Dynamic changes in quality of jujube wine during fermentation

Impact of ultra-high-pressure treatment on microbial community composition and flavor quality of jujube juice: Insights from high-throughput sequencing technology, intelligent bionic sensory system, and metabolomics approach

Ultra-high-pressure (UHP1) technology for cold pasteurization is a viable alternative to traditional heat sterilization for preserving food nutrients and flavor compounds during fruit juice processing. In this study, cutting-edge techniques, including high-throughput sequencing technology, intelligent bionic sensory systems, and metabolomics, were used to examine the impact of UHP treatment on microbial community composition, odor, and taste quality of jujube juice. The UHP treatment demonstrated its effect by inducing a reddish-yellow color in the jujube juice, thereby enhancing its brightness, overall color, and stability. The most significant enhancement was observed at 330 MPa. The microorganisms responsible for spoilage and deterioration of jujube juice during storage were categorized into three clusters: bacterial clusters at 0-330 MPa, 360-450 MPa, and 480-630 Mpa. The results showed no distinct distribution patterns for fungi based on the pressure strength. The dominant bacterial genera were Lactobacillus, Nocardia, Achromobacter, Enterobacter, Pseudomonas, Mesorhizobium, and Rhodococcus, whereas the dominant fungal genera were yeast and mold. Notably, Lactobacillus, Achromobacter, Enterobacter, and Pseudomonas were responsible for the significant differences between the 360 MPa to 450 MPa and 480 MPa to 630 MPa clusters in terms of bacterial spoilage, whereas Torulaspora, Lodderomyces, Wickerhamomyces, and Fusarium were the primary fungal spoilage genera. UHP treatment exerted no significant impact on the taste of jujube juice but influenced its sourness. Treatment at 330 MPa had the most pronounced effect on the presence of aromatic compounds and other odorants, which were substantially increased. Further analysis revealed the prevalence of organic acids, such as malic acid, succinic acid, and tartaric acid, in jujube juice and demonstrated a consistent relationship between changes in organic acids and sourness. In addition, nine distinct odorants with VIP values greater than 1 were identified in the jujube juice. Among these, methyl acetate and methyl caproate exhibited substantial increases following the UHP treatment at 330 MPa.

Functional Nutrients and Jujube-Based Processed Products in Ziziphus jujuba

Jujube (Ziziphus jujuba Mill.) is the first tree species in China, with a long history and abundant yield. However, fresh jujubes have a short shelf-life and are not resistant to storage. Therefore, more and more processed jujube products are being studied. These processed products can extend the shelf-life of jujubes and attract widespread attention for their rich functional nutrients. This review summarized changes in nutrients of fresh jujube and processed products and the research progress of different preparation methods of jujubes. Meanwhile, the pharmacological effects of bioactive components in jujube-based products were concluded. Jujube and its processed products contain rich polysaccharides, vitamin C, and other functional nutrients, which are beneficial to humans. As the initial processing method for jujubes, vacuum freezing or microwave drying have become the most commonly used and efficient drying methods. Additionally, processed jujube products cannot be separated from the maximum retention of nutrients and innovation of flavor. Fermentation is the main deep-processing method with broad development potential. In the future, chemical components and toxicological evaluation need to be combined with research to bring consumers higher quality functional jujube products and ensure the sustainable development of the jujube industry.

Optimization of fermentation conditions and quality evaluation of Chaenomeles sinensis glutinous rice wine

The present study was conducted to optimize fermentation conditions for preparation of Chaenomeles sinensis Glutinous Rice Wine (CRW). The dynamic changes of main substances in the liquor during fermentation process, aroma components, biologically active substances and antioxidant capacity in the CRW after 6 months of aging were tested. The results showed that under optimized conditions, the yield and alcohol content of wine was 44.97 and 20.00%, respectively. After aging, 64 aroma components were detected in the wine, mainly alcohols and esters. The alcohol content of the CRW was 14.8%. Polyphenols and flavonoids reached 0.23 g/L and 0.037 g/L respectively. Furthermore, the CRW had an excellent free radical scavenging ability.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-024-05934-0.

