Although surface-enhanced Raman spectroscopy (SERS) substrates have achieved high sensitivity, it is still difficult to apply these SERS protocols to the on-site detection of real samples due to the SERS substrate being fabrication-complexed, unstable, reproducible, or unable to be applied in batch production. Here, a large-scale ordered two-dimensional array of Au nano-hemispheres was developed through electron beam vaporization of Au onto the easy-available commercialized anodic aluminum oxide (AAO) template with two-layer nanostructures of different diameters. The uniform Au nano-hemisphere is reliable for SERS detection of malachite green (MG) due to the relative standard deviation (RSD) of the SERS intensities at different locations less than 10%. With the optimized excitation wavelength, solvent effect and pH environment, the linear range of MG detection spans from 10–10 to 10–6 mol/L with a limit of detection (LOD) of 4×10–10 mol/L. The enhancement factor can reach 1.2×106. After extraction with acetonitrile and dichloromethane, MG in the spiked tilapia was detected with satisfactory recovery. The results indicate that the Au nano-hemisphere array can be expected to greatly facilitate SERS practical applications in detecting harmful food additives and chemicals due to the advantages of chemical inertness, physical robustness, simple fabrication, controllability, large-area uniformity, and large-batch production.

In this study, integrative metabolomics and transcriptomics analyses were conducted to investigate the effects of 1-methylcyclopropene (1-MCP) on apple fruit quality during long-term cold storage. The results showed that 1-MCP (1 μL/L) treatment could maintain fruits apparent quality (i.e. external color and firmness), inhibit the increase of rot rate and soluble solids content/titratable acidity ratio, decrease ethylene release, and respiratory intensity during cold storage, and extend shelf life. Moreover, 1-MCP had long-term effects on the accumulation of many qualities related to metabolite and gene expression in fruits. 1-MCP affected genes related to metabolism at the early stage of storage, specifically those of the glycolysis and tricarboxylic acid cycle pathways. Genes related to the degradation of sucrose, starch, and cellulose were inhibited, and some starch and cellulose synthesis genes were up-regulated by 1-MCP. Apart from ethylene synthesis and signal transduction being inhibited by 1-MCP, several enzymes (pectinesterase, pectate lyase, polygalacturonase) were involved in pectin degradation, and degradation products of the cell wall (i.e. D-galacturonic acid and D-glucuronic acid) were also strongly inhibited, further maintaining fruit firmness. Cysteine, as precursor glutathione (GSH) related to plant resistance, up-regulated the synthase gene. However, the expression of genes related to cyanoalanine synthase and amino acid utilization pathways was suppressed by 1-MCP. Collectively, 1-MCP could maintain the postharvest quality of apple fruits.

Milk fatty acids significantly contribute to human nutrition and clinical health. However, previous evidence for changes in the fatty acid profiles of different dairy species following homogenization and heat treatment is lacking. Here, changes in fat globule particle size and fatty acids in samples of Holstein, goat, buffalo, yak, and camel milk following homogenization (20 MPa) and heat treatment (63 °C for 30 min and 90 °C for 15 min) were investigated using a laser particle sizer and gas chromatography approach. The results indicated that the milk fat globule particle size of all studied dairy species significantly decreased after homogenization and heat treatment, in which there was no difference. The fatty acid composition of C10:0 and medium-chain fatty acid in goat milk, C18:0 and long-chain fatty acid in camel milk, and C16:0 in buffalo and yak milk served as the characteristic traits of these milks. Changes in the relative contents of several fatty acids (C4:0, C10:0, C16:0, C18:0, C18:1n9c, and C18:3n3) were dependent on homogenization, heat treatment, and the type of dairy species. In particular, C18:3n3 significantly decreased in goat and camel milk after homogenization and heat treatment. These findings provide new insights into how homogenization and heat treatment affect the fatty acid profile and can be used to further improve the heat treatment of milk from minor dairy species.

Detection of fruit traits by using near-infrared (NIR) spectroscopy may encounter out-of-distribution samples that exceed the generalization ability of a constructed calibration model. Therefore, confidence analysis for a given prediction is required, but this cannot be done using common calibration models of NIR spectroscopy. To address this issue, this paper studied the Gaussian process regression (GPR) for fruit traits detection using NIR spectroscopy. The mean and variance of the GPR were used as the predicted value and confidence, respectively. To show this, a real NIR data set related to dry matter content measurements in mango was used. Compared to partial least squares regression (PLSR), GPR showed approximately 14% lower root mean squared error (RMSE) for the in-distribution test set. Compared with no confidence analysis, using the variance of GPR to remove abnormal samples made GPR and PLSR showed approximately 58% and 10% lower RMSE on the mixed distribution test set, respectively (when the type 1 error rate was set to 0.1). Compared with traditional one-class classification methods, the variance of the GPR can be used to effectively eliminate poorly predicted samples.

