The tender shoots harvested from regular leaf color tea cultivars such as 'Longjing 43', as well as albino tea germplasms including 'Huangjinya' and its offspring, were processed into ultra-fine green tea powders in later spring and autumn. The quality characteristics of 'Huangjinya' and its albino offspring ultra-fine green tea powders were comprehensively evaluated through sensory evaluation, analysis of particle size and color difference, determination of tea polyphenols and catechins, and detection of alkaloid and amino acid components. The results showed that the appearance and color of the ultra-fine green tea powders made from 'Huangjinya' and its albino offspring were significantly different from those of regular leaf color cultivars, and the umami and freshness of the tea infusions were better than those of regular leaf color cultivars. The particle sizes of ultra-fine green tea powders made from 'Huangjinya' and its albino offspring (D90, 56.50~67.05 μm) were similar to those of regular leaf color cultivars (D90, 57.47~62.69 μm), indicating that the grinding characteristics of albino and regular leaf color tea germplasms were basically same. The brightness of ultra-fine green tea powder made from 'Huangjinya' and its albino offspring (L^* value, 71.65~81.43) was higher than that of regular leaf color cultivars (L^* value, 65.50~72.65), and the greenness (a^* value, −5.31~−0.12) was lower than that of regular ones (a^* value, −6.45~−2.85). Compared with regular leaf color cultivars, the total free amino acid content (29.72~104.36 mg/g) and amino acid composition with various flavors in the powder from 'Huangjinya' and its albino offspring were higher, while contents of tea polyphenols (165.99~243.72 mg/g), catechins (79.74~172.09 mg/g), ratio of tea polyphenols to free amino acids (1.59~7.94), and caffeine content (18.34~32.27 mg/g) were lower. The results showed that the color of the ultra-fine green tea powder made from 'Huangjinya' and its albino offspring in autumn was more yellow than that in spring; the aroma was mainly light, but the taste intensity of autumn tea powder was generally higher than that of spring. The particle sizes of ultra-fine green tea powder in spring were similar to those in autumn (60.58 vs 61.41, μm). The L^* value (77.21 vs 74.16) and b^* value (27.31 vs 27.07) of ultra-fine green tea powder in spring was higher than that in autumn, but the seasonal variation of the a^* value (−2.14 vs −2.66) was large. The total free amino acid content (60.74 vs 35.93, mg/g) and amino acid composition in the powder from 'Huangjinya' and its albino offspring of spring were higher than that of autumn, while contents of tea polyphenols (199.87 vs 211.17, mg/g), catechins (102.44 vs 149.66, mg/g), caffeine content (24.52 vs 26.04, mg/g), and ratio of tea polyphenols to free amino acids (3.79 vs 6.14) were lower. The results of orthogonal partial least squares discriminant analysis (OPLS-DA) showed that 17 physical and chemical indicators, including color difference, amino acids, alkaloids, and so on, could be used to distinguish characteristics of green tea powders made from the regular leaf color and albino cultivars such as 'Huangjinya'. The different contents of 22 metabolites, including amino acids, alkaloids, and catechins, in the ultra-fine green tea powder were the key reasons for the seasonal quality differences of 'Huangjinya' and its albino offspring. This study can provide theoretical basis for establishing a comprehensive quality evaluation system of the ultra-fine green tea powders and developing the identification indicators of cultivar breeding for tea plant germplasms with specific leaf colors.

