In the present study, we evaluated the physicochemical and microbial properties, microbial diversity, and volatile organic compounds (VOCs) of Jinhua ham prepared using Taihu black pigs during a ripening period of 210 days. During the eight timepoints, the protein oxidation, proteolysis indexes, and TBARS values of Jinhua ham had different change trends. The growth of total bacteria and total Staphylococcus showed a decline, while the growth trend of total fungi was parabolic. Staphylococcus equorum was the dominant bacterial species, and the relative abundance were 19.3% (day 180)-76.7% (day 120). Debaryomyces hansenii and Eurotium sp. were the dominant fungus species, with opposite change trends. GC–IMS analysis detected 84 volatile compounds, with alcohols and aldehydes being the dominant volatile compounds in the late ripening period. The correlation analysis between microbial diversity and VOCs showed that Staphylococcus equorum was significantly negatively correlated with eight VOCs, while Debaryomyces hansenii and Eurotium sp. were significantly correlated with 31 and 29 VOCs respectively. Our findings reveal the quality, microbial diversity at species level, volatile compound characteristics, and relationship between microbial communities and flavor formation of Jinhua ham prepared using Taihu black pigs.
Spoilage of ready-to-eat carbonado chicken during storage usually causes safety concerns and economic losses. A novel edible nanoemulsion coating with natural antimicrobial and antioxidant was applied to improve carbonado chicken shelf life. The nanoemulsion based on gelatin and chitosan incorporated a mixture of rosemary extract and ε-poly- l -lysine (ε-PL) and was fabricated by high pressure homogenization. Emulsion droplet size and ζ-potential were examined by a zetasizer, and the mean droplet sizes were 257 nm and 1122.44 nm for the nanoemulsion and a coarse emulsion, respectively. A higher ζ-potential was obtained for the nanoemulsion (+32.50 mV) than for the coarse emulsion (+26.25 mV). The rheological properties of the coating solutions showed shear-thinning behavior. Microstructure analysis of the coating showed that the nanoemulsion possessed smoother and more homogeneous surfaces without pores and with better structural integrity than those of the coarse emulsion. Ready-to-eat carbonado chicken coated with the gelatin-chitosan solution, coarse emulsion, or nanoemulsion and uncoated samples were prepared for a preservation study. Samples coated by the nanoemulsion displayed the lowest total viable bacterial counts (TVC), mold and yeast counts, TBARS values, and pH changes under 4 °C refrigeration over 16 days. The nanoemulsion-coated carbonado chicken shelf life was prolonged by at least 6 days compared to that of the control. The nanoemulsion-based edible coating , as a novel antimicrobial and antioxidant material, effectively sustained active compound release to the meat surface and is a promising technology to improve the safety and quality of ready-to-eat meat products.
Ji Wang,Xu-Hui Huang,Yu-Ying Zhang,Chengzhen Nie,Dayong Zhou,Lei Qin
Salt has a great influence on food flavor formation. In this study, electronic tongue and nose, gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, and lipid oxidation levels were used to investigate the influence of different NaCl concentrations on the flavor formation of lightly salted large yellow croaker. The results showed that salt improves the sensory characteristics of the product. Hexanal, 2,5-octanedione, octanal, 1-octen-3-ol, nonanal, and heptanal were key flavor compounds. Phospholipids containing 18-carbon fatty acids are major flavor precursor substances. The TBARS values in samples increase with the increase of salt levels significantly ( p < 0.05). Products marinated in 6% NaCl showed the highest lipase activity. Thus, NaCl promotes the hydrolysis and oxidation of phospholipids by increasing lipase activity to produce key flavor substances. This study provides valuable insights into the effects of NaCl on flavor formation, which may help to regulate the flavor of salt-reduced food.
危险品化学品经营许可证（带存储）