Siraitia grosvenorii is widely used in functional foods, and drying is essential for long-term preservation. Drying methods significantly impact the fruit quality. Here, we evaluated how hot air drying (HAD), heat pump drying (HPD), microwave vacuum drying (MVD), and vacuum freeze drying (VFD) affect bioactive compounds in S. grosvenorii fruit. HAD-treated fruit showed elevated phenolic, flavonoid, and sugar contents, together with strong ·OH scavenging capacity. In contrast, VFD better preserved green color and native flavor of fresh fruit and yielded higher ascorbic acid and mogroside V contents than thermal drying. Under HAD and HPD, differentially accumulated metabolites (DAMs) were mainly enriched in linoleic acid, tryptophan, and purine metabolism. Under VFD, luteolin-7-O-glucoside was positively correlated with mogroside IV, mogroside V, and 11-oxomogroside V, whereas under HAD and HPD, protocatechualdehyde and vanillin (4-hydroxy-3-methoxybenzaldehyde) were positively correlated with mogroside IV. These findings provide a theoretical basis for selecting appropriate processing strategies for S. grosvenorii fruit.

Siraitia grosvenorii fruit, a traditional medicinal and edible plant, undergoes significant alterations in quality and bioactive composition during the dehydration process. This study investigated the effects of hot-air drying at various temperatures on the physicochemical properties, antioxidant activity, and drying kinetics of S. grosvenorii fruit. The drying process was terminated when fruit moisture content reached 15%, with corresponding drying durations of 420, 225, 144, 96, and 51 h at 40 °C, 50 °C, 60 °C, 70 °C and 80 °C, respectively. Among the ten mathematical models evaluated, the Midilli–Kucuk model provided the most accurate description of the drying kinetics of S. grosvenorii fruit. Quality analysis revealed that drying reduced the sugar/acid ratio, contents of mogrosides and ascorbic acid, while increasing total phenolic and flavonoid levels. Microstructural analysis revealed that higher temperatures increased drying rates by expanding the porosity of the pulp. Based on the retention of bioactive components and antioxidant capacity, 70 °C was identified as the optimal drying temperature. Overall, these findings suggest that oven-drying optimizes drying efficiency and ensures the retention of essential bioactive constituents in S. grosvenorii.

Low-temperature storage, a common method for mango preservation, effectively reduced postharvest respiration and delayed fruit senescence. However, mangoes are cold-sensitive and develop chilling injury when stored below 12 degrees C. In this study, 'Guire 82' mangoes were used to explore the effect of n-butanol on postharvest mango chilling injury. Results showed that 1% n-butanol treatment significantly alleviated chilling injury symptoms. nButanol treatment enhanced the antioxidant capacity of mangoes, by boosting the activities of ascorbate peroxidase and superoxide dismutase. Additionally, n-butanol treatment maintained the integrity of mango cell membranes, by inhibiting the activity of phospholipase C and phospholipase D, reducing electrolyte leakage, and lowering malondialdehyde content. n-Butanol treatment also increased ATP and ADP content, decreased AMP content, and thereby enhanced energy level during the early stage of low-temperature storage. Furthermore, molecular analysis further indicated that n-butanol treatment systematically regulated the expression patterns of genes involved in membrane lipid metabolism and energy homeostasis. These findings suggested that n-butanol could effectively reduce postharvest mango chilling injury by regulating membrane lipid metabolism.

Mango (Mangifera indica L.) is a commercially important fruit crop whose quality attributes are shaped by genetic background and cultivation environment, yet the relative contributions of geographic origin, climatic factors, and cultivar identity remain poorly resolved across China's diverse production regions. Forty mango samples representing six major cultivars (Tainong No. 1, Jinhuang, Guifei, Guire 82, Keitt, and Eagle-mouth) were collected from four principal production provinces (Guangxi, Hainan, Sichuan, and Yunnan), spanning latitudes from 19°N to 27°N and elevations from 6 to 1668 m. Twelve quality traits, including dietary fiber fractions, soluble sugars, organic acids, carotenoids, and pectin, were quantified alongside nine environmental variables. PCA captured 41.2% of total variance but revealed substantial interprovincial overlap, indicating limited discriminatory power of geographic origin alone. OPLS-DA identified mean relative humidity (VIP = 1.48) and extreme maximum temperature (VIP = 1.15) as the primary environmental discriminators. Hierarchical clustering confirmed that samples from the same province frequently dispersed across multiple clusters, underscoring the dominance of cultivar-specific genetic factors. Cultivar-level analyses revealed distinct environment-quality interaction signatures, with Guifei exhibiting the most extensive correlation network. These findings establish that mango fruit quality is governed predominantly by cultivar identity, with local microclimate and geographic provenance serving as modulating factors. Such insights offer evidence-based guidance for regional cultivar deployment and quality-oriented orchard management, particularly in cultivar selection for targeted fresh-market and processing applications.

