Camellia seed oil (CSO) is rich in polyphenols, but conventional processing can result in significant loss of phenolic compounds such as phenolic acids, flavonoids and lignans. This study developed an enzyme-assisted fresh pressing (EFP) method to extract oil from fresh Camellia seeds. The extraction process was optimized using a 3.3% mixed enzymes (cellulase, protease, and pectinase of 1:1:1 (v/v/v)) at 55°C for 54 min under pH=3.8. Compared with hot pressing (HP) and fresh pressing (FP), EFP significantly increased oil yield and enhanced total phenol content and antioxidant capacity. In contrast, the fatty acid composition of CSO was slightly affected by the extraction method, indicating that EFP preserved the intrinsic lipid profile of the oil. Notably, benzoic acid, salicylic acid and 3, 4-dihydroxybenzoic acid were three phenolic acids unique to EFP oil. These findings highlight the potential of EFP as a green and efficient method for producing polyphenol-enriched CSO, providing a reference for sustainable oil processing.

While phospholipids are known to affect the antioxidant efficacy of polyphenols in oils, the molecular-scale mechanism underlying this interaction remains unclear. This study elucidated this mechanism through an integrated approach combining quantum chemical calculations, accelerated oxidation experiments, and molecular dynamics simulations. Among four tested polyphenols (camelliaside A, camelliaside B, kaempferol, and quercetin), quercetin demonstrated the highest antioxidant activity, with the lowest IC50 values for scavenging DPPH (43.78 mu mol/L) and ABTS radicals (178.40 mu mol/L), and the highest inhibition (87.68%) against lipid hydroperoxides (LOOH). Quantitative interaction analysis using mixture effect (ME) values revealed that, among all polyphenol-phospholipid combinations, the quercetin-phosphatidylethanolamine (PE) pair uniquely a nearadditive effect (ME = 0.97) without significant antagonism. Molecular dynamics simulations revealed that PE self-assembles into reverse micellar structures within the oil phase, which recruit and concentrate quercetin at the oil-water interface. This interfacial localization likely mitigates the antagonistic interactions observed in other combinations, preserving the additive antioxidant efficacy. The quercetin-PE combination achieved 94.85% LOOH inhibition, outperforming butylated hydroxytoluene (92.28%), demonstrating the practical potential of optimizing interfacial behavior rather than seeking synergism per se. The findings provide a mechanistic basis for designing effective, natural antioxidant systems to improve vegetable oil stability.

Antioxidant mechanism revelation for antioxidant from different sources depends on not only physicochemical properties of antioxidant and the matrix, but also evaluation method. Results in present work demonstrated that rosemary-derived antioxidants significantly inhibited volatile aldehydes production in camellia seed oil (CSO) in Schaal oven test beside of promoting the formation of hexanal by carnosic acid (CA) and nonanal by carnosol (CN). In Rancimat test, CA and CN all could significantly promote the (E)-2-undecenal generation, CA could significantly inhibit the generation of (E)-2-decenal in Rancimat test. CA inhibited the degradation of fatty acids and volatile aldehydes formation because of promoting the degradation of oleic acid-8-hydroperoxide and linoleic acid-9-hydroperoxide, while CN acted as an antioxidant in Schaal oven test but as an oxidizing agent in Rancimat test. The findings of results provided a theoretical basis for selecting methods to evaluate the oxidative stability of lipids.

Camellia seed oil (CSO) exhibits low-bioaccessibility and high-susceptible to oxidation. Here, a whey protein isolate–quercetin (WPI–Que) complex was developed to fabricate CSO in water emulsions. The optimal complex (10 mg Que was dissolved in 100 mL WPI solution) presented an excellent emulsifying performance with the absolute Zeta potential value of 16.26 ± 0.03 mV. Furthermore, the emulsion consisted by 5 pieces of CSO (g) and 10 pieces of emulsifier solution (mL) was constructed with the aid of homogenizing, of which the absolute Zeta potential value was more than 30 mV and the microstructure showed a core–shell droplet construction. The emulsion presented a bioaccessibility of 69.13 ± 0.83% in vitro, which exceeded the bulk oil by 15%. These findings suggested that the WPI–Que complex can be used as emulsifier for constructing CSO delivery in functional food systems.

