DPPH Free Radical Scavenging Rate Research Articles

A novel multi-functional skin-care dry mask based on Bletilla Striata polysaccharide electrospun nanofibers

The dual challenges of additive safety and environmental sustainability in the current cosmetics market have attracted significant attention. In this study, we obtained raw materials from natural Chinese medicine, combined with electrospinning technology, developed a new type of environmentally friendly dry nanofiber multifunctional mask with Bletilla striata polysaccharide (BSP) as the material and loaded with the sodium ferulate (SF). The optimal manufacturing process was screened by scanning electron microscopy (SEM), and the diameters of the dry nanofiber facial mask (DNFM) were mainly distributed in the range of 180–240 nm. Volunteer experiments and water contact angle assessments showed that the DNFM had good moisture retention and solubility. The experimental findings showcased that the water vapor transmission rate of the PVA/BSP/SF DNFM was 4607.77 ± 74.12 g/m2/day, and the tyrosinase inhibition rate was 52.88 %, over 98 % inhibition rates against Propionibacterium acnes (P. acnes), and a 94.99 ± 0.24 % DPPH free radical scavenging rate. The mouse group treated with the DNFM displayed stronger resistance to UV damage. Cell Counting Kit-8 (CCK8) and Live/Dead staining experiments verified its safety and biocompatibility. The combined application of electrospinning technology and natural Chinese medicine components provides a new strategy for the development of an environmentally friendly and convenient mask product.

The Role of Camellia Shell Substrates in Modulating the Nutritional Characteristics of Pleurotus pulmonarius.

Camellia shells are the main by-product of camellia seed processing and are usually incinerated or disposed of as agricultural waste. In this study, camellia shells were employed in the Pleurotus pulmonarius cultivation process using five distinct formulae substituting for cottonseed shells. Our results show that as the substitution rate of camellia shells increased from 0% to 35%, the protein content in P. pulmonarius significantly increased from 34.05% to 53.35%. The polysaccharide content reached a peak value of 5.62% at 30% substitution of camellia shells. The DPPH free radical scavenging rate reached its maximum of 82.70% at 20% substitution of camellia shells. Furthermore, increases in the total amino acid contents in P. pulmonarius were positively correlated with the substitution rate of camellia shells. Considering the yield characteristics, the formula of 20% camellia shell substitution tested in this study appears to be optimal for P. pulmonarius cultivation. These findings not only provide a substrate to enhance the nutritional quality of P. pulmonarius but also demonstrate a novel approach for the ecological utilization of camellia shells.

Integrated deep eutectic solvent extraction and resin adsorption for recovering polyphenols from citrus reticulata Blanco peels: Process optimization, compositional analysis, and activity determination

The recovery of polyphenols from Citrus reticulata Blanco peels was studied based on integrated deep eutectic solvent (DES) extraction and resin adsorption. The DES prepared with choline chloride and ethylene glycol (molar ratio 1:4) and hydrophobic interaction/weakly acidic cation exchange mixed-mode adsorption resin HD-1 were used as the extractant and adsorbent respectively. The operating parameters of integrated process were optimized using completely randomized design and response surface methodology (RSM). The extraction kinetics was studied and the composition of extract was analyzed by UPLC-MS. Finally, the antioxidant activity of extract and its inhibitory ability on α-glucosidase and α-amylase were determined. Under the optimal operating conditions (liquid–solid ratio of 20:1, extraction temperature of 43 °C, extraction time of 4.8 h, resin amount of 6.6 g), the polyphenols yield of integrated process was increased by 2.15-fold and the time was shortened by 52.48 % compared with that of traditional sequential process. The extraction kinetic curves of both integrated and sequential processes conformed to pseudo-first-order kinetic model, and the extraction speed of integrated process was significantly higher than that of sequential process. The main polyphenols in extract were neohesperidoside, poncirin, narirutin, and hesperidin, etc. The extract exhibited a strong antioxidant capacity with DPPH free radical scavenging rate of extract reached 79.54 % of that of vitamin C. The inhibition ratios of extract against α-glucosidase and α-amylase were 97.81 % and 427 % of that of acarbose respectively. The results indicated that the extract has a potential application for prevention and control of type 2 diabetes mellitus.

