Structure and physicochemical properties of polysaccharides from Poria cocos extracted by deep eutectic solvent.

Poria cocos, a famous traditional Chinese medicine and a well-known food or food supplement, has shown therapeutic potential against cancer and the uneasiness of the mind. In addition, polysaccharides (PCPs) in this fungus were found to be various bioactive. In this work, one such PCP, PCP-1, extracted by deep eutectic solvent (DES) and separated using Sephadex G-15 columns, was characterized using GC-MS, HPGPC, FT-IR, and NMR, while also tested for physicochemical properties. Results indicated that PCP-1 contained 96.89 ± 3.21% total sugars and was a glucan with molecular weight of 3.2 kD. The main glycosidic linkage was 1,3-linked Glcp with 96.82 mol% content and a triple helix structure, and ß-D-Glcp-(1 → linkage connected to the main chain through an O-6 atom was the backbone structure. In terms of the physicochemical property, PCP-1 was soluble in water, but not in organic solvent, and processed a relative high water-holding capacity (8.64 ± 0.14 g/g) and low oil-holding capacity (2.52 ± 0.21 g/g). In addition, in vitro, PCP-1 was found to have the ability of scavenging DPPH, hydroxyl free radical, superoxide anion radical and reducing ferric at different levels. This research would be useful for the further application of PCP-1.

Oral Administration of Omega-3 Fatty Acids Attenuates Lung Injury Caused by PM2.5 Respiratory Inhalation Simply and Feasibly In Vivo.

For developing an effective interventional approach and treatment modality for PM2.5, the effects of omega-3 fatty acids on alleviating inflammation and attenuating lung injury induced by inhalation exposure of PM2.5 were assessed in murine models. We found that daily oral administration of the active components of omega-3 fatty acids, docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA) effectively alleviated lung parenchymal lesions, restored normal inflammatory cytokine levels and oxidative stress levels in treating mice exposed to PM2.5 (20 mg/kg) every 3 days for 5 times over a 14-day period. Especially, CT images and the pathological analysis suggested protective effects of DHA and EPA on lung injury. The key molecular mechanism is that DHA and EPA can inhibit the entry and deposition of PM2.5, and block the PM2.5-mediated cytotoxicity, oxidative stress, and inflammation.

Effects of cuticular wax on the postharvest physiology in fragrant pear at different storages.

BACKGROUND: Epidermal wax is an important factor affecting the storage quality of fruits and vegetables. Previous studies have shown that the epidermal wax of fruits undergoes significant changes during storage, but there are few studies on the effects of different storage methods on the changes in waxes and the relationship with storage quality. To investigate the effect of cuticular wax on the postharvest physiology in fragrant pear, equal numbers of fragrant pear fruits were stored in room temperature storage (control), cold storage and controlled atmosphere (CA) storage environs, respectively. RESULTS: Gas chromatography-mass spectrometry analysis revealed that the prevailing compositions of cuticular wax of fragrant pear were alkanes, alkenes, alcohols, aldehydes, esters and fatty acids. Compared with the control, cold storage and CA storage significantly inhibited changes in postharvest physiology, total wax contents and wax compositions of fragrant pear, and the effects of CA storage were more pronounced than cold storage. Under different storage methods, total wax contents and wax compositions show different correlations with various physiological indicators. CONCLUSION: The results obtained in the present study indicate that cold storage and CA storage altered the fragrant pear cuticular wax contents and constituents, thus changing the postharvest physiology quality. The changes in the metabolism of wax components caused by the changes in storage environment mainly affect the changes in the hardness of fragrant pears. The present study provides a theoretical basis for the preservation and storage of fruits. © 2022 Society of Chemical Industry.

Physicochemical, Structural, and Biological Properties of Polysaccharides from Dandelion.

