Scavenging Rate Research Articles

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.

Optimizing elicitation strategy of salicylic acid for flavonoid and phenolic production of fed-batch cultured Oplopanax elatus adventitious roots.

Oplopanax elatus is a valuable medicinal plant, but its plant resource is lacking. Adventitious root (AR) culture of O. elatus is an effective way for the production of plant materials. Salicylic acid (SA) exerts enhancement effect on metabolite synthesis in some plant cell/organ culture systems. To clarify the elicitation effect of SA on fed-batch cultured O. elatus ARs, this study investigated the effects of SA concentration, and elicitation time and duration. Results showed that flavonoid and phenolic contents, and antioxidant enzyme activity obviously increased when the fed-batch cultured ARs were treated with 100μM SA for 4 days starting on day 35. Under this elicitation condition, total flavonoid and phenolic contents reached 387 rutin mg/g DW and 128 gallic acid mg/g DW, respectively, which were significantly (p<0.05) higher than those in the SA-untreated control. In addition, DPPH scavenging and ABTS+ scavenging rates, and Fe2+ chelating rate also greatly increased after SA treatment, and their EC50 values were 0.0117, 0.61, and 3.34mg/L, respectively, indicating the high antioxidant activity. The findings of the present study revealed that SA could be used as an elicitor to improve the flavonoid and phenolic production in fed-batch O. elatus AR culture.

Technological exploration and antioxidant activity determination of purple compound fruit wine

When it comes to processing, purple pepper and purple corn are poorly utilised even though they are rich in anthocyanins and other nutrients. Therefore, studies focusing on their processing are vital for resolving their underutilisation. In the present work, purple pepper and corn were used to prepare a compound fruit wine. The fermentation process parameters were optimised using single factor tests and response surface design. The sensory characteristics of the compound fruit wine were used as an indicator. The antioxidant potential of the purple compound fruit wine was also assessed using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH·) and hydroxyl radical (·OH) scavenging rates. A purple compound fruit wine with a sensory score of 94.2 and 8.6% alcohol by volume was obtained using a combination of 72.0% purple pepper juice and 28.0% purple corn juice (with an initial sugar content of 23.3%), followed by inoculation with 6.2% Saccharomyces cerevisiae and fermentation for 7.8 d at 23°C. The resulting purple compound fruit wine had a typical harmonious fruit aroma and a mellow taste. Furthermore, the content of anthocyanins in purple compound fruit wine was 1.38 ± 0.14 mg/mL, and the half inhibitory concentration (IC50) values against DPPH· and ·OH were 51.31 and 49.08 mg/mL, respectively. This optimised fermentation process could serve as a theoretical basis for the industrial utilisation of purple pepper and corn.

Impact of solid‐state fermentation by Aspergillus niger 4Q and Cyberlindnera fabianii J2 on antioxidant and flavor properties of whole grain barley

AbstractBackground and ObjectivesAspergillus niger 4Q and Cyberlindnera fabianii J2 were isolated from a traditional Chinese sweet rice wine starter because of their better fermentation characteristics and sensory properties of final products. To understand the impacts of the cofermentation with Aspergillus niger 4Q and Cyberlindnera fabianii J2 in a solid state on the nutritional and physico‐chemical properties of whole grain barley, yellow barley and black barley were used as raw materials. Content of chemical and nutritional compositions, in vitro antioxidant activity, color, and volatile flavor compound analysis of untreated, cooked and fermented barley samples were evaluated.FindingsThe contents of total phenolic compounds, total flavonoids, and anthocyanin of black barley were 1.25 times, 1.21 times, and 2.05 times higher than those in yellow barley (p &lt; .05). After fermentation, the proteins, water‐soluble dietary fiber, and β‐glucan contents of both black barley and yellow barley samples were about respectively 1.3 times, 4.6 times, and 1.2 times higher than those in raw materials (p &lt; .05). Total proportion of phenolic compounds and flavonoids, along with the antioxidant capacity, free radical scavenging rate and Fe2+ chelating activity were significantly increased (p &lt; .05). Lighter and brighter color were observed in fermented barleys which might be credit to the reduced anthocyanins. The acidic methyl esters, uniquely existed in untreated barley, were transformed into acetate esters after fermentation. Ethyl 3‐methyl‐acetate, with a fruity aroma, was the major proportion of esters in fermented barley, endued the unique flavor to fermented barley.ConclusionsSolid‐state fermentation of yellow barley and black barley by A. niger 4Q and C. fabianii J2 could effectively improve their nutritional and physico‐chemical properties.Significance and NoveltyThis study may contribute to providing a solution for improving the nutritional and sensory preterits of whole grain barley, as well as a theoretical support for promoting the direct utilization of barley in food processing.