This study employed headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) to analyze the volatile flavor profiles of four chive cultivars ('White Chive''Black Chive''Local Red Chive' and 'Tiegan Red Chive') from the Luxi region of Yunnan. A total of 797 volatile compounds across 15 classes were identified. Esters (140), terpenoids (123), and alcohols (97) were the most abundant in variety, while sulfur-containing compounds (128.51 mg/kg), ketones (107.27 mg/kg), and terpenoids (106.39 mg/kg) were the highest in content, and 166 differential aroma compounds were selected using the cutoff of variable importance in projection (VIP)>1 with a P value<0.05. Dipropyl disulfide was identified as key odorants contributing to grassy, onion, and sulfur notes. Orthogonal partial least squares-discriminant analysis (OPLS-DA) of compounds with OAV>10 revealed 22 significant aroma compounds (VIP>1, P<0.05), among them, citronellal and (S)-3,7-dimethyl-6-octenal exhibited the highest VIP values (2.62) and were identified as critical aroma differential compounds. Further analysis characterized the primary aroma attributes as grassy, sulfurous, coffee, and minty. 'White Chive' and 'Black Chive' exhibited prominent grassy notes, whereas 'Local Red Chive' and 'Tiegan Red Chive' displayed stronger sulfurous, coffee, minty, vegetal, nutty, and leafy aromas, with 'Tiegan Red Chive' having the most distinct nutty character. This study has not only provided a scientific basis for flavor quality evaluation, but also has laid a foundation for the diversified flavor selection and deep processing of Luxi chives.

To improve the quality of early-summer white tea, further optimize its processing technology, and explore the quality and material basis of white tea processed with different techniques. This study used fresh leaves of the 'Fuding Dabai' cultivar, harvested at the stage of one bud and two leaves, as raw materials. Based on the traditional indoor withering and combined indoor-outdoor withering, light-rolling and shaking-green treatments were introduced, respectively. Through sensory evaluation, major biochemical analyses, and determination of volatile aroma components via headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), the influence of different processing techniques on the finished tea was investigated. The sensory evaluation results indicated that the white teas processed with light-rolling and shaking-green exhibited a more refreshing, pronounced, and lasting aroma, along with a sweeter and more pleasant taste, and consequently, a superior overall sensory quality. The analysis of biochemical components demonstrated that the water extract contents of the light-rolled and shaking-greened teas were 32.19% and 34.56%, respectively, and the soluble sugar contents were 4.75% and 4.61%, respectively, both of which were significantly higher than those of the traditionally withered tea (P<0.05). The analysis of aroma components led to the detection of 1172 compounds in total, which included 408 isomers. Based on the differences in their primary functional groups, the detected aroma components were classified into 15 major categories, with terpenoids, esters, ketones, and alcohols being the most abundant. Relative odor activity value (ROAV) analysis identified dihydro-2-methyl-3(2H)-furanone, (E)-β-damascone, (E,Z)-2,6-nonadienal, (E)-2-hexenal, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone as key aroma compounds. The findings demonstrate that light-rolling and shaking-green are effective techniques for enhancing the sensory and key physicochemical properties of early-summer white tea. This study provides critical data and a theoretical foundation for innovating processing techniques and achieving precise quality management.

This study investigated the effects of stem presence and freezing rate on the freezing quality of Lycium barbarum, nitogen (N₂) and air were employed as heat transfer medium for quick freezing (NF_{−30 ℃,} NF_{−50 ℃,} NF_{−70 ℃,} NF_{−90 ℃,} NF_{−100 ℃}) and freezer quick freezing (AF_{−40 ℃}, AF_{−20 ℃}). The freezing characteristics and quality changes of Lycium barbarum with and without stems were analyzed and compared. The results indicated that the weight loss rate for the air group and the N₂ group with stems were 20% to 22% and 8% to 17% lower respectively, than those without stems. Additionally, the nutrient retention rates increased by 8% to 23% and 6% to 53%, respectively. Notably, the difference in weight loss rates between Lycium barbarum with stems and those without was significant when the freezing rate was below 1.58 ℃/min. The freezing rate in the N₂ group (1.58~5.09 ℃/min) was approximately 2~24 times greater than that of the air group (0.21~0.78 ℃/min). The quality retention effect could be ranked as NF_{−90 ℃}≥NF_{−100 ℃}>NF- _70℃>NF_{−50 ℃}>NF_{−30 ℃}>AF_{−40 ℃}>AF_{−20 ℃}. Under a freezing rate of 3.94 ℃/min (NF_{−90 ℃} treatment group), a higher the freezing rate, resulted in better quality preservation. The nutritional quality of Lycium barbarum with stems in the NF_{−90 ℃} treatment group maintained more than 75% of the fresh wolfberry quality, with the color closely resembling fresh wolfberry, and a weight loss rate of only 0.93%. Pearson and cluster analyses further confirmed that the optimal freezing mode of Lycium barbarum was NF_{−90 ℃} with stems. The results indicated that when the freezing rate was below 1.58 ℃/min, the protective effect of wolfberry stems on fruit freezing characteristics was more pronounced, and the impact of heat transfer medium on quality was greater than that of freezing temperature. The freezing rate was the decisive factor for quality when Lycium barbarum was frozen with stems. The factors affecting the freezing quality of Lycium barbarum could be ranked as follows: Lycium barbarum stems>freezing rate>heat transfer medium>freezing temperature. This study provides a theoretical basis and technical guidance for the freezing processing of Lycium barbarum.

