A comparison study on polysaccharides extracted from banana flower using different methods: Physicochemical characterization, and antioxidant and antihyperglycemic activities.

This work investigated and compared the physicochemical characteristics, and antioxidant and antihyperglycemic properties in vitro of polysaccharides from a single banana flower variety (BFPs) extracted by different methods. BFPs extracted using hot water (HWE), acidic (CAE), alkaline (AAE), enzymatic (EAE), ultrasonic (UAE) and hot water-alkaline (HAE) methods showed different chemical composition, monosaccharide composition, molecular weight, chain conformation and surface morphology, but similar infrared spectra characteristic, main glycosidic residues, crystalline internal and thermal stability, suggesting that six methods have diverse impacts on the degradation of BFPs without changing the main structure. Then, among six BFPs, the stronger antioxidant activity in vitro was found in BFP extracted by HAE, which was attributed to its maximum uronic acid content (21.67 %) and phenolic content (0.73 %), and moderate molecular weight (158.48 kDa). The highest arabinose and guluronic acid contents (18.59 % and 1.31 % in molar ratios, respectively) and the lowest uronic acid content (14.30 %) in BFP extracted by HWE contributed to its better α-glucosidase inhibitory activity in vitro (66.55 %). The data offered theoretical evidence for choosing suitable extraction methods to acquire BFPs with targeted biological activities for applications, in which HAE and HWE could serve as beneficial methods for preparing antioxidant BFP and antihyperglycemic BFP, respectively.

Genome-wide transcriptome analysis uncovers gene networks regulating fruit quality and volatile compounds in mango cultivar 'Tainong' during postharvest.

Mango is one of the most economically important fruit; however, the gene regulatory mechanism associated with ripening and quality changes during storage remains largely unclear. This study explored the relationship between transcriptome changes and postharvest mango quality. Fruit quality patterns and volatile components were obtained using headspace gas chromatography and ion-mobility spectrometry (HS-GC-IMS). The changes in mango peel and pulp transcriptome were analyzed during four stages (pre-harvesting, harvesting, maturity, and overripe stages). Based on the temporal analysis, multiple genes involved in the biosynthesis of secondary metabolites were upregulated in both the peel and pulp during the mango ripening process. Moreover, cysteine and methionine metabolism related to ethylene synthesis were upregulated in the pulp over time. Weighted gene co-expression network analysis (WGCNA) further showed that the pathways of pyruvate metabolism, citrate cycle, propionate metabolism, autophagy, and SNARE interactions in vesicular transport were positively correlated with the ripening process. Finally, a regulatory network of important pathways from pulp to peel was constructed during the postharvest storage of mango fruit. The above findings provide a global insight into the molecular regulation mechanisms of postharvest mango quality and flavor changes.

Screening and Characteristics Analysis of Polysaccharides from Orah Mandarin (Citrus reticulata cv. Orah).

This study aimed to screen out polysaccharides with the ability to activate NK cells. Ten polysaccharides (OP) were isolated from orah mandarin (Citrus reticulata cv. Orah) peel using hot-water extraction combined with the alcohol precipitation method and the ultrafiltration-membrane separation method. After measuring the effects of 10 OPs on NK-92MI cell proliferation and cytotoxicity, it was found that the polysaccharide OP5 had the highest activity in vitro. OP5 can significantly promote the proliferation of and increase the gene expression of perforin, granzyme B and IFN-γ in NK-92MI cells. Its molecular weight was between 50 and 70 kDa. The identification results of monosaccharide composition indicated that OP5 was composed of arabinose (31.52%), galacturonic acid (22.35%), galactose (16.72%), glucose (15.95%), mannose (7.67%), rhamnose (2.39%), fucose (1.41%), xylose (1.30%), glucuronic acid (0.42%) and ribose (0.27%). The sugar ring of the ß-configuration was the main, and that of the α-configuration was the auxiliary. These results would provide a foundation for the functional product development of OPs.

Development of Green Banana Fruit Wines: Chemical Compositions and In Vitro Antioxidative Activities.

