Proposing processomics as the methodology of food quality monitoring: Re-conceptualization, opportunities, and challenges

Characterization of donkey-meat flavor profiles by GC–IMS and multivariate analysis

The distinctive flavor compounds of donkey meat are unknown. Accordingly, in the present study, the volatile compounds (VOCs) in the meat from SanFen (SF) and WuTou (WT) donkeys were comprehensively analyzed by gas chromatography–ion mobility spectrometry (GC-IMS) combined with multivariate analysis. A total of 38 VOCs, of which 33.33% were ketones, 28.89% were alcohols, 20.00% were aldehydes, and 2.22% were heterocycles, were identified. Ketones and alcohols were significantly more abundant for SF than for WT, whereas aldehydes showed the opposite trend. The donkey meats from the two strains were well differentiated using topographic plots, VOC fingerprinting, and multivariate analysis. A total of 17 different VOCs were identified as potential markers for distinguishing the different strains, including hexanal-m, 3-octenal, oct-1-en-3-ol, and pentanal-d. These results indicate that GC–IMS combined with multivariate analysis is a convenient and powerful method for characterizing and discriminating donkey meat.

iTRAQ-based proteomic analysis reveals the underlying mechanism of postmortem tenderization of refrigerated porcine Longissimus thoracis et lumborum muscle

The isobaric tags for relative and absolute quantitation (iTRAQ) technology was used for differential proteomic analysis of refrigerated porcine Longissimus thoracis et lumborum (LTL) muscle at different time points postmortem (45 min, 4 h, 8 h, 12 h, 24 h, 48 h, 72 h and 96 h) to mechanistically elucidate the postmortem tenderization. Compared with the proteins identified in porcine LTL muscle at 45 min postmortem (control), 862 proteins were significantly expressed at 4 h, 8 h, 12 h, 24 h, 48 h, 72 h and 96 h postmortem. Moreover, clustering and path analysis showed that the quality traits of porcine LTL muscle, including pH, shear force, myofibril fragmentation index, correlated significantly with 2, 6 and 6 differentially expressed proteins, respectively, with the lowest or highest expression at 8 h or 12 h postmortem. Overall, the tenderness of refrigerated porcine LTL muscle might be significantly affected by changes in quality traits at 8 h and 12 h postmortem.

Identification of novel biomarkers in chilled and frozen chicken using metabolomics profiling and its application

Merchants used frozen chicken to pass it off as chilled chicken, resulting in Economically Motivated Adulteration incidents. Here in this work, firstly, we established OPLS-DA and OPLS-R models based on metabolomics to obtain differential metabolites in chilled and frozen chicken (with different storage times), the PLS-DA model based on above differential compounds could achieve accuracy of 91% (training) and 100% (testing) for the adulteration identification of uncooked chilled and frozen chicken. Secondly, cooking study was carried out to identify the discrepancy of the cooked chilled and frozen chicken. Higher nicotinamide, o-acetyl-l-carnitine, hypoxanthine, and IMP levels indicated better nutrition quality and more desirable flavor in chilled chicken nuggets, while higher bitter and sour peptides in frozen chicken nuggets indicated the loss of freshness.