In this study, chemical analysis and membership function were employed to systematically compare the physicochemical properties of Nongxiangxing Daqu of different grades (premium, first and second) at the middle stage of storage (day 45). Additionally, high-throughput sequencing was used to analyze the microbial community structure and diversity characteristics. The results showed that premium-grade Daqu exhibited the highest fermentation activity (0.41 g/(0.5 g·72 h)) and esterification activity (385.39 mg/(50 g·7 d)), whereas first-grade Daqu had the highest amino acid nitrogen content (4.24 g/kg), and second-grade Daqu exhibited the highest acidity (1.29 mmol/10 g) and acid protease activity (42.54 U/g). The dominant bacterial phyla in all three grades of Daqu were Firmicutes, Proteobacteria, and Actinobacteria, while the fungal community was dominated by the phylum Ascomycota. Bacillus, Thermoascus, and Thermomyces were the dominant genera in these grades of Daqu, with their relative abundances varying among different grades. Linear discriminant analysis effect size (LEfSe) (LDA score ≥ 2, P < 0.05) identified 8 differential bacterial genera and 4 differential fungal genera, among which Bacillus and Thermomyces were the core microbial communities of Daqu at the middle stage of storage. Correlation analysis indicated that dominant genera such as Saccharopolyspora and Aspergillus were significantly correlated with various indicators such as acidity and acid protease activity (P < 0.05). PICRUSt analysis revealed grade-related differences in carbohydrate, amino acid, and nucleotide metabolic pathways. In conclusion, these findings provide a theoretical basis for precise regulation and quality management during the Daqu storage process.

The purpose of this study was to investigate the synergistic effect of a mixed aqueous solution of pectin, calcium ion and sugar on the hardening of low-sugar preserved kiwifruit. The effects of different treatments (purified water (control), 1% pectin, 1% pectin + 0.3% CaCl₂, 1% pectin + 0.3% CaCl₂ + 20% sucrose, and 1% pectin + 0.3% CaCl₂ + 10% stevia) on the quality of preserved fruits were systematically evaluated by measuring the solid content, texture characteristics, water activity, drying kinetics, retention rate of reduced ascorbic acid, and microstructure. The results showed that the combined treatment significantly improved the hardening effect: the pectin + calcium ion system formed a dense gel network through ion crosslinking, and resulted in a higher solid content when compared with the control group. Texture analysis showed that the pectin + CaCl₂ + stevia group had a cutting force of 5915.71 g, and the elasticity and supporting capacity were the best. Low-field nuclear magnetic resonance (NMR) and drying curves showed that sucrose and stevia delayed the loss of water activity and improved the drying efficiency (the moisture content was reduced to 20% after 5 hours). Scanning electron microscopy (SEM) confirmed that hardening treatment with the mixed solution led to the formation of a uniform gel network, supporting the walls of cells disrupted by cryopreservation. The pectin + CaCl₂ + stevia group showed the lowest loss of reduced ascorbic acid and outstanding antioxidant activity. In conclusion, the combined treatment (1% pectin + 0.3% CaCl₂ + 10% stevia) demonstrates significant advantages in improving the hardening effect, maintaining the nutritional quality, and meeting the demand for low-sugar products. This study provides a theoretical basis and process reference for the development of functional preserved fruits.

