This study evaluated the effects of three freezing methods (traditional refrigerator freezing, RF, spiral tunnel freezing, SF, and liquid nitrogen immersion freezing, LF) on the flavor profile of shredded pork with green pepper dishes, using fresh samples as controls. Flavor analysis was performed using an electronic nose (E-nose) combined with headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Multivariate statistical approaches including principal component analysis (PCA), orthogonal partial least squares discriminant analysis (OPLS-DA), and odor activity value (OAV) calculations were employed to characterize key flavor compounds. The E-nose results showed that the W1W sensor, which detected sulfur compounds, exhibited the strongest response, indicating a high concentration of sulfur-containing volatiles. GC-MS analysis identified 81 volatile compounds, with hexanal and camphene levels increasing significantly after freezing, while benzaldehyde and β-bisabolene decreased significantly (P<0.05). Through OAV and OPLS-DA analyses, 27 flavor-active compounds and 35 treatment-discriminatory volatiles were identified. Ten key compounds with both OAV>1 and variable importance in projection (VIP) >1 were determined to be critical for flavor, including benzaldehyde (almond-like) and 2,5-dimethylpyrazine (meaty and green pepper-like notes). Notably, RF treatment led to accumulation of off-flavor compounds like hexadecane and (Z)-2-decenal, while SF and LF treatments better preserved the fresh-like flavor profile. This study identifies the key flavor compounds in shredded pork with green pepper dishes and provides practical insights for maintaining flavor quality in preprepared foods through optimized freezing processes.

Sweet cherries are susceptible to quality deterioration during postharvest storage and transportation, including flesh softening and spoilage, which greatly reduce their commercial value. In order to preserve postharvest quality and extend the shelf life of the fruit, this study utilized 'Samituo' sweet cherries as the experimental material to investigate the effects of pre-harvest spraying with alginate oligosaccharides at concentrations of 50, 100, and 200 mg/L on fruit quality-related parameters and the activities of cell wall degrading enzymes during low-temperature storage. The results indicated that the pre-harvest application of alginate oligosaccharides at various concentrations effectively delayed the decline in soluble solids content, titratable acidity, and fruit firmness, while also reducing the rate of fruit weight loss, as compared to the control group. Treatment with alginate oligosaccharides delayed the decline of L^*, a^*, and b^* values and color saturation, while also inhibiting the activities of pectate lyase, pectin methylesterase, polygalacturonase, cellulase, β-galactosidase, β-glucosidase, pectin methylesterase and polygalacturonic acid transeliminase. Among the treatments, 200 mg/L alginate oligosaccharides exhibited the most pronounced effect. The correlation analysis reveals that titratable acidity was significantly and positively correlated with the activities of β-galactosidase and pectin methylesterase, while was distinctly negatively correlated with the activities of polygalacturonase and cellulase. In contrast, soluble solids content exhibited a significant negative correlation with polygalacturonase, cellulase, polygalacturonic acid transeliminase, pectate lyase, and β-galactosidase activities. Furthermore, fruit hardness showed a significant negative correlation with the activities of polygalacturonase, cellulase, pectate lyase, and β-glucosidase. Weight loss was significantly positively correlated with polygalacturonase and cellulase activities, whereas it was significantly negatively correlated with the activities of polygalacturonic acid transeliminase, pectin methylesterase, pectate lyase, β-glucosidase, β-galactosidase, and pectin methylesterase. These findings suggest that pre-harvest application of alginate oligosaccharides can delay fruit softening and maintain storage quality by suppressing the activity of enzymes related to fruit cell wall degradation.

This study developed a high-stability indicator film containing a roselle (Hibiscus sabdariffa) anthocyanin extract (RAE)-oxalic acid (OA) co-pigment indicator (RAO), investigated the stability of the RAO indicator and its effects on the structure and performance of the indicator film, and applied the film to monitor the freshness of channel catfish (Ictalurus punctatus). The results showed that the stability of the RAO indicator improved compared with single RAE indicator. Moreover, the film with the RAO indicator showed enhanced performance. The tensile strength and elongation at break of the indicator film increased from 16.10 MPa and 280.95% to 17.81 MPa and 349.45%, respectively. Its moisture content and water solubility decreased from 19.10% and 42.71% to 13.98% and 34.69%, respectively. Under conditions of 4 ℃, 45% humidity, and no light exposure, the RAO indicator film could be stored for up to 82 days (ΔE<5). When used for monitoring the freshness of channel catfish at 4 ℃, the indicator film changed from rose-red to yellow-gray as the fish spoiled, demonstrating its accuracy in monitoring the spoilage process and its great potential for freshness monitoring applications.

In this study, the effects of different treatment times (40, 50, 60 s) on the changes of physicochemical properties and enzyme activities of postharvest fresh-cut Dendrocalamus brandisii (D. brandisii) shoots during storage were investigated using dielectric barrier discharge-cold plasma (DBD-CP). The results showed that DBD-CP improved the brightness of fresh-cut D. brandisii shoots with the highest contents of total phenols, total flavonoids, soluble proteins, and soluble sugars compared with CK group. At the 30th day of storage of CP₁, CP₂, and CP₃-treated D. brandisii shoots, peroxidase activity decreased by 11.13, 15.96, and 5.03 U/g (P<0.05), polyphenol oxidase activity decreased by 0.28, 1.21, and 0.62 U/g (P<0.05), phenylalanine deaminase activity decreased by 1.99, 7.19, and 5.81 U/g (P<0.05), 4-coumaroyl-coenzyme A ligase activity decreased by 3.17, 4.41, and 1.81 U/g (P<0.05), pectin content increased by 23.61%, 58.33%, and 44.44% (P<0.05), and cumulative synthesis of cellulose and lignin decreased by 7.81, 37.24, and 13.86 mg/g (P<0.05), 0.54, 0.68, and 0.55 mg/g (P<0.05), respectively. Principal component analysis showed that CP₂ had the smallest confidence circle, indicating that it had the best quality stability of D. brandisii shoots. This study provides some theoretical basis for the application of DBD-CP technology in the field of postharvest preservation and processing of D. brandisii shoots.

