An Overview on Cyclic Fatty Acids as Biomarkers of Quality and Authenticity in the Meat Sector

Challenges and opportunities in characterisation of phytochemicals in pasture-fed meat produce

Consumers are becoming increasingly concerned with the origin, welfare, and nutritional quality of meat they consume. Existing literature suggests that pasture-fed livestock can absorb phytonutrients from their feed into their meat. Advanced analytical methods such as liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) have now made it possible to identify plant-derived non-volatile compounds in meat. These biomarkers are crucial for authenticating pasture-fed meat to underpin stringent meat quality regulations and assurance systems, thus enhancing industry reputation and competitiveness. Studies have shown that animals fed with a diet rich in phytochemicals exhibit higher total polyphenol content (TPC) in their muscle compared to those fed with a concentrate diet. However, there is limited information available on the bioavailability of phytochemicals in meat. The aim of this review is to comprehensively analyse the latest methods for extracting, purifying, and characterising non-volatile biomarkers in meat, and to evaluate their effectiveness as indicators of meat authenticity and nutrition.

Effect of Diet on CPFAs Used as Markers in Milk for the Detection of Silage in the Ration of Dairy Cows

In hay milk production, fermented feed, like silage, is forbidden. This study aims to reveal the presence of silages made from maize or grass in the diet of dairy cows through the detection of cyclopropane fatty acids (CPFAs) in their milk. It also investigates how CPFAs in their milk declines when the diets of the cows are transitioned from one containing silage to one that does not include silage. CPFAs were quantified in silages collected on the farm, and the relationship between the dietary intake of CPFAs from silages and the marker concentration in milk was investigated. Except for one sample (below LOQ), CPFAs were never detected in hay milk, while they were found in 98% and 85% of milk samples obtained from cows whose diet included maize or grass silage as the only fermented component, respectively. CPFAs were found to still be detectable in milk 56 days after the removal of maize silage from the diet, while they were no longer detectable about three weeks after removing grass silage from the ration. A quantitative positive relationship was detected between CPFAs content in the milk and the dietary intake of CPFAs from silages. CPFAs can be regarded as reliable markers to detect the occurrence of silages in the ration, but it is more effective for maize than for grass silage.

Usability of volatile organic compounds from exhaled breath compared with those from ruminal fluid, serum, urine, and milk to identify diet-specific metabolite profiles in lactating dairy cows

To investigate dietary influences on the volatilome, the volatile subcategory of the metabolome, we performed a comparative untargeted volatilome analysis of exhaled breath, ruminal fluid, serum, urine, and milk from lactating Holstein cows fed different diets. Thirty-two cows (83.3 ± 31.40 DIM, 30.6 ± 5.03 kg of milk/d) were assigned to 4 diets. The experiment lasted 16 wk. Throughout the experiment, half of the animals were fed a hay-based diet (HD; n = 16), and the other half were fed a silage-based diet (SIL; n = 16). In experimental wk 5 to 12, half of the animals in each group received the control concentrate (CON), and the other half was fed with the CON supplemented with a blend of essential oils (EXP). We hypothesized that the basal diet and the essential oils influence the volatile organic compound (VOC) profiles of the cows through potential changes in ruminal fermentation, digestion, and metabolism (hypothesis 1). Furthermore, we hypothesized that the potential effects of essential oils would have a delayed onset and a carryover effect (hypothesis 2). Every 4 experimental weeks (i.e., in wk 4, wk 8, wk 12, and wk 16), samples of exhaled breath, ruminal fluid, serum, urine, milk, and feed were collected for dynamic headspace extraction and gas chromatographic analysis of VOC in their gaseous phase. Milk yield, milk composition, BW, and feed intake were recorded regularly. Linear mixed models and multivariate and univariate data analyses were performed. The total DMI and basal diet intake was similar between cows fed HD and SIL diets. However, SIL cows consumed less of the concentrate, NDF, and water-soluble carbohydrates and more starch than HD cows. The SIL cows had a higher milk production than the HD cows. No effect was found regarding the concentrate type on feed intake or milk production. Irrespective of diet, 2,957 VOC were detected in the gaseous phase of serum; 2,771 in exhaled breath; 1,016 in urine; 1,001 in milk; and 921 in ruminal fluid. Across the experimental wk 4, 8, 12, and 16, the basal diet altered the VOC profiles of ruminal fluid, urine, and exhaled breath but not those of serum and milk. The concentrate type affected only the VOC profiles of the exhaled breath. Most diet-influenced VOC in the affected biological matrices were identified as dietary components. The experimental week influenced the VOC profiles of all matrices, especially those of exhaled breath. The VOC profile of exhaled breath strongly correlated with that of urine, followed by that of ruminal fluid, milk, and serum. This study provides the first description of diet- and time-specific VOC profiles from the biological matrices of dairy cows. The identified discriminatory VOC seem suitable as markers to discriminate between HD and SIL cows. Exhaled breath may be a promising, sensitive, and less invasive tool to follow diet- and time-related metabolic changes.