Under oven test and Rancimat test conditions, the fatty acids changes, the aldehyde formation, and the inhibitory effect of rosemary extract on rapeseed oil (RO) oxidation had been comparatively analyzed in this work. Results demonstrated that the aldehyde compounds generated from RO were (E)-2-decenal, (E)-2-undecenal, and (E,E)-2,4-decadienal both in oven test and Rancimat test, however, nonanal is generated in not Rancimat test but oven test. Meantime, rosemary-derived antioxidants effectively inhibited the formation of (E)-2-decenal, (E)-2-unde-cenal, and (E,E)-2,4-decadienal both in oven tests and Rancimat tests, while, it promoted the production of nonanal only in the oven test. The mechanism whereby nonanal is generated exclusively in oven test may be attributed to the higher likelihood of beta-cleavage occurring at the proximal end of peroxide double bonds compared to the Rancimat test. Meanwhile, the effective inhibition of alkenal/alkadienal formation by rosemary antioxidants is primarily due to their selective suppression of beta-cleavage at the distal end of peroxide double bonds both in test of oven and Rancimat. All results indicated that rosemary-derived antioxidants promoting the double bond-proximal beta-scission exhibited differences in test of between oven and Rancimat, and provide a theoretical basis for evaluating the selection of lipid oxidation detection methods.

The inhibition mechanism of rosemary-derived antioxidants on volatile aldehydes formation in Camellia seed oil (CSO) during heating at 180 degrees C was investigated by measuring acid value (AV), peroxide value (POV), and p-anisidine value (p-AV), and 1H NMR analysis. The results showed that the more unsaturated the fatty acid, the more effective rosemary-derived antioxidants were in enhancing its thermo-oxidative stability. It was carnosic acid (CA) not carnosol (CN) that promoted thermo-oxidative stability of unsaturated fatty acids (UFA) in CSO. The improved stability of CSO is attributed to the ability of rosemary extract to inhibit fatty acid degradation, especially for unsaturated fatty acids (UFA), which in turn suppresses volatile aldehydes formation. Mechanistic studies revealed that rosemary-derived antioxidants selectively suppressed double bond-distal (3-scission over the proximal one, thereby effectively inhibiting alkenal/alkadienal formation. This work provides mechanistic insight into how rosemary-derived antioxidants enhance thermo-oxidative stability of vegetable oils.

This study compared the metabolome of 15 Camellia seed samples of five cultivars (Camellia oleifera Abel., Camellia chekiangoleosa, Camellia yuhsienensis, Camellia meiocarpa and Camellia vietnamensis), and investigated the anti-enteritis effects of their ethanol extracts (EECS). Using UPLC-MS and molecular docking, the potentially anti-enteritis polyphenolic compounds were identified. Their anti-enteritis activity was further validated through in vitro lipoxygenase (LOX) inhibitory activity testing and in vivo inhibiting rate assessment in a Drosophila enteritis model. A total of 924 metabolites were identified. The five cultivars clustered into two distinct metabolic phenotypes: one included Camellia oleifera Abel., Camellia chekiangoleosa and Camellia yuhsienensis, enriched with Chrysin 7-O-beta-gentiobioside, Daidzein, and Bayin; the other one included Camellia meiocarpa and Camellia vietnamensis, enriched with Camelliaside A, and Lancerin. All EECS showed significant inhibition against LOX activity and Drosophila enteritis. The LOX inhibiting rates of trans-trimethylresveratrol, β-artemether, cardamonin, macranthoidin B, and eupatilin were 93.93%, 93.18%, 90.80%, 88.97%, and 81.87%, respectively. Their corresponding enteritis inhibiting rates in Drosophila model were 50.00%, 73.33%, 75.44%, 60.00%, and 73.33%, all higher than (p < 0.05) the positive control drug sulfasalazine (23.33%).

This study systematically characterized the flavor characteristics of Rice-aroma Baijiu under low, atmospheric, and high pressure distillation using QDA, E-nose, HS-GC-IMS, and HS-SPME-GC-MS. Sensory evaluation indicated that low-pressure spirits were characterized by pronounced rice, grassy, and sweet notes, whereas high-pressure spirits displayed more prominent floral and honey notes; the atmospheric-pressure spirit presented a well-balanced flavor profile. The E-nose clearly discriminated samples obtained under different pressures. A total of 248 volatile compounds were identified by HS-GC-IMS and HS-SPME-GC-MS combined (with 19 shared by both), comprising 82 esters, 29 alcohols, 28 aromatic compounds, 20 aldehydes, 15 terpenes, 10 acids, and others. PLS-DA screened 47 key differential volatiles (VIP > 1, P < 0.05). High-pressure spirits contained the highest proportion of esters, while atmospheric distillation favored alcohols. ROAV-based screening identified ethyl isobutyrate, ethyl caprylate, limonene, Isoamyl acetate, ethyl 2-methylbutyrate, isoamyl propionate, and isoamyl butyrate as key aroma compounds. The mantel test revealed a significant positive correlation (P < 0.05) between Isoamyl acetate and Ethyl 2-methylbutyrate and grassy, sweet, and rice notes in low-pressure samples. Conversely, limonene, Isoamyl propionate, and isoamyl butyrate were associated with fruity and floral characteristics in high-pressure samples. These findings provide a scientific basis for flavor design and quality enhancement of Rice-aroma Baijiu.