In order to investigate the effects of pre-harvest salicylic acid (SA) spraying on post-harvest quality and antioxidant metabolism of prunes (Prunus domestica L.), 'French' prune trees in Xinjiang were treated with SA solutions at concentrations of 1, 2, or 4 mmol/L. Applications were made during four key developmental stages: fruit set, expansion, color change, and maturity. A control group received water sprays. Following harvest, fruit were stored at 1.0±1.0 ℃ and 90%~95% relative humidity. Quality parameters and antioxidant metabolism indicators were assessed at 15 days intervals over the 90 days storage period. Results demonstrated that pre-harvest spraying of SA could significantly maintain the hardness, soluble solids content and titratable acid level of plum fruits during post-harvest storage, and inhibit the color blackening, respiration and weight loss rate of fruits. The 2 mmol/L SA treatment proved most effective. At the end of storage, the activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), ascorbate peroxidase (APX), and glutathione reductase (GR) in the 2 mmol/L SA-treated prunes were 1.17, 1.40, 1.54, 1.23, and 1.26 fold those of the control group, respectively (P<0.05). The contents of ascorbic acid (AsA) and glutathione (GSH) were 2.70 and 1.08 fold those of the control group, enhancing the antioxidant enzyme activities and effectively maintaining AsA and GSH levels. Additionally, the production rate of superoxide anion (O₂⁻·), hydrogen peroxide (H₂O₂), and malondialdehyde (MDA) accumulation, as well as cell membrane permeability, were suppressed. This indicated that spraying SA before harvest could maintain the post-harvest quality of prunes by enhancing their antioxidant metabolism capacity.

This study aimed to extract the active substance from Laminaria japonica (L. japonica) and evaluate their composition and hypolipidemic activity. The alcohol extract of L. japonica (LJA), water extract of L. japonica (LJW), enzymic hydrolysates of L. japonica (LJE) and dietary fiber extract of L. japonica (LJDF) were prepared by using different polar solvents combined with ultrasound-assisted alcohol extraction, water extraction, complex proteolytic enzymes and sodium carbonate acid, and their composition was analyzed. The above four active substances were mixed to obtain the total active substances of L. japonica (LJM). This study adopted C. elegans as a model organism to investigate the effects of bioactive compounds derived from L. japonica on lipid metabolism-related biochemical parameters and Messenger RNA (mRNA) transcription levels. The result revealed that the main components of LJA included choline, phospholipids, pyrimidines, terpenoids, arachidonic acid, steroids, polyphenols and disaccharides; LJW mainly consisted of two polysaccharides with molecular weights of 368.0 kDa and 1.0 kDa, with monosaccharide composition of glucose, galactose, fucose, mannose and arabinose; LJE mainly consisted of protein active peptides, containing six proteins (YP_006639117.1, AIW62928.1, WDS74817.1, WDS74887.1, QBF51285.1 and ABB80121.1), 43 peptides; LJDF mainly consisted of two polysaccharides with molecular weights of 717.073 kDa and 11.502 kDa, with monosaccharide composition of mannose aldehyde, gulonose aldehyde, galactose and fucose. The result of C. elegans experiments demonstrated that the L. japonica active substances significantly reduced triglyceride (TG) and malondialdehyde (MDA) levels (P<0.01). Meanwhile, these substances also increased total superoxide dismutase (T-SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) levels (P<0.01). At the mRNA transcription level, the L. japonica active substances significantly upregulated genes NHR-49, FAT-5, FAT-6, FAT-7, DAF-2, and DAF-16 (P<0.01). Conversely, the substances significantly downregulated genes MOD-1, ACS-2, and AGE-1 (P<0.01). This suggested that the L. japonica active substances improved C. elegans lipid peroxidation and reducing lipid accumulation in C. elegans through regulating fatty acid β-oxidation (NHR-49, MOD-1 and ACS-2), fatty acid synthesis (FAT-5, FAT-6 and FAT-7) and insulin (DAF-2, AGE-1, DAF-16) signaling pathways.

This study investigated the antioxidant activity and stability of walnut peptide-metal chelates using walnut peptides (WP, Mw<1 kDa) as raw material. The antioxidant capacity of WP chelates with different metal ions prepared by coordination was systematically evaluated, followed by screening of optimal-activity chelates and comprehensive assessment of their antioxidant capacity and stability. Molecular docking was employed to identify the peptide segment exhibiting the strongest antioxidant capacity within walnut peptides and elucidate its specific binding interactions. Results showed that the walnut peptide-calcium chelates (WP-Ca) exhibited significantly enhanced antioxidant activity（P<0.05）, achieving 74.00%±0.54% DPPH and 85.27%±0.67% ABTS⁺ radical scavenging rates, surpassing other metal-ion chelates. WP-Ca also maintained high stability across various pH, temperatures, and simulated gastrointestinal digestion. Molecular docking identified NALVAPHY as the optimal peptide for DPPH chelation, with its antioxidant activity mediated by electrostatic interactions and hydrogen bonding with DPPH. This study provides theoretical support for valorizing walnut processing by-products and advances the development of novel metal-chelated peptide antioxidants, with particular implications for functional foods and nutraceuticals.