Effects of Airflow Ultrafine-Grinding on the Physicochemical Characteristics of Tartary Buckwheat Powder.

Five different ultrafine milled flours (UMFs) were prepared from Tartary buckwheat via airflow ultrafine-grinding at different grinding pressures. The airflow ultrafine-grinding resulted in marked differences in particle size (from 100 to 10 µm). The UMFs were all brighter in appearance (higher L*) than Tartary buckwheat common flour (TBCF). Illustrated by the example of 70 °C, the UMFs were also found to have a greater water holding capacity (from 4.42 g/g to 5.24 g/g), water solubility (from 12.57% to 14.10%), and water solubility index (from 5.11% to 6.10%). Moreover, as the particle sizes reduced, the moisture content decreased (from 10.05 g/100 g DW to 7.66 g/100 g DW), as did the total starch content (from 68.88 g/100 g DW to 58.24 g/100 g DW) and the protein content (from 13.16% to 12.04%). However, the grinding process was also found to have negative effects on the mineral content of the Tartary buckwheat. Additionally, several substantial variations were found in their hydration properties along with grinding pressure changes in the differently ground UMFs. Consequently, fine Tartary buckwheat powders of a bright yellow color, with superior food processing properties, were prepared in this study by airflow ultrafine-grinding.

Antifungal Effect of Chitosan/Nano-TiO2 Composite Coatings against Colletotrichum gloeosporioides, Cladosporium oxysporum and Penicillium steckii.

Postharvest pathogens such as C. gloeosporioides (MA), C.oxysporum (ME) and P. steckii (MF) are the causal agents of disease in mangoes. This paper presents an in vitro investigation into the antifungal effect of a chitosan (CTS)/nano-titanium dioxide (TiO2) composite coating against MA, ME and MF. The results indicated that, the rates of MA, ME and MF mortality following the single chitosan treatment were 63.3%, 84.8% and 43.5%, respectively, while the rates of mycelial inhibition were 84.0%, 100% and 25.8%, respectively. However, following the addition of 0.5% nano-TiO2 into the CTS, both the mortality and mycelial inhibition rates for MA and ME reached 100%, and the mortality and mycelial inhibition rate for MF also increased significantly, reaching 75.4% and 57.3%, respectively. In the MA, the dry weight of mycelia after the CTS/0.5% nano-TiO2 treatment decreased by 36.3% in comparison with the untreated group, while the conductivity value was about 1.7 times that of the untreated group, and the protein dissolution rate and extravasation degree of nucleic acids also increased significantly. Thus, this research revealed the potential of CTS/nano-TiO2 composite coatings in the development of new antimicrobial materials.

Antimicrobial Nanoparticles Incorporated in Edible Coatings and Films for the Preservation of Fruits and Vegetables.

Edible coatings and films (ECF) are employed as matrixes for incorporating antimicrobial nanoparticles (NPs), and then they are applied on the fruits and vegetables to prolong shelf life and enhance storage quality. This paper provides a comprehensive review on the preparation, antimicrobial properties and mechanisms, surface and physical qualities of ECF containing antimicrobial NPs, and its efficient application to vegetables and fruits as well. Following an introduction on the properties of the main edible coating materials, the preparation technologies of ECF with NPs are summarized. The antimicrobial activity of ECF with NPs against the tested microorganism was observed by many researchers. This might be mainly due to the electrostatic interaction between the cationic polymer or free metal ions and the charged cell membrane, the photocatalytic reaction of NPs, the detachment of free metal ion, and partly due to the antimicrobial activity of edible materials. Moreover, their physical, mechanical and releasing properties are discussed in detail, which might be influenced by the concentration of NPs. The preservation potential on the quality of fruits and vegetables indicates that various ECF with NPs might be used as the ideal materials for food application. Following the introduction on these characteristics, an attempt is made to predict future trends in this field.

Scented Tartary Buckwheat Tea: Aroma Components and Antioxidant Activity.