Background and objectives Skin defects are one of the primary problems that occur in post-harvest grading and processing of loquats. Skin defects lead to the loquat being easily destroyed during transportation and storage, which causes the risk of other loquats being infected, affecting the selling price. Materials and Methods In this paper, a method combining band radio image with an improved three-phase level set segmentation algorithm (ITPLSSM) is proposed to achieve high accuracy, rapid, and non-destructive detection of skin defects of loquats. Principal component analysis (PCA) was used to find the characteristic wavelength and PC images to distinguish four types of skin defects. The best band ratio image based on characteristic wavelength was determined. Results The band ratio image (Q782/944) based on PC2 image is the best segmented image. Based on pseudo-color image enhancement, morphological processing, and local clustering criteria, the band ratio image (Q782/944) has better contrast between defective and normal areas in loquat. Finally, the ITPLSSM was used to segment the processing band ratio image (Q782/944), with an accuracy of 95.28%. Conclusions The proposed ITPLSSM method is effective in distinguishing four types of skin defects. Meanwhile, it also effectively segments images with intensity inhomogeneities.

Polycarboxylic acids (PACs) are important metabolic products in almost all living bodies, yet current analytical methods for detection of PACs in tea beverages are still unsatisfactory due to the complex matrix and physicochemical properties of PACs. In this work, a rapid method was developed for the simultaneous determination of 7 PACs, including tartaric acid, α-ketoglutaric acid, malic acid, malonic acid, cis-aconitic acid, succinic acid, and fumaric acid, in beverages, based on selective removal of the matrix in combination with liquid chromatography–mass spectrometry (LC-MS) analysis. By stirring with activated carbon and the Na2CO3 solution, the matrix in beverages was selectively removed, and PACs were almost retained in the supernatant of diluted Na2CO3 solution. Under optimized parameters, the limit of quantitation for the PACs was in the range of 1–50 ng/mL, and the content of the PACs in 8 beverages was determined with the recovery range of 72.2%–122.5%. The contents of malic acid, malonic acid, and succinic acid in tea beverages were found to be greater than those in non-tea beverages. Moreover, the concentration of these PACs in beverages was found to be multiplied many times in their deterioration period, especially for fumaric acid and α-ketoglutaric acid. These results indicated that PACs can be selected as a criterion to differentiate qualified tea beverages from spoiled beverages.

Objectives The aim of this study is to determine the mechanism through which 1-methylcyclopropene (1-MCP) affects the quality of red ‘Fuji’ apples, which were stored for a short duration. Materials and Methods Red ‘Fuji’ apples were treated with 1-MCP (1.0 μl/L), stored at 25 °C for 0, 12, 24, 48, 72, and 96 h, and ethylene production was measured. An integrated metabolomic and transcriptomic analysis was performed on apples stored for 24 h. Results The release of ethylene was significantly delayed from red ‘Fuji’ apples subjected to 1-MCP treatment. By performing an integrated transcriptome and metabolome analyses, we identified 117 differentially expressed genes (DEGs) and 44 differentially accumulated metabolites (DAMs). By performing functional enrichment analysis, we found that DEGs were involved in the following pathways: carbon metabolism (LPD2, gpmA, LTA2, ACC, PSAT1, MdCAS2), phytohormone signal transduction (EBF1), amino acid metabolism (MdACS-1), fatty acid metabolism (LOX1.5, KCS4, KAS1), energy metabolism (Lhcb1, Lhcb6, PsbY, GPDHC1, PUMP5), metabolic pathways (TRE1, HEXO1) and cell wall metabolism (CSLG2). Thus, these DEGs were involved in the ripening of fruits, and they controlled the quality of fruits at the post-harvest stage. The metabolites were enriched with DAMs. These were found to be individually involved in the metabolic pathway, secondary metabolite biosynthesis, phenylpropanoid biosynthesis, flavonoids, and flavonol synthesis. Conclusions The results indicate that 1-MCP inhibits the biosynthesis of ethylene and suppresses energy metabolism. Moreover, it also downregulates metabolic pathways and the enzymatic genes related to fruit quality. Therefore, 1-MCP delays the ripening of fruits at the post-harvest stage. This study helps us understand how 1-MCP treatment affects the ripening and quality of fruits.