Physiological, metabolome, and transcriptome analysis revealed the effect of ethyl 3-amino-3-thioxopropanoate on the browning of fresh-cut banana during storage

The quality of fresh-cut bananas is often affected by surface browning, which does not meet consumer expectations. The ethyl 3-amino-3-thioxopropanoate (EAT) is an ethyl ester organic compound screened from Maillard reaction products that may have browning inhibition effects. However, there is still a lack of research on the practical application of EAT. This study investigated the impact of exogenous EAT on the browning process and the underlying mechanisms in fresh-cut banana through a comprehensive analysis involving physiological, metabolomic, and transcriptomic approaches. Treatment with EAT effectively mitigated the discoloration of the cut surface of slices and decreased the browning index by 74 % at the end of storage. Additionally, EAT application significantly reduced polyphenol oxidase activity, increased phenylalanine ammonia-lyase activity and total phenolic content, inhibited lipoxygenase activity, decreased malondialdehyde accumulation, enhanced antioxidant enzyme activity, and improved DPPH free radical scavenging rate to 68.49 %. Moreover, 839 metabolites were identified through non-targeted metabolomics analysis. Metabolomic and transcriptomic analysis further highlighted the importance of lipid metabolism, amino acid metabolism and secondary metabolites in influencing the sensitivity to post-cutting browning. EAT treatment also influenced the expression levels of key genes related to browning. Thus, it could be speculated that the mechanism by which EAT produces its anti-browning effect may be by reducing phenolase activity, improving levels of phenols and amino acids, enhancing the antioxidant capacity of the fruit, and alleviating membrane lipid peroxidation. In summary, this study provides valuable insights into the response mechanism employed by exogenous EAT to inhibit browning in freshly cut bananas. However, the application security and mass production methods of EAT still need further clarification.

Peptide incorporation in frozen dough and steamed bread: Characteristics and structure-function relationship

Antarctic krill peptide (AKP), a bioactive compound, has garnered significant attention in recent years. This study aimed to explore the effects of varying levels of AKP addition (ranging from 0% to 2.0%, based on the flour, w/w) and different freezing time (0, 1, 2, 4, and 6 weeks) on the rheological properties, rheo-fermentation properties, water distribution, and microstructure of dough. The results revealed that the addition of AKP led to a reduction in the freezable water content, T2 relaxation time, and free sulfhydryl content of frozen dough. After 6 weeks of freezing, the viscoelastic properties of the dough with AKP were higher than those of the control. Additionally, the fermentation height of dough containing 1.5% AKP increased by 25.85% compared with the control, resulting in increased springiness and specific volume, and decreased hardness in the resulting steamed bread. Pearson correlation analysis showed a positive correlation between freezable water content and free sulfhydryl groups, while a negative correlation was observed with springiness. Furthermore, springiness showed a positive correlation with the DPPH free radical scavenging rate. These findings highlight the potential of AKP as a novel food cryoprotectant capable of significantly enhancing the quality and nutritional value of frozen wheat products.

Variation in Chongqing finger citron components and antioxidant activity from essential oils in several organs