The edible and medicinal perennial herb dandelion is known to have antitumor, antioxidant, and anticomplement properties. However, the structural characterization and biological effects of its polysaccharides are not well understood. Here, we aimed to extract and investigate a novel polysaccharide from dandelion. A water-soluble polysaccharide, PD1-1, was successfully obtained from dandelion through ultrasonic-assisted extraction and purification using diethylaminoethyl (DEAE)-Sepharose fast flow and Sephadex G-75 columns. The results showed that PD1-1 is an inulin-type polysaccharide with a molecular weight of 2.6 kDa and is composed of glucose (52.39%), and mannose (45.41%). Glycosidic linkage analysis demonstrated that PD1-1 contains terminal α-d-Man/Glcp-(1→ and →1)-ß-d-Man/Glcf-(2→ glycosidic linkage conformations. A physicochemical analysis indicated that PD1-1 has a triple helix structure and exhibits important properties, including good swelling, water-holding, and oil-holding capacities. Furthermore, PD1-1 showed good antioxidant activities in DPPH and hydroxyl free radical scavenging abilities, with IC50 values of 0.23 mg/mL and 0.25 mg/mL, respectively, and good hypoglycemic activities in α-amylase and α-glucosidase inhibition, with IC50 values of 0.53 mg/mL and 0.40 mg/mL, respectively, in a concentration-dependent manner. Results suggest that PD1-1 possesses efficacious antioxidant and hypoglycemic properties and has potential applications as a functional food ingredient.

Impact of Titanium Dioxide and Fullerenol Nanoparticles on Caco-2 Gut Epithelial Cells.

The application of nano-products in the food industry increases the risk of people exposed to nanoparticles. Titanium dioxide nanoparticles (T-NPs) are typically and widely used in food field, while fullerenol nanoparticles (F-NPs) have great promise to be used as food additives. Therefore, it is necessary and important to understand the safety of T-NPs and F-NPs in foods. In the present study, Caco-2 gut epithelial cell line was selected as a model to investigate the impact of T-NPs and F-NPs. The viability and proliferation of Caco-2 gut epithelial cells incubated with different concentrations of T-NPs and F-NPs were observed. The results showed that the two kinds of nanoparticles did not induce cell death even lasting for 48 h. The results of apoptosis and DNA damages in the cells indicated that both T-NPs with 50 and 100 µg/mL caused Caco-2 gut epithelial cell apoptosis, but didn't cause significantly DNA damages. F-NPs with 200 and 500 µg/mL concentrations also can induce cell apoptosis but no DNA damage.

Amino acid composition, molecular weight distribution and gel electrophoresis of walnut (Juglans regia L.) proteins and protein fractionations.

As a by-product of oil production, walnut proteins are considered as an additional source of plant protein for human food. To make full use of the protein resource, a comprehensive understanding of composition and characteristics of walnut proteins are required. Walnut proteins have been fractionated and characterized in this study. Amino acid composition, molecular weight distribution and gel electrophoresis of walnut proteins and protein fractionations were analyzed. The proteins were sequentially separated into four fractions according to their solubility. Glutelin was the main component of the protein extract. The content of glutelin, albumin, globulin and prolamin was about 72.06%, 7.54%, 15.67% and 4.73% respectively. Glutelin, albumin and globulin have a balanced content of essential amino acids, except for methionine, with respect to the FAO pattern recommended for adults. SDS-PAGE patterns of albumin, globulin and glutelin showed several polypeptides with molecular weights 14.4 to 66.2 kDa. The pattern of walnut proteins in two-dimension electrophoresis (2-DE) showed that the isoelectric point was mainly in the range of 4.8-6.8. The results of size exclusion chromatogram indicated molecular weight of the major components of walnut proteins were between 3.54 and 81.76 kDa.

Comparison of different drying pretreatment combined with ultrasonic-assisted enzymolysis extraction of anthocyanins from Lycium ruthenicum Murr.

Extraction of anthocyanins from Lycium ruthenicum Murr. (L. ruthenicum) is a notable challenge in food production, requiring methods that balance efficiency and safety. In this study, we conducted a comparative analysis the extraction of anthocyanins by natural air drying (NAD), vacuum freeze drying (VFD), hot air drying (HAD), and vacuum microwave drying (MVD) combined with ultrasonic-assisted enzymolysis extraction (UAEE). The results demonstrated that the extraction yield and antioxidant activity of anthocyanins were significantly higher in VFD. This phenomenon can be attributed to the modification of raw material's microstructure, leading to an increased extraction yield of specific anthocyanins such as Cyanidin-3-galactoside, Delphinidin chloride, Cyanidin, and Petunidin. According to the pretreatment results, the extraction process of anthocyanins was further optimized. The highest yield (3.16 g/100 g) was obtained in following conditions: 0.24 % pectinase, 48 °C, solid:liquid = 1:21, and 21 min ultrasonic time. This study improves the commercial value and potential application of L. ruthenicum in food industry.