Objectives Benzimidazoles (BZs) are commonly used for the treatment of soil-transmitted helminth infections in veterinary clinics; however, misuse and overdosing of BZs will cause residual problems and have the potential to damage human health through the food chain. Thus, the existence of BZs in foods needs more attention. This study aims to establish a broad-spectrum immunoassay for rapid detection and to simultaneously monitor BZs in milk. Materials and Methods Based on structure analysis, a ‘zero epitope loss’ strategy, which introduced a spacer arm into the imino group of the imidazole ring of albendazole, was first adopted for hapten modification to obtain an ultra-sensitive and broad-spectrum antibody. An indirect competitive enzyme-linked immunosorbent assay (icELISA) was established for the detection of 18 BZs in milk sample with a single-step pretreatment. A quantitative structure–activity relationship model was constructed to interpret and predict the recognition. Results The antibody could recognize 20 BZs and the half-inhibitory concentrations ranged from 0.054 to 417.58 ng/mL, the limits of detection of icELISA ranged from 0.4 to 89.4 ng/mL, and the mean recovery rates ranged from 76.49% to 120.40%, with a coefficient of variation <20%. Substituent R1 of BZs was considered to be the main influencing factor for recognition, and the comparative molecular field analysis model (q2=0.724, r2=0.998) was finally chosen for further prediction. Conclusions The results indicated that the established icELISA could simultaneously identify 18 BZs, with good accuracy and precision, which was suitable for rapid detection of BZs in milk.

The temperature difference of fruit itself will affect its near infrared spectrum and the accuracy of its soluble solids content (SSC) prediction model. To eliminate the influence of apple temperature difference on the SSC model, a diffuse transmission dynamic online detection device was used to collect the spectral data of apples at different temperatures, and four methods were used to establish partial least squares correction models: global correction, orthogonal signal processing, generalized least squares weighting and external parameter orthogonal (EPO). The results show that the temperature has a strong influence on the diffuse transmission spectrum of apples. The 20 ºC model can get a satisfactory prediction result when the temperature is constant, and there will be great errors when detecting samples at other temperatures. The effect of temperature must be corrected to establish a more general model. These methods all improve the accuracy of the model, with the EPO method giving the best results; the prediction set correlation coefficient is 0.947, the root mean square error of prediction is 0.489%, and the prediction bias is 0.009%. The research results are of great significance to the practical application of SSC prediction of fruits in sorting workshops or orchards.

In this paper, the effect of different concentrations of sucrose stress on color formation of the Staphylococcus xylosus was investigated. The results showed that the highest a* value and the best coloring effect similar to those of nitrite were observed after the addition of 0.05 g/mL sucrose to stress the S. xylosus. UV-Vis and electron spin resonance spectra analysis showed that production of coloring product Mb-NO was significantly enhanced after 0.05 g/mL sucrose stress. The growth curve, reactive oxygen content, cell cycle, nitric oxide synthase (NOS) activity, zeta potential, cell size, and protein composition of S. xylosus were investigated to reveal the mechanism of sucrose stress to enhance the coloring effect of the strain. The result showed that sucrose inhibited the growth of S. xylosus, which changed the physiological state by activating the oxidative stress response. The stress altered the rate of intracellular metabolism of S. xylosus by delaying the cell cycle and increasing cell surface zeta potential and cell particle size. These changes altered the protein composition of the cells and significantly enhanced the activity of intracellular NOS, which could improve the chromogenic ability of S. xylosus. This study will provide theoretical support for sucrose stress on S. xylosus to enhance its coloring effect, and sucrose stress for S. xylosus might be a promising biological alternative to nitrite in meat products.

The quality changes of shelled Pacific oysters (Crassostrea gigas) were examined in relation to the effects of superchilling storage at −1 °C for 28 d by measuring changes in biochemical properties (microbial analysis, adenosine triphosphate (ATP)-related compounds, pH, free amino acids) and sensory evaluations in this study. The results indicated that microorganism growth was significantly inhibited during superchilling storage. Adenosine diphosphate (ADP) and adenosine monophosphate (AMP) accumulated while ATP rapidly decreased in the adductor muscle. ATP and ADP were the primary components in the other 3 tissues including mantle, gill, and body trunk of oysters, and they remained ­relatively stable over time. The pH and adenylate energy charge in the adductor muscle could be utilized as freshness indicators for shelled oysters. However, there were no significant differences (P>0.05) among the free amino acids during whole storage. According to the sensory evaluations, oysters could be alive and tolerated up to 21 d at −1 °C storage. The study demonstrated that superchilling storage at −1 °C could better maintain the eating quality of shelled oysters and the shelf life was extended to 21 d.