The finger citron (Citrus medica L.var. sarcodactylis Swingle) is a both medicinal and edible species specified by the China Ministry of Health, It is also a regional medicinal plant grown in Chinaʼs Chongqing Municipality. We explored the utilization value of flower, leaf, and branch resources of non-medicinal sections of finger citron of Chongqing origin and identified variations in its yield, content, and antioxidant activity in essential oils in several organs. From several finger citron organs, essential oils were extracted using ultrasonic-assisted steam distillation, and their essential components were identified using gas chromatography-mass spectrometry (GC–MS). To assess antioxidant properties of various finger citron organs, DPPH free radical scavenging rate, ABTS free radical scavenging rate, and total reducing power of essential oils were determined. A total of 71 chemical components were discovered, and a cluster heat map revealed that d-limonene, Citral, (Z)-3,7-dimethylocta-2,6-dienal, γ-Terpinene, OCymene, and Ocimene were the most significant components and that their composition and concentration in essential oils of different organs varied substantially, with the average total amount in the four major organs in descending order: branches (79.34 %), leaves (73.40 %), flowers (68.85 %), and dried fruits (55.69 %). Finger citron's non-medicinal sections and organs' essential oils exhibited some level of antioxidant activity. The maximal clearance rate of the final flower group was 19.26 % when the essential oil concentration of each group was 4.0 mg·mL−1 for the assessment of DPPH free radical scavenging activity. DPPH free radical clearance rates of the bud group, initial flower group, full flower group, final flower group, branch group, and young leaf group were significantly different from the medicinal parts dried fruits group (P < 0.05), whereas there was no significant difference in the old leaf group (P > 0.05). When the essential oil concentration of each group was 0.10 mg·mL−1 for the ABTS radical scavenging ability measurement, the bud group had the highest scavenging rate of 32.24 %, and significant differences in the ABTS radical scavenging rates of the bud group, primary flower group, full flower group, final flower group, and branch group were observed when compared to the dried fruits group (P < 0.05). Between the young leaf and old leaf groups, there was no significant difference (P > 0.05). When the essential oil concentration was 3.0 mg·mL−1 for the measurement of overall reduction capacity, the old leaf group's highest absorbance value was 0.310. and the total reduction capacity of the bud group, first flower group, complete flower group, last flower group, branch group, young leaf group, and old leaf group substantially differed from the dried fruits (P < 0.05). This study provides a reference for the formation of “green” concurrent consumption and development of medicinal and non-medicinal elements of Chinese medicinal materials as well as theoretical support for the diverse utilization of finger citron resources.

Changes in Polyphenols and Antioxidant Activity in Fermentation Substrate during Maotai-Flavored Liquor Processing.

To investigate the changes in phenols and antioxidant capacity in fermented grains during different stages of the fermentation process (Xiasha, Zaosha, and single-round stages) of Maotai-flavored liquor, the total phenolic contents of 61 samples, collected in different stages, were analyzed via the Folin-Ciocalteu method, and the phenolic compounds were then identified by high-performance liquid chromatography (HPLC). Subsequently, the antioxidant activities were determined using the DPPH free radical scavenging rate and ABTS and FRAP antioxidant capacities. The correlations among the total phenolic contents, individual phenolics, and three antioxidant activities of the samples were analyzed. The results show that the total phenolic contents of the fermented samples did not change significantly in the Xiasha and Zaosha stages but showed an upward trend in the single-round stage. A total of 12 phenol acids were identified in the fermented grains, including 5 phenolic acids (e.g., ferulic acid and caffeic acid), 4 flavonoids (e.g., luteolin and apigenin), and 3 proanthocyanidins (e.g., apigeninidin), for which the DPPH free radical scavenging rates and ABTS and FRAP antioxidant capacities of all of the fermented grain samples ranged from 78.91 ± 4.09 to 98.57 ± 1.52%, 3.23 ± 0.72 to 13.69 ± 1.40 mM Trolox, and 5.06 ± 0.36 to 14.10 ± 0.69 mM FeSO4, respectively. The total phenolic contents of the fermented grain samples were significantly and positively correlated with the ABTS and FRAP (p ≤ 0.05), while no significant correlations were found between total phenolic content and DPPH. In general, the total phenolic content, phenolic substances, and antioxidant capacity of the fermented grains exhibited changes during the fermentation process in liquor production, and the phenolic components contributed more to the antioxidant properties of the fermented grains. The present study provides a theoretical reference for analyzing the dynamic changes and antioxidant properties of functional phenolic components in fermented grains.

Gelatin/agar pH-indicator film based on cranberry extract loaded with linalool nanoparticle: Survey on physical, antimicrobial, and antioxidant properties

In this study, linalool-nanoparticles (L-NPs) were prepared (encapsulation efficiency was 68.54 %) and introduced pH-indicator film based on cranberry-extract (CEF) to develop multifunctional smart films. XRD analysis and FTIR spectroscopy indicated that cranberry-extract (CE) and L-NPs were uniformly distributed in the gelatin/agar matrix and could change the intermolecular structure of the film. Color change of smart films showed that CE endowed the film with pH-sensitive property. As CE and L-NPs were added to the film, the water contact angle (WCA) was increased from 57.03° to 117.73°, the elongation at break (EAB) was increased from 12.30 % to 34.60 %. Additionally, the introduction of L-NPs enhanced the antioxidant activity (DPPH free radical scavenging rate increased from 26.80 % to 36.35 %) and antibacterial activity (against S. aureus and E. coli) of the smart film, which were verified by its retarding effect on pork spoilage.

