after depectinization, depending on whether the appropriate time-temp. conditions for incubation wereavailable during depectinization.