Ready-to-eat (RTE) salmon products face persistent safety challenges from Listeria monocytogenes, limiting shelf life and contributing to food waste. Soluble gas stabilisation (SGS) technology, which dissolves CO2 into the salmon muscle before packaging, may offer an additional hurdle to enhance microbial safety. This study investigated the effect of SGS pretreatment on the growth of Listeria innocua (CCUG 15531, used as a surrogate for L. monocytogenes) and the natural microbiota of vacuum-packed RTE salmon stored at 4 °C and 8 °C. Salmon portions were pretreated with pure CO2 (SGS) or air (CTRL) for 18.5 h, at 4 °C. SGS pretreatment significantly inhibited the growth of L. innocua, total aerobic bacteria, psychrotrophic bacteria and H2S-producing bacteria across both storage temperatures. Complete inhibition of L. innocua was observed for up to 30 days at 4 °C. SGS pretreatment also led to reduced microbial diversity; however, Photobacterium spp. remained dominant. Freshness and spoilage indicators (K value, H value, and biogenic amines) were mainly influenced by storage temperature and time, with SGS pretreatment mainly delaying freshness loss at 4 °C. Overall, SGS pretreatment represents a promising strategy for controlling Listeria in RTE salmon, with robust effects maintained even under minor temperature abuse conditions.
Carboxymethyl cellulose (CMC) is widely used in food packaging; however, its performance is often interpreted mainly in relation to substitution degree, with less consideration of how cellulose origin may affect substitution under comparable modification conditions. This study investigates the influence of cellulose source and carboxymethylation conditions on the properties of CMC films derived from jicama (Pachyrhizus erosus) peel and pulp. Cellulose fractions were converted into CMC using different monochloroacetic acid (MCA) loadings to obtain varying degrees of substitution. Spectroscopic, thermal, and crystalline analyses indicated differences in substitution behavior and structural organization between peel- and pulp-derived CMC. These differences were associated with variations in film permeability and packaging performance. Films prepared from pulp-derived CMC showed lower oxygen levels within packages, reduced weight loss, delayed softening, and lower lipid peroxidation in cherry tomatoes compared with peel-derived and commercial CMC films. In contrast, peel-derived CMC exhibited more limited modification, which influenced film structure and barrier properties. Overall, the results highlight relationships between cellulose origin, modification conditions, and film performance, demonstrating the potential of jicama residues as alternative sources for CMC-based packaging materials.
This study investigated the effect of high-pressure processing (HPP, 200-600 MPa for 5-20 min) on the aging characteristics of hawthorn wine (HW) using sensory evaluation, gas chromatography-mass spectrometry/olfactometry and high-performance liquid chromatography. HPP significantly accelerated oxidation and esterification, leading to a decrease in alcohols by 7.3%-37% and an increase in esters by 14%-30%, respectively, while avoiding the loss of volatile aroma compounds (VOCs) compared with natural aging. Odor Activity Value of 19 key VOCs was significantly enhanced by HPP (p < 0.05), particularly esters (e.g., ethyl octanoate, ethyl acetate) and terpenes (terpinolene, (+)-limonene). Consequently, “fruity”, “floral” and “sweet” sensory aromas were intensified by HPP (p < 0.05), alongside suppression of the pungent “fermented” odor by 20%-57%. Additionally, HPP mitigated the taste attributes of “bitterness” and “astringency” by 48%-63% and 2.4%-58%, respectively, while enhancing “sweetness” and “umami” (p < 0.05), which were consistent with the changes in aroma precursors. A total of 14 compounds were identified as key markers distinguishing HPP-aged samples, such as ethyl hexanoate, phenylethanol, methionine. Importantly, HPP achieved efficient flavor enhancement within only 5-20 min (25 °C), greatly shortening the conventional 30-day natural aging (15 °C) period and lowering time-and-space costs. Nevertheless, high equipment investment remains a practical barrier for broad-scale deployment, and further cost optimization is required for industrial fruit-wine applications.
