Chinese traditional fermented vegetables are made from fresh vegetables through microbial metabolism and a series of chemical reactions. During the fermentation process, the microbial community structure is complex, and the dominant microorganisms at different stages play different roles, which has a great impact on the quality, flavor and safety of fermented vegetables. Based on this, this article reviews the effect of the microbial diversity on the quality, flavor, and safety of Chinese traditional fermented vegetables as well as the abiotic factors affecting the microbial diversity, aiming to provide a theoretical basis for improving the quality and safety of fermented vegetables.

During the freezing, storage, and thawing process, physicochemical changes occur in raw meat, which will inevitably lead to quality deterioration mainly including decreased water-holding capacity and the deterioration of color and texture. The quality deterioration can be effectively reduced by novel freezing and its assistive technologies. This article summarizes the quality deterioration mechanism of raw meat during freezing and frozen storage, and reviews the approaches for improving frozen meat quality, such as novel freezing techniques, cryoprotectants, novel packaging techniques and novel thawing techniques, which will provide a theoretical basis and technical guidance for improving the quality of frozen meat.

The effects of the co-inoculation of Debaryomyces hansenii separately with 3 lactic acid bacteria (LAB), Lactobacillus sakei, Lactobacillus plantarum and Lactobacillus curvatus, on the taste and odour profiles of dry sausages were investigated. The co-inoculated sausages showed higher free amino acid and organic acid contents than the non-inoculated control and sausages inoculated with D. hansenii alone. Meanwhile, the sausages inoculated with D. hansenii + L. plantarum, D. hansenii + L. sakei and D. hansenii + L. curvatus had the highest contents of aldehydes, esters and alcohols, respectively. The results of electronic tongue, electronic nose and sensory evaluation demonstrated that compared with the sausage inoculated with D. hansenii, the sour taste and floral odour increased and the fatty odour decreased in the sausage inoculated with D. hansenii + L. sakei; this was more favourable for the development of a desirable flavour in sausages. Moreover, the partial least squares regression analysis indicated that 10 taste and 33 odour compounds were mainly responsible for the differences in the flavour profiles among the sausages. Overall, these findings contributed to a more comprehensive understanding of the formation of sensory characteristics in dry sausages co-inoculated with yeast and LAB.

The influence of different wood species (in the form of wood chips) on the formation of heterocyclic aromatic amines (HAAs) in smoked Harbin red sausages was investigated. Four common species of wood (pear, oak, apple, beech) were used for smoking. The smoking process significantly affected the moisture content, water activity, pH, lipid oxidation (thiobarbituric acid-reactive substances), protein oxidation (carbonyl content) and HAA content. It was found that the wood species significantly influenced the contents of HAAs in the smoked samples. Total HAA contents were highest in samples smoked using wood chips produced from pear, followed by oak, beech and apple. The contents of Norharman and Harman were much higher than those of the other HAAs. Lipid oxidation and protein oxidation were significantly associated with the formation of total HAAs in samples. It is shown that the type of wood chips used for smoking is one of the critical parameters affecting the contamination of HAAs in smoked meat products.