To investigate the effects of brewing conditions on the nutritional quality and flavor of Xanthoceras sorbifolium leaf green tea, tea infusions prepared with different combinations of brewing temperature and duration were analyzed for concentrations of nutrients such as total phenols, free amino acids, flavonoids, caffeine, and soluble sugars, taste and volatile components. The results showed that the nutritional quality and flavor of tea infusion both differed significantly under different brewing conditions, and the infusion state of active substances also varied. Infusion at 70 ℃ for 60 min led to the highest concentration of total phenols (0.66 mg/mL). The concentration of free amino acids peaked at 18.44 mg/mL after infusion at 80 ℃ for 360 min. The level of flavonoids reached a maximum value of 0.56 mg/mL after 180 min of infusion at 90 ℃, and the concentrations of caffeine (0.14 mg/mL) and soluble sugars (10.39 mg/mL) were the highest after 720 min. Comprehensive analysis using membership function showed that the tea infusions brewed at 80 ℃ for 360 min, 90 ℃ for 30 min, and 70 ℃ for 720 min received relatively high scores. Furthermore, electronic tongue analysis revealed that these infusion samples had similar overall taste profiles, with the sensor responses to umami, bitterness, and richness being the highest. Electronic nose results indicated that the W1W sensor exhibited the highest response to all three tea infusions. Using gas chromatography-ion mobility spectrometry (GC-IMS), we identified 66 volatile compounds in the tea infusions, from which 21 differential volatile compounds and 12 key volatile compounds were selected. Among these, 1-octen-3-one, 2-methylbutanal D, and n-octanol were the most important aroma components. This study provides guidance for the scientific consumption of X. sorbifolium leaf tea.

Sweet sorghum, characterized by its elevated saccharide content and substantial lignocellulosic biomass, has emerged as a highly promising candidate for bioenergy production through biomass conversion technologies. However, the intricate lignocellulosic network structure within sweet sorghum poses a significant barrier to the accessibility of anaerobic microorganisms and enzymes, resulting in reduced hydrolysis efficiency and digestion reaction kinetics. Considering the seasonal harvesting pattern of sweet sorghum, the development of effective storage and pretreatment methodologies capable of simultaneously disrupting the lignocellulosic anti-degradation barrier is crucial for enhancing its bioenergy conversion efficiency. This study conducted a systematic comparative analysis to investigate the effects of various additives on the bio-augmented pretreatment of ensiled sweet sorghum and their subsequent impact on methane production during anaerobic digestion. The research evaluated the influence of four distinct additives, such as rumen fluid, biogas slurry, cellulase, and xylanase on the lignocellulosic composition alterations and microstructural changes of sweet sorghum. The investigation aimed to discern the variances impacts of via bio-augmented pretreatment on the bioenergy conversion benefits of sweet sorghum, in terms of the methane production process, digestive fluid characteristics, and system stability. The results revealed that, in comparison to the un-ensiled sweet sorghum, the bio-augmented ensiling pretreatment significantly reduced the content of hemicellulose and lignin in sweet sorghum by 14.67%-30.99% and 10.30%-47.23%, respectively, while the cellulose content increased by 6.32%-35.93%. Additionally, the relative crystallinity index (CrI) of ensiled sweet sorghum increased by 1.34%-13.08%. Furthermore, the extension of pretreatment time was found to progressively facilitate the disintegration of lignocellulosic anti-degradation barrier structure. It was found that the complex microbial communities and enzyme systems in biogas slurry and rumen fluid have a superior disruptive effect on the anti-degradation structure of ensiled sweet sorghum. The anaerobic digestion process maintained exceptional operational stability, with optimal pH (7.73-8.25) and ammonia nitrogen concentration (1350-1600 mg/L) ranges throughout the anaerobic digestion period. The ensiling pretreatment could effectively increase the removal rate of chemical oxygen demand (COD) by approximately 11.81%-34.32% and shortened the anaerobic digestion lay phase (0.8-1.37 days). All ensiling pretreatment strategies resulted in an average increase of 24.32% in daily methane production, while the CK showed the highest cumulative methane enhancement (49.16%), which attributable to the optimization of the volatile fatty acids (VFAs) composition. From an economic perspective, methane production benefits were significantly higher in all ensiled pretreatment groups compared to the un-ensiled sweet sorghum. Particularly, biogas slurry emerged as the most economically viable bio-augmentation additive, demonstrating a substantial economic benefit of 681.73 Yuan/t. This study provides critical insights into the efficacy of bio-augmented ensiling pretreatment for enhancing the energy conversion efficiency of sweet sorghum, with particular emphasis on the strategic use of biogas slurry as an additive. The substantial economic and environmental advantages of this approach significantly contribute to advancing sustainable biomass conversion strategies, which are imperative for the shift towards a renewable and eco-friendly energy sector. Consequently, considering the practical situation of large-scale biogas projects, it is recommended to utilize biogas slurry as an additive for the enhancing pretreatment of sweet sorghum. This approach not only enhances the energy conversion efficiency of sweet sorghum but also mitigates the costs associated with of biogas slurry, thereby facilitating the recycling of biogas slurry resources for the large-scale biogas plant.

