Yan Zhao

Rice storage under suboptimal conditions leads to rapid quality deterioration. In this study, effects of low-temperature (LT, 20 °C) combined with nitrogen-controlled atmospheric conditions (NCA, 95%) on physicochemical properties, nutrient, mycotoxins and metabolites of rice during 180 d storage were comprehensively evaluated, to explore a potential preservation technique for rice. The LT + NCA treatment significantly inhibited the accumulation in free fatty acid value, malondialdehyde and electrolyte leakage, while maintaining higher catalase activity, lower amylose content and better pasting properties (higher breakdown, lower final viscosity and setback). Crucially, mycotoxin accumulation remained within safe limits across all groups, with LT + NCA showing the lowest levels. Metabolomics analysis identified 653 metabolites, with LT + NCA significantly modulating pathways related to carbohydrate metabolism (e.g., promoting raffinose accumulation while inhibiting the pentose phosphate pathway) and amino acid metabolism (enhancing glutathione metabolism and suppressing arginine biosynthesis). These metabolic rearrangements reduced oxidative damage, stabilized membrane integrity, and preserved cooking quality. Therefore, LT + NCA could be a superior strategy for delaying oxidative stress, maintaining nutritional and cooking quality, and ensuring the safety of stored rice.

Higher moisture content in wheat benefits processing but impairs storage stability. Current research on quality changes in high-moisture wheat under varying storage temperatures remains limited. This study systematically evaluated wheat with 14% moisture content stored at 15 °C, 20 °C, 25 °C, and 30 °C over 180 d, assessing quality parameters, mycotoxin levels, and fungal community composition. Results indicated that wheat stored at 15 °C and 20 °C maintained stable storage and processing quality. Meanwhile, the concentrations of aflatoxin B₁, deoxynivalenol, and zearalenone in wheat across all storage temperatures remained below their respective regulatory limits of 5.00 μg/kg, 1.00 mg/kg, and 60.00 μg/kg. No visible mold appeared in wheat stored at 15 °C, 20 °C, or 25 °C for 180 d, whereas initial mold characteristics emerged at 30 °C. Fungal community analysis revealed that at 15 °C and 20 °C, the dominant genus shifted from Bipolaris to Cladosporium, while at 25 °C and 30 °C, it rapidly transitioned to Aspergillus. Although fungal richness showed no significant differences, diversity indices varied notably across storage temperatures. These findings provide a theoretical basis for the safe storage of high-moisture wheat.

Sweet corn is highly susceptible to infection by Fusarium graminearum (F. graminearum) and Fusarium verticillioides (F. verticillioides) during storage, which substantially compromises its nutritional quality and economic value. However, the specific effects of F. graminearum and F. verticillioides on sweet corn quality during postharvest storage remain poorly understood. This study systematically explored the effects of F. graminearum and F. verticillioides infection on sweet corn quality by evaluating the changes in color, hardness, weight loss rate, malondialdehyde (MDA) content, surface fungal spore count, soluble protein content, and soluble sugar content. Results indicated that the critical time points for visible deterioration were 24 h post-inoculation for F. graminearum and 36 h for F. verticillioides. Compared with the control group, both infections caused significant darkening of kernel color and a marked increase in surface fungal spore counts. Notably, F. verticillioides infection was associated with a significant increase in MDA content, indicating enhanced oxidative stress in infected kernels. These findings elucidate the mechanisms of pathogen-induced quality degradation in sweet corn and provide a scientific basis for preserving and enhancing the value of agricultural products and ensuring food safety.

Sweet corn is highly susceptible to infection by Fusarium graminearum (F. graminearum) and Fusarium verticillioides (F. verticillioides) during storage, which substantially compromises its nutritional quality and economic value. However, the specific effects of F. graminearum and F. verticillioides on sweet corn quality during postharvest storage remain poorly understood. This study systematically explored the effects of F. graminearum and F. verticillioides infection on sweet corn quality by evaluating the changes in color, hardness, weight loss rate, malondialdehyde (MDA) content, surface fungal spore count, soluble protein content, and soluble sugar content. Results indicated that the critical time points for visible deterioration were 24 hours post-inoculation for F. graminearum and 36 hours for F. verticillioides. Compared with the control group, both infections caused significant darkening of kernel color and a marked increase in surface fungal spore counts. Notably, F. verticillioides infection was associated with a significant increase in MDA content, indicating enhanced oxidative stress in infected kernels. These findings elucidate the mechanisms of pathogen-induced quality degradation in sweet corn and provide a scientific basis for preserving and enhancing the value of agricultural products and ensuring food safety.

In recent years, as two globally recognized green grain storage technologies, CO₂-modified atmosphere (CO₂) storage and temperature-controlled (TC) storage have gained prominence. However, research on their integrated application remains limited. This study monitored quality dynamics and microbial activity in rice stored for 360 days under CO₂ + TC versus conventional storage (control), with analyses conducted at stratified sampling points (upper, middle, and lower layers). Compared to conventional storage, CO₂ + TC preserved rice color more effectively, while retarding the increase in fatty acid value and the decline in brown rice yield, head rice yield, and germination percentage. Furthermore, CO₂ + TC storage effectively suppresses the proliferation of Fusarium and Aspergillus, thereby retarding aflatoxin B1 (AFB1) accumulation by inhibiting fungal metabolic activity. Non-targeted metabolomics analysis further verified that CO₂ + TC storage enhanced rice antioxidant capacity and disease resistance by modulating amino acid, carbohydrate, and linolipid metabolic pathways. This technology effectively maintained nutrient retention (e.g., amino acids and proteins) and delayed quality deterioration in stored rice. These findings elucidated the underlying mechanism of CO₂ + TC on rice quality, offering a novel perspective for grain storage technology.