Biphasic Fermentation of Trapa bispinosa Shells by Ganoderma sinense and Characterization of Its Polysaccharides and Alcoholic Extract and Analysis of Their Bioactivity.

Trapa bispinosa shells (TBs) and its flesh (TBf) have been recognized for their medicinal properties, including antioxidant, antitumor, and immunomodulatory effects. Despite these benefits, TBs are often discarded as waste material, and their applications remain to be further explored. In this study, we optimized the solid-state fermentation process of Ganoderma sinense (GS) with TBs using a response surface experiment methodology to obtain the fermented production with the highest water extract rate and DPPH free radical scavenging activity. We prepared and characterized pre-fermentation purified polysaccharides (P1) and post-fermentation purified polysaccharides (P2). Alcoholic extracts before (AE1) and after (AE2) fermentation were analyzed for active components such as polyphenols and flavonoids using UPLC-QTOF-MS/MS (ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry). Mouse macrophages (RAW 264.7) were employed to compare the immune-stimulating ability of polysaccharides and the antioxidant activity of AE1 and AE2. Optimal fermentation conditions comprised a duration of 2 days, a temperature of 14 °C, and a humidity of 77%. The peak water extract yield and DPPH free radical scavenging rate of the water extract from TBs fermented by GS were observed under these conditions. The enhanced activity may be attributed to changes in the polysaccharide structure and the components of the alcoholic extract. The P2 treatment group indicated more secretion of RAW 264.7 cells of NO, iNOS, IL-2, IL-10, and TNF-α than P1, which shows that the polysaccharides demonstrated increased immune-stimulating ability, with their effect linked to the NF-кB pathway. Moreover, the results of the AE2 treatment group indicated that secretion of RAW 264.7 cells of T-AOC and T-SOD increased and MDA decreased, which shows that the alcoholic extract demonstrated enhanced antioxidant activity, with its effect linked to the Nrf2/Keap1-ARE pathway. Biphasic fermentation of Trapa bispinosa shells by Ganoderma sinense could change the composition and structure of the polysaccharides and the composition of the alcoholic extract, which could increase the products' immunomodulatory and antioxidant activity.

Reactive extrusion of caffeic acid functionalized ε-polylysine with low-density polyethylene as an antimicrobial and antioxidant film

In this work, a novel grafted film with both antimicrobial and antioxidant properties was developed. ε-polylysine (EPL) and caffeic acid (CA) were used as raw materials, and EPL-CA was synthesized by grafting CA onto EPL by the carbodiimide coupling method. Using dicumyl peroxide (DCP) as a radical initiator, EPL-CA was crosslinked with low-density polyethylene (LDPE) by reactive co-extrusion to produce grafted films with both antimicrobial and antioxidant properties. Compared with pure LDPE film, all graft films show antimicrobial and antioxidant properties. Specifically, when the EPL-CA concentration is >3%, the inhibition rates against Escherichia coli (>91%) and Staphylococcus aureus (>97%) significantly increase, and the DPPH free radical scavenging rate (>60%) also significantly increases. Compared with the control film, the grafted film exhibits increased tensile strength and decreased elongation at break. In addition, the migration levels of all graft films in food simulants are below the migration standards set by the European Union. Overall, immobilizing EPL-CA on the LDPE matrix improves antimicrobial, antioxidant, and mechanical properties. Among them, the film exhibits the best comprehensive performance when the EPL-CA content is 3%. Therefore, the development of antimicrobial and antioxidant active LDPE film is proposed. These results indicate that active packaging films can be prepared through reactive extrusion, a promising and industrializable technology, and have broad prospects in improving food safety and other aspects.

Study on extraction of antioxidant polypeptides from byproducts of Procambarus clarkii

This article primarily focuses on studying the peptide extraction method and antioxidant properties of crayfish by-products using alkaline protease. Taking the degree of protein hydrolysis as a measurement indicator, and considering enzyme dosage, solid-liquid ratio, and hydrolysis time as optimization factors, we utilized single-factor and orthogonal experiments to refine the extraction process. Additionally, we assessed its antioxidant activity using the DPPH method. The findings revealed that the optimal process conditions were as follows: an enzyme dosage of 2% alkaline protease, a solid-liquid ratio of 1:20, and an enzymatic hydrolysis time of 2 hours. The measured protein hydrolysis degree was 21.08%, and its DPPH free radical scavenging rate reached 70.55%. When compared to vitamin C, it demonstrated superior antioxidant capabilities in scavenging free radicals.