Roasting Chinese torreya (Torreya grandis cv. Merrillii) kernels significantly influences the quality of oil. However, the changes of oxidative stability of T. grandis kernel oil are still unclear. Herein, oxidative stability index (OSI) was conducted to investigate the oil obtained at different roasting temperatures (60 degrees C, 90 degrees C, 120 degrees C, and 150 degrees C) and duration (25, 50, 75, 100 and 125 min). Furthermore, Maillard reaction, antioxidant compounds, microstructure and widely targeted lipidomics analysis were integrated to analyze the changes of kernels and oils roasted at 150 degrees C. Roasting kernels at 150 degrees C for 25 min resulted in the highest oil yield and disrupted the cellular structure, facilitating the release of tocopherols. 150 degrees C, 25 min roasting had a pronounced effect on the lipid composition, particularly on phosphatidylcholines (PCs) and lyso-phosphatidylcholines (LPCs). A total of 26 lipids emerged as potential markers for distinguishing T. grandis kernel oils with varying roasting intensities, primarily associated with glycerophospholipid metabolism. Pearson correlation showed that the increase of tocopherols and LPC (LPC (22:5), P173) may contribute to enhanced OSI (8.13 h). These findings provide new insight into the change mechanism of oxidative stability in T. grandis oil obtained from high-temperature pretreatment.

Phenolic compounds have been serving as primary antioxidants in retarding lipid oxidation, however, the conventional method for screening phenolic candidates is time-consuming and costly. In this study, phenolics were selected in accordance with the bond dissociation energy (BDE) of O-H and the Gibbs free energy change (ΔG) of the scavenging reaction via quantum chemistry calculation, the efficiency of selected phenolics was subsequently assessed by free energy barrier (ΔG‡), eventually, the suppression efficiency of the candidates was verified by using electron paramagnetic resonance (EPR) determination. Among six catechinic compounds, (-)-gallocatechin gallate (GCG) and (-)-epigallocatechin gallate (EGCG) were identified as the most promising candidates, both of which showed potential efficiency for scavenging alkyl peroxyl (•OOR), alkoxyl (•OR), oleic acid (•OA-C11) and linoleic acid (•LA-C11) radicals. In the thermally-induced camellia oil model (180 °C, 20 min), the inhibition rates of EGCG against alkyl (•R), alkoxyl (•OR) and DMPO oxidative free radicals (•X) were 60.06 ± 0.38 %, 59.74 ± 2.57 % and 92.05 ± 1.70 %, respectively, analogously, the efficiencies of GCG scavenging these radicals ranged from 68.40 ± 0.82 % to 94.27 ± 0.33 %. This indicates that the proposed methodology can effectively screen lipid antioxidants, furthermore, both GCG and EGCG are capable of retarding oxidation in camellia oil.

This study established an aqueous-based method for extracting camellia oil (CO). The optimized process, determined on the basis of bulk oil yield, consisted of sequential procedures: steaming (20 min), enzymatic hydrolysis (1% cellulase, 1% alkaline protease) and aqueous extraction. This process was named steaming aqueous enzymatic extraction (SAEE). Compared with the unheated sample, steaming pretreatment contributed to a 17.56% enhancement in the extraction rate of bulk oil, which was attributed to its degrading effect on cell wall structure and its reduction effect on cellulose crystallinity. In addition, CO was further evaluated in terms of fatty acid profile, deterioration indicators and lipid concomitants. Oleic, linoleic, palmitic and stearic acids were the dominant fatty acids, and oleic acid had the highest content (77.34% ± 0.38% to 77.58% ± 0.24%). The acid values ranged from 0.30 ± 0.02 to 0.35 ± 0.03 mg KOH per g, and the peroxide values were between 0.03 ± 0.00 and 0.04 ± 0.00 g per 100 g. Moreover, phenolics, α-tocopherol, squalene and phytosterols were present in the CO, and α-tocopherol was the distinguishing component, ranging from 277.62 ± 0.77 to 281.33 ± 4.86 mg kg-1. These results suggested that SAEE could be a promising method for producing high-grade CO.