Using lactic acid bacteria (LAB) to ferment Huyou peel and pomace could provide a reference for making full use of Huyou resources and provide valuable suggestions for the industrial production of functional foods. The effects of LAB fermentation on the bioactive composition, volatile compounds and antioxidant activity of Huyou peel and pomace were studied. Results showed that both Huyou peel and pomace were good substrates for LAB growth. LAB had remarkable influence on bioconversion of organic acids, among which ascorbic acid content was increased significantly. In addition, LAB could produce flavonoids with enhanced bioactivity and absorption. In particular, the contents of rhoifolin, quercitrin and quercetin were increased by over 100%. Besides, the volatile compounds contents and aroma complexity were improved. Furthermore, the antioxidant activity was enhanced. Thus, our study provides high-value applications of Huyou, and fermented products with improved nutritional value and flavor are potentially beneficial to human health.

Seed-borne bacterial pathogens cause severe yield loss and biotoxin contamination in rice, leading to increasing concern on the global food supply and environmental safety. Plant native microbes play an important role in defending against diseases, but their actions are often influenced by the chemical fungicides applied in the field. Here, Bacillus licheniformis mmj was isolated from rice spikelet, which uniquely showed not only fungicide-responsiveness but also broad-spectrum antimicrobial activity against major rice bacterial pathogens including Xanthomonas oryzae pv. oryzae, Burkholderia plantarii and Burkholderia glumae. To understand the hallmark underlying the environmental adaptation and antimicrobial activity of B. licheniformis mmj, the genome sequence was determined by SMRT and subjected to bioinformatics analysis. Genome sequence analysis enabled the identification of a set of antimicrobial-resistance and antibacterial activity genes together with an array of harsh environment-adaptive genes. Moreover, B. licheniformis mmj metabolites were analyzed with gas chromatography coupled to triple quadrupole mass spectrometry, and the volatile components that were linked with the antimicrobial activity were preliminarily profiled. Collectively, the present findings reveal the genomic and metabolic landscapes underlying fungicide-responsive B. licheniformis, which offers a new opportunity to design harsh environment-adaptive biopesticides to cope with prevalent bacterial phytopathogens.

Maize straw, an abundant agricultural residue, has potential as an eco-friendly resource. The aim of this study was to investigate the structure and effect on Bifidobacterium longum of exopolysaccharide produced by Weissella cibaria using maize straw as a carbon source. In this work, an exopolysaccharide-producing strain was isolated from vegetable juice, which was identified as W. cibaria. Our results demonstrated that exopolysaccharide produced by W. cibaria is a linear glucan containing an α-1,6 glycosidic bond with a molecular weight of 9462 Da. In addition, scanning electron microscopy of exopolysaccharide from W. cibaria revealed the flake structures. In vitro assays showed that the exopolysaccharide from W. cibaria has the ability to stimulate the proliferation of B. longum strain and its metabolism to produce acetic acid. This work provides a scientific reference for the potential application of maize straw and a new insight into an eco-friendly carbon source to produce exopolysaccharide.

As a famous fruit worldwide, citrus is susceptible to green mold caused by Penicillium digitatum, which causes large economic losses every year. ε-Poly-L-lysine (ε-PL) is a novel preservative with strong inhibitory effects on fungi, and has the capacity to induce disease resistance in fruit, but the mechanism has been reported rarely, especially in citrus. In the present study, 800 μg/mL ε-PL and P. digitatum spores were inoculated in two different wounds on the citrus pericarp at an interval of 24 h. The results revealed that ε-PL inhibited that the development of green mold without direct contact with P. digitatum, indicating that the disease resistance of citrus was activated. Transcriptome analysis revealed that ε-PL activated amino acid metabolism and phenylpropanoid biosynthesis. Besides, the accumulation of glutamic acid, proline, arginine, serine, lysine, phenylalanine, and tyrosine were changed during storage. In phenylpropanoid biosynthesis, ε-PL increased phenylalanine ammonia-lyase (PAL), cinnamate 4-hydroxylase (C4H), and 4-coumarate:coenzyme A ligase (4CL) activities and total phenolic and flavonoid contents. Importantly, among these phenolic compounds, ε-PL promoted the accumulation of individual phenolic compounds including ferulic acid, chlorogenic acid, p-coumaric acid, caffeic acid, gallic acid, catechins, epicatechin, and narirutin. In conclusion, ε-PL enhanced the resistance of citrus through amino acid metabolism and accumulation of phenolic compounds. These results improved the knowledge of the mechanism of ε-PL–induced disease resistance and provided a fresh theoretical basis for the use of ε-PL in postharvest citrus preservation.

