One typical way of meat adulteration is by adding low-priced meat ingredients into high-priced meat products. In this study, a duplex droplet digital polymerase chain reaction (ddPCR) method was developed to accurately identify bovinederived ingredients in meat products. By analyzing the single-copy β-actin gene sequences of 14 animal species, bovinespecific primers and probes as well as universal primers and probes for animal-derived ingredients were designed to develop a duplex ddPCR system. The formula to calculate the relationship between the mass of bovine-derived ingredients (M, mg) and the number of copies of specifically amplified genes (C, copies/μL) was established as follows: M = 0.033C + 2.37. The results of this method for mixed meat samples containing a known amount of beef and different beef cuts basically agreed with the actual values. Moreover, the relative copy number was helpful to judge whether beef products could be adulterated with non-bovine-derived ingredients. The developed method was successfully applied to detect the adulteration of commercial beef products. We believe that this method will provide technical support for the quantitative detection of adulterated beef products and grading and identification of meat mixtures from different animal specices.

The meat characteristics of castrated Holstein bulls were analyzed and exploited through determining its nutritional, processing, and eating quality and comparing them with those of two other commercial cattle breeds (Angus and Simmental) and with literature data. Compared with Angus and Simmental beef, the total amount of amino acids and the proportions of threonine, valine, isoleucine and tryptophan in Holstein beef were increased (P < 0.05); in particular, the content of tryptophan was 1.16%, which was 5–8 times of other samples. The fatty acid composition was distributed evenly and the content of polyunsaturated fatty acid was higher. In terms of processing quality, Holstein beef had better water retention and gelation properties. In terms of eating quality, tenderness and intramuscular fat content were higher in Holstein beef (P < 0.05), with richer marbling. The number and amount of flavor compounds were higher in Holstein beef than in Angus and Simmental beef (P < 0.05). Holstein beef contained 46 volatile compounds. Notably, the contents of prominent flavor compounds of beef including nonanal, 3-hydroxy-2-butanone and 1-octen-3-ol were significantly higher in Holstein beef than in Angus and Simmental beef (P < 0.05).

Protein, fat, shear force, color, and chewiness were the primary factors to evaluate the characteristics of cooked marinated meat products. Overall contents of protein and fat of cooked marinated meat products in black pigs (144.0 g/100 g) were higher than that of white pigs (131.3 g/100 g). The tenderness of cooked marinated meat products of black pigs was higher than white pigs. Total content and number of flavour components of cooked marinated meat products from black pigs were higher than those of white pigs. The flavour contents were 11 163.33 and 3 478.79 μg/g of cooked marinated meat products in black and white pigs, respectively. 2-Pentyl-furan, nonanal, octanal, hexanal, eucalyptol, hexanoic acid, 1-octen-3-ol, 2-octen-1-ol were the most prevalent odor-active compounds of cooked marinated meat products. The cooked marinated meat products from black pigs were associated with aldehydes, ketones, alcohol, esters, acid, pyrrole, and hydroxylamine. The cooked marinated meat products from white pigs were mainly associated with alcohol, ester, acid, phenol, furfural and alkane. Theoretical basis and guidance from these findings support the use of modern meat science and technology for enhancing the quality of traditional Chinese meat products in large-scale production. This would facilitate the global trade of these products. Meanwhile, this study, for the first time, provided some profound insights into the industrial production and flavour control of traditional cooked marinated meat products.

This study aimed to investigate the relationship among physicochemical quality, water status and protein degradation of pork samples during superheated steam (SHS) cooking. Pork samples were cooked with SHS (120, 150 and 180 ℃ and traditional steam (TS) to 40, 60 and 80 ℃. The results showed that SHS cooking at 150 and 180 ℃ significantly reduced the values of lightness (L*), yellowness (b*), cooking loss and increased the value of redness (a*). Moreover, SHS cooked samples had lower shear force, hardness and chewiness value than TS cooked samples, indicating a better mouth feel quality. Low-field nuclear magnetic resonance (LF-NMR) analysis results showed that relaxation time T₂₁, T₂₂ and T₂₃ increased with SHS temperature, T₂ (TS-cooked) < T₂ (SHS-cooked), SHS had higher P₂₂ values but lower P₂₃ values than TS. The secondary structure of pork protein cooked by TS tends to be loose than SHS, promoting more immobilized water into free water. Furthermore, SHS led to a low exposure of hydrogen bonds and hydrophobic bonds which reduced protein aggregation. The protein degradation and water status could explain the quality differences between SHS and TS cooked pork.