Maize stover can be one of the most valuable waste resources in modern agriculture. Particularly, there is the a significant potential to for the waste-to-energy conversion and carbon emission reduction via anaerobic digestion. However, conventional anaerobic digestion can be limited to the scalability and practical application, such as the low tolerance for high organic loading, accumulation of volatile fatty acids, and instable unstable biogas production. Alternatively, biochar and attapulgite have emerged as the promising functional additives, in order to enhance the performance of the anaerobic digestion. Acidification can be mitigated to promote the microbial colonization and buffering capacity. The synergistic effects can be produced to provide a feasible strategy for the efficient anaerobic digestion. Nevertheless, the systematic studies still remain scarce on the dynamic regulation of the biochar-attapulgite composites under varying organic loading rates, as well as their overall effects on the energy efficiency and economic viability. In this study, a systematic investigation was made to explore the effects of the biochar and attapulgite (applied both individually and in combination) on the semi-continuous anaerobic digestion of ensiled maize stover under varying organic loading rates. Ensiled maize stover was taken as the substrate. A semi-continuous anaerobic digestion was operated at five organic loading rates: 0.5, 1.0, 1.5, 2.5, and 3.5 g/(L·d). Methane production and anaerobic digestion were compared on in the stability. The treatments were set as a control group (CK), a biochar group (BC), an attapulgite group (AT), and three composite additive groups with biochar-to-attapulgite mass ratios of 7:3, 5:5, and 3:7. The key parameters were monitored, including the daily gas production, methane content, volatile fatty acids (VFAs) concentration, pH, and intermediate alkalinity to partial alkalinity ratio (IA/PA). Energy conversion efficiency was then calculated after 43 days of continuous operation. The results showed that both methane concentration and methane production efficiency were gradually enhanced with the increasing loading rates, when the organic loading rate (OLR) fell within the range of 0.5-1.5 g/(L·d). The methane volume fraction of the BC/AT 7:3 group reached 54.97%, resulting in a methane yield of 367.46 mL/g, under an organic loading rate of 2.5 g/(L·d). This yield was 15.09%, 9.20% and 3.02% higher than those of the CK (319.27 mL/g), the BC (338.08 mL/g), and the AT group (359.82 mL/g). Meanwhile, the IA/PA ratio in the BC/AT 7:3 group was remained stable, ranging from 0.26 to 0.39. The pH was maintained between 7.1 and 7.3. While the concentration of VFAs was fluctuated between 15.83 and 42.23 mg/L. All parameters were remained below inhibitory thresholds, indicating the robust operational stability of the anaerobic digestion. In addition, the combined addition of biochar and attapulgite increased the soluble chemical oxygen demand (_SCOD) and conductivity during the anaerobic digestion of ensiled maize stover. The methane efficiency was enhanced by the substrate hydrolysis, acidification, and direct interspecific electron transfer (DIET) between microorganisms. The BC/AT 7:3 group also demonstrated an energy conversion efficiency as high as 73.21%, thus marking a 9.38 percentage points increase, compared with the CK group. There were the enhancements of 4.46 and 4.49 percentage points over the BC and AT group, respectively. The high methane production was primarily attributed to high energy conversion efficiency. In summary, the anaerobic digestion performance of ensiled maize stover was significantly enhanced under the organic loading rate of 2.5 g/(L·d) with the BC/AT 7:3 ratio. This strategy was achieved the simultaneous optimization of methane production and system stability. Engineering feasibility was also demonstrated to enhance the stover consumption and energy conversion efficiency. Thereby, the finding can also provide a scientific basis approach to developing the an efficient energy conversion of agricultural wastes.