Products and Properties of Components from Heat-Denatured Peanut Meal Following Solid-State Fermentation by Aspergillus oryzae and Saccharomyces cerevisiae

In heat-denatured peanut meal (HDPM), proteins are denatured and polysaccharides are degraded and browned. It can only be used as feed or fertilizer, and not using it as such is a waste of resources. To achieve high-value HDPM use, solid-state fermentation by Aspergillus oryzae and Saccharomyces cerevisiae was investigated. Conditions were optimized by response surface methodology and high-value antioxidant peptides (APs), nonstarch polysaccharides (NSPs), and fermentation products of heat-denatured peanut meal (FHDPM) were obtained. Optimal culture conditions were strain ratio 6:5, inoculation volume 2 mL, and fermentation for 42 h at 35 °C. Under optimal conditions, the theoretical soluble nitrogen concentration, 1,1-Diphenyl-2-picrylhydrazyl radical scavenging rate, hydroxyl free radical scavenging rate, and NSP yield reached 44.78 mg/mL, 62.44%, 94.95%, and 3.73%, respectively; however, their experimental values were 46.80 ± 1.23 mg/mL, 72.18 ± 0.78%, 96.79 ± 0.55%, and 4.42 ± 0.21%, respectively. NSPs, Aps, and FHDPM exhibited four higher classes and eight types of antioxidant activities. Moreover, levels of amino acids and trace elements, and physicochemical properties including emulsion activity index, emulsion stability index, foam capacity, foam stability, water holding capacity, and oil absorption capacity were enhanced by fermentation. The results indicate that APs and NSPs could serve as promising natural antioxidants in the food industry, and FHDPM could be used as a new type of high-value nutritional product in the feed industry. The findings provide new insight for comprehensive processing and utilization of HDPM.

Biotransformation and bioaccessibility of active ingredients from Radix Astragali by Poria cocos during solid-state fermentation and in vitro digestion and antioxidant activity evaluation

Radix Astragali is one of the most famous and frequently used health food supplements and herbal medicines. Among more than 227 components of Radix Astragali, Astragaloside IV (AG IV) is famous functional compound and is commonly used as a quality marker for Radix Astragali. However, the relatively low content of AG IV in Radix Astragali (< 0.04%, w/w) severely limits its application. The purpose of this study is to improve the biotransformation of AG IV and its bioaccessibility during in vitro digestion by Poria cocos solid fermenting Radix Astragali. The optimum fermentation conditions were as follows: Inoculation amount 8 mL; fermentation time 10 d; fermentation humidity 90%. Through fermentation, the content of AG IV was increased from 384.73 to 1986.49 μg/g by 5.16-fold. After in vitro digestion, the contents of genistin, calycosin, formononetin, AG IV, Astragaloside II (AG II) and total flavonoids in fermented Radix Astragali (FRA) of enteric phase II (ENTII) were 34.52 μg/g, 207.32 μg/g, 56.76 μg/g, 2331.46 μg/g, 788.31 μg/g, 3.37 mg/g, which were 2.08-fold, 2.51-fold, 1.05-fold, 8.62-fold, 3.22-fold and 1.50-fold higher than those of control, respectively. The Scanning electron microscopy (SEM) of FRA showed rough surface and porous structure. The DPPH and ABTS radical scavenging rate of FRA were higher than those of control. These results showed that the Poria cocos solid fermentation could increase the content of the AG IV in Radix Astragali and improve the bioaccessibility and antioxidant activity of Radix Astragali, which is providing new ideas for future development and utilization of Radix Astragali.