Bovine mastitis is the most complex and costly disease in the dairy industry worldwide. Somatic cell count (SCC) is accepted as an international standard for diagnosing mastitis in cows, but most instruments used to detect SCC are expensive, or the detection speed is very low. To develop a rapid method for identifying mastitis degree, the dielectric spectra of 301 raw milk samples at three mastitis grades, i.e., negative, weakly positive, and positive grades based on SCC, were obtained in the frequency range of 20–4500 MHz using coaxial probe technology. Variable importance in the projection method was used to select characteristic variables, and principal component analysis (PCA) and partial least squares (PLS) were used to reduce data dimension. Linear discriminant analysis, support vector classification (SVC), and feed-forward neural network models were established to predict the mastitis degrees of cows based on 22 principal components and 24 latent variables obtained by PCA and PLS, respectively. The results showed that the SVC model with PCA had the best classification performance with an accuracy rate of 95.8% for the prediction set. The research indicates that dielectric spectroscopy technology has great potential in developing a rapid detector to diagnose mastitis in cows in situ or online.

Objectives Based on the information from the random inspection of foods by the China Food and Drug Administration in 2022, the contamination levels of lead ions are high in many edible products. Traditional methods of detecting lead ions cannot meet the requirements of on-site analysis of food due to the need for large equipment. The immunochromatographic assay (ICA) is an effective, rapid, on-site analytical technique for determining lead ions in foods. However, the performance of ICA based on the traditional probe (AuNP-mAb) is limited by ignoring the influence of the antibody orientation. Materials and Methods In this study, we developed an efficient technology for constructing a universal probe (AuNP-PrA-mAb) based on the oriented immobilization of antibody. The performance of ICA was largely improved due to specific binding of the Fc region of the antibody with recombinant protein A (PrA) on the surface of a gold nanoparticle (AuNP). The ICA based on a universal probe was applied for the qualitative and quantitative detection of lead ions in Procambarus clarkii within 30 min. Meanwhile, a simple and fast pretreatment method based on dilute acid extraction was developed for pretreating the P. clarkii containing lead ions. Results The visual limit of detection and the scanning limit of quantization of the developed ICA strip for lead ions were 0.5 ng/mL and 0.28 ng/mL, respectively. The sensitivity of ICA based on universal probe was 10-fold higher than that of the ICA using traditional probe. Furthermore, the detection results had no obvious difference between the ICA and ICP-MS with t-test statistical method. Conclusions The developed ICA based on a universal probe presented broad application prospects in detecting contaminants in foods.

Refrigeration is considered a prime technology for preserving meat products. Temperature alterations are commonly ignored by industry during refrigeration, which have impacts on product quality. Thus, we conducted research on pork loin and salmon fillets that were preserved for 0, 5, 9, 12, and 15 d, where different temperature fluctuations and shocks were established on 4 °C. Data revealed that several meat parameters such as total volatile basic nitrogen, total viable count, and lipid oxidation were significantly changed in the ±2 °C fluctuations group compared with the constant temperature group. Additionally, both the temperature fluctuations and shocks groups had accelerated myofibril protein degradation, while desmin expression and species richness/diversity of bacteria were significantly reduced in the ±2 °C fluctuations group compared with the constant temperature group. Briefly, temperature fluctuations and shocks accelerated the destruction of muscle structural integrity. Furthermore, both conditions accelerated meat spoilage by progressively expanding the water-loss channels, which can reduce meat edibility. This study provides a new theoretical basis for the proper use of refrigerated temperatures for storing meat products.

Objectives The secondary products of lipid oxidation are one of the main factors inducing protein oxidation. The effects of oxidation treatment with malondialdehyde (MDA) on the immunoreactivity of amandin and its digestion were studied. Materials and Methods The rabbit IgG binding ability of amandin was analyzed by western blotting, and the changes in amandin oxidation and immunoreactivity during digestion of amandin with different degrees of oxidation were investigated in combination with an almond allergen enzyme-linked immunosorbent assay kit. Alteration of linear epitopes of amandin by oxidation was investigated by liquid chromatography–tandem mass spectrometry (LC-MS/MS). Results The results showed that the immunoreactivity of amandin was significantly reduced after 1 mmol/L MDA and 100 mmol/L MDA treatment. However, the 1 mmol/L MDA treatment was owing to cleavage of linear epitope peptide in amandin and oxidation of the active amino acid. The 100 mmol/L MDA treatment was due to aggregation of amandin and significant decrease in its solubility. Oxidation also reduced digestibility of amandin and significantly affected immunoreactivity during digestion. LC-MS/MS also identified four oxidation-prone methionine sites (aa 264–274, 298–308, 220–240, and 275–297) in gamma conglutinin 1. Conclusions MDA treatment reduced the immunoreactivity of amandin. MDA treatment also led to protein aggregation, which slowed down the digestion of amandin and altered the immunoreactivity of amandin during digestion.