Cuticle properties, wax composition, and crystal morphology of Hami melon cultivars (Cucumis melo L.) with differential resistance to fruit softening.

Cuticle wax chemicals are cultivar-dependent and contribute to storage quality. Few research reported on wax analysis between melting flesh-type (MF; 'Jinhuami 25') and nonmelting flesh-type (NMF; 'Xizhoumi 17' and 'Chougua') Hami melons. Chemicals and crystal structures of Hami melon cuticular wax, cell wall metabolism related to fruit melting, and fruit physiology were analyzed to observe wax functions. Results showed that Hami melon cuticle wax predominantly consists of esters, alkanes, alcohols, aldehydes, and terpenoids. MF-type has a lower alkane/terpenoid ratio, concomitant to its higher weight loss and cuticle permeability. Micromorphology of wax crystals appears as numerous platelets with irregular crystals, and the transformation of wax structure in NMF Hami melon is delayed. Waxy components affect cell wall metabolism and physiological quality, which results in the pulp texture difference between MF-type and NMF-type during storage. Results provide a reference for the regulation of wax synthesis in both types of melons.

Effects of ultrasonication and freeze-thaw pretreatments on the vacuum freeze-drying process and quality characteristics of apricot (Prunus armeniaca L. cv. Diaoganxing).

The combination of pretreatment and vacuum freeze-drying (VFD) technology is an effective technique for extending the shelf life of apricots, reducing costs and energy consumption. However, the impact of pretreatment on the freeze-drying and quality characteristics of apricots is still unclear. The effects of ultrasound (US), freeze-thaw (FT), and their combination (FT-US) on water migration and quality characteristics of apricot slices on VFD were studied. LR-NMR and SEM showed that pretreatment significantly reduced the time (19.05%-33.33%) and energy consumption (17.67%-35.66%) of the VFD process. Compared with the control group, the US, FT, and FT-US improved the color, texture, rehydration ability, and flavor of apricot slices. Among them, FT-US retained the most biologically active substances and antioxidant capacity, with the highest sensory score. Overall, FT-US pretreatment induced changes in the microstructure and chemistry of apricots, which contributed to the production of high-quality VFD apricot slices.

Effects of variable-temperature drying on the qualities and sweet-substance profile of Zizyphus jujuba Mill. cv. Junzao.

The changes in the qualities and sweet-substance levels of Junzao jujube during variable-temperature drying (VTD) were investigated. The results showed that VTD retains the original color of jujube, reduces its hardness and chewiness, and decreases its wrinkling while shortening the drying time by 13.2% compared with that of constant temperature drying (CTD). "Electronic-tongue" taste analysis showed that the sweetness of VTD jujube is significantly higher than that for CTD. This is shown to be related to the contents of sucrose, fructose, and glucose, as well as the activities of invertase and sucrose synthase enzymes. In addition, the content trends for sweet amino acids are correlated with the temperature gradient used in VTD. Thus, the present study elucidates the factors governing the transformation of sugar substances in jujube during VTD, as well as providing a practical reference for the application of VTD in the jujube industry.

1-Methylcyclopropene and UV-C Treatment Effect on Storage Quality and Antioxidant Activity of 'Xiaobai' Apricot Fruit.