Progress in oat protein concentrates is constrained by the need to improve recovery yields without adversely affecting functionality or sensory quality. This study examined how pretreatments, including heating and supercritical carbon dioxide defatting, and extraction pH affect protein yield, composition, functionality, and flavour during alkaline extraction–acid precipitation of oat protein concentrates. Oat flours were prepared from non-heated (NH), commercially heated (CH), severely heated (SH), and mildly heated (MH) groats, with or without defatting, and extracted at pH 8 or 10. Yield, composition, techno-functionality , volatiles and sensory attributes were evaluated, and correlation analysis was used to identify quality-driving process variables. Heat treatment altered flour properties more than defatting, with treatment severity linked to lower protein extractability. Strong protein–lipid yield correlations indicated lipid co-extraction. Increasing pH strongly reduced protein extractability and water holding capacity, while defatting slightly reduced those properties. Compared with NH, CH samples had higher denaturation enthalpy, better flavour, and similar functionality. Higher extraction pH partly improved flavour, whereas partial defatting impaired flavour in NH samples. Off-odours correlated with lipid-oxidation volatiles. Optimising heat treatment, defatting and extraction pH can enhance industrial oat protein production by improving recovery while limiting lipid oxidation and preserving functionality and flavour.
This study optimized ultrasound-assisted osmotic dehydration (USOD) followed by convective drying of litchi (Litchi chinensis) using Response Surface Methodology based on a Box–Behnken design. Four processing variables ultrasound amplitude (20–40%), sonication time (10–30 min), sucrose concentration (20–60%, w/w), and drying temperature (50–70°C) were evaluated for their effects on moisture content, water activity, colour change, hardness, shrinkage, rehydration ratio, total phenolic content, and antioxidant activity. A second-order polynomial model adequately described the responses, with high coefficients of determination (R2 > 0.92) and non-significant lack-of-fit, indicating strong model reliability. Numerical optimization identified the optimum conditions as 30% ultrasound amplitude, 20 min sonication, 40% sucrose concentration, and 58°C drying temperature, with an overall desirability of 0.82. Under these conditions, predicted values were 10.76% moisture content, 0.41 water activity, 15.02 colour difference, 21.53 N hardness, 74.29% shrinkage, 2.67 rehydration ratio, 10.79 mg GAE/g DW total phenolic content, and 53.76% antioxidant activity. Experimental validation showed relative errors below 5%. Microstructural analysis confirmed enhanced porosity, while FTIR indicated improved antioxidant preservation and sensory evaluation further validated these benefits, with optimized USOD-treated samples scoring higher in overall acceptability compared to control samples, demonstrating the effectiveness of integrated USOD and convective drying optimization for quality retention in dried litchi.
Irradiation is widely used for spice sterilization. This study evaluated the impact of 60Co-γ irradiation on white cardamom (WC) sensory properties and chemical composition. The minimum effective dose meeting pharmacopoeial microbial limits was 6 kGy. Irradiation caused slight color changes but significant odor differences detected by electronic nose. GC-MS identified 70–95 volatile compounds, mainly prenol lipids (65.48%). Twenty differential metabolites were found, with increases in prenol lipids and the carcinogen safrole. Among 10–15 key aroma compounds, eucalyptol, caryophyllene, and eugenol changed significantly, while α-maaliene and two other volatiles disappeared after irradiation, suggesting they could be irradiation markers. UPLC-Q Exactive HFX analysis revealed 2606 components, with 84 differential compounds across irradiated groups and five common to all comparisons. Volatile compounds (β-terpineol, ethyl (Z)-cinnamate, valerena-4,7(11)-diene, trans-carveol, β-pinene) and non-volatiles (methyl 1-methyl-9H-β-carbolin-7-yl ether, 2-indanone) were mainly responsible for irradiation-induced differences. PCA of E-nose, GC-MS, and UPLC-MS data clearly distinguished irradiated from non-irradiated samples. Using a multi-platform approach (E-nose, GC-MS, UPLC-MS) together with the putative irradiation markers, the irradiation status of WC can be reliably identified. This study represents the first integration of volatilomics, metabolomics, and chemometrics to evaluate 60Co-γ irradiation's impact on WC, establishing a robust framework for irradiation detection and quality control.
The fruit quality attributes of black currants (‘Heifeng’, ‘Hanfeng’, and ‘Brodtorp’) were evaluated at various developmental stages, including the young, half-veraison, veraison, and maturity stages. Aroma components were characterized using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and electronic nose (E-nose) analysis. Results indicated that ‘Hanfeng’ exhibited superior firmness, total soluble solids (TSS), pH, total phenolic content (TPC), and antioxidant capacity. A total of 138 aroma components were identified across all cultivars and stages: 93 in ‘Brodtorp’, 78 in ‘Heifeng’, and 74 in ‘Hanfeng’. The main aroma components across all cultivars included hydrocarbons, alcohols, and esters, of which hydrocarbons were the most abundant. E-nose sensors W1S and W5S showed the highest sensitivity to these aroma components. This study provides a preliminary characterization of the aroma profile and fruit quality of black currants, laying the groundwork for further exploration of their functional properties in food applications.