In this study, the aroma compounds of Huantai tartary buckwheat tea (TBH), three laboratory-produced scented tartary buckwheat teas, as well as the antioxidant activity of tea infusion was investigated. In total, 103 aroma components were isolated and identified from all samples. Tartary buckwheat rose tea (TBR) contained 57 aroma components and tartary buckwheat jasmine tea (TBJ) had 53, both of which were higher than those in others. In addition, the total flavonoid content (TFC) and the total phenolic content (TPC) of scented tartary buckwheat tea were much higher than those of TBH. After the tartary buckwheat tea (TBT) was soaked in hot water twice, the antioxidant activity of all samples decreased, and the antioxidant activity of TBR and TBJ infusions was more stable than those of others. Further, the antioxidant activity of the first tea infusion (FTI) of the TBT was higher than that of the second tea infusion (STI). Overall, considering the diverse aroma compounds of scented tartary buckwheat tea and higher antioxidant activity of tea infusions, the combination of scented tea and tartary buckwheat is a feasible approach to develop tartary buckwheat scented tea.

Flavor Compounds in Pixian Broad-Bean Paste: Non-Volatile Organic Acids and Amino Acids.

Non-volatile organic acids and amino acids are important flavor compounds in Pixian broad-bean paste, which is a traditional Chinese seasoning product. In this study, non-volatile organic acids, formed in the broad-bean paste due to the metabolism of large molecular compounds, are qualitatively and quantitatively determined by high-performance liquid chromatography (HPLC). Amino acids, mainly produced by hydrolysis of soybean proteins, were determined by the amino acid automatic analyzer. Results indicated that seven common organic acids and eighteen common amino acids were found in six Pixian broad-bean paste samples. The content of citric acid was found to be the highest in each sample, between 4.1 mg/g to 6.3 mg/g, and malic acid were between 2.1 mg/g to 3.6 mg/g ranked as the second. Moreover, fumaric acid was first detected in fermented bean pastes albeit with a low content. For amino acids, savory with lower sour taste including glutamine (Gln), glutamic acid (Glu), aspartic acid (Asp) and asparagines (Asn) were the most abundant, noted to be 6.5 mg/g, 4.0 mg/g, 6.4 mg/g, 4.9 mg/g, 6.2 mg/g and 10.2 mg/g, and bitter taste amino acids followed. More importantly, as important flavor materials in Pixian broad-bean paste, these two groups of substances are expected to be used to evaluate and represent the flavor quality of Pixian broad-bean paste. Moreover, the results revealed that citric acid, glutamic acid, methionine and proline were the most important flavor compounds. These findings are agreat contribution for evaluating the quality and further assessment of Pixian broad-bean paste.

Preservation Mechanism of Chitosan-Based Coating with Cinnamon Oil for Fruits Storage Based on Sensor Data.

The chitosan-based coating with antimicrobial agent has been developed recently to control the decay of fruits. However, its fresh keeping and antimicrobial mechanism is still not very clear. The preservation mechanism of chitosan coating with cinnamon oil for fruits storage is investigated in this paper. Results in the atomic force microscopy sensor images show that many micropores exist in the chitosan coating film. The roughness of coating film is affected by the concentration of chitosan. The antifungal activity of cinnamon oil should be mainly due to its main consistent trans-cinnamaldehyde, which is proportional to the trans-cinnamaldehyde concentration and improves with increasing the attachment time of oil. The exosmosis ratios of Penicillium citrinum and Aspergillus flavus could be enhanced by increasing the concentration of cinnamon oil. Morphological observation indicates that, compared to the normal cell, the wizened mycelium of A. flavus is observed around the inhibition zone, and the growth of spores is also inhibited. Moreover, the analysis of gas sensors indicate that the chitosan-oil coating could decrease the level of O2 and increase the level of CO2 in the package of cherry fruits, which also control the fruit decay. These results indicate that its preservation mechanism might be partly due to the micropores structure of coating film as a barrier for gas and a carrier for oil, and partly due to the activity of cinnamon oil on the cell disruption.

Preparation and application characteristics of microencapsulated Lactobacillus acidophilus as probiotics for dogs.