In the present study, sodium alginate-based intelligent cross-linked films were prepared using cinnamon essential oil (CEO, 2.0wt%) as the antibacterial component and vacuum-freeze-dried purple sweet potato anthocyanin (PSPA) at concentrations of 0%, 0.2%, 0.6%, 1.0%, 1.4%, and 1.8% w/v as the indicator. The effects of PSPA addition on the film properties (including dissolution, barrier, optical, and antibacterial performances) as well as the response to ammonia compounds and pH were tested. In addition, the effect of the films on real-time monitoring of shrimp freshness was evaluated. The results showed that the addition of CEO and PSPA endowed the films with notable growth inhibitory effects against Escherichia coli and Staphylococcus aureus. The films containing PSPA had greater thickness, water vapor permeability, and oxygen permeability than the control films, whereas the water solubility, water content, swelling ratio, and light transmittance decreased with increasing PSPA concentration. Additionally, incorporation of PSPA enhanced the ultraviolet barrier performance of the films and resulted in clear color responses to concentrated ammonia water, dimethylamine, trimethylamine, and pH1~13 buffer solutions. The results of the shrimp freshness monitoring test indicated that the SA-based films containing PSPA exhibited good color indication effects on the volatile nitrogen-containing compounds produced during the refrigeration process of shrimp and could be used to effectively monitor the changes in freshness of shrimp in real time. Moreover, under the synergistic effect of CEO, the pH, thiobarbituric acid reactive substances (TBARS), volatile basic nitrogen (TVB-N), and total bacterial count (TVC) of shrimp samples during storage were reduced, and the shelf life of shrimp was prolonged. These results indicate that the developed film has significant potential as a packaging material for nondestructive monitoring of the freshness of aquatic products.

This study aimed to investigate the quality changes of ice-coating red swamp crayfish tails during long-term frozen storage. Ice-coated crayfish tails were considered as the research object, and attributes including sensory evaluation, texture profile analysis (TPA), total volatile basic nitrogen (TVB-N), pH, thiobarbituric acid reactive substances (TBARS), protein carbonyl content, and active sulfhydryl content, were systematically monitored over six months of storage at −18 ℃. Correlation analysis was also conducted based on the research results. The results showed that during the 6-month frozen storage at −18 ℃, the indexes of the cooked crayfish tails with ice coating did not exceed the standard limits, but with the extension of the frozen storage time, the contents of TVB-N, TBARS and carbonyl groups in the tail of crayfish coated with ice increased significantly (P<0.05), and the content of active sulfhydryl groups increased first and then decreased, reaching the peak in the 3rd~4th months of storage, and the hardness and elasticity showed a fluctuating downward trend, and the hardness reached the highest value (3680.48 g) at the 3rd month, while the sensory score decreased significantly (P<0.05), and the quality of fresh products was still retained by 80% of the crayfish after 3 months of storage. Based on the changes of the above indicators, it was determined that the best tasting period of ice-coated crayfish tails was 3 months. According to the correlation analysis, protein degradation and fat oxidation might be the dominant factors contributed to the quality deterioration of ice-coated crayfish tails during frozen storage. This work provided theory basis for the promotion of industrial processed crayfish storage quality.