Mixed-species biofilms on food-contact surfaces are persistent sources of cross-contamination in fresh-produce processing. This study compared mixed-species biofilms of Staphylococcus aureus and Escherichia coli O157:H7 on glass, polystyrene, stainless steel 304 (SS), and fresh lettuce, with in-depth analysis on SS and lettuce as abiotic and biotic representatives. Across the four surfaces, mixed-species biofilms exceeded single-species counterparts in viable counts, biomass (OD595, 1.30-3.24), and extracellular polymeric substance (EPS) yield (21.44-72.65 μg/coupon), with lettuce supporting the highest values. FTIR detected a lettuce-specific band at 1,126 cm-1 consistent with nucleic acid-associated vibrations, and HPLC showed a higher ribose proportion in lettuce-derived EPS (12.84%) than in SS-derived EPS (5.27%). Slightly acidic electrolyzed water (SAEW; 20 mg/L, pH 5.5) reduced mixed-species biofilm culturability below the detection limit in 10 h on lettuce and 12 h on SS, while propidium monoazide qPCR confirmed viable-but-non-culturable (VBNC) entry. Compared with SS, lettuce supported 1.83-fold higher autoinducer-2 (AI-2) activity and 2.0-4.0-fold upregulation of lsrA, lsrC, csgA, rpoS, eaeA, and stx1. Under SAEW treatment, rpoS expression increased to 3.25-fold on lettuce, whereas the other five genes were downregulated. The biotic lettuce surface enhances AI-2 activity and accelerates VBNC formation, retaining virulence gene expression undetectable by standard culture.
The low cost, abundance, and shear-thinning nature of starch gels make them promising inks for extrusion-based 3D food printing; nevertheless, amylose retrogradation raises the yield stress, adversely affecting extrudability and printing accuracy. In this study, maltogenic amylase (AM) treatment was applied at annealing temperatures (30-65 °C) to tailor the molecular structure of corn starch and improve its printability. AM treatment markedly reduced amylose content and modified the amylopectin chain-length distribution. Moderate annealing further promoted the transition of short amylopectin chains (DP 6–12) toward medium-to-long chains, thereby regulating gel network formation. These structural changes directly influenced the rheological behavior and printing performance of starch gels. With increasing annealing temperature, AM hydrolysis weakened the amylose-dominated network, decreased yield stress, and improved extrusion continuity. Meanwhile, the increased amylopectin proportion enhanced water retention and adhesiveness, facilitating smoother extrusion and stronger interlayer bonding. However, excessive annealing produced an overly compact and rigid gel network, which hindered extrusion and reduced printing quality. Among all samples, starch treated at 50 °C exhibited the lowest yield stress, optimal viscoelasticity, stable extrusion behavior, and the highest printing accuracy of 82.60%. Overall, AM-assisted modification at annealing temperatures provides an effective strategy for developing starch-based gels with improved extrudability and structural fidelity for 3D food printing.
Trans fats in traditional solid fats are associated with increased cardiovascular risk, creating demand for safer alternatives. This study investigated the structuring effects of beeswax (BW), candelilla wax (CLW), and carnauba wax (CW) on oleogels prepared from coconut oil (CO) and palm kernel oil (PKO). Among the waxes tested, CLW showed the strongest gelling ability, yielding oleogels with the highest hardness, 95% oil-binding capacity, and stable viscoelasticity. The optimized formulation, containing 8% CLW and a CO:PKO ratio of 1:1, exhibited pronounced elasticity and shear-thinning behavior, indicating its potential as a structured fat phase. Microstructural and spectroscopic analyses indicated that CLW promoted densely packed lamellar crystals and stabilized the β′ polymorph, which are commonly associated with plasticity and spreadability in structured lipid systems. FTIR and Raman results further suggested strong chain-packing interactions between wax esters and triacylglycerols, supporting network stability. Overall, the COPKO-CLW oleogel exhibited rheological and structural characteristics relevant to structured fat design while remaining free of trans fats. These findings provide mechanistic insight into wax-based oleogelation and support the development of trans-fat-free structured fat systems.
