The effect of different pretreatment methods on jujube juice and lactic acid bacteria-fermented jujube juice

Abstract

To obtain optimal juice-making methods, three pretreatment methods were selected to evaluate their effects on the quality characteristics of jujube juices before and after lactic acid bacteria fermentation. As a result, significant differences between all detected indicators were observed in fermented and unfermented jujube juices following different pretreatment methods. Jujube juices pretreated with hot water soaking (HS) had better color and higher levels of total sugar, reducing sugar and free amino acids than those pretreated with boiling water steeping (BS) and steam steaming (SS). Remarkably, similar tendencies were also found in the corresponding fermented jujube juices. In contrast, higher levels of total acids were found in all-jujube juices pretreated with BS. After lactic acid bacteria fermentation, however, all of the fermented jujube juices pretreated by the HS method displayed the highest total acid levels. As the major volatile components, the total levels of acids in the HS treatment were also significantly higher than those in the other two pretreatments. Sensory evaluation revealed that the fermented jujube juices after BS treatments showed relatively high acceptability among the panelists. These findings demonstrated valuable direction in improving the product quality of fermented jujube juice.