In this article, preparation and application characteristics of microencapsulated Lactobacillus acidophilus were investigated. Results indicated that the optimum condition for preparation of micro encapsulation were 10% (w/v) wall material and the temperature of 20°C, respectively. Many micropores in the porous starch micro particles was also observed by Scanning Electron Microscope. Furthermore, the released cell counts were increase from 2.43 log cfu/g to 9.17 log cfu/g for the time prolong to 3h in the simulated colonic pH solution. On the other hand, the visible cells of Lactobacillus acidophilus in the dog feces on the 10th day after the probiotics feeding was improve about 34.8% compare to the before feeding, which was decrease about 24.6%for Escherichia coli. Furthermore, the content of is ovaleric acid, indole and 3-methylindole, putrefactive substances in dog feces, before feeding were reduce 24%, 16% and 45% in dog feces on the 10th day after feeding compared to that before feeding, respectively. Micro encapsulation can be considered a useful technology to provide the protection for Lactobacillus acidophilus and better application effective.

Microbial succession in the traditional Chinese Luzhou-flavor liquor fermentation process as evaluated by SSU rRNA profiles.

The community succession of microbes inhabited in the fermenting lees of Luzhou-flavor liquor was investigated based on small-subunit rRNA culture independent method. All sequences recovered from fermenting lees respectively fell into the genera of Lactobacillus, Streptococcus, Bacillus, Staphylococcus, Clostridium, Pelobacter, Actobacter, Serratia, Burkholderia, Rhodoccous, Corynebacterium, Arthrobacter, Microbacterium, Curtobacterium, Leptotrichia, Methanocuuleus, Saccharomyces, Zygosaccharomyces, Saccharomycopsis, Pichia, Talaromyces, Aspergillus, Eurotium, Fomitopsis and Trichosporon. The fungal Pichia, Saccharomycopsis and Talaromyces were most abundant in the lees fermented for 1 day, the fungal Eurotium and the bacteria Burkholderia, Streptococcus and Lactobacillus were dominant in the lees fermented for 7 days, only the bacteria Lactobacillus, Burkholderia were prevalent in the lees fermented for 60 days. Most genera almost existed in the fermenting lees, while their distributions were significantly different in 1, 7 and 60 days fermented lees. The prokaryotic community similarity coefficient was from 0.5000 to 0.5455 and followed to 0.1523, and that of eukaryotic community was from 0.5466 to 0.5259 and to 0.3750 when compared at species level. These results suggested that many microbes in lees have community successions associated with fermenting and that such successions maybe contribute the fermentation process of Luzhou-flavor liquor and is main reasons that the characteristic flavor factors are produced.

Effect of Composite Edible Coatings Combined with Modified Atmosphere Packaging on the Storage Quality and Microbiological Properties of Fresh-Cut Pineapple.

This study investigated the effect of edible coating (EC), modified atmosphere packaging (MAP), and edible coating + modified atmosphere packaging (EC + MAP) treatments on the quality of fresh-cut pineapples during storage at 4 °C. The quality differences were analyzed by measuring the quality, physiological indicators, and total microbial counts. After 8 d of storage, the brightness (L*) values of the EC + MAP and control samples were 72.76 and 60.83, respectively. The water loss and respiratory rate of the EC + MAP were significantly inhibited from 0% and 29.33 mg CO2 kg-1 h-1 to 4.13% and 43.84 mg CO2 kg-1 h-1, respectively. Furthermore, the fresh-cut pineapples treated with EC + MAP presented a good appearance, with lower total soluble solids (TSS) and relative conductivity and higher titratable acid (TA), ascorbic acid (AA), total phenol content, and firmness compared to the other treatment groups. At the end of storage, the EC + MAP samples exhibited the lowest polyphenol oxidase (PPO) activity, peroxidase (POD) activity, and malondialdehyde (MDA) content at 28.53 U, 60.37 U, and 1.47 nmol·g-1, respectively. Furthermore, the efficiency of EC + MAP treatment exceeded that of EC or MAP alone, preventing key problems involving the surface browning and microbiological safety of the fresh-cut pineapples. The results showed that EC + MAP treatment was more successful in maintaining the storage quality and extending the shelf life of fresh-cut pineapples.