Sugarcane-derived Bio‐Amine‐Responsive Colorimetric Films for real-time visual monitoring of the seafood freshness

A new type of bio-amine-response colorimetric film with excellent flexibility and biodegradability was fabricated by the main components of sugarcane, including sugarcane skin anthocyanin (SSA), bagasse cellulose fibers (CF), and cellulose nanofibers (CNF). Benefiting from the rich hydroxyl groups and large specific surface area of CNF, the sample of adding 10 wt% CNF in CF (CF/CNF10/SSA) presented good mechanical properties (33 Mpa), reusability (10 cycles), excellent color change (ΔE＞5), and excellent antioxidant properties (the free radical scavenging rate of ABTS: 86%). Furthermore, the film had good water resistance (water contact angle only decreases about 20° after 60 s), color stability up to 28 days, and rapid response to ammonia (1–2 s). Thus, CF/CNF10/SSA was successfully used as a low-cost, inoxidizable, and pH/NH3 responsive smart tag to monitor the freshness of seafood in real-time, achieving the high-value utilization of sugarcane waste components.

Peptides-carrageenan-xanthan gum: Printing mechanism and anti-oxidation under in vitro digestion

Surimi is a protein-rich food. The peptides hydrolyzed by surimi have many functional activities and showed strong antioxidant activity in ABTS free radical scavenging experiments, hydroxyl radical scavenging experiments and iron ion reduction experiments. The scavenging rates of ABTS ions, hydroxyl radicals and iron ions were 62.83%, 74.81% and 0.035 mg/mL, respectively. 3D printing ink was formulated by compounding carrageenan, xanthan gum and surimi peptides. The surimi polypeptide “ink” contains 3% carrageenan, 4% xanthan gum and 4 mg/mL surimi polypeptide. This “ink” not only has good printability, but also has stable antioxidant properties. The effect of the peptides on the printed structures can also be observed under an inverted fluorescence microscope. In the in vitro digestion experiment, the surimi polypeptide 3D printing ink added with carrageenan and xanthan gum can release most of the peptides. After in vitro digestion experiments, the antioxidant activity of surimi polypeptides increased. The above experiments have proved that surimi polypeptide is a high-quality raw material for preparing 3D printing ink.

Silica nanoparticles loaded with caffeic acid to optimize the performance of cassava starch/sodium carboxymethyl cellulose film for meat packaging

Cassava starch/sodium carboxymethyl cellulose (CC) was used as the substrate to create a multipurpose food packaging film, and caffeic acid@silica nanoparticles (C@SNPs) was added. The encapsulation rate of caffeic acid in C@SNPs was 84.7 ± 0.97 %. According to SEM pictures, the nanoparticles were evenly dispersed throughout the film and exhibited good compatibility with the other polymers. C@SNPs was added, which enhanced the physical characteristics of film and decreased its water solubility. The best mechanical and oxygen barrier qualities among them are found in the C@SCC5:1 film, whose tensile strength rises from 7.17 MPa to 15.44 MPa. The C@SCC5:1 film has scavenging rates of 95.43 % and 84.67 % against ABTS and DPPH free radicals, respectively, and CA can be released continuously in various food systems. In addition, the antibacterial rate of E. coli O157:H7 and S. aureus of C@SCC5:1 film in meat was 99.9 %, and it can effectively delay lipid oxidation and pH rise. In conclusion,C@SCC5:1 film is a new type of antibacterial and antioxidant food packaging material.

