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1,3-Diacylglycerol (DAG) has been well recognized as a safe food component. The metabolic pathway of DAG in the body is different from that of triacylglycerol, and DAG has been demonstrated to contribute to improving metabolism and preventing obesity and cardiovascular diseases. However, the mass fraction of natural DAG in edible oils and fats is less than 10%, so the preparation of high-purity DAG has received widespread attention in recent years. Enzymatic synthesis is the method of choice for the industrial preparation of DAG due to the advantages of eco-friendliness, safety and desirable selectivity over chemical synthesis. Edible livestock and poultry fats, as by-products of slaughter and processing, have a special flavor and nutritional value. However, their undesirable physicochemical properties, especially high melting points and high levels of saturated fatty acids and cholesterols, highly limit their applications in the food industry. In light of this, the synthesis of DAG from edible livestock and poultry fats is a promising approach for their high-value utilization. The current status of the enzymatic synthesis and the potential application of DAG from livestock and poultry fats are reviewed in this article. It is anticipated that this review will provide new ideas for researchers interested in the enzymatic preparation and high-value utilization of DAG from livestock and poultry fats.

The characteristic odorants in duck breast, leg and clavicle meat cooked at 60 and 90 ℃ were analyzed by headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) and were identified by sensory evaluation, electronic nose measurement and flavor substance evaluation. The results showed that duck breast, leg and clavicle meat cooked at 90 ℃ had a stronger odor than at 60 ℃, and there were differences in the odor characteristics of different groups of duck meat samples, which was also confirmed by electronic nose analysis. A total of 61 volatile flavor compounds were identified by HS-GC-IMS. The types of volatile substances in different groups of duck meat samples were basically the same, but there were differences in their relative contents. Based on the sensory evaluation results and the relative odor activity values (ROAV) of flavor substances, a total of 12 characteristic odorants were identified, including nonanal, octanal, heptanal, decanal, pentanal, hexanal, (E)-2-octenal, (E)-2-heptenal, 2-methyl-butanal, 3-methyl-butanal, 2-heptanone and 1-octene-3-ol. The interaction between these substances contributed significantly to the formation of the odor of duck meat. Due to the differences in the types and contents of odorants, duck meat samples cooked at 60 and 90 ℃ had distinct odor characteristics.

In order to explore the effects of different wood types with different chemical compositions and structures on the types and amounts of polycyclic aromatic hydrocarbons produced in traditional smoked meat products, the structural and pyrolysis characteristics of lignin in five kinds of wood commonly used in the production of traditional smoked and roasted meat products, pine, poplar, beech, jujube and apple wood, were investigated by infrared spectroscopy, Raman spectroscopy, thermogravimetry and thermogravimetry coupled with infrared spectroscopy. The results showed that there were differences in the contents of lignin, guaiacyl (G) and syringyl (S) in the five kinds of wood. The pyrolysis process involved three stages, mainly in the range of 200?500 ℃, but the mass loss rate, mass loss temperature, pyrolysis rate and pyrolysis temperature of lignin were different among different kinds of wood, indicating that there are significant differences in the thermal stability of lignin from different wood sources. Differences in lignin content, S/G structure content and side chain structure in smoked and roasted wood could lead to different thermal stability, and different pyrolysis characteristics could in turn affect the formation of harmful substances such as polycyclic aromatic hydrocarbons.

BACKGROUND: Fermented meat products are meat products with a unique flavor, color, and texture as well as an extended shelf life under natural or artificially controlled conditions. Microorganisms or enzymes are used to ferment the raw meat so that it undergoes a series of biochemical and physical changes. Common fermentation strains are lactic acid bacteria, yeasts, staphylococci, molds, and so forth. Studies on the inhibitory effect of yeast fermentation strain on N‐nitrosamines in fermented meat products have not been reported. Two excellent yeast starters were identified to solve the problem of nitrosamines in fermented meat products. RESULTS: Meyerozyma guilliermondii and Debaryomyces hansenii led to weak acid production, strong resistance to NaCl and NaNO2, and high tolerance to low acidic conditions. The inoculated fermented beef exhibited decreased lightness, moisture content, water activity, pH, protein content, nitrite content, and N‐nitrosamine content in comparison with the control group fermented bacon. M. guilliermondii had a better effect, reducing pH from 5.69 to 5.41, protein content from 254.24 to 221.92 g·kg−1, nitrite content from 28.61 to 25.33 mg·kg−1 and N‐nitrosamine by 18.97%, and giving the fermented beef the desired meat color, mouthfeel, odor, taste, and tissue quality. CONCLUSION: In this study, two strains of yeast fermenters that can degrade N‐nitrosamine precursors were identified, which to some extent solves the problem of the high risk of generating nitrosamines such as N‐nitrosodiethylamine (NDEA) by processing fermented meat products with nitrites as precursors. These two strains are likely to be used as starter cultures for fermented meat products. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]