Multi-scale structural characteristics of black Tartary buckwheat resistant starch by autoclaving combined with debranching modification.

The impact of autoclaving or autoclave-debranching treatments on the multi-scale structure of resistant starch (RS) and the relationship with starch digestion remains unclear, despite their widespread use in its preparation. This work investigated the relationship between RS structure in black Tartary buckwheat and its digestibility by analyzing the effects of autoclaving and autoclave-debranching combined treatments on the multi-scale structure of RS. The results showed that black Tartary buckwheat RS exhibited a more extensive honeycomb-like network structure and enhanced thermal stability than either black Tartary buckwheat native starch (BTBNS) or common buckwheat native starch (CBNS). Autoclaving and autoclaving-debranching converted A-type native starch to V-type and possibly the formation of flavonoid-starch complexes. Autoclaving treatment significantly increased the proportion of short A chain (DP 6-12) and the amylose (AM) content, reduced the viscosity and the total crystallinity. Notably, the autoclave-debranching co-treatment significantly enhanced the resistance of starch to digestion, promoted the formation of perfect microcrystallines, and increased the AM content, short-range ordered degree, and the proportion of long B2 chain (DP 25-36). This study reveals the relationship between the multi-scale structure and digestibility of black Tartary buckwheat RS by autoclaving combined with debranching modification.

Effects of different antioxidants combined with high hydrostatic pressure on the color and anthocyanin retention of a blueberry juice blend during storage.

Blueberry juice has been found to undergo severe browning after treatment and cold storage, such as processing by high hydrostatic pressure (HHP) at 550 MPa/10 min/25 °C followed storage at 4 °C for 4 days. This browning may be due to the degradation of anthocyanin (AC) in the berries. Therefore, in this study, gallic acid (GA), ferulic acid (FA), ascorbic acid (VC), citric acid (CA), tea polyphenol (TP) and α-tocopherol (VE) were compared to determine their ability to improve the stability of the AC in HHP-treated blueberry juice. The juice was combined with the six abovementioned antioxidants at different concentrations, then treated by HHP at 550 MPa/10 min/25 °C and stored at 4 °C for 20 days. Thereafter, the pH levels, degrees °Brix, color parameters, total AC content and polyphenol oxidase (PPO) activity of the blueberry juice blend were measured and compared. Gallic acid at 2 g/L was found to be the most effective antioxidant to protect against AC degradation. After storage at 4 °C for 20 days, the AC content of the juice with no added antioxidants had decreased by 62.27% with a PPO relative activity of 50.78%, while the AC content of juice supplemented with 2 g/L GA had decreased by 13.42% with a PPO relative activity of 28.13%. The results of this study, thus, suggest that GA can stabilize the structure of AC in blueberry juice and reduce PPO activity, which may be beneficial in guiding the production of blueberry juice with high AC retention.

Effect of dense phase carbon dioxide treatment on the flavor, texture, and quality changes in new-paocai.

This study investigated the effect of dense phase carbon dioxide (DPCD) treatment on the organoleptic properties of new-paocai. Optimal DPCD treatment (25 MPa/40 °C/40 min) was determined by conducting single-factor and orthogonal experiments with the sensory, bactericidal, and electronic eye evaluations. DPCD treatment (25 MPa/40 °C/40 min) did not significantly affect the nitrite, pH, total acid, and organic acid of the new-paocai brine, and the texture of the radish slices did not display substantial changes. Gas chromatography-mass spectrometry (GC-MS) was employed to characterize the new-paocai brine flavor, revealing 63 and 60 respective flavor compounds with and without DPCD treatment. In addition, DPCD treatment significantly reduced the total organic volatile compound content in the paocai from 48.182 µg/mL to 35.952 µg/mL, DPCD has a great influence on volatile flavor substances. The electronic nose (E-nose) effectively distinguished the flavor differences in the new-paocai brine with and without DPCD treatment. This study combined new food processing technology with traditional food production, could provide a new idea for pickle production technology.