Purposes: This study investigated the effects of 1-linoleoyl-3-chloropropanediol (C_18:2-Me) exposure on urinary metabolites in rats using untargeted metabolomics. Methods: Twenty-four male Sprague-Dawley (SD) rats were randomly divided into a normal group (ND), a low-dose group (LD, 7 mg/kg·BW), and a high-dose group (HD, 70 mg/kg·BW). The LD and HD groups received daily intraperitoneal injections for two consecutive days. Untargeted metabolomics analysis based on gas chromatography-mass spectrometry (GC-MS) was performed to analyze rat urine before and after C_18:2-Me exposure. Additionally, histopathological examination of kidney tissue was performed. Results: A total of 33 differential metabolites were screened out between the ND and HD groups, including 25 upregulated and 8 downregulated metabolites. Pathway analysis revealed that C_18:2-Me exposure primarily perturbed β-alanine metabolism, sulfur metabolism, glycine, serine, and threonine metabolism, retinol metabolism, glyoxylate and dicarboxylic acid metabolism, and starch and sucrose metabolism. Histopathological examination showed separation of tubular epithelial cells from the basement membrane and luminal enlargement in the exposed groups. Conclusions: Exposure to C_18:2-Me induced alterations in urinary metabolites and exerted toxic effects on rat kidneys by disrupting several metabolic pathways. Histopathological findings were consistent with the metabolomics results.

Objective: To investigate the in vitro antioxidant activity and stability of white kidney bean antioxidant peptides (WKBAPs). Method: In order to analyze the effects of pH, temperature, metal ions, food ingredient composition, and simulated gastrointestinal digestion on the stability of antioxidant peptides in white kidney beans, the DPPH free radical scavenging rate, ABTS⁺ free radical scavenging rate, hydroxyl free radical scavenging rate, and total antioxidant capacity were measured, and an oxidative damage model was established in HepG2 cells induced by 2,2'-azodiisobutyramidine dihydrochloride (AAPH) to explore the protective effect of WKBAPs on cellular oxidative damage. Results: Although the antioxidant activity of WKBAPs fluctuated under different processing conditions, the overall performance remained stable, still maintaining a high level of antioxidant activity. Only under strong acid, strong base, high temperatures (>60 ℃), high concentrations of Ca²⁺, Zn²⁺, Cu²⁺, and elevated levels of NaCl, citric acid, and glucose, the antioxidant activity of WKBAPs was significantly diminished (P<0.05). As the K⁺ concentration increased, the DPPH and ABTS⁺ radical scavenging capacities of WKBAPs initially decreased and subsequently stabilized. Meanwhile, the hydroxyl radical scavenging capacity and total antioxidant ability exhibited a slight but non-significant decline (P>0.05). During intestinal digestion, the DPPH and hydroxyl radical scavenging rates were significantly reduced, but the high antioxidant activity was still maintained. At the end of 240 minutes intestinal digestion process, its DPPH radical scavenging rate, ABTS⁺ radical scavenging rate, hydroxyl radical scavenging rate, and total antioxidant capacity were 78.03%±1.01%, 94.05%±0.47%, 74.75%±0.29%, and 0.76±0.02 mmol Fe²⁺/g, respectively. In the AAPH induced oxidative damage model of HepG2 cells, WKBAPs could increase the survival rate of HepG2 cells damaged by AAP oxidation. It significantly reduced the production of reactive oxygen species (ROS), dramatically decreased the release level of lactate dehydrogenase (LDH) into the cell culture supernatant due to membrane damage, inhibited the production of malondialdehyde (MDA), and enhanced the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Conclusion: WKBAPs has good in vitro antioxidant activity and stability, providing a theoretical basis for its application and development in the field of food and healthcare.