To investigate the differences in nutritional quality and flavor characteristics among Morchella esculenta from four different regions (Qilihe and Gaolan, Lanzhou; Xihe and Chengxian, Longnan) in Gansu province, this study used ultraviolet (UV)-visible spectrophotometry, high performance liquid chromatography (HPLC) and inductively coupled plasma-mass spectrometry (ICP-MS) to quantify polysaccharides, polyphenols, vitamins and minerals. Free amino acids were determined using an amino acid analyzer and other non-volatile flavor substances such as soluble sugars, 5’-nucleotides and organic acids using HPLC. In total, 47 volatile aroma components (including alcohols, aldehydes and ketones) were analyzed qualitatively and quantitatively by gas chromatography-ion mobility spectrometry (GC-IMS), and principal component analysis and cluster analysis were used for differentiation and clustering of M. esculenta. The results showed that there were significant differences in the nutritional quality and flavor characteristics of M. esculenta from different regions of Gansu. The crude polysaccharide (20.48%) and total phenol (20.25 mg/g) contents of M. esculenta from Qilihe were significantly higher than those from the other regions. The soluble sugar (74.48 μg/g) and organic acid (58770.72 μg/g) contents of M. esculenta from Xihe were higher than those from the other regions, while the contents of vitamins (21044.01 μg/g), mineral elements (40392.52 mg/kg), amino acids (30318.78 mg/kg) and nucleotides (13561.98 μg/g) in M. esculenta from Chengxian were significantly higher than those of the other regions. Aldehydes, ketones and alcohols were the major aroma compounds of M. esculenta, 1-octen-3-one, 2-methylbutyraldehyde and ethyl 2-methylpentanoate being identified as the key aroma substances. The four production regions were clustered into three classes by principal component analysis (PCA) and cluster analysis: class Ⅰ, Qilihe and Gaolan, which have similar climates; class Ⅱ, Xihe and Chengxian, which share similar ecological environment; class Ⅲ, Gaolan, Xihe and Chengxian, which share similar soil characteristics. These results of this study provide a theoretical basis for expanding the planting area of M. esculenta.

In order to provide valuable information on the current status of research and the hot topics in the field of Baijiu pit mud, a comprehensive bibliometric visual analysis was carried out on 522 pieces of Chinese literature and 112 pieces of English literature in the Web of Science Core Collection (WOSCC) and China National Knowledge Infrastructure (CNKI) databases published from 1980 to 2021. Knowledge graph analysis from the perspectives of annual publication volume, authors and their institutions, highly cited articles and keywords was conducted to summarize recent progress and to predict future trends in this field. Research on Baijiu pit mud is of great significance for the high-quality development of the Baijiu industry and Baijiu quality improvement. The amount of research literature in the field of Baijiu pit mud has shown a trend of fluctuating growth over the past one decade, but it has not yet reached a mature stage, which still has broad development prospects. Chinese scholars are the main force in the field of Baijiu pit mud research. The literature published by the major contributors to this field such as Zhang Wenxue, Tang Yuming, Zhou Rongqing, Wu Chongde, and Xu Yan has a great influence and high academic value. The major institutions that have researched Baijiu pit mud include Sichuan University, Sichuan University of Science Engineering, and Jiangnan University. The research hotspots mainly focus on microbial communities, artificial pit mud, organic acids, butyric acid bacteria, functional bacteria, and so on. The information presented in this paper can help researchers in understanding the current trends and future directions in Baijiu pit mud research and in conducting scientific research and academic exchanges.