Effects of low temperature (LT, 20 °C) combined with nitrogen-modified atmosphere (MA, 95% N₂) storage (LT + MA) on quality, microstructure, and metabolome characteristics of high moisture content (15.5%) during 180 days of storage were investigated to explore a potential preservation technique for high moisture rice. The results showed that after 180 days of storage, the fatty acid value, malondialdehyde content, and amylose content of rice under LT + MA storage were 53.33%, 72.93%, and 91.85% of those under conventional storage (CS, conventional atmosphere, 30 °C, RH 65%), respectively. The color, pasting properties, and scanning electron microscopy (SEM) of the LT + MA treatment were found to be markedly superior to those of the CS treatment. In addition, the differential metabolites sucrose, trehalose-6P, trehalose, 3,7-Di-O-methylquercetin (DMQ), rutin, and vitexin 2″-O-rhamnoside (VOR) were screened to assess for sensitivity to changes in storage conditions. The study demonstrated that the LT + MA effectively suppressed the escalation of FAV, MDA content, and amylose content. In addition, it was observed to inhibit the deterioration of color and pasting properties while concurrently maintaining the polygonal shape of rice starch granules. Furthermore, the differential metabolites of non-targeted metabolomics indicated that the LT + MA group exhibited superior efficacy in retarding rice aging.

Introduction: As one of the main grain crops in China, maize is highly susceptible to Aspergillus infection during processing, storage and transportation due to high moisture at harvest, which results in the loss of quality. The aim of this study is to explore the early warning marker molecules when Aspergillus infects maize kernels.Methods: Firstly, strains MA and MB were isolated from moldy maize and identified by morphological characterization and 18S rRNA gene sequence analysis to be Aspergillus flavus (A. flavus) and Aspergillus niger (A. niger). Next, fresh maize was moldy by contaminated with strains MA and MB. The volatile organic compounds (VOCs) during the contamination process of two fungal strains were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS). A total of 31 VOCs were detected in maize contaminated with strain MA, a total of 32 VOCs were detected in maize contaminated with strain MB, including confirmed monomers and dimers. Finally, heat maps and principal component analysis (PCA) showed that VOCs produced in different growth stages of Aspergillus had great differences. Combined with the results of GC-IMS, total fungal colony counts and fungal spores, it was concluded that the Aspergillus-contaminated maize was in the early stage of mold at 18 h.Results: Therefore, the characteristic VOCs butan-2-one, ethyl acetate-D, Benzaldehyde, and pentan-2-one produced by maize at 18 h of storage can be used as early mildew biomarkers of Aspergillus infection in maize.Discussion: This study provided effective marker molecules for the development of an early warning and monitoring system for the degree of maize mildew in granaries.

A low temperature (LT) is used to delay grain deterioration effectively. In practical applications, a nitrogen-modified atmosphere (N₂) is also an effective way of preventing grain pests and delaying grain deterioration. However, there are few studies on grain quality changes using a combination treatment of an LT and N₂ during storage. In this study, the storage quality, processing characteristics, and metabolites of rice under conventional storage (CS), LT (20 °C), N₂ (95%), and LT+N₂ treatments were analyzed for 180 days, under a controlled humidity of 65% ± 2%. The results showed that compared to the CS, LT, and N₂ treatments, the LT+N₂ treatment had the best effect in retarding the increase in MDA and electrical conductivity and deferring the decrease in CAT activity. In addition, the LT+N₂ treatment maintained the color of the rice better and sustained a better processing quality. Non-targeted metabolomics analysis further confirmed that the LT+N₂ treatment maintained the vigor of the rice and retarded its spoilage by activating the metabolisms of amino acids, carbohydrates, and flavonoids. These results suggest a favorable practice for preventing storage deterioration and increasing the processing quality for rice storage. They provided new insights into the mechanisms of rice quality changes using the combination treatment of an LT and N₂.

Proanthocyanidins are important compounds known for their antioxidant and radical scavenging properties, but they are highly sensitive to light, heat, oxygen, and pH. In our study, proanthocyanidin was encapsulated using sodium alginate and carboxymethyl cellulose to enhance controlled release, pH stability, metal ion tolerance, temperature resistance, time release, the microencapsulation of food additives stability, antioxidant capacity analysis, and the storage period tolerance of proanthocyanidin. Fourier transforms infrared (FTIR) analysis and full-wavelength UV scanning indicated the successful immobilization of proanthocyanidins into the polymeric microcapsules. The flowability and mechanical properties of the microcapsules were enhanced. Moreover, proanthocyanidin microcapsules exhibited higher thermal, pH, metal ion, time, and microencapsulation food additive stability. In addition, due to their high antioxidant properties, the proanthocyanidin microcapsules retained a greater amount of proanthocyanidin content during the gastric phase, and the proanthocyanidin was subsequently released in the intestinal phase for absorption. Thus, the study provided a systematic understanding of the antioxidant capabilities and stability of proanthocyanidin microcapsules, which is beneficial for developing preservation methods for food additives.