Variations in Oxidative Stability of Walnut Oil with Rosmarinic Acid Added under Different Ultraviolet Radiations

Rosmarinic acid (RA) is a natural phenolic compound extracted from the Labiatae family and is a natural antioxidant. In this study, walnut oil added with RA was treated with different ultraviolet radiations, and stabilization effects in terms of the same conditions (0.2 mg/g) were compared with synthetic antioxidant (BHT). In order to compare the effectiveness of three UV treatments, different lab tests were conducted, namely, the acid value, peroxide value, iodine value, anisidine value, DPPH free radical scavenging rate, and malondialdehyde content. The enhanced UV-A, UV-B, and UV-C radiation intensities have increased the oxidation stability of RA-added walnut oil, of which UV-B has the greatest influence on the oxidative stability of walnut oil. When both RA and BHT were added at 0.2 mg/g, the antioxidant effect of RA is superior to the general antioxidant BHT.

Ultrasound-assisted fermentation for antioxidant peptides preparation from okara: Optimization, stability, and functional analyses

This study investigated the effects of ultrasound-assisted fermentation (UAF) on the preparation of antioxidant peptides (UAFP) from okara and examined their content, chemical structures, and antioxidant activity. After the optimal ultrasonic processing (time, 20 min; frequency, 45 KHz; power, 120 W/L), the peptide content yield reached the maximum of 12.36 ± 0.02 mg/mL, and their DPPH free radical scavenging rate was 65.15 ± 0.32 %. UAF increased the number of globular aggregates with deeper gullies, a looser structure, and higher porosity. The experiments conducted using the oxidative stress injury model of HepG2 cells showed that okara UAFP promoted cell growth and exerted a protective effect. Moreover, ultrasonic treatment remarkably improved the environmental stability (NaCl, glucose, sodium benzoate, temperature, pH, metal ions) and antioxidant activity of UAFP. Concisely, optimal ultrasonic processing can aid the fermentation of agroindustrial by-products to prepare antioxidant peptides, such as natural food antioxidant peptides from soybean waste.

Chitosan Oligosaccharide Based Waterborne Polyurethane with UV Resistance and Oxidation Resistance for Functional Fabric

AbstractChitosan oligosaccharide (COS) is an abundant polysaccharide in nature, which has various functions such as antioxidant and antibacterial. The possibilities of using COS can be extended by applying it to polyurethane materials. Herein, Chitosan oligosaccharide‐based waterborne polyurethane (CWPU) with intramolecular crosslinking network is prepared by using COS as chain extender. The mechanical properties of CWPU are improved, with tensile strength and elongation at break reaching 14.83 MPa and 449.63%, respectively. The DPPH free radical scavenging rate of CWPU increases from 8.43% to 70.98%, indicating that CWPU has favorable antioxidant performance. The tensile strength of the CWPU‐treated fabrics obtained by the padding method improve from 542.77 to 605.33N and there is no significant change in the whiteness of the fabric. Furthermore, the CWPU‐treated fabrics, with the UV protection factor of 30.39 and the UVA transmittance below 3%, can be used as UV‐protective fabrics. This work introduces COS into the molecular structure of polyurethanes to obtain functional PUs, expanding the application of COS in polyurethanes.

Effects of chitosan with different molecular weights on storage quality and fungi inhibition of mini-cucumber

The effect of low (LWC, 30 kD), medium (MWC, 150 kD) and high molecular weight chitosan (HWC, 300 kD) coatings on storage quality and fungi inhibition of mini-cucumber was evaluated. Chitosan coatings significantly reduced the weight loss, and delayed the color change and sensory score of mini-cucumber when compared with the control. Chitosan coatings significantly retarded the decrease of DPPH free radical scavenging rate and total phenol content, and inhibited the total number of bacterial colonies and the viable numbers of yeast and molds in mini-cucumber. Chitosan coatings also significantly reduced the disease incidence and disease severity of mini-cucumber artificial inoculated with Botrytis cinerea. LWC coating showed superior preservation effectiveness and antifungal activity to MWC and HWC coating. Compared with the control, LWC coating prolonged the shelf life by 6 days which was evaluated by sensory score, and reduced the total number of bacterial colonies and viable numbers of yeast and molds in mini-cucumber by 4.20 log10 CFU/g and 2.72 log10 CFU/g, respectively. These results suggested that chitosan molecular weights affected preservation effectiveness and antifungal activity against B. cinerea and LWC could be used to prolong the shelf life of mini-cucumber and maintain its quality after harvest.

