Hexanal as a Predictor of Development of Oxidation Flavor in Cured and Uncured Deli Meat Products as Affected by Natural Antioxidants

Effects of dietary arginine supplementation on muscle structure, meat characteristics and lipid oxidation products in lambs and its potential mechanisms of action

This study aimed to assess the effect of dietary arginine supplementation on muscle structure and meat characteristics of lambs also considering lipid oxidation products and to contribute to reveal its mechanisms of action using tandem mass tagging (TMT) proteomics. Eighteen lambs were allocated to two dietary treatment groups: control diet or control diet with the addition of 1% L-arginine. The results revealed that dietary arginine supplementation increased muscle fibre diameter and cross-sectional area (P < 0.05), which was attributable to protein deposition, as evidenced by increased RNA content, RNA/DNA ratio, inhibition of apoptotic enzyme activity, and alterations in the IGF-1/Akt signaling pathway (P < 0.05). In addition, dietary arginine elevated pH24h, a* values, and IMF content, decreased shear force value and backfat thickness (P < 0.05), as well as decreased the formation of lipid oxidation products involved in meat flavor including hexanal, heptanal, octanal, nonanal and 1-octen-3-ol by increasing the antioxidant capacity of the muscle (P < 0.05). The proteomics results suggested that seven enrichment pathways may be potential mechanisms by which arginine affected the muscle structure and meat characteristics of lambs. In summary, arginine supplementation in lamb diets provides a safe and effective way to improve meat quality, and antioxidant capacity of muscle of lamb.

A comprehensive analysis of aroma quality and perception mechanism in ginger-infused stewed beef using instrumental analysis, sensory evaluation and molecular docking

The ginger-infused stewed beef exhibited a satisfactory odor in Chinese cooking meat. This study aimed to reveal its aroma quality and perception mechanism through electronic nose, sensory evaluation and gas chromatography-mass spectrometry (GC-MS), gas chromatography-ion mobility spectrometry (GC-IMS) coupled with chemometric methods and molecular docking. Sensory evaluation and electronic nose analysis indicated ginger could greatly modify aroma profile of beef. Most C6-C10 aldehydes significantly decreased and terpenes increased in ginger-infused stewed beef. Orthogonal partial least squares-discriminant analysis (OPLS-DA) found 7 key markers for distinguishing stewed beef with or without ginger. Ginger additions could reduce fatty acids consumption. Moreover, the key contributors of fatty, bloody, meaty, ginger and mint aroma attributes, namely (E)-2-octenal, 1-octen-3-ol, 2-acetylthiazole, zingiberene and γ-elemene, respectively, selected by partial least squares regression (PLSR) analysis were docked with the olfactory receptor. Hydrogen bonds and hydrophobic interactions were the main interaction forces between olfactory receptor and the five compounds.

Effects of Pulsed Pressure Curing on Beef Quality

The study was proposed to investigate the effects of pulsed pressure curing on the beef absorption of the curing solution, cooking loss, moisture content, centrifugal loss, salt content, sensory attributes, texture, microstructures and volatile compounds. Curing methods include the following four treatments: (1) control group 1-static curing (SC); (2) control group 2-vacuum curing (VC); (3) control group 3-pressurized curing (PC); and (4) treatment group-pulsed pressure curing (PPC). The acquired results revealed that pulsed pressure curing significantly boosts the curing efficiency and moisture content, decreases cooking loss in beef, brightens meat color, and enhances texture compared to static curing, vacuum curing, and pressurized curing. Additionally, centrifugal losses were not impaired, and sensory findings revealed that PPC significantly improved the saltiness of beef. TPA results showed that the springiness and cohesiveness of PPC were greatly increased, and hardness and chewiness were significantly reduced. Moreover, PPC significantly reduced the content of 1-octen-3-ol and 1-hexanol. Scanning electron microscopy (SEM) images documented that pulsed pressure curing can effectively increase the tenderness of beef. This study demonstrates that processed meat product efficiency and sensory attributes should be taken into account when selecting a curing technique, and the PPC technique has an advantage in both areas.

Formation and Analysis of Volatile and Odor Compounds in Meat-A Review

The volatile composition and odor of meat and meat products is based on the precursors present in the raw meat. These are influenced by various pre-slaughter factors (species, breed, sex, age, feed, muscle type). Furthermore, post-mortem conditions (chiller aging, cooking conditions, curing, fermentation, etc.) determine the development of meat volatile organic compounds (VOCs). In this review, the main reactions leading to the development of meat VOCs such as the Maillard reaction; Strecker degradation; lipid oxidation; and thiamine, carbohydrate, and nucleotide degradation are described. The important pre-slaughter factors and post-mortem conditions influencing meat VOCs are discussed. Finally, the pros, cons, and future perspectives of the most commonly used sample preparation techniques (solid-phase microextraction, stir bar sorptive extraction, dynamic headspace extraction) and analytical methods (gas chromatography mass spectrometry and olfactometry, as well as electronic noses) for the analysis of meat VOCs are discussed, and the continued importance of sensorial analysis is pinpointed.