Osteoporosis is a typical physiological disease, the main symptoms of which are brittle fracture, bone pain and easily deformed. As an individual ages, the prevalence of osteoporosis increases year by year. In the present study, selenium with antioxidant, immunomodulatory and anti-tumor effects was used to prevent osteoporosis induced by retinoic acid. The serum calcium contents in the selenium-treated groups (sodium selenite and selenomethionine) were significantly higher (P<0.05) than those in the model group in both the prevention and treatment studies. After prevention, glutamic-oxalacetic transaminase transaminase (GOT), glutamate transaminase (GPT), alkaline phosphatase (ALP) and tartrate-resistant acid phosphatase (TRACP) levels were significantly (P<0.05) decreased. In the treatment study, the serum calcium and phosphorus contents of the rats increased after selenium treatment. There was no significant change (P>0.05) in the activity of GOT and GPT. The content of ALP decreased obviously and the TRACP enzyme activity increased. Overall, these results showed that different forms of selenium compounds have great potential in preventing and treating osteoporosis.

Bacillus species have been widely used as probiotics in a number of food products. However, these are vulnerable to bacteriophage infections, which poses fermentation failure and eventually result in economic losses. Given this, we designed this study in which the bacteriophage of lysogenic Bacillus methylotrophicus, phage BM-P1, was induced successfully, and its biological characteristics and genome information were researched. The obtained results showed that phage BM-P1 belonged to Myoviridae family. The maximum number of infections for this phage was 10, with a burst size of 104.48±2.70 counts expressed per milliliter per infective center. Additionally, this phage was temperature- and pH-sensitive and divalent ions (Ca2+, Mg2+) and chloramphenicol did not have a significant influence on its adsorption capacity. Genomic analysis revealed that the genome size of phage BM-P1 was 153 087 bp with 41.94% GC content, including 258 coding sequences. Furthermore, 52 bacteriophages of Bacillus were classified into two clades by using phylogenetic analysis. Among them, phage BM-P1 with phage VB_BsuM-Goe3 and vB_BveM-Goe7 had the highest average nucleotide identity values, 95.23% and 95.28%, respectively. However, synteny analysis revealed transposition, deletion, and insertion in the genome of BM-P1. Considering this, it could be extrapolated that this phage is a new lysogenic phage. In conclusion, this study furthers the knowledge on the properties of B. methylotrophicus phages and provides seminal insights for designing effective antiphage strategies for fermentation industry.

In traditional beekeeping, the two most important methods for extracting honey are centrifugation and honeycomb-pressing. In this study, the physicochemical composition of honey samples extracted using two distinct procedures was compared, as well as the impact of antioxidant capacity and nutritional potency on the lifespan and learning memory of worker bees. Honey samples were collected from ten colonies of Apis cerana: five samples via centrifugation and five via honeycomb-pressing. Our results showed that honey extraction methods influence the nutritional composition and potency of honey. Most parameters were superior in pressed honey, and the amylase activity in centrifuged honey was higher. The effects of antioxidant capacity and nutritional potency on worker bees’ lifespans and learning memory were also superior in pressed honey. Pressed honey had higher nutritional composition and potency. However, whether pressed honey, which is rich in pollen, spoils more easily requires further investigation.

Background Wheat flour maturation affects the aggregation and structural stability of proteins. The number of high-molecular-weight glutenin subunits (HMW-GSs) differs in various wheat varieties. The effects of Dx2 absence on the protein aggregation characteristics and thermal stability of flour were investigated during 120 d of maturation using near-isogenic lines (NILs). Results The absence of Dx2 delayed and decreased the protein aggregation of flours during maturation, i.e. the maturation-induced increases were later and smaller for glutenin, glutenin macropolymer (GMP), glutenin/gliadin ratio, β-sheets, and β-sheet/α-helix ratio in HMW-D1a without Dx2 than in HMW-D1p with Dx2; these differences were ascribed to the weaker interactions between the sulfhydryl (-SH) groups, disulfide bonds (-S-S-), and hydrophobicity in the flours without Dx2. Flour maturation caused the dough microstructures to be more compact and denser, thereby increasing the flour thermal stability as observed by a higher denaturation peak temperature (Tp), enthalpy of thermal transition (ΔH), and degradation temperature (Td), These changes led to better dough properties such as dough development time, dough stability time, and protein weakening, but the optimal stage in HMW-D1a without Dx2 was reached later. Conclusion These findings deepen the understanding of how HMW-GS Dx2 modifies protein structures during flour maturation.