Effect of autoclave-cooling cycles combined pullulanase on the physicochemical and structural properties of resistant starch from black Tartary buckwheat.

A starch-rich portion is produced as a by-product of black Tartary buckwheat processing. The effect of enzymatic combined with autoclaving-cooling cycles (one, two, or three times) on the physicochemical and structural properties of black Tartary buckwheat type 3 resistant starch (BRS) was evaluated. The autoclaving-cooling cycles enhanced solubility and reduced swelling, with the BRS content increasing from 14.12% to 25.18%. The high crystallinity of the BRS reflected a high molecular order. However, increasing the number of autoclaving-cooling cycles did not result in higher BRS content. The highest BRS yield in the autoclaved starch samples was 25.18% after double-autoclaving-cooling cycles. Furthermore, the autoclaving-cooling cycles altered the crystalline structure of black Tartary buckwheat, and the subsequent crystallinity changed from 36.33% to 42.05% to 38.27%. Fourier-transform infrared spectroscopy shows that the number of cycles results in more efficient double-helical packing within the crystalline lamella. Principal component analysis showed that the autoclaving-cooling cycle treatment leads to significant changes in the molecular structure of resistant starch (RS). These results indicated that autoclaving-cooling cycles might be a feasible way for producing RS from black Tartary buckwheat starch with better structural stability to expand their application range.

Green synthesized TiO2 nanoparticles: Structural characterization and photoinduced antifungal activity against P. steckii.

This study synthesized titanium dioxide (TiO2 ) nanoparticles (NPs) from mango leaf extract and investigated the features and antibacterial capabilities of three different. The microscopic morphological observation, scanning electron microscopy, and transmission electron microscopy results showed that all three NPs showed agglomeration phenomenon, and the TN-1 sample existed as large agglomerates, whereas the agglomeration phenomenon of TN-3 sample was improved by the modified, without large agglomerates. The biosynthetic TN-2 and TN-3 NPs were spherical and uniform in size, whereas those of the TN-3 sample was the smallest, ranging from 10 to 30 nm. X-ray diffraction and Raman spectroscopy results exhibited that these were highly pure anatase NPs. The result of ultraviolet (UV)-visible-near-infrared spectral analysis showed that the TN-2 and TN-3 samples displayed higher UV absorption properties than the TN-1 samples and were highest in the modified NPs, which was more suitable for preparing chitosan-based nanocomposite material in future experiments and studies. The colony diameters of the TN-1, TN-2, and TN-3 treatment groups were 7.99, 7.80, and 6.86 mm, respectively, after 120 min of UV light induction at a wavelength of 365 nm. Significant differences were evident between the TN-3 and the other two groups (p < 0.05), indicating that the TN-3 sample more effectively inhibited Penicillium steckii than the other TiO2 NPs. PRACTICAL APPLICATION: Nanomaterials coated film preservation is widely used in fruit and vegetable preservation. In this paper, TiO2 nanomaterials will be green synthesized using mango leaf and structurally characterized, whereas antibacterial tests will be conducted against the mango fruit-specific bacterium Penicillium steckii, which will provide a theoretical basis for the storage and preservation of mango.

Effect of different drying technologies on the characteristics and quality of lemon slices.