The 'Xiaobai' apricot fruit is rich in nutrients and is harvested in summer, but the high temperature limits its storage period. To promote commercial quality and extend shelf life, we investigated the effectiveness of Ultraviolet C (UV-C) combined with 1-methylcyclopropene (1-MCP) treatment on 'Xiaobai' apricot fruit stored at 4 ± 0.5 °C for 35 days. The results revealed that the combination treatment of 1-MCP and UV-C performed better than either UV-C or 1-MCP alone in fruit quality preservation. The combination treatment could delay the increase in weight loss, ethylene production, and respiration rate; retain the level of soluble solid content, firmness, titratable acid, and ascorbic acid content; promote the total phenolics and flavonoids accumulation; improve antioxidant enzyme activity and relative gene expression, and DPPH scavenging ability; and reduce MDA, H2O2, O2.- production. The combined treatment improved the quality of apricot fruit by delaying ripening and increasing antioxidant capacity. Therefore, combining UV-C and 1-MCP treatment may be an effective way to improve the post-harvest quality and extend the storage period of the 'Xiaobai' apricot fruit, which may provide insights into the preservation of 'Xiaobai' apricot fruit.

Exogenous melatonin activates the antioxidant system and maintains postharvest organoleptic quality in Hami melon (Cucumis. melo var. inodorus Jacq.).

Hami melon is prone to postharvest perishing. Melatonin is a signaling molecule involved in a variety of physiological processes in fruit, and it improves fruit quality. We hypothesized that melatonin treatment would improve the storage quality of Hami melon by altering its respiration and reactive oxygen species (Graphical abstract). Our results indicated that optimal melatonin treatment (0.5 mmol L-1) effectively slowed the softening, weight loss, and respiratory rate of the Hami melon fruit. Furthermore, melatonin markedly improved the antioxidant capacity of the fruit and protected it from oxidative damage by decreasing its contents of superoxide anions, hydrogen peroxide, and malondialdehyde. Melatonin significantly enhanced the activities of superoxide dismutase, catalase, ascorbate peroxidase, and peroxidase. The total phenol, total flavonoids, and ascorbic acid contents were maintained by melatonin treatment. This treatment also repressed the activities of lipase, lipoxygenase, and phospholipase D, which are related to lipid metabolism. Thus, exogenous melatonin can maintain postharvest organoleptic quality of Hami melon fruit by increasing its antioxidant activity and inhibiting reactive oxygen species production.

Effect of salicylic acid treatment on antioxidant capacity and endogenous hormones in winter jujube during shelf life.

This study investigated the effects of exogenous salicylic acid (SA) treatment (0, control; 3 mmol L-1) on the antioxidant and hormone levels of winter jujube during shelf life (20 d) at 4 °C. The results showed that 3 mmol L-1 SA treatment preferably maintained firmness, color, titratable acidity, and total soluble solids, and effectively reduced the respiratory intensity and TSS/TA value (13.08%) of the fruit. Compared with the control group, the SA group had a higher content of sucrose (14.03%) and malic acid (29.13%). Meanwhile, SA reduced the accumulation of H2O2 (27.73%) and O2- (45.44%) by enhancing the activity of antioxidant enzymes (superoxide dismutase, peroxidase, catalase, ascorbate peroxidase) and the content of antioxidant substances (ascorbic acid, total phenols, total flavonoids, and glutathione) in the fruit. In addition, 3 mmol L-1 SA treatment led to higher levels of endogenous abscisic acid (18.49%) and SA (20.47%) in fruit, and lower concentration of jasmonic acid (42.68%), but had a weak effect on indole acetic acid levels.

Comparative elucidation of bioactive and volatile components in dry mature jujube fruit (Ziziphus jujuba Mill.) subjected to different drying methods.

This study investigated the effects of convective drying(CD) and freeze drying(FD) on bioactive and volatile components in jujube. No significant difference in total phenolic, total flavonoids and antioxidant capacity among CD60, CD70, CD80 and FD samples (P > 0.05). LC-MS/MS analysis showed that this trend mainly originated from the dynamic equilibrium relationships between caffeic acid, chlorogenic acid, p-hydroxybenzoic acid, rutin, epicatechin, and quercetin. HS-SPME-GC-MS identified 31 volatile organic compounds (VOCs) comprising more than 80% aldehydes and acids. Principal component analysis distinguished the VOC characteristics of samples subjected to different drying methods. Six VOCs had an odor activity value (OAV) >1, most of which were fatty acid oxidation or Maillard reaction products. Combined with the precursor components, these reactions were speculated to be the major VOC-producing pathways in dried jujube. Considering the bioactive components and flavor retention, CD at 60 °C was an effective drying method with potential to replace FD.