The effects of mulberry polyphenols on the digestibility and absorption properties of pork myofibrillar protein in vitro

The objective of the present study was to explore the effect of mulberry polyphenols on the digestibility and absorption properties of myofibrillar protein (MP) in vitro. MP was extracted from the Longissimus et thoracis muscle of 18 different pig carcasses and the MP-mulberry polyphenols complex was prepared. The antioxidant activity of digestive juice, degradation of both MP and polyphenols, and the metabolism of MP and the MP-polyphenols complex by intestinal microbial activity during digestion and fermentation in vitro were compared. The results showed that mulberry polyphenols significantly affect the digestibility of MP and the antioxidant activity of digestive juices during digestion (P < 0.05). After the modification of the polyphenols, the hydrolysis of MP increased from 55.4% to 64.0%, and the molecular weight of protein digestion product significantly decreased (P < 0.05). The scavenging rates of 2, 2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and 2,2-diphenyl-1-picrylhydrazyl in the final digestive juice were 350.1 μmol Trolox/mg protein and 34.0%, respectively, which were 0.34 and 0.47-fold higher than those of the control (P < 0.05). Furthermore, the release and degradation of phenolic compounds mainly occurred during intestinal digestion, and polyphenols that reached the colon after digestion, through the fermentation of intestinal microorganisms in vitro, enriched Lactobacillus and promoted the production of short-chain fatty acids which has obvious potential to improve intestinal health.

Robust microfluidic construction of polyvinyl pyrrolidone microfibers incorporated with W/O emulsions stabilized by amphiphilic konjac glucomannan

In this work, we prepared polyvinyl pyrrolidone (PVP) microfibers incorporated water-in-oil (W/O) emulsions. The W/O emulsions were fabricated by hexadecyl konjac glucomannan (HKGM, emulsifier), corn oil (oil phase) and purple corn anthocyanins (PCAs, water phase). The structures and functions of emulsions and microfibers were characterized by confocal laser scanning (CLSM) and scanning electron microscopy (SEM), Fourier transform infrared (FT-IR), Raman and nuclear magnetic resonance (NMR) spectroscopy. The results showed that W/O emulsions exhibited good storage stability for 30 d. Microfibers presented ordered and uniform arrays. Compared with pure PVP microfiber films, the addition of W/O emulsions with PCAs improved the water resistance (WVP from 1.28 to 0.76 g mm/m2 day kPa), mechanical strength (Elongation at break from 18.35 % to 49.83 %), antioxidation (free radical scavenging rate from 2.58 % to 16.37 %), and antibacterial activity (inhibition zone against E. coli: 27.33 mm and inhibition zone against S. aureus: 28.33 mm) of microfiber films. Results showed that microfiber film exhibited controlled release of PCAs in W/O emulsions, and about 32 % of the PCAs were released from the microfiber film after 340 min. The as-prepared microfiber films exhibited potential applications for food packaging.

Effect of Nisin on the Quality and Antioxidant Activity of Fresh-Cut Pumpkins (Cucurbita moschata Duch.)

Fresh-cut pumpkins refer to fresh pumpkin that has been graded, cleaned, peeled, sliced, preserved, and packaged. It has the qualities of freshness, nutrition, convenience, and being 100% edible. However, mechanical damages during the cutting processing can accelerate the quality deterioration, aging, and loss of nutritional values of fresh-cut pumpkins. Nisin, a natural preservative, has been widely used in fruits and vegetables with good preservation effects. To investigate the effect of different concentrations (0, 0.2, 0.4, and 0.6 g/L) of nisin on the quality of fresh-cut pumpkins, the critical indexes involved in weight loss, firmness, color, respiration intensity, reactive oxygen species (ROS) metabolism, ascorbate (AsA)—glutathione (GSH) cycle, and antioxidant capacity were monitored for fresh-cut pumpkins during storage at 4 °C for 10 days. The results showed that 0.4 g/L nisin was the best preservation concentration. Compared with 0 g/L nisin, 0.4 g/L nisin reduced the weight loss rate and whitening rate of fresh-cut pumpkins by 13.53% and 13.61%, inhibited respiration rate by 45.83%, and maintained hardness by 1.18 times. Meanwhile, 0.4 g/L nisin increased the activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR) and maintained higher contents of GSH and AsA. It prevented the rapid increase in ROS levels by improving antioxidant capacity, including DPPH, ABTS free radical scavenging rate, and T-AOC (total antioxidant capacity). The collected results showed that nisin has an obvious influence on the quality by regulating physiological and antioxidant activity metabolism. It is envisaged that the combination of nisin and physical and chemical preservation technology will further enhance the quality of fresh-cut pumpkins during storage in the future.