This experiment aimed to investigate the effects of four drying methods, namely, hot air drying (HAD), microwave drying (MD), vacuum drying (VD), and microwave vacuum drying (MVD), on the quality of lemon slices. The relevant indicators, including total phenolic content, ascorbic acid content, browning, color, reducing sugar content, volatile component measurements, and principal component analysis of 0 and 30 days storage, were compared after exposure to the four drying methods. The shortest time of 64 min was used to treat the lemon slices via MVD at 1 KW. These samples displayed the least damage after drying and the highest rehydration ratio of 4.12. The contents of VC, reducing sugars, and total phenols of MVD samples were significantly higher than those in the HAD, VD, and MD groups, retaining 105.94 mg/100 g, 21.35 g/100 g, and 77.81 mg GAE/g, respectively, while their color difference values were also the smallest, with a browning degree of 3.55, significantly lower than those in the other treatment groups (p < 0.05), and the degree of browning of the samples in the HAD treatment group was the most serious; in terms of volatile flavor substances, the lemon slice samples in the MVD and HAD treatment groups were more diverse and of better quality. The order of product sensory evaluation was: MVD > VD > HAD > MD. The final scores after comprehensive analysis revealed the order of the four drying methods as MVD, HAD, VD, and MD. Therefore, MVD had a better effect on the sensory perception and nutritional properties of the lemon slices, providing a useful alternative to the conventional drying method. PRACTICAL APPLICATION: Lemon slices during drying are affected by various aspects, leading to changes in its color, aroma substances, and nutrient composition. The results of this work will not only provide a technical reference for the future production of high-quality dried lemon slices, but also have important implications for fresh-cut lemons in processing and storage. It also generates important implications for fresh-cut lemons in processing and storage.

Structural Characterization and Biological Activity of Polysaccharides from Stems of Houttuynia cordata.

In this study, water-soluble natural polysaccharides were extracted from the stems of Houttuynia cordata Thunb (HCPS). The optimization of the hot water extraction process using response surface methodology (RSM), and the extraction factors, were analyzed by multiple stepwise regression analysis and Pearson analysis. Then, the structural characterization and biological activity of the HCPS were investigated. The results indicated that the maximum extraction yield (2.43%) of the HCPS was obtained at the optimal condition (extraction temperature for 90 °C, extraction time for 5 h, solid-liquid ratio for 1:30 g/mL). The extraction temperature was determined to be the primary factor influencing the extraction yield. The HCPS molecules had an average molecular weight of 8.854 × 103 kDa and were primarily of mannose (Man), rhamnose (Rha), glucuronic acid (GlcA), galacturonic acid (GalA), glucose (Glc), and xylose (Xyl). In addition, the backbone of the HCPS might consist of →6)-α-d-Glcp-(1→ and →6)-ß-d-GalpA-(1→. The HCPS had no triple-helix structure. The scanning electron microscopy (SEM) results showed that the HCPS presented a smooth and uniform appearance, and some sheet and chain structures existed. Moreover, the HCPS exhibited significant anti-oxidant activity and inhibited the activity of α-amylase and α-glucosidase. These findings showed that HCPS might be developed into a potential material for hypoglycemia, and provides a reference for the development of Houttuynia cordata polysaccharide applications in food.

Photo-Induced Antifungal Activity of Chitosan Composite Film Solution with Nano-Titanium Dioxide and Nano-Silver.

ABSTRACT: This study was conducted to investigate the UV light-induced effect of chitosan-titanium dioxide-silver (CTS-TiO2-Ag) nanocomposite film solution against Penicillium steckii and the underlying physiological mechanism of this effect. With longer UV exposure time, pathogen inhibition increased. UV-photoinduced treatment for 120 min produced the smallest P. steckii colony diameter, at 4.85 mm. However, when this treatment was followed by 8 h of storage, the conductivity of the P. steckii culture medium reached its highest level, at 713 microsiemens per cm. After a 120-h growth period on mangoes under the same conditions, the lesion diameters and proportion of infected mangoes reached 12.61 mm and 41.67%, respectively. Because the P. steckii cell membrane was severely disrupted, its permeability increased, causing serious extravasation of intracellular protein and nucleic acid material. Malondialdehyde, catalase, and superoxide dismutase in the P. steckii cells reached maximum concentrations (2.1106 µmol/mL, 44.06 U/mL, and 24.67 U/mL, respectively) after 8 h of incubation. These results indicate significant P. steckii inhibition by the UV light induction of the CTS-TiO2-Ag nanocomposite film solution.

Comparison of Different Varieties on Quality Characteristics and Microbial Activity of Fresh-Cut Pineapple during Storage.