This study aimed to develop functional fruit wines using whole fruit, pulp, and peels from green bananas. The boiled banana homogenates were mixed with cane sugar before wine fermentation. Quality parameters, phenolic compounds, flavor components, and antioxidative properties of the green banana peel wine (GBPW), green banana pulp wine (GBMW), and whole banana wine (GBW) were determined. High-performance liquid chromatography was used to determine the phytochemical compounds in three wines, and the flavor components were further analyzed using headspace solid-phase microextraction combined with gas chromatography-mass spectrometry. The flavor components and in vitro antioxidant activities were, respectively, determined using the relative odor activity value and the orthogonal projections on latent structure discrimination analysis (OPLS-DA). In vitro antioxidative capacities for these wines were evaluated using antioxidant chemical assays and cell culture methods. The total phenolic and total tannin content of the GBPW, GBMW, and GBW showed reducing trends with increasing fermentation days, whereas the total flavonoid content of the wine samples exhibited downward trends. The antioxidant capacities of the three wine samples were higher than those of the raw fruit samples, except for the metal chelation rate (%). Additionally, the main flavor component in the wine samples was 3-methyl-1-butanol. Its percentages in the GBPW, GBMW, and GBW were 72.02%, 54.04%, and 76.49%, respectively. The OPLS-DA results indicated that the three wines presented significantly different antioxidant activities. The cell-culture-based antioxidant analysis showed that these wine samples had protective effects against the oxidative stress of the 3T3-L1 preadipocytes induced by hydrogen peroxide. This study provided a theoretical basis for defining the antioxidant characteristics of banana wines and expanding novel channels for using banana peels to develop nutraceuticals.

Evaluation of Bioactive Compounds and Bioactivities in Plum (Prunus salicina Lindl.) Wine.

With the increase in demand of fruit wine year by year, it is necessary to develop novel fruit wine with high functional activities. Prunus salicina Lindl. (named as Niuxin plum) is a remarkable material for brewing fruit wine owing to its suitable sugar-acid ratio, characteristic aroma and bioactive compounds. This study intends to modify the fermentation technology, identify and quantify nutritional compositions and volatile profiles, as well as bioactive substances in Niuxin plum wine, as well as evaluate the antioxidant and hypoglycemic activities in vitro of major bioactive components from Niuxin plum wine. According to single-factor and orthogonal tests, the optimal fermentation conditions of 13.1% vol Niuxin plum wine should be Saccharomyces cerevisiae Lalvin EC1118 at 0.1% and a fermentation temperature of 20°C for 7 days. A total of 17 amino acids, 9 mineral elements, 4 vitamins, and 55 aromatic components were detected in plum wine. Polysaccharides from Niuxin plum wine (named as NPWPs) served as the major bioactive components. The NPWP with a molecular weight over 1,000 kDa (NPWP-10) demonstrated extraordinary DPPH free radical scavenging capacity and α-glucosidase inhibitory activity among all NPWPs having different molecular weight. Moreover, the structural characterization of NPWP-10 was also analyzed by high performance liquid chromatography (HPLC), fourier-transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectra studies. NPWP-10 was composed of mannose, rhamnose, arabinose, galactose and galacturonic acid with molar ratios of 2.570:1.775:1.045:1.037:1. NPWP-10 contained α-configuration as the main component and ß-configuration as the auxiliary component. This study highlights NPWP-10 is an importantly biological polysaccharide from Niuxin plum wine, as well as provides a scientific basis for developing the plum wine industry.

Influence of polysaccharide-based edible coatings on enzymatic browning and oxidative senescence of fresh-cut lettuce.

Fresh-cut lettuce has a short shelf-life due to enzymatic browning and oxidative senescence. The present study investigated effects of polysaccharide-based edible coatings (alginate, chitosan, and carrageenan) on enzymatic browning and antioxidant defense system of fresh-cut lettuces during cold storage (4°C) for 15 days. The results showed that three coatings could inhibit enzymatic browning through maintaining total phenolics (TP) content and decreasing polyphenol oxidase (PPO) and phenylalanine ammonialyase (PAL) activities. These coatings also reduced phospholipase D (PLD) and lipoxygenase (LOX) activities, lowered malondialdehyde (MDA) content, and enhanced antioxidant enzymes (superoxide dismutase, SOD; peroxidase, POD; catalase, CAT; ascorbate peroxidase, APX) activities. Besides, all coatings positively affected sensory properties of fresh-cut lettuces after 3 days storage. Additionally, among three coating treatments, chitosan coating had the most positive effects on quality of fresh-cut lettuce and was the most suitable coating for retarding enzymatic browning and alleviating membrane oxidative damage. These results indicated that polysaccharide-based edible coatings were helpful to maintain quality, inhibit enzymatic browning, and postpone senescence of fresh-cut lettuce.

Comprehensive evaluation on tailor-made deep eutectic solvents (DESs) in extracting tea saponins from seed pomace of Camellia oleifera Abel.

Tea saponins from Camellia oleifera Abel. seed pomace are new sources of commercial saponins. This study established an eco-friendly and efficient extraction method for tea saponins from C. oleifera seed pomace. A ternary deep eutectic solvent (DES) composed of l-proline, glycerol and sucrose (4:10:1 in molar ratio, abbreviated as PGS-5) achieved the highest extraction yield of tea saponins among all screened DESs. A maximum extraction yield of 23.22 ± 0.28% was obtained using PGS-5 under the optimized extraction time, DES concentration and liquid-solid ratio. Through ultraviolet, Fourier transform infrared spectroscopy and ultrahigh-performance liquid chromatography-Q Exactive HF mass spectroscopy, as well as analyses of antioxidant and antimicrobial activities, it was determined that extracted saponins did not altered during processing. Therefore, PGS-5 can serve as a solvent to obtain stable and beneficial tea saponins from C. oleifera seed pomace.