Electrospinning of gelatin nanofibers containing sesamol nanoparticles

The aim of this study was to analyze the bioactivity of gelatin nanofiber membranes based on electrospinning different concentrations of sesamol nanoparticles. Sesamol (Ses) can be encapsulated with zein and chitosan to form nanoparticles (Ses-NPs). Then, Ses-NPs were mixed into gelatin nanofiber membrane (G-Ses-NPs-NF) by the electrospinning method. The results showed that Ses provided the nanofiber membranes with antioxidant and antibacterial activities. When the concentration of Ses was 1.125 mg/mL, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2′-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) radical scavenging rates were 80.36 ± 0.62% and 91.00 ± 0.38%, respectively. In addition, G-Ses-NPs-NF can inhibit Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Candida albicans (C. albicans). Additionally, when added with zein-chitosan and gelatine, the functional nanofiber membrane exhibited sustained-release capabilities. Therefore, G-Ses-NPs-NF can be considered as a material with good biologically activity, which has research value in the development of functional food and other fields.

Optimization of Rare Ginsenosides and Antioxidant Activity Quality of Ginseng Jiaosu Based on Probiotic Strains and Fermentation Technology

The primary active components of plant ginseng are saponins, and rare saponins play a specific antitumor action. In this study, Lactobacillus that can efficiently transform rare saponins were screened as fermentation strains of ginseng enzymes. The fermentation process was optimized to investigate the changes in various biochemical indicators and antioxidant activities of the enzymes before and after fermentation. The results showed that Lactiplantibacillus plantarum had the highest conversion efficiency for diol saponins, among which the content of rare ginsenoside-CK increased by 256%. The optimum optimizing method was a 1 : 1 : 10 ratio of ginseng extract/concentrated apple juice/water, fermentation time of 16 days, initial pH of 6.0, fermentation temperature of 37°C, and sterilization amount of 1.0%. The contents of rare ginsenoside-Rh1, ginsenoside-F2, ginsenoside-Rg3, and ginsenoside-CK increased by 18.48%, 135.73%, 343.03%, and 441.80%, respectively, and the process was stable and controllable. After fermentation, the scavenging rates for hydroxyl radical, DPPH radical, and superoxide anion radical were increased by more than 9%, and new organic acids were produced. In general, this study established an efficient, stable, and controllable ginseng fermentation process to improve the rare saponin content and biological activity of ginseng enzymes, which can provide new ideas for traditional Chinese medicine and medicinal health food in China.

Antioxidant effects of Bifidobacterium longum T37a in mice weight loss and aging model induced by D-galactose

BackgroundProbiotics can reduce free radical scavenging rate and oxidative damage, and improve activity of crucial antioxidative enzymes in host cells. This study aimed to isolate Bifidobacterium spp. from faeces of babies, and investigate the antioxidant effects of the Bif. longum T37a in mice weight loss and aging model induced by D-galactose.ResultsT37a have good antioxidant properties in the DPPH assay and anti-lipid peroxidation test. Compared with the model group, T37a low group significantly increased the thymus index and the levels of T-AOC and GSH-Px of mice. T37a high group significantly decreased the spleen and liver index of mice and the levels of MDA in liver, significantly increased in liver HDL-C levels, and decreased LDL-C in liver.ConclusionsT37a may be an anti-aging and weight-loss probiotics for its antioxidant capacity, and it is necessary to study further the molecular mechanism of T37a as antioxidant.

