Acta Scientiarum Polonorum Technologia Alimentaria

Background. Jujube (Ziziphus jujuba Mill.) is a widely cultivated crop in China. However, its perishable nature makes it challenging to store over long periods. To avoid spoilage of unsold dates, they are usually processed into beverages and concentrated juice, but there are no jujube drink products fermented with water kefir grains. Therefore, this study aims to explore a new method for deep processing of jujube and provide a reference for the full utilization of jujube.
Methods. The effects of fermentation time, fermentation temperature, and the inoculation amount of water kefir grains on the DPPH free radical scavenging rate (DPPH), sensory evaluation score (SES), pH, Titrable acidity (TA) and soluble solid content (SSC) in jujube water kefir were investigated in a single factor experiment employing response surface methodology.
Results. The optimal fermentation conditions predicted by the model were fermentation at 29℃ for 30 hours with an inoculum size of 1%. Under these conditions, the DPPH free radical scavenging rate was 81.06 ±0.29 %, the SES was 88.00 ±2.71, the pH was 3.93 ±0.04, the TA was 3.87 ±0.14 g/L, and the SSC was 11.00 ±0.10 %.
Conclusion. The model’s predicted values and actual values correlated well. Fermenting jujube juice with water kefir grains is a good method for the deep processing of jujube, which has acceptable sensory evaluation and high antioxidant activity.