Comparison of the quality of beef jerky processed by traditional and modern drying methods from different districts in Inner Mongolia

Generation of key aroma compounds in fat and lean portions of non-smoked bacon induced via lipid pyrolysis reaction

This study explored the evolution of key aroma compounds and their lipid precursors in the lean (LN) and fat (FT) portions of non-smoked bacon during hot air drying. The results showed that the LN portion contained most of the aroma compounds in the bacon (>88%). The volatile content of the FT portion increased as the drying time increased, whereas that of the LN portion reached a maximum within 24 h and then decreased. Based on the highest volatile contents (4889.48 ± 202.06 µg/kg) and sensory scores, 24 h was considered the optimal drying time. For key aroma compounds, hexanal and 2,3-octanedione were derived from free fatty acids and polar lipids. Notably, 1-octen-3-ol was generated only from polar lipids in the FT and LN portions. The 2-undecenal and (E, E)-2,4-decadienal were produced by the oxidation of neutral lipids in the FT portion. Dihydro-5-pentyl-2(3H)-furanone was derived from polar lipids in the LN portion. Altogether, these findings provide theoretical insights into improving the aroma of bacon by optimizing raw material selection and processing methods.

Exploring potential lipid precursors for aroma formation in non-smoked bacon during hot air drying via untargeted lipidomics and oxidation model

The effect of drying on the lipid profiles of the lean (LN) and fat (FT) portions of non-smoked bacon was investigated based on a lipidomic approach. The study identified 989 lipids belonging to 26 subclasses in bacon, with triglyceride and phosphatidylethanolamine being the most abundant. Triglycerides, phosphatidylcholines, and phosphatidylethanolamines were significantly decreased, whereas diglycerides, free fatty acids, and lysophospholipids were increased after drying. TG (16:1/18:1/18:2) and TG (16:0/18:1/18:1) were the primary lipids responsible for the binding of volatiles. Based on VIP > 1 and P < 0.05, 355 and 444 differential lipids were observed in the FT and LN portions, respectively. In total, 26 lipids were screened as key precursors for the production of key aroma compounds of bacon in the FT portion, while 127 were screened in the LN portion. PE (18:0/18:2) is believed to be the primary lipid molecule precursors responsible for the development of aroma in both lean and fat portions. This research has enhanced the comprehension of the generation of key aroma compounds derived from lipid oxidation.

Analysis and comparison of the quality and flavour of traditional and conventional dry sausages collected from northeast China

In this study, the physicochemical properties and flavour profile of traditional dry sausages (T-SH, T-DXAL, T-HG, T-MDJ, T-HRB) collected from various wet markets were compared with those of conventional dry sausages (C-QL, C-ND, C-YSD, C-YC, C-HRL) collected from various food companies in northeast China. Traditional dry sausages were characterised by a low moisture content, a low water activity, and a high shear force after a long fermentation time compared with conventional dry sausages. Electronic nose and electronic tongue signals combined with chemometrics methods were applied for a comprehensive qualitative analysis of the odour and taste of dry sausages. A total of 61 volatile compounds were identified using gas chromatography-mass spectrometry, and the multivariate chemometrics analysis confirmed the difference in volatile compounds between traditional and conventional samples. Moreover, the sensory evaluation revealed that conventional dry sausages lacked the characteristic fermented flavour of traditional dry sausages.

Improving the quality and processing efficiency of beef jerky via drying in confined conditions of pre-stretching

Inspired by the mechanical enhancement of hydrogel via drying in confined conditions, we applied this strategy to beef jerky manufacture for improving the quality and processing efficiency. In our study, beef strips were pre-stretched and then dried in a tensile state, and the confined conditions were achieved by controlling the stretched strains from 20% to 120%. Compared with the sample dried freely, beef jerky dried in confined conditions of different pre-stretching strains exhibited improved quality based on texture and sensory analysis. Additionally, this method also enhanced processing efficiency by reducing approximately 50% drying time. The excellent sensory quality and good texture of beef jerky were obtained as the pre-stretching strain was 80%. Drying beef strips in confined conditions made muscle fibers tense and enhanced hydrophobicity of myofibrillar proteins, leading to a compact structure with high shear force and anisotropy, and rapid water loss in beef jerky. This facile and green method provides a promising route to enrich the existing technologies of jerky processing.