Dual-crosslinked methacrylamide chitosan/poly(ε-caprolactone) nanofibers sequential releasing of tannic acid and curcumin drugs for accelerating wound healing

The objective of this research study is to develop novel composite nanofibers based on methacrylamide chitosan (ChMA)/poly(ε-caprolactone) (PCL) materials by the dual crosslinking and coaxial-electrospinning strategies. The prepared ChMA/PCL composite nanofibers can sequentially deliver tannic acid and curcumin drugs to synergistically inhibit bacterial reproduction and accelerate wound healing. The rapid delivery of tannic acid is expected to inhibit pathogenic microorganisms and accelerate epithelialization in the early stage, while the slow and sustained release of curcumin is with the aim of relieving chronic inflammatory response and inducing dermal tissue maturation in the late stage. Meanwhile, dual-drugs sequentially released from the membrane exhibited a DPPH free radical scavenging rate of ca. 95 % and an antibacterial rate of above 85 %. Moreover, the membrane possessed great biocompatibility in vitro and significantly inhibited the release of pro-inflammatory factors (IL-1β and TNF-α) in vivo. Animal experiments showed that the composite membrane by means of the synergistic effect of polyphenol drugs and ChMA nanofibers, could significantly alleviate macrophage infiltration and accelerate the healing process of wounds. From the above, the as-prepared ChMA-based membrane with a stage-wise release pattern of drugs could be a promising bioengineered construct for wound healing application.

Extraction of functional natural products employing microwave-assisted aqueous two-phase system: application to anthocyanins extraction from mulberry fruits

Aqueous two-phase extraction (ATPE) has been extensively utilized for the extraction and separation of tiny-molecule substances as a new system (system with short-chain ethanol and inorganic salts). In this study, an innovative method of extracting anthocyanins from mulberry was developed, employing microwave-assisted extraction with ethanol/ammonium sulfate as a biphasic extractant. Response surface methodology (RSM) was utilized to optimize anthocyanin extraction conditions: 39% ethanol (w/w), 13% ammonium sulfate (w/w), and liquid-to-solid ratio of 45:1, microwave duration 3 min, microwave temperature 32 °C, and microwave power 480 Watt (W). High-performance liquid chromatography (HPLC) analysis demonstrated no significant differences in the structure of mulberry anthocyanins before and after MAATPE treatment, furthermore. The extraction behavior of MAATPE was due to hydrogen bonding, according to Fourier transform infrared spectroscopy (FT-IR). Scanning electron microscopy analysis found that MAATPE damaged the cell structure via a microwave enhancement effect, which was more favorable to anthocyanin dissolution than standard extraction methods. The DPPH free radical scavenging rate of mulberry extracts at 0.5 mg/mL was higher than that of vitamin C (96.4 ± 0.76%), and the ABTS free radical scavenging rate (82.52 ± 2.13%) was close to that of vitamin C, indicating that MAATPE-derived mulberry extracts have good antioxidant activity.

Preparation and characterization of dialdehyde starch-soybean protein isolate stabilized carvacrol emulsion composite films

In order to reduce the harm of “petroleum-based plastics” with the problem of health and environment, the emulsion composite films with carvacrol nano-emulsions as antibacterial agent and polyvinyl alcohol (PVA) as matrices were prepared via the solvent-casting method. The average particle size of nano-emulsions was 175 nm with PDI value being 0.240. The transmittance of the emulsion composite films was close to zero in the UV-B region, with obvious UV barrier performance. The DPPH free radical scavenging rate was 60.96%, and the inhibition zone of the film forming emulsions was (21.5 ± 0.87) mm for S.aureus and (26.8 ± 1.01) mm for E.coli. Compared with the pure PVA film, the tensile strength and the water contact angle of the emulsion composite films were improved, the water vapor permeability was decreased by 28.7%. X-ray Diffraction and Fourier Transform Infrared Spectroscopy results showed the successful introduction of carvacrol nano-emulsions without a changeable structure. Therefore, the emulsion composite films have shown obvious application potential as packaging materials in modern food packaging.