This study compared the quality and storage characteristics of four pineapple varieties to select those displaying adequate storage resistance and those suitable for freshly cut processing. Four varieties of pineapple, namely Tainong No.16, Tainong No.17, Tainong No.11, and Bali, were used to analyze the quality differences in freshly cut pineapple during storage by measuring the quality, physiological indicators, and total microbial count. The results indicated that the nutritional quality and storability of freshly cut pineapples differed significantly among the varieties. During refrigeration at 4 °C, Tainong No.11 and Bali displayed the shortest storage period of 4 d, while Tainong No.17 and Tainong No.16 presented storage periods of 5 d and 6 d, respectively. A sensory evaluation indicated that the Tainong No.16 variety was superior in terms of consumer preference, while the Bali slices were generally rated lower than the other cultivars. Additionally, the sensory properties, weight loss, firmness, and ascorbic acid (AA) content of Tainong No.16 changed the least during storage, with values of 60.75%, 6.48%, 75.15%, and 20.44%, respectively. Overall, the quality order of the four varieties of freshly cut pineapples during storage was: Tainong No.16 > Tainong No.17 > Tainong No.11 > Bali. Moreover, two-way ANOVA showed that the main effect of variety and storage time on the storage quality of fresh-cut pineapple was significant (p < 0.05). The interaction effect of variety and storage time on other quality characteristics of fresh-cut pineapple was significant (p < 0.05) except for Titratable acid (TA) and AA. In conclusion, Tainong No.16 displayed higher storage potential than the other varieties. The results of this work provide application possibilities to promote the successful processing of pineapple cultivars as freshly cut produce.

Effect of different superfine grinding technologies on the physicochemical and antioxidant properties of tartary buckwheat bran powder.

The effect of shear crushing, airflow comminution, and wet grinding on the physical and chemical properties of Tartary buckwheat bran (TBB) powder was compared. Superfine grinding significantly reduces the particle size of bran (1.644 µm), while increasing the protein content (23.60%), water-holding capacity (4.38 g g-1), solubility (21.077 g 100 g-1), bulk density (0.34 g mL-1), and tap density (0.53 g mL-1) providing good processing characteristics. The antioxidant properties of bran powder prepared by the three methods mentioned above were compared. The results showed that different bran powders subjected to superfine grinding displayed varying levels of antioxidant capacity. The quercetin content (2.18 g 100 g-1) of the wet-grinding bran powder (WGBP) was twice that of the control group, while no rutin was detected. The total flavonoid content (TFC) and total phenolic content (TPC) were significantly different from those of other groups. The DPPH, ˙OH, and ABTS+ removal rates were 60.74%, 86.62%, and 92.98%, respectively, while that of ˙OH was significantly higher than in the other treatment groups. The control group, shear crushed, and airflow comminution bran exhibited no significant differences in TFC, TPC, and oxidation resistance, except for the ability to remove ˙OH. TBB powder obtained via superfine grinding displayed superior taste and functional characteristics, providing a theoretical reference for the processing of this bran.

Characterization and Antimicrobial Activity of Silver Nanoparticles Synthesized with the Peel Extract of Mango.

The green synthesis of silver nanoparticles (AgNPs) from biological waste, as well as their excellent antibacterial properties, is currently attracting significant research attention. This study synthesized AgNPs from different mango peel extract concentrations while investigating their characteristics and antibacterial properties. The results showed that the AgNPs were irregular with rod-like, spherical shapes and were detected in a range of 25 nm to 75 nm. The AgNPs displayed antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), showing a more significant impact when synthesized with 0.20 g/mL of mango peel extract. Therefore, the antibacterial effect of different diluted AgNP concentrations on the growth kinetic curves of E. coli and S. aureus after synthesis with 0.20 g/mL mango peel extract was analyzed. The results indicated that the AgNP antibacterial activity was higher against S. aureus than against E. coli, while the AgNP IC50 in these two strains was approximately 1.557 mg/mL and 2.335 mg/L, respectively. This research provides new insights regarding the use of postharvest mango byproducts and the potential for developing additional AgNP composite antibacterial materials for fruit and vegetable preservation.