Fatty acid metabolism-related genes are associated with flavor-presenting aldehydes in Chinese local chicken

Aldehydes are primary volatile organic compounds (VOCs) in local Chinese chicken meat and contribute green grass, fatty, citrus, and bitter almond aromas to chicken meat. To understand the genetic basis of these aldehyde VOC aromas, we used approximately 500 Chinese Jingxing Yellow (JXY) chickens to conduct genome-wide association studies (GWAS) on the flavor traits with the data of single nucleotide polymorphisms (SNPs) and insertions and deletions (INDELs). In total, 501 association variants (253 SNPs and 248 INDELs) were found to be suggestively (SNPs: p-value < 2.77e-06 and INDELs: p-value < 3.78e-05) associated with total aldehydes (the sum of nine aldehydes), hexanal, heptanal, benzaldehyde, (E,E)-2,4-nonadienal, octanal, (E)-2-decenal, nonanal, decanal, and octadecanal. Of them, six SNPs and 23 INDELs reached a genome-wide significance level (SNPs: p-value < 1.38e-07 and INDELs: p-value < 1.89e-06). Potential candidate aldehyde genes were functionally annotated for lipid metabolism, especially fatty acid-related pathways and phospholipid-related gene ontology (GO) terms. Moreover, the GWAS analysis of total aldehydes, hexanal, and nonanal generated the most significant signals, and phenotypic content differed between different genotypes at candidate gene-related loci. For total aldehydes and hexanal traits, candidate genes were annotated based on the significant and suggestive variants on chromosomes 3 and 8 with highly polymorphic linkage blocks. The following candidate genes were also identified: GALM, MAP4K3, GPCPD1, RPS6KA2, CRLS1, ASAP1, TRMT6, SDC1, PUM2, ALDH9A1, MGST3, GMEB1, MECR, LDLRAP1, GPAM and ACSL5. We also found that polyunsaturated fatty acids (PUFAs) (C18:2n6c linoleic acid and C18:3n3 linolenic acid) were significantly correlated with total aldehydes and hexanal contents. PUFAs are important aldehyde precursors, and consistently, our results suggested that candidate genes involved in fatty acid pathways and phospholipid GO terms were identified in association loci. This work provides an understanding of the genetic basis of aldehyde formation, which is a key flavor-forming compound.

The Influence of Acid Whey on the Lipid Composition and Oxidative Stability of Organic Uncured Fermented Bacon after Production and during Chilling Storage

The aim of this research was to evaluate the effect of acid whey on changes in the fatty acid profile, oxidative stability, physico-chemical parameters, and microbiological and sensory quality of traditional organic uncured fermented Polish bacon after production and during chilling storage. Three different treatments of fermented bacon were produced: C—control bacon with a nitrite curing mixture; T—bacon with a nitrate curing mixture; and AW—bacon with acid whey and NaCl. The acid whey used in the production of uncured fermented pork bacon positively changed the sensorial characteristics, directly after the ripening process, and had a positive effect in terms of a decrease in the pH of the product. All of the fermented bacon treatments in general were of good microbiological quality. A higher lactic acid bacteria (LAB) level was observed in the AW treatment after the fermentation process, and the bacteria number did not change during storage, whereas in the C and T treatments, the LAB level increased during storage (p < 0.05). The application of acid whey did not limit the formation of secondary oxidation products (TBARS) during bacon ripening (1.68 mg MDA kg⁻¹), but had a reduced value during storage time (0.73 mg MDA kg⁻¹). The highest polyunsaturated fatty acid (PUFA) levels, after ripening and after four weeks of refrigerated storage, were found in the C treatment. In the AW treatment, it was found that the PUFA level increased; likewise, the content of n-3 and n-6 fatty acids increased, while saturated fatty acids (SFAs) decreased during storage (p < 0.05). The opposite tendency was observed in the C treatment. After four weeks of storage, the PUFA/SFA ratio was the lowest in the nitrate treatment, and higher values of the PUFA/SFA ratio were obtained in the acid whey and nitrite treatment (p < 0.05).

Microcapsules Consisting of Whey Proteins-Coated Droplets of Lipids Embedded in Wall Matrices of Spray-Dried Microcapsules Consisting Mainly of Non-Fat Milk Solids

The effects of wall composition and heat treatment on the formation and properties of core-in-wall emulsions (CIWEs) consisting of whey protein-coated milkfat (AMF) droplets and a dispersion of non-fat milk solids (MSNF) were investigated. Microcapsules were prepared by spray drying these CIWEs. The d_3.2 of the CIWEs ranged from 0.36 to 0.54 μm. Surface excess of the CIWEs ranged from 1.39 to 6.57 mg/m², and was influenced by concentration of whey proteins and heat treatment (30 min at 90 °C). Results indicated a preferential adsorption of β-lg at the O/W interface. Whey proteins accounted for up to 90% of the proteins adsorbed at the O/W interface. The core retention during spray drying ranged from 90.3% to 97.6% and microencapsulation efficiency ranged from 77.9% to 93.3%. The microcapsules exhibited an excellent long-term oxidative stability at 20 and 30 °C that was superior to that of microcapsules consisting of milkfat and MSNF, where the O/W interface was populated mainly by caseins. The superior oxidative stability could be attributed to the formation of dense whey-proteins-based films at the O/W interfaces of the CIWEs that isolated the core domains from the environment. The results open new opportunities in developing highly stable lipids-containing microcapsules and dairy powders.