Foodborne Pathogen Prevalence and Biomarker Identification for Microbial Contamination in Mutton Meat

Microbial contamination and the prevalence of foodborne pathogens in mutton meat and during its slaughtering process were investigated through microbial source tracking and automated pathogen identification techniques. Samples from mutton meat, cutting boards, hand swabs, knives, weighing balances, and water sources were collected from four different retail sites in Coimbatore. Total plate count (TPC), yeast and mold count (YMC), coliforms, E. coli, Pseudomonas aeruginosa, Salmonella, and Staphylococcus were examined across 91 samples. The highest microbial loads were found in the mutton-washed water, mutton meat, and cutting board samples. The automated pathogen identification system identified Staphylococcus species as the predominant contaminant and also revealed a 57% prevalence of Salmonella. Further analysis of goat meat inoculated with specific pathogens showed distinct volatile and metabolite profiles, identified using gas chromatography-mass spectrometry (GC-MS). Multivariate statistical analyses, including principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), and sparse partial least squares discriminant analysis (sPLS-DA), identified potential biomarkers for pathogen contamination. The results highlight the significance of cross-contamination in the slaughtering process and suggest the use of volatile compounds as potential biomarkers for pathogen detection.

Maillard reaction of food-derived peptides as a potential route to generate meat flavor compounds: A review

Plant-based meat analogues (PBMA) are promising foods to address the global imbalance between the supply and demand for meat products caused by the increasing environmental pressures and growing human population. Given that the flavor of PBMA plays a crucial role in consumer acceptance, imparting meat-like flavor is of great significance. As a natural approach to generate meat-like flavor, the Maillard reaction involving food-derived peptides could contribute to the required flavor compounds, which has promising applications in PBMA formulations. In this review, the precursors of meat-like flavor are summarized followed by a discussion of the reactions and mechanisms responsible for generation of the flavor compounds. The preparation and analysis techniques for food-derived Maillard reacted peptides (MRPs) as well as their taste and aroma properties are discussed. In addition, the MRPs as meat flavor precursors and their potential application in the formulation of PBMA are also discussed. The present review provides a fundamental scientific information useful for the production and application of MRPs as meat flavor precursors in PBMA.

Study on the Effect of Ensiling Process and Ruminal Digestion on the Synthesis and Release of Cyclopropane Fatty Acids in Cow Feeding

Cyclopropane fatty acids (CPFA) were found in milk fat from cows fed maize silage and suggested to be synthesized by lactic acid bacteria during ensiling. This study aimed to elucidate some gaps of knowledge about the microbial synthesis of CPFA, to strengthen the current authentication method based on their detection in cheese fat and performed for Parmigiano Reggiano (UNI11650), whose Specifications forbid the use of silage. CPFA were screened in different ensiled cows' feeding by gas chromatography-mass spectrometry, and the effect of feed ingredients and ruminal digestion on CPFA microbial production were further examined by in vitro tests. Results showed that solely the environmental conditions developed in silos for specific plant materials (e.g., maize) are essential for the bacterial synthesis of CPFA, whereas rumen activity did not affect CPFA levels in feeds. This supports the suitability of using CPFA as biomarkers of a crop silage-based diet forbidden by certain PDO feedstock regulations.

Cyclopropane Fatty Acids as Quality Biomarkers of Cheeses from Ewes Fed Hay- and Silage-Based Diets

This study aimed to investigate cyclopropane fatty acids (CPFAs) as quality biomarkers of forage feedings in cheese fat obtained from ewe's milk, based on two different dietary treatments (hay and silage). The gas chromatography-mass spectrometry (GC-MS) analysis detected CPFAs in most cheese samples, both from hay and silage-based diets. CPFA levels in cheese fat from hay feeding were positively correlated to the total trans-monounsaturated fatty acids (MUFAs) and n-6 polyunsaturated fatty acids (PUFAs), whereas they were negatively correlated to cis-MUFAs, odd- and branched-chain fatty acids (i.e., C13:0 anteiso, C16:0 iso, and C17:1), and C22:5n-3, which are mainly associated with a low starch intake and grass pasture. Overall, the presence of CPFAs in ovine cheese fat suggests the use of silage, but it can also be an indicator of poor-quality hay forages. This approach confirmed the reliability of CPFAs as biomarkers of forage quality, especially in relation to the use of conserved forages and good livestock practices.

Occurrence of Cis-11,12-Methylene-Hexadecanoic Acid in the Red Alga Solieria pacifica (Yamada) Yoshida

Fatty acids in marine algae have attracted the attention of natural chemists because of their biological activity. The fatty acid compositions of the Solieriaceae families (Rhodophyceae, Gaigartinales) provide interesting information that unusual cyclic fatty acids have been occasionally found. A survey was conducted to profile the characteristic fatty acid composition of the red alga Solieria pacifica (Yamada) Yoshida using gas chromatography-mass spectrometry (GC-MS), infrared spectroscopy (IR), and proton nuclear magnetic resonance spectroscopy (¹H-NMR). In S. pacifica, two cyclopentyl fatty acids, 11-cyclopentylundecanoic acid (7.0%), and 13-cyclopentyltridecanoic acid (4.9%), and a cyclopropane fatty acid, cis-11,12-methylene-hexadecanoic acid (7.9%) contributed significantly to the overall fatty acid profile. In particular, this cyclopropane fatty acid has been primarily found in bacteria, rumen microorganisms or foods of animal origin, and has not previously been found in any other algae. In addition, this alga contains a significant amount of the monoenoic acid cis-11-hexadecenoic acid (9.0%). Therefore, cis-11,12-methylene-hexadecanoic acid in S. pacifica was likely produced by methylene addition to cis-11-hexadecenoic acid.