To address the limitations of current methods for detecting physicochemical indicators of wine grapes, such as sample destruction, time-consuming, energy-consuming, and not suitable for large-scale detection, this study used three varieties (‘Dunkelfelder’, ‘Marselan’, and ‘Petit Verdot’) with different ripening times to establish prediction models for the soluble solids content (SSC) and titratable acid (TA) content of wine grapes using hyperspectral imaging (HSI) combined with chemometric methods. Back propagation neural network (BPNN) and random forest (RF) were found to be the best models for predicting the SSC and TA content, respectively. The coefficients of determination for prediction (R_P²) of the BPNN and RF models were 0.9559 and 0.9253, with root mean square error of prediction (RMSEP) of 0.9965 °Brix and 2.0451 g/L, and residual predictive deviation (RPD) of 4.3602 and 3.0081, respectively. These results demonstrate that the combination of HSI and chemometric methods enables rapid and non-destructive detection of the SSC and TA content of wine grapes, thereby providing a solution for the rapid and non-destructive detection of physicochemical indexe of wine grapes.

Malolactic fermentation, started by lactic acid bacteria, plays a crucial role in the production of high-quality wines. As global warming increases the ethanol content in wines, the success of malolactic fermentation depends on selecting ethanol-tolerant strains, especially for wines from increasingly warm climates. Lentilactobacillus hilgardii Q19 was isolated and characterized as an indigenous malolactic bacterium with higher ethanol tolerance properties. In this study, it was indicated that ethanol stress had significant effects on ATPase activity, antioxidant system, and cell membrane of L. hilgardii Q19 by measuring the physiological indicators under stress which include H⁺-ATPase, Na⁺/K⁺-ATPase, Ca²⁺/Mg²⁺-ATPase activity, glutathione content, superoxide dismutase (SOD) activity and intracellular reactive oxygen species (ROS) content. The main metabolic pathways involved in ethanol stress such as ATP-binding cassette (ABC) transporters, pentose phosphate pathway, phosphotransferase system, glutathione metabolic pathway and two-component systems were screened by transcriptome sequencing analysis. The functions of the pentose phosphate pathway, pyruvate metabolic pathway and glycerolipid metabolism under ethanol stress were verified by constructing the L. hilgardii Q19 ethanol stress related key genes gntK, pyk, and glpK overexpression vectors. The above findings may contribute to our understanding of the metabolic pathways and regulatory mechanisms of L. hilgardii Q19 in response to ethanol stress.

The survival rate and storage period of lactic acid bacteria (LAB) are affected by numerous factors in the vacuum freeze-drying process. Hence, optimizing the freeze-drying process and storage conditions is an effective method to improve the survival rate and prolong the storage period of LAB. This paper reviews the factors that influence the survival rate of LAB during the vacuum freeze-drying process and explores how to optimize the freeze-drying process and storage conditions to improve the survival rate and extend the storage period of LAB. We expect that this review will provide a basis and reference for the preparation of lyophilized LAB formulations with high activity and good storage stability.

Grape production is an important part of the agricultural economy, which has economic and widespread social benefits. Monitoring and evaluation of grape berries during growth is an important guarantee for the production of high-quality grape berries. Traditional testing techniques are time-consuming, laborious and destructive, while non-destructive testing techniques represented by hyperspectral technology can successfully solve this problem. This paper summarizes recent progress in the application of hyperspectral technology in grape shape measurement, chemical substance detection, ripeness discrimination and defects and damage identification. It also analyzes the advantages and disadvantages of hyperspectral technology in the detection of different quality indexes, and discusses the potential of and prospects for the application of hyperspectral technology in the detection of grape quality, which is aimed at providing a reference to the research and developing non-destructive techniques for the quality detection of grape berry.

Lactic acid bacteria and the fermentation environment interact to form an intertwined system. Lactic acid bacteria are constantly evolving to adapt to different fermentation environments, causing changes in their physiological processes. To achieve a targeted improvement of their adaptability to various environments, a detail analysis of their evolutionary physiological processes is required. While several studies have been carried out in the past by using single-omics techniques to investigate their response to environmental stress, most researchers are now using a multi-omics approach to explore more detail in the biological regulatory networks and molecular mechanisms of lactic acid bacteria in response to environmental stress, thereby overcoming the limitations of single- omics analysis. In this review, we describe the various single-omics approaches that have been used to study environmental stress in lactic acid bacteria, present the advantages of various multi-omics combined analysis approaches, and discuss the potential and practicality of applying emerging single-cell transcriptomics and single-cell metabolomics techniques to the molecular mechanism study of microbes response to environmental stress. Multi-omics approaches enable the accurate identification of complex microbial physiological processes in different environments, allow people to comprehensively reveal the molecular mechanisms of microbes response to stress from different perspectives. Single-cell omics techniques, analyze the targeted regulation of microbial functions in a multi-dimensional space, provides a new perspective on understanding microbes responses environment stress.