Selenium application during fruit development can effectively inhibit browning of fresh-cut apples by enhancing antioxidant capacity and suppressing polyphenol oxidase activity

Browning is a crucial factor affecting the quality of fresh-cut apples. A safe, simple, and effective method to inhibit browning is urgently needed in fresh-cut apple production. We carried out this study to explore the effect mechanism of exogenous selenium (Se) fertilizer on fresh-cut apple browning. During the development of apples, 0.75 kg/plant Se fertilizer was exerted on the ‘Fuji’ apple tree at the critical stage of the young fruit stage (late May), early fruit expansion stage (late June), and fruit expansion stage (late July), an equal amount of Se-free organic fertilizer was used as control. Polyphenol oxidase (PPO), peroxidase (POD), and phenylalanine ammonia-lyase (PAL) activities, phenolic and malondialdehyde (MDA) content, antioxidant enzymes activity, and DPPH free radical scavenging rate of the apple at different development stages were investigated. The highest Se accumulation efficiency was observed in apple fruit one month after applying Se fertilizer, which was 41.1%. Se-rich apples exhibited a more remarkable ability to resist browning than control after fresh-cut. The anti-browning effect of the fertilization group (M7) was the best, the PPO activity decreased to 0.5 × 103 U kg−1, and the browning index was 28.6. The total Se content (TSC) of 331.4 μg kg−1 DW and organic Se content (OSC) of 292.0 μg kg−1 DW were the highest in the apple samples, reached the classification standard of Se content in Se-rich food. The correlation analysis found that fresh-cut apple browning was closely related to antioxidant capacity and PPO activity. The stronger the antioxidant capacity of fresh-cut apples treated with Se fertilizer, the lower their browning degree. Therefore, exogenous Se can alleviate fresh-cut apples browning by improving antioxidant capacity and reducing PPO activity. Se-rich apples could increase the Se content of the human essential trace element and inhibit the browning of fresh-cut apples, which would become a new, safe and effective way to solve the fresh-cut apples browning.

Integrated non-targeted and targeted metabolomics analysis reveals the mechanism of inhibiting lignification and optimizing the quality of pea sprouts by combined application of nano-selenium and lentinans.

Lignification causes a detrimental impact on the quality of edible sprouts. However, the mechanism of inhibition of lignification of edible sprouts by nano-selenium and lentinans remains unclear. To reveal the mechanism of lignification regulation of sprouts by nano-selenium and lentinans, this study investigated the changes in antioxidant indicators, phytohormones, polyphenols, and metabolites in the lignin biosynthesis in pea sprouts following sprays of nano-selenium or/and lentinans twice. There was an overall increase in the aforementioned indices following treatment. In particular, the combined application of 5 mg L-1 nano-selenium and 20 mg L-1 lentinans was more effective than their individual applications in enhancing peroxidase, catalase, DPPH free-radical scavenging rate, luteolin, and sinapic acid, as well as inhibiting malondialdehyde generation and lignin accumulation. Combined with the results from correlation analysis, nano-selenium and lentinans may inhibit lignification by enhancing antioxidant systems, inducing phytohormone-mediated signaling, and enriching precursor metabolites (caffeyl alcohol, sinapyl alcohol, 4-coumaryl alcohol). In terms of the results of non-targeted metabolomics, the combined application of 5 mg L-1 nano-selenium and 20 mg L-1 lentinans mainly affected biosynthesis of plant secondary metabolites, biosynthesis of phenylpropanoids, phenylpropanoid biosynthesis, arginine and proline metabolism, and linoleic acid metabolism pathways, which supported and complemented results from targeted screenings. Overall, the combined sprays of nano-selenium and lentinans showed synergistic effects in delaying lignification and optimizing the quality of pea sprouts. This study provides a novel and practicable technology for delaying lignification in the cultivation of edible sprouts. © 2023 Society of Chemical Industry.