Siraitia grosvenorii fruit is a traditional ingredient in Chinese tea beverages with medicinal values. Postharvest ripening of S. grosvenorii fruit involves the alteration of sweetness and the accumulation of various metabolites. This study systematically investigated the dynamic changes in physiological properties, metabolomic profiles, and gene expression patterns during postharvest ripening of S. grosvenorii fruits across four stages (P0, P3, P7, and P14). Physiological analysis revealed that prolonged ripening significantly increased moisture loss rate, soluble solid content, relative conductivity, and pericarp color change, while respiratory rate remained stable. Metabolomic profiling identified 3066 metabolites, with amino acids and their derivatives as the most abundant class. Differential accumulation analysis demonstrated that the transitions from P3-to-P7 and P7-to-P14 were crucial phases in the postharvest ripening process, characterized by significant enrichment in amino acid metabolism, aminoacyl-tRNA biosynthesis, and secondary metabolite biosynthesis pathways. Notably, the accumulation of sweet mogrosides (11-oxomogroside V and mogroside V) peaked at the late stage (P14), whereas less-sweet variants (mogroside III and IV) declined progressively. Weighted gene co-expression network analysis identified the MEturquoise module as positively correlated with desirable mogrosides and fruit quality traits. The qPCR validation revealed stage-specific upregulation of key biosynthesis genes, with SgUGT85–269–4 peaking at P3 and SgUGT94–289–3 showing highest expression at P7. These findings demonstrate that controlled postharvest ripening (up to 14 days) is essential for maximizing mogroside sweetness and fruit quality, providing a scientific basis for optimizing processing schedules in S. grosvenorii fruits production. The identified metabolic modules and gene targets offer valuable resources for future genetic and agronomic strategies to enhance mogroside yields.

Mangoes are chilling-sensitive fruits and prone to suffering chilling injury (CI) when stored below 13 degrees C, compromising their economic value. Methyl jasmonate (MeJA) is an essential phytohormone that affects the development and postharvest quality of mangoes. However, the effects and mechanisms of MeJA on CI in stored mangoes are inadequately understood, especially in green-peel ripening mango varieties. This study investigated how MeJA treatment impacted the green mango cv. 'Guire 82' during 4 degrees C storage. The results show that MeJA significantly reduced CI and delayed firmness loss. MeJA also improved the antioxidant activities (superoxide dismutase, peroxidase, and catalase) and up-regulated their gene expression. MeJA inhibited 12-oxophytodienoate reductase (key enzyme of JA biosynthesis) activity. Although adenosine triphosphate, adenosine diphosphate, and adenosine monophosphate levels declined in MeJA-treated fruits, a transient increase in energy charge during early storage. The above results support the use of exogenous MeJA to alleviate CI in postharvest mango, indicating its role in bolstering antioxidant defense system, maintaining membrane integrity, and affecting energy metabolism. Our findings enrich the postharvest biology regarding the application of MeJA for improving cold tolerance in green-peel ripening mangoes.

To develop active packaging materials for postharvest preservation of fresh fruits, a novel zein-pullulan (Pul)-sodium alginate (SA) composite film loaded with Melaleuca alternifolia essential oil (tea tree oil, TTO) was prepared using a tape-casting technique. At a zein solution-to-Pul/SA solution mass ratio of 1:2.5, the film exhibited enhanced tensile strength and elongation at break. The film also exhibited optimal barrier properties, with the water vapor transmission rate and carbon dioxide permeability reduced to 5.97 × 10-8 and 3.6 × 10-6 g·m/m2·h·Pa, respectively. Fourier transform infrared spectroscopy and X-ray diffraction analyses confirmed good compatibility among TTO, zein, Pul, and SA. Furthermore, treatment of mangoes with film-forming emulsion regulated reactive oxygen species metabolism. When the TTO concentration was 1%, the coating further enhanced the scavenging of reactive oxygen species. Overall, the TTO-containing composite film showed strong potential as a functional material for fruit packaging applications.

In order to identify a suitable drying method for the extraction of antioxidant and antidiabetic polysaccharides, fresh Mesona chiensis Benth was subjected to various drying methods. These methods included conventional air drying (CD), hot-air drying (HD), freeze drying (FD), microwave drying (WD), and micro-fermentation drying (MD). Following the drying process, five polysaccharides derived from M. chiensis (MBPs) were extracted using hot water extraction. These polysaccharides exhibited variations in chemical composition, molecular weight, monosaccharide composition, and surface morphology. However, they displayed similar core glycosidic residues, crystallinity, and thermal stability. This indicates that the five drying methods exerted different effects on the degradation of polysaccharides, while simultaneously maintaining their fundamental structural characteristics. Additionally, a comprehensive evaluation system employing positive criteria and non-dimensionalization revealed that among five different MBPs, the MBP derived from the MD method exhibited the most potent antioxidant and antidiabetic activities in vitro. The micro-fermentation dried sample demonstrated a substantial DPPH radical scavenging capacity of 83.51% and an impressive inhibition of islet cell apoptosis activity, measured at 99.75%. The findings of this study provide that micro-fermentation drying has been identified as the most effective method for the extraction of significant antioxidant and antidiabetic polysaccharides from M. chiensis.