Virulence factors and biofilm formation of L. monocytogenes are key to its pathogenicity and persistent food cross-contamination. This study aims to elucidate the specific action of juglone (a natural naphthoquinone) in inhibiting these traits. The results indicated that juglone inhibited the secretion of listeriolysin O and downregulated the expression of virulence genes (inlA、inlB、hly、plcA、plcB、actA、prfA), thereby reducing bacterial invasiveness and pathogenicity. Regarding biofilm, juglone reduced biofilm formation (11.28%–50.99%) and decreased metabolic activity (49.98%–73.13%). It also interfered with bacterial adhesion by altering cell surface hydrophobicity, inhibiting auto-aggregation ability, and reducing extracellular polymeric substance (EPS) production. Furthermore, juglone significantly suppressed swimming (55.84%–94.37%) and swarming (45.63%–80.23%) motilities, and negatively impacted flagellum formation. SEM and CLSM observations further confirmed that juglone disrupted the compactness and integrity of biofilm architecture. RT-qPCR analysis revealed downregulation of quorum sensing-related genes. Molecular docking revealed that hydroxyl and carbonyl groups of juglone form hydrogen bonds with key residues (Tyr-20, Phe-180, Asn-372, and Thr-391) of quorum sensing-related proteins. Proteomic analysis identified ribosome, bacterial chemotaxis, alanine, aspartate and glutamate metabolism, and quorum sensing as primary pathways for the anti-biofilm activity of juglone. These findings provide insights into the molecular mechanisms of juglone against virulence and biofilm formation in L. monocytogenes, supporting its potential as a novel antimicrobial agent.
The application of dealkaline lignin (DAL) has attracted increasing attention in the field of food science. Herein, complex coacervation between DAL and chitosan with varying molecular weights (MWs) was explored for fish oil encapsulation. Complex coacervation of fish oil@chitosan emulsion droplets with DAL occurred across a broad pH range of 7.0–4.0. Both the interfacial tension and viscosity of the coacervation system at different pH values increased with increasing chitosan MWs, whereas the Zeta potential did not. Chitosan MWs did not show significant effects on the morphologies but show obvious effects on the Fourier transform infrared spectroscopy information of the resulting fish oil@chitosan-DAL powders. The chitosan MWs affected the physicochemical properties, thermal stability, oxidative stability, and in vitro digestion behavior of the resulting fish oil@chitosan-DAL powders, although no clear monotonic or consistent relationships were observed. Notably, the oil powders achieved encapsulation efficiencies ranging from 12.4% to 19.0% and exhibited maximum peroxide values between 34.45 and 50.29 mmol/kg oil. Collectively, these findings demonstrated that chitosan-DAL complex coacervation represents a promising wall material system to prepare protein-free, oil-encapsulated food products.
Whole-fruit juicing represents a sustainable zero-waste approach for citrus processing, yet it introduces significant stability challenges due to the complex colloidal system. This study investigated high-pressure homogenization (HPH) as a physical intervention to stabilize whole-fruit Gonggan juice. Results demonstrated that HPH treatment above 200 bar significantly improved suspension stability by reducing particle size and increasing aggregation symmetry. Treatment at 400 bar/2 cycles yielded the most negative Zeta potential. HPH effectively released tightly bound pectin. Water-soluble pectin (WSP) content increased by 1.46 times, while chelate-soluble pectin (CSP) first rose then fell, and sodium carbonate-soluble pectin (NSP) remained stable. HPH increased RG-I branching , especially in WSP treated at 400 bar for 2 cycles ((Gal+Ara)/Rha ratio reached 28.70 ± 0.24). the Atomic force microscopy (AFM) revealed WSP backbone degradation under high pressure, while CSP and NSP chains exhibited enhanced aggregation. HPH promoted aggregation in high molecular weight pectins (CSP, NSP), with low molecular weight fragments likely converting to WSP. This study identified the appropriate HPH parameters for whole-fruit Gonggan juice, providing a scientific basis for optimizing this key processing step.
Traditional Japanese apricot syrup production is time-consuming and typically requires a high sugar content. Here, we developed an integrated process combining isomalto-oligosaccharide (IMO) substitution, freezing pretreatment, and ultrasound (US)-assisted aging. We systematically evaluated the effects of sugar type (IMO or white sugar), pretreatment (freezing or room temperature), and US power (200, 400, or 500 W) on syrup quality using ultra-performance liquid chromatography (UPLC) and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS). Seven-day IMO maceration after freezing pretreatment, followed by US treatment at 400 W (IF7d-US400W), provided the best overall performance. This treatment shortened processing time while producing syrup with an attractive color, balanced sweetness and acidity, satisfactory antioxidant activity, and a diverse profile of desirable volatile compounds, including butyrolactone. It also markedly reduced nitrite levels. These findings provide a rapid, health-oriented strategy for producing high-quality Japanese apricot syrup.