Reverse micelles ubiquitously assemble in the presence of water and amphiphilic substances in edible oils and are the primary locations for oxidation-related reactions. This study revealed the role of reverse micelles in controlling the efficiencies of epigallocatechin gallate (EGCG) and epigallocatechin (EGC) in suppressing the heating-induced deterioration of camellia oil. Using hydroperoxides, conjugated dienes, and carbonylic compounds, we determined that reverse micelles could dually regulate the efficiencies of EGCG and EGC in suppressing the degradation of camellia oil. In particular, reverse micelles in an aliquot containing 500 mu mol/kg EGC positively controlled EGC activity; however, those containing 500, 10, and 10 mu mol/kg of EGCG, EGC, and EGCG, respectively, showed negative effects to corresponding phenolic compounds. Thus, the influence of reverse micelles depends on the concentration and polarity of phenolic compounds. This study provides a new perspective for the development of antioxidant strategies for camellia oil.Practical Application: This study highlights the critical role of reverse micelles in modulating the antioxidant efficiency of epigallocatechin gallate (EGCG) and epigallocatechin (EGC) in camellia oil. Understanding how reverse micelles influence these antioxidants' activity depending on their concentration and polarity provides valuable insight for optimizing antioxidant formulations in edible oils. These results can guide the design of more effective antioxidant delivery systems or processing conditions to enhance the oxidative stability and shelf life of camellia oil and potentially other edible oils.

Pesticide residues pose a serious threat to public health, necessitating the development of rapid and reliable analytical methods to ensure food safety. To achieve simultaneous discrimination of multiple pesticides, a novel Cu/Ce-MOF nanozyme with multienzyme-like activities (including peroxidase-, oxidase-, and laccase-like activities) was synthesized. By exploiting the differential regulatory effects of various pesticides on these activities, a three-channel sensing array was established, enabling the simultaneous discrimination of six pesticides, with a minimum discriminating concentration of 0.5 μg/mL. The sensor array exhibited a wide discriminating concentration range (0.5-35 μg/mL) and successfully discriminated complex pesticide mixtures, including structurally similar compounds such as glyphosate and glufosinate ammonium. Moreover, the method exhibited excellent anti-interference capability and strong applicability to real samples (corn, oat, and jujube). This approach provided a simple and efficient strategy for identifying multiple pesticides, offering substantial potential for strengthening food safety supervision.

BACKGROUND:The integration of high-performance liquid chromatography (HPLC) with rapid post-column biochemical detection techniques has gained widespread application in the pinpoint of antioxidant components in complex natural matrices. However, the use of PEEK reaction coils in on-line antioxidant analysis often encounters issues with poor mixing of the reaction solution, leading to peak broadening and a decrease in peak capacity. This may adversely affect the sensitivity and precision of the analysis. Microfluidic technology provides a unique opportunity for rapid solution mixing. Despite many continuous flow-based micromixers being reported, developing an ultrafast micromixer remains challenging. RESULTS:Here, we demonstrated a new microfluidic mixer and used it to create a highly sensitive on-line HPLC-ABTS system for antioxidant screening, replacing the PEEK reaction coil. The mixer utilizes the engulfment flow to achieve complete mixing of two solutions within sub-microseconds (∼0.6 µs). The system demonstrated consistent half-peak widths under 0.63 min for five phenolic compounds, with a 0.1 min delay time. Optimization of the HPLC-ABTS assay included determining the ideal ABTS•+ concentration and flow rate ratio of ABTS•+ solution to post-column mobile phase. Validation showed that the system exhibited low detection limits (0.3-1.4 μg/mL), superior linearity (r > 0.9900), acceptable recovery (92.33-109.33 %), high stability (RSD < 4.96 %), and excellent reproducibility (RSD < 2.3 %). These observations highlight the advantages of employing the micromixer in on-line analysis. SIGNIFICANCE:Peak broadening reduces the selectivity and accuracy of on-line HPLC assays for detecting antioxidants in complex matrices. Compared to conventional on-line assays utilizing a PEEK coil for radical scavenging, our newly developed system demonstrates enhanced selectivity and precision. This on-line system can be combined with mass spectrometry or on-line extraction devices, which presents a promising alternative for the rapid screening of antioxidant compounds in plant products.

The detection techniques for glyphosate residues have garnered attention due to the potential toxicity associated. Herein, we introduced a fluorescent "turn-on" strategy, leveraging competitive coordination with iron, for glyphosate detection. We synthesized iron-based metal-organic frameworks (Fe-MOFs) at room temperature. Among them, 2,5-dihydroxyterephthalic acid (DOBDC) acted as a ligand to produce strong fluorescence, and iron ions acted as a quencher to quench the fluorescence of DOBDC. Another ligand, 2-nitroterephthalic acid, contained nitro quenching of the fluorescence, giving it a lower background. Glyphosate competed with the ligands for ions, weakening the interaction between ions and the ligands. This disruption restored the fluorescence emission at 535 nm, enabling glyphosate detection. To facilitate field application, Fe-MOFs were encapsulated within agarose to create a functional hydrogel. Glyphosate penetrated the hydrogel and resulting in fluorescence "turn-on". Remarkably, this method facilitated visual detection through smartphone photography coupled with RGB (red/green/blue) analysis, offering a user-friendly and portable solution.