In order to study the difference of antioxidant activities among the extracellular polysaccharide (POFP), mycelium polysaccharide (POMP) and fruiting body polysaccharide (POP) of Pleurotus ostreatus by liquid fermentation, this study prepared POFP and POMP through liquid-state fermentation of edible fungi, polysaccharide isolation and purification, as well as other techniques, followed by a comparative evaluation of their antioxidant activities with POP. The study assessed the in vitro antioxidant activity of the three polysaccharides using DPPH radical, ABTS⁺ radical, and OH radical scavenging activities as well as total reducing power. Additionally, yeast cell models subjected to ultraviolet (UV)-induced oxidative damage and H₂O₂-induced oxidative damage were employed to evaluate their protective effects against oxidative injury. The results showed that the three kinds of polysaccharides were composed of two kinds of components with different molecular weights, which ranged from 375.31~9788.14 Da, and the order of molecular weight was POP>POMP>POFP. All three polysaccharides demonstrated significant scavenging activities against DPPH, ABTS⁺, and OH radicals, along with notable reducing power, all of which exhibited a dose-dependent manner. Among them, POFP displayed the strongest total reducing power, achieving an OD₇₀₀ value of 0.51±0.04 at a concentration of 5 mg/mL, which was higher than that of POMP and POP. Furthermore, all three polysaccharides significantly increased the survival rates of yeast cells subjected to UV- and H₂O₂-induced oxidative damage. Among them, POP demonstrated stronger protective effects, restoring the viability of UV-damaged yeast cells to 96.05%±4.02% at a concentration of 25 mg/mL, and that of H₂O₂-damaged yeast cells to 91.6%±3.26% at 15 mg/mL, which was comparable to the effects observed in the vitamin C (V_C) treatment group. In summary, Pleurotus ostreatus polysaccharides from different sources exhibited significant antioxidant activities, and liquid fermentation technology provided a new way for the preparation of new antioxidant natural products.

This study aimed to systematically compare the in vitro antioxidant activities of aqueous extracts and polysaccharides isolated from the bulbs and flowers of Fritillaria thunbergii Miq., and to investigate the composition of floral polysaccharides as well as their in vivo antioxidant effects and preliminary mechanisms in the model organism Caenorhabditis elegans, thereby providing experimental evidence for the utilization of F. thunbergii Miq. flowers. Bulb decoctions (FTD), bulb polysaccharides (FTP), flower decoction (FTFD), and floral polysaccharides (FTFP) from F. thunbergii Miq. were prepared using water extraction. Their in vitro antioxidant activities were evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical scavenging assays, as well as a ferric ion reducing capacity (ferric reducing antioxidant power, FRAP) assay. Furthermore, the C. elegans model was used to assess the antioxidant effects of the most active component screened. The regulatory effects on the expression of oxidative stress-related genes were explored by analyzing the fluorescence intensities of transgenic C. elegans CF1553 (sod-3p::GFP) and CL2166 (gst-4p::GFP). The results revealed that the flower-derived extracts (FTFD and FTFP) exhibited significantly stronger antioxidant capacities than the bulb-derived extracts (FTD and FTP). Among these, FTFP (1 mg/mL) showed the strongest ferric reducing ability (0.97±0.011 mmol/L), along with high scavenging rates against DPPH radicals (76.58%±0.68%) and ABTS cation radicals (58.63%±8.58%). In vivo experiments showed that C. elegans treated with FTFP (0.04~4 mg/mL) exhibited significantly enhanced resistance to heat and oxidative stress and up-regulated the expression of the antioxidant genes sod-3 and gst-4 in a concentration-dependent manner. Composition analysis revealed that FTFP was an acidic heteropolysaccharide primarily composed of galacturonic acid (GalA, 70.02%), and contained rhamnose, glucose, galactose, xylose, and arabinose. High-performance gel permeation chromatography (HPGPC) showed that it primarily contained two components with average molecular weights of 363.05 and 26.04 kDa, respectively. In conclusion, FTFP is the primary active component responsible for its antioxidant effects, as it effectively scavenges free radicals as well as enhances the resistance of organism to oxidative stress by upregulating sod-3 and gst-4 expressions. This study provides an important theoretical basis for the development and use of F. thunbergii flower resources.