This study systematically investigated how Metschnikowia pulcherrima XX04 competes with Penicillium digitatum, Penicillium italicum, and Geotrichum citri-aurantii for iron ions to control these major postharvest citrus pathogens. Exogenous Fe3+ addition significantly reduced the inhibitory activity of the pigment-producing yeast against these pathogens on both agar medium and fruit. Pearson correlation analysis revealed a strong positive relationship between pigment production and antagonistic effectiveness of M. pulcherrima XX04. Comparative analysis of iron-capturing proficiency between M. pulcherrima XX04 and three pathogenic fungi on PDA medium and citrus wounds indicated that M. pulcherrima XX04 exhibited superior iron sequestration capabilities. Colony growth viability assay performed on Pulcherrimin-containing PDA (Pul-PDA) solid medium showed M. pulcherrima XX04 could utilize pulcherrimin-bound iron for growth and metabolism, and further evidenced by the significant upregulation of PUL3, a putative transporter involved in the utilization of extracellular pulcherrimin-iron complexes, whereas the pathogens exhibited limited or no ability to assimilate iron from this source. Growth assay of three pathogens under iron-limited, iron-rich, and iron-replenish conditions showed that P. digitatum was the most sensitive to iron deficiency, followed by P. italicum, while G. citri-aurantii displayed the highest tolerance to low-iron environments. This observation was further validated by iron chelation sensitivity assays using the agar well diffusion method with two specialized chelators, 2,2'-dipyridyl and tropolone. Overall, the pigment-producing yeast M. pulcherrima XX04 may have a greater capacity than the three tested pathogens to compete for and acquire iron in an iron-limited coexistence environment. This capability facilitates the induction of iron deprivation by M. pulcherrima against various fungal pathogens and represents a key determinant of its biocontrol efficacy. Our findings provide new insights into elucidating the mechanism of competitive iron consumption mediated by antagonistic yeasts. Furthermore, strategies based on inducing iron starvation could offer a promising alternative for managing postharvest diseases in citrus fruits.

In this research, ultrasound-assisted aqueous two-phase extraction (UA-ATPE) was utilized to isolate polysaccharides from Siraitia grosvenorii (SGPs). Based on the results of model optimization experiments, the extraction parameters were determined. The total extraction rate of SGPs was 25.77 %, which was 1.39 times higher than that obtained through conventional hot water extraction (HWE). Various analyses indicated that all SGPs were acidic polysaccharides with similar molecular weights. However, there were slight variations in the monosaccharide composition, surface morphology, and infrared spectral characteristics. These structural features endowed SGPs with various antioxidant, hygroscopic, and moisturizing properties, which provided valuable data for the development of the cosmetic raw materials and also presented new ideas for the application of SGPs.

Mechanical damage to banana fruit during transportation leads to substantial quality loss and shortened shelf life. This study investigated the effects of different concentrations (10, 20, and 50 μM) of methyl jasmonate (MeJA) on mechanically injured banana fruits stored at 25°C for 14 days. The results showed that the 10 μM MeJA treatment was identified as optimal, delaying the respiration peak by 2 days and maintaining fruit greater firmness (95.86 N) on Day 14. It also effectively suppressed the rise in ripening index, decay rate, total soluble solids (TSS) content, and malondialdehyde (MDA) content, thereby preserving better appearance and edible quality. In addition, 10 μM MeJA enhanced antioxidant enzyme activities and strengthened the activities of enzymes associated with disease resistance. On Day 14, the activities of ascorbate peroxidase (APX) and phenylalanine ammonia-lyase (PAL) were significantly higher than those of the control by 2.02- and 1.73-fold, respectively. Meanwhile, the activities of peroxidase (POD), polyphenol oxidase (PPO), β-1,3-glucanase (GLU), and chitinase (CHT) were maintained at levels 48.37%, 37.30%, 13.61%, and 47.77% higher than the control, respectively, at the end of storage. This study indicated that treatment with 10 μM MeJA effectively enhanced the antioxidant ability and disease resistance of mechanically injured banana fruits, thereby maintaining fruit quality during storage and improving the storability.