Effects of Microbial Communities on Volatile Profiles and Biogenic Amines in Beef Jerky from Inner Mongolian Districts

Beef jerky is a traditional fermented meat product from Inner Mongolia, handcrafted by artisans. We investigated the bacteria of the microbial community, volatile flavor components, and biogenic amines of Inner Mongolia beef jerky via high-throughput sequencing, solid-phase microextraction with gas chromatography−mass spectrometry, and high-performance liquid chromatography, respectively. Thirty-three bacteria were identified, predominantly from the genera Pseudomonas (45.4%), Ralstonia (13.4%), and Acinetobacter (7.3%). Fifty-nine volatile flavor compounds and eight biogenic amines were detected. Based on Spearman’s correlation coefficient, 20 bacterial genera were significantly associated with the dominant volatile compounds in the beef jerky samples (p < 0.05). The results demonstrated that beef jerky may be toxic due to cadaverine, putrescine, and histamine; moreover, the amounts of putrescine and cadaverine were positively correlated with the abundance of unclassified_f_Enterobacteriaceae (p < 0.05). These findings shed light on the formation of the microbial community, flavor components, and biogenic amines of beef jerky, thereby providing a basis for improving its quality.

Effect of Biogenic Amine-Degrading Lactobacillus on the Biogenic Amines and Quality in Fermented Lamb Jerky

This study compares five types of lamb jerky, namely, CO (without starter culture), PL-4 (with producing putrescine, cadaverine, histamine, and tyramine), BL4-8 (degrading putrescine, cadaverine, histamine, and tyramine), CL4-3 (degrading putrescine and tyramine), and X3-2B (degrading histamine and tyramine). A study was performed to examine the effects of starter culture on the physical−chemical quality, flavor, and biogenic amines (BAs) during fermentation and ripening. At the end of fermentation, the pH value of the BL4-8 group (4.75) was significantly lower than that of other groups (p < 0.05). After high-temperature roasting, the water activity (0.55), water content (22.6%), nitrite residue (0.41 mg/kg), and TBARS value (0.27 mg/100 g) of the X3-2B group were significantly lower than those of other groups (p < 0.05). The findings show that adding starter BL4-8, CL4-3, and X3-2B can increase the variety and content of flavor in the product. The levels of histamine, putrescine, and tyramine were significantly lower in the BL4-8, CL4-3, and X3-2B groups than in CO and PL-4 groups. This study shows that BL4-8, CL4-3, and X3-2B are potential starters for fermented meat products.

Effect of Differentiated Relative Humidity of Air on the Quality of Traditional Speciality Guaranteed “Krakowska Sucha Staropolska Sausage”

The aim of the study was to determine the effects of air relative humidity (RH: 60 and 80%) during the drying process of “krakowska sucha staropolska” (KSS) sausages on selected quality characteristics. The composition and production process of KSS sausages complied the requirements of traditional specialities guaranteed. It was found that the use of lower RH of drying air allowed a time reduction of 20%. Lowering the RH of air during the drying process did not affect the cross-sectional colour and odour of the sausages, colour components, TBARS values, protein, fat and salt content. However, the acceleration of the drying process resulted in very dried outer layers and less dry interior of KSS sausages. As a result, the sausages had lower scores in the sensory evaluation of hardness and overall acceptability. For this reason, shortening the drying process of sausages by using air with lower relative humidity is not recommended.

Sensory Properties and Main Differential Metabolites Influencing the Taste Quality of Dry-Cured Beef during Processing

This study adopted widely targeted high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) metabolomics and multivariate data analysis methods to evaluate the correlation between changes in metabolites and their taste formation in dry-cured beef during processing. The physicochemical profile changed significantly in the maturity period (RG), especially due to the continuous hydrolysis and oxidation of proteins. The sensory characteristic of dry-cured beef was highest in saltiness, umami, overall taste, and after-taste in RG. Overall, 400 metabolites were mainly identified, including amino acids, peptides, organic acids, and their derivatives, nucleotides, and their metabolites, as well as carbohydrates. Cysteine and succinic acid were significantly up-regulated during the process of dry-curing beef compared to the control group (CG). Moreover, glutamine and glutathione were significantly down-regulated in the fermentation period (FG) and in RG. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis revealed that glyoxylate and dicarboxylate metabolism, glutathione metabolism, alanine, aspartate, and glutamate metabolism, arginine biosynthesis, taurine, and hypotaurine metabolism were the main metabolic pathways influencing the taste of dry-cured beef during processing. Results of correlation analysis revealed that umami is positively correlated with salty, L-cysteine, L-arginine, inosine, creatinine, and succinic acid. Our study results provide a better understanding of the changes in taste substances and will contribute to quality evaluation of dry-cured beef.