As an environmental-friendly renewable polymer material, nanocellulose (NCC) has great application potential and ecological benefits. In this paper, we introduce the structural properties and preparation techniques of NCC, give an overview of the methods used to characterize and modify NCC, and elaborate on the latest advances in the application of food industry. Additionally, we use bibliometrics to analyze and summarize the research hotspots in the NCC field. It is expected that the green and efficient production of NCC and the development of functional composites for different purposes will be research priorities in the future.

This study investigated the dynamic changes of quality formation and metabolite profiles during the development of Morchella fruiting bodies. Morchella fruiting bodies at three developmental stages: primordium (YJ), small mushroom (XG), and mature ascocarp (ZNG) were used to identify key metabolites that affect the quality of the mushroom by the combined use of routine tests and untargeted metabolomics. The results demonstrated that during the growth and development of Morchella fruiting bodies, the contents of major nutritional components, including proteins, polysaccharides and crude fat, increased significantly (P < 0.05). Across the three developmental stages, 16 free amino acids including aspartic acid, glutamate and threonine, and 6 nucleotides including 5’-cytidine monophosphate (CMP), 5’-uridine monophosphate (UMP), and 5’-xanthosine monophosphate (XMP), were detected, and the total contents of free amino acids and nucleotides ranged from 1291.01–5857.72 mg/kg and 792.74–1903.82 μg/g, respectively. Furthermore, untargeted metabolomics analysis identified 1624 metabolites at these three developmental stages, predominantly comprising organic acids, amino acids and lipids. The vitamin B₆ metabolism, riboflavin metabolism, arginine and proline metabolism, arginine biosynthesis, and nucleotide metabolism pathways were significantly enriched. Among 37 key differential metabolites involved in these significantly enriched pathways, 4-acetamidobutanoate and N⁶-(1,2-dicarboxyethyl)-adenosine monophosphate (AMP) were significantly positively correlated with the nutritional and flavor compounds of Morchella fruiting bodies, while L-arginine, agmatine, hypoxanthine, xanthine, deoxyinosine, inosine, and xanthosine were significantly negatively correlated with them. These metabolites participated in amino acid metabolism and energy metabolism during the growth of Morchella fruiting bodies, serving as potential factors regulating the quality formation of Morchella fruiting bodies.

The fungal community structure, the relationship between fungal flora and physicochemical factors, and the prediction of fungal function in pit muds from different spatial positions of 10-and 50-year-old cellars at Jinhui liquor Co. Ltd. were studied by using Illumina NovaSeq high-throughput sequencing, redundancy analysis and Fungi Functional Guild (FUNGuild). The results showed that the fungal diversity and richness of the 10-year-old pit mud decreased with increasing depth; the fungal diversity of the 50-year-old pit mud showed an overall increasing trend, while the fungal richness initially decrease and then increased. Moreover, for the 10-year-old pit, the fungal diversity and richness of the upper layer of the pit wall were significantly higher than those of the other positions (P < 0.05), while for the 50-year-old cellar, the fungal diversity and richness of the bottom layer were significantly higher than those of the other locations (P < 0.05). The fungal diversity and richness were significantly higher in the wall of the 10-year-old cellar than the 50-year-old cellar (P < 0.05), but were significantly higher in the bottom of the 50-year-old cellar than the 10-year-old cellar (P < 0.05). A total of 21 fungal phyla and 520 genera were detected in all pit mud samples, the relative abundance of four dominant phyla (Ascomycota, Basidiomycota, Mortierellomycota and Rozellomycota) and most dominant genera such as Aspergillus and Kazachstania showed significant changes among pit ages and spatial locations (P < 0.05). Fusarium, Aspergillus, Saccharomyces and Monascus were positively correlated with the contents of water, humus, K⁺ and Ca²⁺, while Cladosporium and Vishniacozyma were positively correlated with pH. Seven nutritional modes of fungi were observed, mainly including saprophytic and pathological-saprophytic-symbiotic nutritional modes, and four single and seven mixed functional groups were determined. This study provides a theoretical basis for clarifying the structure and spatial distribution of fungal community in Jinhui Baijiu pit mud.