Effects of Different Winemaking Yeasts on the Composition of Aroma-Active Compounds and Flavor of the Fermented Jujube Wine

For the winemaking bioprocess of jujube wine, the selection of optimal starter cultures is one of the major concerns before fermentation. In this study, we investigated the effects of different winemaking yeasts on the composition of aroma-active compounds in the fermented jujube wine and identified the principal components that determine the flavor quality. It showed that the starter winemaking yeasts produced a total of 43 aroma-active compounds, of which esters (e.g., ethyl caprylate, ethyl decanoate, ethyl hexanoate, and phenethyl acetate) contribute more to the wine quality attributes, especially for the improvement of the aroma. Moreover, the composition of aroma-active compounds, for example, the ratio of the content of esters and alcohols, exerts a great impact on the flavor quality of jujube wine. Different starter winemaking yeasts resulted in significant differences in the composition (both species and content) of aroma-active compounds, and thus formed different flavors in the jujube wine. Thus, we propose that screening of a desirable starter winemaking yeast is essential before the fermentation of jujube wine at a large scale, and more considerations should be taken into the resulting composition of aroma-active compounds.

Bacterial diversity and flavor profile of Zha-Chili, a traditional fermented food in China

Zha-chili is a traditional Chinese fermented food with special flavor, which is often used as an appetizer in condiments and an important energy source. The final quality of zha-chili is closely related to its microbial community structure. However, the differences of bacterial diversity in zha-chili from different regions and how bacterial species affect zha-chili fermentation process and flavor quality have not been reported. In this study, the bacterial diversity and flavor quality of zha-chili samples from different regions were analyzed using Illumina Miseq high-throughput sequencing, electronic nose and electronic tongue technology. Twenty-three bacterial phyla and 665 bacterial genera were identified in all zha-chili samples. Firmicutes, Proteobacteria and Actinobacteria were the dominant bacterial phyla in zha-chili samples, while Lactobacillus, Pseudomonas, Pediococcus, Weissella and Staphylococcus were the dominant bacterial genera. The bacterial community structure of zha-chili samples from different regions was significantly diverse (p < 0.05). The flavor of zha-chili samples also varied in different regions, and the discrepancy of taste was much greater than that of aroma. Moreover, there were significant correlations (p < 0.05) between 6 dominant bacterial genera and 8 flavor indicators (3 aroma indicators, 5 taste indicators). In addition, the results of microbiome phenotypes prediction by BugBase and bacterial functional potential prediction using PICRUSt showed that eight out of nine predicted phenotypic functions of zha-chili samples from different regions were significantly different (p < 0.05), bacterial metabolism was vigorous in the zha-chili samples, and Lactobacillus was the dominant bacterial genus involved in metabolism during fermentation.

Pretreatment methods affecting the color, flavor, bioactive compounds, and antioxidant activity of jujube wine

In the case of wine production, the selection of optimal pretreatment methods and starter cultures are the 2 key points before fermentation. In this research, the fresh jujube was separately underwent alcoholic fermentation at 20°C with 3 different pretreatment methods (with peel, without peel, and juice) and 5 different starter cultures, respectively. Color analysis, electronic sense analysis, bioactive compound analysis, and antioxidant activity analysis combined with multivariate statistical analysis were applied to evaluated the effects of pretreatment methods and starter cultures on the overall quality of jujube wine. It was found that both pretreatment methods and starter cultures have effects on the quality of jujube wines, in which pretreatment methods have much more significant effects. The jujube wines fermented with different pretreatment methods were classified clearly by their overall quality, and that of the jujube wines fermented with peel was the best among all, since it can not only enhance the color and flavor quality of the wine, but also maximize the preservation of bioactive compounds and antioxidant activity of jujube for better consumer acceptance. This will provide a theoretical reference and application basis for the quality improvement of jujube wine.