Characterisation of flavour profile of beef jerky inoculated with different autochthonous lactic acid bacteria using electronic nose and gas chromatography-ion mobility spectrometry

The flavour profiles of beef jerky separately inoculated with different autochthonous lactic acid bacteria (LAB) strains (Lactobacillus sakei BL6, Pediococcus acidilactici BP2, and Lactobacillus fermentum BL11) and a non-inoculated control were analysed using electronic nose (E-nose) and gas chromatography-ion mobility spectrometry (GC-IMS). GC-IMS results revealed a total of 42 volatile compounds in beef jerky. Inoculation of the three LAB strains decreased the levels of lipid autoxidation-derived aldehydes (e.g., hexanal, heptanal, octanal, and nonanal). In addition, inoculation of P. acidilactici BP2 increased the levels of esters. Principal component analysis of the E-nose and GC-IMS results could effectively differentiate non-inoculated beef jerky and beef jerky separately inoculated with different LAB strains. Furthermore, there was a high correlation between the E-nose and GC-IMS results, providing a theoretical basis for the identification of different beef jerky formulations and selection of autochthonous starter cultures for beef jerky fermentation.

Dynamics of heat transfer and moisture in beef jerky during hot air drying

The aim of this study was to investigate the surface temperature, moisture migration, muscle shrinkage and microstructure of beef jerky during hot air multi-stage drying. Temperatures were sequentially increased from 40 to 50 to 60 °C, and corresponding times were 0.5 h - 1 h - 2.5 h, 0.5 h - 2 h - 1.5 h, 1 h - 1 h - 2 h and 1 h - 2 h - 1 h in 4 groups. With increasing temperature, moisture content and diffusivity of the sample decreased, the surface temperature, moisture migration, muscle shrinkage and the gaps (spacing) between muscle fibres increased. The jerky in groups 3 and 4 attained high overall acceptability. The jerky dried at 40 °C for 1 h, 50 °C for 1 h and 60 °C for 2 h had highest quality. The results cover the range of temperature and time used in beef drying and can be used to optimize the drying process of beef.

High hydrostatic pressure combined with moisture regulators improves the tenderness and quality of beef jerky

The influence of high hydrostatic pressure (HHP) at different pressure levels (0.1, 100, 200, and 300 MPa) combined with moisture regulators (MR) on the tenderness, water content, and quality of beef jerky was investigated. HHP treatment reduced the shear force (SF) of beef jerky (P < 0.05). The beef jerky treated with MR+HHP exhibited higher tenderness than the beef jerky treated only with HHP (P < 0.05). The MR+HHP samples had significantly higher moisture content than the HHP samples (P > 0.05) when the water activity was maintained at approximately 0.7. MR+HHP contributed to a shorter T₂₁ value and a higher P₂₁ value, which indicated an improvement in the water-binding ability of the beef muscle. Analysis of the microstructure showed that MR+HHP led to the fracture of the Z-line and destruction of the sarcomere structure. Sensory analysis showed that MR+HHP-200 samples had significantly higher tenderness and overall acceptable scores than other samples (P < 0.05).

Evaluation of volatile flavor compounds in bacon made by different pig breeds during storage time

The oxidation and volatile constituents of bacon (which made of white pig (Duroc × Landrace × Yorkshire) and black pig (Beijing Black × Yorkshire)) during refrigerated storage were analyzed by thiobarbituric acid reactive substances (TBARS), total thiol groups, gas chromatography-mass spectrometry (GC-MS) and gas chromatography coupling with ion mobility spectrometry (GC-IMS). The TBARS value of tested samples increased while the total thiol groups decreased during 60 days storage (P < 0.05). Volatile fingerprint results were obtained by GC-MS and GC-IMS detector, the classes and contents of volatile compounds detected in WP bacon were much abundant than BP bacon. Higher phenols and acids concentrations were observed in WP bacon, while alcohols, ketones, and nitrogen-containing compounds were more determined in BP bacon. Besides, WP bacon was more notably affected by storage rather than BP bacon, and the difference of raw material is the main reason for the flavor in WP and BP bacon comparing with the storage process.

Dynamic changes in the qualities and heterocyclic aromatic amines of roasted pork induced by frying temperature and time

The effects of different frying temperatures (150, 175, 200, 225 and 250 °C) and times (0.5, 1.0, 1.5, 2.0 and 2.5 min) on yield, shear force, color and sensory characteristics, and heterocyclic aromatic amine (HAA) contents of roasted pork were investigated. The results showed significant decreases in yield, shear force and L* and increases in a*, b* and the amounts of HAA of roasted pork with increased frying temperature and time (P < 0.05). The highest score of overall acceptability in crispy and darker roast pork fried at 225 °C for 1 min was obtained. However, the principal component analysis demonstrated that higher HAA contents of roasted pork under high frying temperature (225-250 °C) and long frying time (2-2.5 min) occurred. Considering the various qualities and the amounts of HAA, frying roasted pork at 175 °C for 1.5-2 min was the most suitable condition for preparing roasted pork.