Background Acacia seyal gum (ASG) is an abundant source of natural polyphenolic compounds (NPPCs) and antioxidant activity with numerous benefits and is often used in cancer treatment. The type of extraction technique can significantly impact the yield and isolation of NPPCs from ASG. The traditional use of maceration extraction reportedly yields fewer NPPCs. Objectives This study investigated five extraction techniques for NPPCs and ASG antioxidant activity, namely: homogenisation, shaking, ultrasonication, magnetic stirring, and maceration. Materials and methods The evaluation of the antioxidant activity (AoA) of the extracted NPPCs from ASG used five assays, namely: total flavonoids content, Folin–Ciocalteu index, 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, ferric reducing antioxidant power, and cupric reducing antioxidant capacity. Results To minimise the data set dimensionality requires principal component analysis. The ultrasonic and maceration techniques were the best techniques to extract NPPCs and examine the AoA of ASG, with a high correlation between the NPPCs and AoA. However, the maceration process was slow (12 h) compared to ultrasonication (1 h). Slow extraction can result in a decline of the NPPCs due to polyphenol oxidase–enzyme and impact productivity. Conclusions These findings provide an essential guide for the choice of extraction techniques for the effective extraction of NPPCs from ASG and other plant materials.

Microbes on fresh apples are closely associated with fruit disease, preservation, and quality control. Investigation into the microbial communities on apples from different producing regions could reveal the microbial specificity and help disease prevention and quality control. In this paper, the apple surface microbes of 44 samples from two main Chinese apple-producing regions, Bohai Bay (BHB) and the Loess Plateau (LP), were investigated by sequencing fungal internal transcribed spacer and bacterial 16S rRNA hypervariable sequences. BHB and LP apples contained significantly different bacterial and fungal communities. BHB apples had a higher fungal diversity than LP apples. A total of 102 different fungal and bacterial taxonomies were obtained between apples from the two regions, in which 24 genera were predominant. BHB apples had higher phytopathogenic fungal genera, such as Tilletiopsis, Acremonium, Candida, and Phoma, indicating the higher phytopathogenic risks of apples from the humid climate of the BHB region. LP apples contained more bacterial genera identified as gut microbes, indicating the potential risks of contaminating apples with foodborne pathogens in the arid environment of the LP. This study highlighted the environment-oriented microbial specificity on apples from two main apple-producing regions, and provided a basis for further investigation.

A microelectrode glucose biosensor based on a three-dimensional hybrid nanoporous platinum/graphene oxide nanostructure was developed for rapid glucose detection of tomato and cucumber fruits. The nanostructure was fabricated by a two-step modification method on a microelectrode for loading a larger amount of glucose oxidase. The nanoporous structure was prepared on the surface of the platinum microelectrode by electrochemical etching, and then graphene oxide was deposited on the prepared nanoporous electrode by electrochemical deposition. The nanoporous platinum/graphene oxide nanostructure had the advantage of improving the effective surface area of the electrode and the loading quantity of glucose oxidase. As a result, the biosensor achieved a wide range of 0.1–20.0 mmol/L in glucose detection, which had the ability to accurately detect the glucose content. It was found that the three-dimensional hybrid nanostructure on the electrode surface realized the rapid direct electrochemistry of glucose oxidase. Therefore, the biosensor achieved high glucose detection sensitivity (11.64 μA·L/(mmol·cm2), low detection limit (13 μmol/L) and rapid response time (reaching 95% steady-state response within 3 s), when calibrating in glucose standard solution. In agricultural application, the as-prepared biosensor was employed to detect the glucose concentration of tomato and cucumber samples. The results showed that the relative deviation of this method was less than 5% when compared with that of high-performance liquid chromatography, implying high accuracy of the presented biosensor in glucose detection in plants.

