This research investigated the effects of salt concentration on the fermentation of watermelon soybean paste. Three experimental groups were constructed with gradient salt concentrations, and multi-dimensional analyses were performed on physicochemical properties, volatile aroma profiles, and microbial community succession throughout the fermentation process. Group X (lowest salt) exhibited the highest total acid (34.49 g/kg) and lowest pH (p < 0.05) after 60 d. Using headspace gas chromatography time-of-flight mass spectrometry (HS-GC-TOF-MS), a total of 97 volatile compounds were identified, of which 18 were defined as key flavor compounds (relative odor activity value (ROAV) > 0.1 and variable importance in projection (VIP) > 1). High-throughput sequencing demonstrated that Proteobacteria and Firmicutes represented the core bacterial communities while Ascomycota emerged as the dominant fungal phylum. The Shannon diversity index for bacteria ranged from 4.28 to 5.47 across groups. Aspergillus relative abundance in Group X decreased from 75.30% (30 d) to 43.17% (60 d). Group X was distinctly separated from Y and Z in PLS-DA and PCoA analyses. Aspergillus exhibited significant positive correlations with eugenol and 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (p < 0.05). These findings provide an integrated understanding of the associations between volatile compound evolution and microbial succession during natural fermentation, providing a basis for further investigation and process optimization.

Sauced beef is a traditional Chinese meat product, yet the volatile and sensory signatures of potential aroma-active compounds remain insufficiently characterized. Five commercial sauced beef products (B1–B5) were analyzed by electronic nose (E-nose), gas chromatography–ion mobility spectrometry (GC-IMS), chemometrics, and fuzzy comprehensive evaluation (FCE). Volatile organic compounds (VOCs) identified by GC-IMS were screened by principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). An FCE model based on texture profile analysis (TPA) was established, with color, taste, flavor, texture, and acceptability as sensory evaluation indicators. E-nose responses indicated that sulfur-containing compounds, aromatic components, alkanes, and alcohols contributed strongly to overall aroma. GC-IMS tentatively identified 73 VOCs, with ketones, alcohols, and aldehydes as the dominant classes. Dual screening (variable importance in projection (VIP) > 1 and odor activity value (OAV) ≥ 1) identified 14 potential aroma-active compounds. Nine compounds were common to all five products, and five were detected in only a subset of products. Under equal weighting, the fuzzy evaluation ranked overall quality as B2 > B4 > B3 = B5 > B1. Pearson correlation revealed that sensory attributes, especially taste and flavor, were positively correlated with 3-(Methylsulfanyl)propanal and (Z)-2-pentenal, while negatively correlated with (R/S)-linalool, 2-Butanone-3-hydroxy, and alpha-Pinene. These integrated approaches revealed differences among the five commercial products investigated, identified potential aroma-active compounds, and support product-specific characteristics and quality assessment of sauced beef products.

Different heat treatment temperatures (85–115 °C) were evaluated for their effects on the quality and flavor of luncheon meat. As the heating temperature increased, the weight loss rate increased, and its color became darker. Low-field nuclear magnetic resonance (LF-NMR) revealed that immobilized water decreased progressively while bound and free water both increased. During heat treatment, alterations in the spatial structure of proteins reduced the hardness and chewiness of luncheon meat, accompanied by significant variations in amino acid contents. The MDA content increased from 0.34 to 0.69 mg/kg with increasing temperature, confirming enhanced lipid oxidation. Through gas chromatography–ion mobility spectrometry (GC-IMS) analysis, a total of 38 volatile organic compounds (VOCs) were identified, primarily aldehydes, ketones, and esters; the total aldehydes content increased by 57.5% from 85 °C to 115 °C. Combining odor activity values (OAV > 1) with orthogonal partial least squares-discriminant analysis (OPLS-DA, VIP > 1), 9 core flavor compounds were identified. Heating at 95 °C balanced aldehyde–ester flavor development with minimal quality loss. This study provides key theoretical foundations for optimizing heat treatment parameters in the industrial production of luncheon meat.

This preliminary within-animal study focuses on the comprehensive characterization of pork jowl (PJ) by comparing it with pork belly (PB), Boston butt (BB), and spare ribs (SR) collected from the same ten castrated Duroc × Landrace × Yorkshire (DLY) pigs; headspace volatile analysis used a matched subset of six pigs. Instrumental quality, proximate composition, amino-acid and fatty-acid profiles, low-field nuclear magnetic resonance (LF-NMR) water distribution and headspace solid-phase microextraction–gas chromatography–mass spectrometry (HS-SPME-GC-MS) volatile profiles were evaluated. PB exhibited the lowest shear force, hardness, and chewiness. Across the four pork cuts, crude protein content ranged from 16.87% to 18.10%, whereas crude fat content ranged from 13.03% to 22.20%. BB had the lowest crude fat content (13.03%) and relatively high protein (18.10%) and amino-acid contents. PJ showed highest content of monounsaturated fatty acids (MUFAs) and the lowest numerical atherogenic (AI) and thrombogenic indices (TI), but also the highest n-6/n-3 polyunsaturated fatty acids (PUFA) ratio. LF-NMR showed that PJ had the highest T₂₃ and P23 values, consistent with its higher cooking and centrifugal losses. Sixty-five headspace volatile compounds were tentatively identified under the standardized 80 °C HS-SPME conditions. OPLS-DA differentiated the four cuts, and ten compounds meeting the combined criteria of VIP > 1, q < 0.05, and OAV > 1 were retained as candidate discriminant aroma-relevant compounds. Overall, the four cuts exhibited distinct quality profiles: PJ combined a MUFA-rich lipid fraction with greater free-water mobility and water loss, PB showed the greatest instrumental tenderness, BB had the lowest crude fat content and relatively high protein and amino-acid contents, and SR exhibited the greatest headspace volatile abundance. The data provide a reference for cut-specific utilization of pork raw materials.