Monascus spp., as an important model microorganism in food and medical research, has been used in China for thousands of years. Monascus spp. can produce many beneficial secondary metabolites, including pigments (food colorants), monacolins (cholesterollowering agents), γ -amino butyric acid (antihypertensive substance), and dimerumic acid (antioxidant), and some Monascus strains can also produce citrinin, a nephrotoxic metabolite. Currently, the main industrialized production through Monascus is monascus red pigment and monacolin K. The monascus yellow and orange pigments possessing high protein coloring ability and many biological effects have not been industrially produced by fermentation so far. However, to our knowledge, few systematic review related to monascus yellow pigments research have been reported. This paper provides a systematic review the breeding of Monascus strain and its fermentation processes optimization, the identification of monascus yellow pigments and their structures, the pharmacological properties and biosynthesis pathway of monascus yellow pigments. Finally, an academic view on the future of monascus yellow pigments from the perspective of industrialized production is presented.

The rapid discrimination and detection of pesticide residues represent a critical strategy for mitigating food safety risks associated with pesticide contamination. We designed and synthesized three distinct iron-based metal-organic frameworks (Fe-MOFs) nanozymes incorporating varied organic ligands. Owing to the differential modulation of their peroxidase-like activity by different pesticides, a facile yet efficient three-channel sensing array was constructed using these Fe-MOF nanozymes, allowing for the simultaneous discrimination of five pesticides (the minimum distinguishable concentration was 1 μg/mL). By converting pesticide-specific response signals into fingerprint profiles and subjecting them to analysis, including linear discriminant analysis and hierarchical cluster analysis, we achieved the classification of diverse pesticide species. Notably, the sensing platform exhibited good discriminative capability even for complex pesticide mixtures and real samples (corn and oat). This approach established a reliable and efficient strategy for pesticide screening, offering significant potential for enhancing food safety monitoring and safeguarding public health.

Food safety incidents threaten human health and life safety. It is an effective method to prevent and control the occurrence of food safety events by enhancing the rapid and sensitive detection of food contaminants. Emerging porous materials provide for the development of efficient and stable detection methods. Covalent organic frameworks (COFs) are favored by researchers for their highly ordered pore structure, large specific surface area, and good structural and functional designability. Especially in the sensing field, COFs play the roles of carriers, conductors, quenchers, and reporters, and have broad application prospects. To better understand COFs-based sensing studies, this review briefly introduces the characteristics and different functional roles of COFs in food safety analysis, focusing on the applications of COFs in the detection of various food contaminants (including foodborne pathogens, mycotoxins, pesticides, antibiotics, heavy metals, and others). Finally, the challenges and opportunities for COFs-based sensing are discussed to facilitate further applications and development of COFs in food safety.

The extensive use of glyphosate poses a potential threat to food safety, human health, and the ecological environment. Hence, detecting glyphosate residues in food is of great significance for food safety. In this work, the synthesis of zinc-organic frameworks (Zn-MOFs) was achieved through the coordination of Zn2+ with the 2,5dihydroxyterephthalic acid (DOBDC) ligand. Upon excitation at 350 nm, these Zn-MOFs exhibited robust fluorescence emission at 533 nm. However, upon the addition of iron ions, the Zn-MOFs structure disintegrated, forming a blue Fe-DOBDC complex, resulting in fluorescence quenching. In the presence of glyphosate, the iron ions were chelated by glyphosate, causing the system to lighten in color and restore fluorescence. Further, the mechanism of this strategy was investigated, which was achieved by utilizing the competitive interaction of glyphosate and Zn-MOFs for iron ions. The binding stoichiometry and binding constant of glyphosate:Fe3+ are 1:1 and 7.59 x 103 M- 1 using the Job's plot and Benesi-Hildebrand equation, respectively. To enhance glyphosate detection, this study introduced an ingenious dual-mode strategy. By analyzing the colorimetric and fluorescence changes before and after glyphosate addition, we can accurately determine its concentration in the system. The combined colorimetric and fluorescent modalities offer improved reliability and applicability, boasting simplicity, rapidity, and cost-effectiveness. This innovative method is anticipated to find widespread applications and offers novel perspectives on pesticide detection platforms based on ligand competition effects.