The Role of 1-Methylcyclopropene in the regulation of ethylene biosynthesis and ethylene receptor gene expression in Mangifera indica L. (Mango Fruit).

Mango (Mangifera indica L.) is respiratory climacteric fruit that ripens and decomposes quickly following their harvest. 1-methylcyclopropene (1-MCP) is known to affect the ripening of fruit, delaying the decay of mango stored under ambient conditions. The objective of this study was to clarify the role of 1-MCP in the regulation of ethylene biosynthesis and ethylene receptor gene expression in mango. 1-MCP significantly inhibited the 1-aminocyclopropane-1-carboxylic acid (ACC) content. The activity of ACC oxidase (ACO) increased on days 6, 8, and 10 of storage, whereas delayed ACC synthase (ACS) activity increased after day 4. The two homologous ethylene receptor genes, ETR1 and ERS1 (i.e., MiETR1 and MiERS1), were obtained and deposited in GenBank® (National Center for Biotechnology Information-National Institutes of Health [NCBI-NIH]) (KY002681 and KY002682). The MiETR1 coding sequence was 2,220 bp and encoded 739 amino acids (aa). The MiERS1 coding sequence was 1,890 bp and encoded 629 aa, similar to ERS1 in other fruit. The tertiary structures of MiETR1 and MiERS1 were also predicted. MiERS1 lacks a receiver domain and shares a low homology with MiETR1 (44%). The expression of MiETR1 and MiERS1 mRNA was upregulated as the storage duration extended and reached the peak expression on day 6. Treatment with 1-MCP significantly reduced the expression of MiETR1 on days 4, 6, and 10 and inhibited the expression of MiETR1 on days 2, 4, 6, and 10. These results indicated that MiETR1 and MiERS1 had important functions in ethylene signal transduction. Treatment with 1-MCP might effectively prevent the biosynthesis of ethylene, as well as ethylene-induced ripening and senescence. This study presents an innovative method for prolonging the storage life of mango after their harvest through the regulation of MiETR1 and MiERS1 expression.

Polyphenols and Alkaloids in Byproducts of Longan Fruits (Dimocarpus Longan Lour.) and Their Bioactivities.

The longan industry produces a large amount of byproducts such as pericarp and seed, resulting in environmental pollution and resource wastage. The present study was performed to systematically evaluate functional components, i.e., polyphenols (phenolics and flavonoids) and alkaloids, in longan byproducts and their bioactivities, including antioxidant activities, nitrite scavenging activities in simulated gastric fluid and anti-hyperglycemic activities in vitro. Total phenolic and total flavonoid contents in pericarp were slightly higher than those in seeds, but seeds possessed higher alkaloid content than pericarp. Four polyphenolic substances, i.e., gallic acid, ethyl gallate, corilagin and ellagic acid, were identified and quantified using high-performance liquid chromatography. Among these polyphenolic components, corilagin was the major one in both pericarp and seed. Alkaloid extract in seed showed the highest DPPH radical scavenging activity and oxygen radical absorbance capacity. Nitrite scavenging activities were improved with extract concentration and reaction time increasing. Flavonoids in seed and alkaloids in pericarp had potential to be developed as anti-hyperglycemic agents. The research result was a good reference for exploring longan byproducts into various valuable health-care products.

Fermentation process optimization and chemical constituent analysis on longan (Dimocarpus longan Lour.) wine.

Based on single factor and orthogonal experiments, optimal fermentation conditions for longan wine were Saccharomyces cerevisiae strain of Lalvin KD, juice content of 70% and alcohol content of 10°. Sixteen amino acids were detected. Proline, alanine, glutamic acid and aspartic acid contents were relatively high. Sixty-three volatile aroma compounds were identified using solid-phase micro extraction and gas chromatography (SPME-GC). Ethyl lactate content was the highest, followed by octanoic acid ethyl ester, isoamyl alcohol and decanoic acid ethyl ester. Main functional components were polysaccharides. Longan wine polysaccharide (LWP) with molecular weight 10-30 kDa exhibited the highest hypoglycemic and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activities. 10-30 kDa polysaccharides mainly consisted of glucose, mannose, galactose, arabinose, galacturonic acid and glucuronic acid in molar ratio of 167.72:3.38:3.13:3.46:2.33:1. Infrared and nuclear magnetic resonance spectra confirmed that the sugar ring of 10-30 kDa polysaccharides was in the 〈beta〉-configuration.