Dissecting the Chloroplast Proteome of the Potato (Solanum Tuberosum L.) and Its Comparison with the Tuber Amyloplast Proteome.

The chloroplast, the energy organelle unique to plants and green algae, performs many functions, including photosynthesis and biosynthesis of metabolites. However, as the most critical tuber crop worldwide, the chloroplast proteome of potato (Solanum tuberosum) has not been explored. Here, we use Percoll density gradient centrifugation to isolate intact chloroplasts from leaves of potato cultivar E3 and establish a reference proteome map of potato chloroplast by bottom-up proteomics. A total of 1834 non-redundant proteins were identified in the chloroplast proteome, including 51 proteins encoded by the chloroplast genome. Extensive sequence-based localization prediction revealed over 62% of proteins to be chloroplast resident by at least one algorithm. Sixteen proteins were selected to evaluate the prediction result by transient fluorescence assay, which confirmed that 14 were distributed in distinct internal compartments of the chloroplast. In addition, we identified 136 phosphorylation sites in 61 proteins encoded by chloroplast proteome. Furthermore, we reconstruct the snapshots along starch metabolic pathways in the two different types of plastids by a comparative analysis between chloroplast and previously reported amyloplast proteomes. Altogether, our results establish a comprehensive proteome map with post-translationally modified sites of potato chloroplast, which would provide the theoretical principle for the research of the photosynthesis pathway and starch metabolism.

The Role of Cell Wall Polysaccharides Disassembly and Enzyme Activity Changes in the Softening Process of Hami Melon (Cucumis melo L.).

To investigate the physiological and molecular properties relating to cell wall carbohydrate metabolism in fruit, the ultrastructure and polysaccharides compositions of the cell wall, as well as the fruit quality and activities of enzymes relating to fruit softening, were studied for three Hami melon varieties ('Xizhoumi 17', 'Jinhuami 25', and 'Chougua') representing three different storability levels. The results showed that 'Chougua' maintained a higher firmness on day 18, with the lowest decay incidence (0%). 'Chougua' showed a better storage quality and intact cell wall structure. The molecular weight and monosaccharide composition of cell wall polysaccharides for Hami melons underwent great changes during storage, and the degradation of pectin polysaccharides was obvious, involving the depolymerization of macromolecular polymers accompanied by the production of new macromolecular polymers and composition changes in pectin monosaccharides (glucose, galactose, and arabinose) during the softening process of the Hami melons. Polygalacturonase, pectin methylesterase, xyloglucan endo-transglycosylase/hydrolase, α-arabinofuranosidase, ß-galactosidase, and cellulase were associated with fruit softening at different stages of storage. There were similar softening mechanisms in the three Hami melons. This study will provide reference for further study on the fruit softening mechanisms of Hami melons.

Postharvest UV-C irradiation inhibits blackhead disease by inducing disease resistance and reducing mycotoxin production in 'Korla' fragrant pear (Pyrus sinkiangensis).

Blackhead disease is a major fungal disease causing the quality deterioration of postharvest 'Korla' fragrant pear. In this study, the relationships of resistance to blackhead disease with the enzyme activity, phenolic compounds, and mycotoxin metabolism of 'Korla' fragrant pear were investigated, through UV-C irradiation of 0.12, 0.24, 0.36, 0.48, 0.72 and 1.08 kJ/m2 on 'Korla' fragrant pear inoculated with Alternaria alternata (Fries) Keissler (A. alternata). The results showed that the low-dose UV-C irradiation (0.36 kJ/m2) effectively controlled blackhead disease. The activities of chitinase (CHI), ß-1,3-glucanase (GLU), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), phenylalanine ammonia-lyase (PAL), and the content of phenolic compounds in fruit were enhanced, whereas the activities of lipoxygenase (LOX), polyphenol oxidase (PPO), and the contents of hydrogen peroxide (H2O2) and mycotoxins (including AOH, AME, and TeA) were decreased. Therefore, the low-dose UV-C irradiation could improve the resistance to blackhead disease and reduce the production of mycotoxins in 'Korla' fragrant pear. This study proves that UV-C irradiation may be a potentially effective strategy for the control of blackhead disease and the improvement of quality of postharvest 'Korla' fragrant pear.