Objectives Chilling injury is a prominent physiological disorder in longkong fruit pericarp when stored under 13 °C for a prolonged period. This study aimed to investigate the effects of individual salicylic acid (SA) and ultrasonication (US) treatments and of the combination salicylic acid and ultrasonication (SA-US) on alleviating the chilling injury symptoms in longkong fruit pericarp when in prolonged cold storage. Materials and methods SA (1 mmol/L) and US (40 kHz, 10 min at 90% amplitude, 350 W) were used as individual and combined (SA-US) treatments to control the chilling injury in longkong pericarp. The various quality measures were checked every 2 days in longkong for up to 18 days of cold storage (13 °C, 90% relative humidity). Results The results revealed that the control fruits treated with water exhibited severe chilling injury symptoms followed in rank order by US, SA, and SA-US cases. Treatments such as US and SA alone were more effective in controlling chilling injuries than control, while only minimal significant differences were noticed between them. On the other hand, the longkong pericarp treated with the SA-US combination had significantly increased antioxidant enzyme (superoxide dismutase and catalase) activities and decreased levels of membrane lytic (phospholipase D and lipoxygenase) enzymes and browning-inducing enzymes (phenylalanine ammonia lyase and polyphenol oxidase). Consequently, in the longkong pericarp, the chilling injury index, electrolytic leakage, respiration rate, weight loss, firmness, malondialdehyde content, changes in unsaturated and saturated fatty acid contents, and reactive oxygen species were significantly controlled by this treatment. Conclusions The present study concludes that longkong fruit treatment with a combination of US and SA is an excellent alternative for controlling the chilling injury symptoms and extending the shelf-life.

Fresh-cut Chinese water chestnuts (CWCs) are prone to quality deterioration during storage, which does not meet consumer demand. In this study, the effect of exogenous melatonin (5 mmol·L?1) on the quality and potential mechanisms in fresh-cut CWC was investigated. The results showed that melatonin treatment alleviated the cut-surface discoloration of CWCs. Not only did this treatment significantly slow down the increase in browning degree and yellowness (b?) as well as the decrease in lightness (L?), but it also significantly delayed the loss of weight and total soluble solids. Further investigations indicated that melatonin-treated fresh-cut CWCs exhibited significantly lower total phenolics and soluble quinones and suppressed the activities of phenylalanine ammonia-lyase, polyphenol oxidase, and peroxidase. Meanwhile, when fresh-cut CWCs were treated with melatonin, the total flavonoid concentration was significantly decreased compared to the control. Additionally, melatonin significantly inhibited the accumulation of H2O2 and malondialdehyde as well as enhanced the activities of superoxide dismutase and catalase by promoting the production of O2–?. In summary, melatonin treatment may delay the surface discoloration of fresh-cut CWCs by inhibiting phenolic compound metabolism and improving antioxidant capacity, thereby effectively maintaining the quality and prolonging the shelf life of fresh-cut CWCs.

In the present study, the bactericidal efficacy of slightly acidic electrolyzed water (SAEW) against Listeria monocytogenes (L. monocytogenes) planktonic cells and biofilm on food-contact surfaces including stainless steel and glass was systematically evaluated. The results showed that SAEW (pH 5.09 and available chlorine concentration (ACC) of 60.33 mg/L) could kill L. monocytogenes on food-contact surfaces completely in 30 s, a disinfection efficacy equal to that of NaClO solutions (pH 9.23 and ACC of 253.53 mg/L). The results showed that long exposure time and high ACC contributed to the enhancement of the disinfection efficacy of SAEW on L. monocytogenes on food-contact surfaces. Moreover, the log reduction of SAEW treatment presented an increasing tendency within the prolonging of treatment time when SAEW was used to remove the L. monocytogenes biofilm formed on stainless steel and glass surfaces, which suggested that SAEW could remove L. monocytogenes biofilm effectively and its disinfection efficacy is equal to (in the case of stainless steel) or higher than (in the case of glass) that of high-ACC NaClO solutions. In addition, the results of the crystal violet staining and scanning electron microscopy also demonstrated that SAEW treatment could remove the L. monocytogenes biofilm on food-contact surfaces.

In the present study, the bactericidal efficacy of slightly acidic electrolyzed water (SAEW) against Listeria monocytogenes (L. monocytogenes) planktonic cells and biofilm on food-contact surfaces including stainless steel and glass was systematically evaluated. The results showed that SAEW (pH 5.09 and available chlorine concentration (ACC) of 60.33 mg/L) could kill L. monocytogenes on food-contact surfaces completely in 30 s, a disinfection efficacy equal to that of NaClO solutions (pH 9.23 and ACC of 253.53 mg/L). The results showed that long exposure time and high ACC contributed to the enhancement of the disinfection efficacy of SAEW on L. monocytogenes on food-contact surfaces. Moreover, the log reduction of SAEW treatment presented an increasing tendency within the prolonging of treatment time when SAEW was used to remove the L. monocytogenes biofilm formed on stainless steel and glass surfaces, which suggested that SAEW could remove L. monocytogenes biofilm effectively and its disinfection efficacy is equal to (in the case of stainless steel) or higher than (in the case of glass) that of high-ACC NaClO solutions. In addition, the results of the crystal violet staining and scanning electron microscopy also demonstrated that SAEW treatment could remove the L. monocytogenes biofilm on food-contact surfaces.