This study investigated the effects of guar and xanthan gums on the physicochemical, bioactive, structural, color, textural, and sensory properties of carrot pomace and tomato pulp leathers dried at 60°C. κ-Carrageenan failed to produce continuous leathers in either matrix, whereas guar and xanthan gums supported successful leather formation. Xanthan gum generally improved structural integrity, color retention, bioactive compound preservation, texture, and sensory acceptance, although its effects were matrix-and concentration-dependent. In carrot leather, 1% xanthan gum provided the most favorable overall sensory performance and enhanced carotenoid and phenolic retention, whereas 2% xanthan gum produced the highest overall sensory acceptance and lycopene retention in tomato leather. Guar gum showed advantages for certain properties, including water absorption and browning control. SEM analysis confirmed hydrocolloid-induced modifications in pore structure, while correlation analysis demonstrated relationships among bioactive compounds, acidity, browning, and dry matter. These results support converting vegetable processing residues into low-moisture, nutrient-rich products, thereby supporting waste valorization and sustainable food innovation.
Ice recrystallization during frozen storage causes water loss, structural damage, and oxidative deterioration in muscle foods. This study evaluated the cryoprotective properties of arginine–glucose Maillard reaction products (AG-MRPs) and their effectiveness in frozen pork sausages. Maillard reaction systems were screened using a catalase protection assay, and the selected AG-MRPs were assessed for thermal hysteresis and ice recrystallization inhibition. Cryoprotective activity reached a plateau after 80 min, while the corresponding unreacted precursors showed no comparable protection. AG-MRPs exhibited a thermal hysteresis activity of 1.00 °C and limited the mean grain size to 83.76% ± 5.99% after five annealing cycles, compared with 161.73% ± 12.55% in the control. In pork sausages, 0.5% (w/w) AG-MRPs provided the most balanced protection after five freeze-thaw cycles, reducing thawing and cooking losses to 6.58% and 11.91%, respectively, while maintaining a water-holding capacity of 72.75%. Low-field nuclear magnetic resonance analysis indicated reduced conversion of immobilized water into free water. AG-MRPs also alleviated textural deterioration and reduced lipid oxidation, protein carbonyl formation, and TVB-N accumulation without markedly altering the characteristic flavor profile. These findings support the potential of AG-MRPs as food-compatible cryoprotective ingredients for frozen meat products.
Epigallocatechin gallate (EGCG) and curcumin (Cur) co-encapsulated composite films were prepared using konjac glucomannan (KGM) incorporating Pickering emulsion stabilized by β-cyclodextrin (β-CD). And then the composite films were applied for strawberry preservation. The structure and properties of the films were systematically characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis, scanning electron microscopy (SEM), antibacterial property and biodegradability. The results showed that Pickering emulsion (0.2 g/L) enhanced the thermal stability, increased tensile strength to 33.17 MPa, dropped EAB from 70% to 40% with water vapor permeability of 2.5×10-13 g·m/(m2·s·Pa) and a denser structure. Both of S6 and S8 displayed high DPPH scavenging ability and strongest antibacterial effect on S. aureus and E. coli. The S8 composite film showed the inhibition zone of 16.08±2.73 mm and 19.97±0.97 mm respectively. Strawberry preservation experiments demonstrated that the film effectively delayed fruit weight loss, hardness reduction, and pH increase, thereby extending the preservation from 6 days to 8 days. Moreover, all Pickering emulsion film completely degraded in soil within 9 days, indicating good biodegradability.
Polyphenols constitute the major antioxidant constituents of rice and substantially influence its nutritional value and storage quality. Herein, a marked increase in total polyphenol content was observed in rice grain after 12 months of natural storage, which conferred enhanced antioxidant capacity. Polyphenol metabolomic profiling identified 565 polyphenol metabolites in both fresh and stored rice grains. Flavonoids and phenolic acids represented the major differential polyphenol metabolites between fresh and stored rice, of which most phenolic acid metabolites were up-regulated in stored rice. Kaempferide, dihydrobisdemethoxycurcumin, methyl acetoxy-[6]-gingerol, and methyl-6-paradol contents significantly increased in all stored rice samples, indicating their potential utility as polyphenol biomarkers for monitoring rice quality deterioration. The polyphenol biosynthesis pathway was upregulated during rice natural storage, as evidenced by the significantly increased activities of phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, 4-coumarate CoA ligase, and flavanone-3-hydroxylase in stored rice. This study provides a comprehensive characterization of polyphenol composition and biosynthesis during rice natural storage and offers new perspectives for quality assessment and value-added utilization of stored rice.