Incorporation of 1-methylcyclopropene and salicylic acid improves quality and shelf life of winter jujube (Zizyphus jujuba Mill. cv. Dongzao) through regulating reactive oxygen species metabolism.

Winter jujube fruit is susceptible to aging, peel reddening, dehydration, shrinkage, and tissue softening during shelf life after it is removed from the cold storage conditions. In this study, the effects of 1-methylcyclopropene (1-MCP) and salicylic acid (SA) on the quality of winter jujube fruit during shelf life were investigated by measuring physiological indexes and the activities of antioxidant enzymes and enzymes related to reactive oxygen species (ROS) metabolism of winter jujube fruit. The results showed that 1-MCP treatment and SA treatment suppressed weight loss, respiratory rate, malondialdehyde (MDA) content, H2O2 content, and O 2 - · production rate, but improved firmness, color difference (ΔE), soluble solid content (SSC), titratable acidity (TA), superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), phenylalanine ammonia-lyase (PAL) activities, ascorbic acid content, glutathione content, total phenolic content, and total flavonoid content in comparison with the control. Particularly, the combined treatment of 1-MCP and SA (1-MCP+SA treatment) showed the maximum efficacy compared to the 1-MCP treatment and SA treatment alone. 1-MCP+SA treatment exhibited the best preservation effect, followed by SA treatment and 1-MCP treatment. Thus, the combined treatment of 1-MCP and SA is an effective approach to maintain the postharvest quality of winter jujube fruit and extend the shelf life.

Comparative analysis of total wax content, chemical composition and crystal morphology of cuticular wax in Korla pear under different relative humidity of storage.

The cuticular wax of Korla pear stored under different relative humidity (0 ± 1 ℃, 50-55%, 70-75% and 90-95%) was examined in terms of total wax content, chemical composition and crystal morphology. The cuticular wax was composed of alkanes, olefins, fatty acids, alcohols, aldehydes, esters and terpenoids. High humidity maintained the content of total wax, alkanes and aldehydes at sufficient levels, especially C29 alkane and C18 aldehyde, which could positively regulate the quality of the pear fruits. Cuticular wax contributes to the capacity of preserving water, maintaining cell wall and delaying senescence. Scanning electron microscopy showed that wax crystals appeared as numerous platelets with irregular ovate crystals, high humidity delayed the transformation of wax structure. Taken together, high humidity delayed the ripening and aging by effectively maintaining wax, which was essential for postharvest storage and provide a reference for the production of synthetic wax for Korla pear fruits.

Optimising nutrients in the culture medium of Rhodosporidium toruloides enhances lipids production.

Rhodosporidium toruloides is a useful oleaginous yeast, but lipids production is affected by various factors including nutrients in the culture medium. Herein, the R-ZL2 high-yield mutant strain was used to investigate the effects of different carbon sources (sucrose, glucose, xylose), nitrogen sources (ammonium sulphate, ammonium nitrate), and C/N ratio on lipids production capacity, get the following conclusion (1) Compared with glucose and xylose, sucrose was a superior carbon source for lipids production; (2) When using ammonium sulphate as the nitrogen source, a C/N ratio of 200:1 achieved the highest biomass, lipids production and lipids content (10.7 g/L, 6.32 g/L and 59%, respectively), and lipids produced under different C/N conditions have potential for biodiesel production (except for C/N = 40 and C/N = 80); (3) When using ammonium nitrate as the nitrogen source, a C/N ratio of 200:1 achieved the highest biomass, lipids production and lipids content (12.1 g/L, 8.25 g/L and 65%, respectively), and lipids produced under different C/N ratio conditions have potential for biodiesel production. Thus, a combination of sucrose and ammonium nitrate was optimal for the lipid accumulation in R-ZL2. The findings will lay a foundation for further improving lipids yields.