Sugar content critically determines mango fruit quality and varies significantly among varieties. Preliminary studies indicate that fructokinases (MiFRKs) MiFRK1 and MiFRK2 likely regulate intervarietal sugar variation. We characterized these MiFRKs using heterologous expression in tomato. Both isoforms phosphorylate fructose, promoting downstream catabolism, with R-MiFRK2 (from low-sugar ‘Renong No. 1’) exhibiting higher activity than T-MiFRK2 (high-sugar ‘Tainong No. 1’) and MiFRK1. Transcriptomic and metabolic analyses reveal that MiFRK overexpression inhibits sugar accumulation by altering the expression of key metabolic genes, including sucrose degradation enzymes (invertases), starch breakdown genes (β-amylases), and glycolytic genes (enolases). Intriguingly, MiFRK1 and MiFRK2 exhibit distinct regulatory effects on these pathways, suggesting functional specialization between the two isoforms. These findings provide novel insights into the molecular mechanisms through which MiFRKs govern sugar metabolism in mango, highlighting their potential as key targets for metabolic engineering to enhance fruit quality.

Phenolics are important secondary metabolites and antioxidants in plants. Mango fruit accumulate abundant phenolic compounds, while the effect of light on the accumulation of different phenolic components in mango peel and the relevant molecular mechanism are still unknown. In this study, mature ‘Guifei’ mango fruit was subjected to postharvest UV-B/white light treatment, fruit peel was sampled for metabolomic and transcriptomic analyses. The results showed that light induced the accumulation of anthocyanins, flavonoids, and phenolics, thus increasing the antioxidant capacity in mango peel. A total of 1223 phenolic metabolites were detected in mango peel, 36 phenolic compounds were defined as key differentially accumulated metabolites (DAMs) regulated by light. Among the DAMs, the accumulation of 33 compounds was promoted by light, and 30 of these were flavonoids. Light up-regulated most phenolics biosynthesis and light signaling pathway genes and also regulated expression of plant hormone signaling pathway genes. Transcription factors (TFs) such as MYB, C2H2 and HSF were identified as candidates regulating phenolics biosynthesis in mango. Our findings not only provide information for commercial application of light in promoting mango fruit appearance and increasing phenolics content and antioxidant capacity, but also reveal important aspects of the molecular regulation of light-induced phenolics accumulation in mango peel.

Fruit peel color is an important index of mango fruit quality. Therefore, increasing the anthocyanin accumulation and improving coloration in red mango are crucial for mango industry. The anthocyanin accumulation in mango is light-regulated. However, the effect of white light combined with different doses of UV-B on anthocyanin biosynthesis has not been clarified. Also lacking is a comprehensive analysis of responses of mango fruit peel to UV-B/white light treatments. In this study, green mature 'Guifei' mango fruits were subjected to white light combined with low (WL + UV-BL) or high dose UV-B (WL + UV-BH). Anthocyanin concentration, anthocyaninrelated gene expression, reactive oxygen species (ROS), antioxidant, and plant hormone concentrations, and antioxidant enzyme activity were measured. The results showed that especially a WL + UV-BH regimen promoted anthocyanin formation in mango peel. Anthocyanin- and light signal-related gene expression, ROS content, antioxidant enzyme activity, antioxidant concentrations, and total antioxidant capacity were also increased by UV-B/white light. Such treatments led to higher concentrations of jasmonic acid and cytokinin, but decreased content of 1-aminocyclopropane-1-carboxylic acid and salicylic acid. Commercially, our findings may contribute to improving the commercial quality of mango. Scientifically, the present data sheds light on the mango fruit peel-specific molecular and physiological response network under UV-B/white light treatments.

Pomegranate (Punica granatum L.) is an ancient fruit crop that has been cultivated worldwide and is known for its attractive appearance and functional metabolites. Fruit color is an important index of fruit quality, but the color formation pattern in the peel of evergreen pomegranate and the relevant molecular mechanism is still unknown. In this study, the contents of pigments including anthocyanins, carotenoids, and chlorophyll in the peel of ‘Danruo No. 1’ pomegranate fruit during three developmental stages were measured, and RNA-seq was conducted to screen key genes regulating fruit color formation. The results show that pomegranate fruit turned from green to red during development, with a dramatic increase in a* value, indicating redness and anthocyanins concentration, and a decrease of chlorophyll content. Moreover, carotenoids exhibited a decrease–increase accumulation pattern. Through RNA-seq, totals of 30, 18, and 17 structural genes related to anthocyanin biosynthesis, carotenoid biosynthesis and chlorophyll metabolism were identified from differentially expressed genes (DEGs), respectively. Transcription factors (TFs) such as MYB, bHLH, WRKY and AP2/ERF were identified as key candidates regulating pigment metabolism by K-means analysis and weighted gene co-expression network analysis (WGCNA). The results provide an insight into the theory of peel color formation in evergreen pomegranate fruit.