High-strength collagen/delphinidin film incorporated with Vaccinium oxycoccus pigment for active and intelligent food packaging

This study developed an active and intelligent collagen-based packaging film with high strength for visually monitoring the freshness of fish. The results of scanning electron microscopy and atomic force microscopy showed that the film based on cross-linked collagen/delphinidin catalyzed by laccase exhibited a denser layer structure and a rougher surface. The dry and wet tensile strengths of the laccase-catalyzed collagen/delphinidin film (Col/Dp-LA film) increased by 41.74 MPa and 13.13 MPa in comparison with that of the pure collagen film, respectively. Moreover, the Col/Dp-LA film presented good antioxidant and barrier properties demonstrated by the results of free radical scavenging rate, light transmission rate, and water vapor permeability. The intelligent collagen-based film was obtained by incorporating Vaccinium oxycoccus pigment into the Col/Dp-LA film, which could change color under different pH values. When applied to the preservation of fish fillets, the film could release Dp to minimize oxidative rancidity and prolong the shelf life of the fish for 2 days. Meanwhile, the film showed visual color changes from purplish-red to greyish-blue after the fish spoilage. These results indicated that the collagen film treated with delphinidin, laccase, and Vaccinium oxycoccus pigment has potential application value in the field of active and intelligent food packaging.Graphical

The effect of theabrownins on the amino acid composition and antioxidant properties of hen eggs

Pu-erh tea theabrownins (TBs) exert beneficial effect on egg quality and antioxidant properties of eggs, but the underlying mechanisms behind this response are unclear. In this study, we investigate the effect of TBs on egg antioxidative activity, amino acid and fatty acid profiles, and the underlying relationship between the TBs and oxidant-sensitive Nrf2 signaling pathway in laying hens. Eighty layers were fed a basal diet (control) and 400 mg/kg of TBs supplemented diet for 12 wk. TBs led to an increase in albumen height and Haugh unit (P < 0.05). The albumen lysine, valine, and tryptophan were higher in layers fed TBs, whereas yolk tryptophan, methionine, vitamin A, and α-tocopherol content were enhanced by TBs (P < 0.05). Eggs albumen and yolk showed higher total antioxidant capacity (T-AOC), reducing power (RP), and the scavenging rate of 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH), and lower MDA content than those of eggs from the control group (P < 0.05). Also, magnum Nrf2, hemeoxygenase 1 (HO-1), NAD(P)H quinone dehydrogenase 1 (NQO1), and Bcl2 expression were up-regulated by TBs, whereas magnum proapoptotic gene (Bax, caspase 3, Cyt C) were down-regulated by TBs (P < 0.05). Our findings suggest that TBs improved egg albumen quality and antioxidant activity, and the Nrf2-ARE pathway were found to be involved in this process.

Evaluating the Application Potential of a Recombinant Ganoderma Protein as Bioactive Ingredients in Cosmetics

The aim of this study was to evaluate the application potential of a recombinant fungal immunomodulatory protein from Ganoderma lucidum (rFIP-glu). First, a recombinant plasmid pPIC9K::FIP-glu-His was transferred into Pichia pastoris for the production of protein. The protein was then to assess its free radical scavenging abilities and the effect on the viability of both human immortalized keratinocytes (HaCaT cells) and mouse B16-F10 melanoma cells (B16 cells) in vitro, followed by the effect on the melanin synthesis of B16 cells. The results of SDS-PAGE and western blot showed that rFIP-glu was successfully expressed. Furtherly, a bioactivity assay in vitro indicated that the scavenging rate of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals reached 84.5% at 6.0 mg/mL (p ≤ 0.0001) of rFIP-glu, showing strong antioxidant activity. Subsequently, a safety evaluation demonstrated that rFIP-glu promoted the proliferation of HaCaT cells, with the cell viability reaching 124.3% at 48 μg/mL (p ≤ 0.01), regarding the cell viability of B16 cells after exposure to rFIP-glu (48 μg/mL) significantly inhibited, to 80.7% (p ≤ 0.01). Besides, rFIP-glu inhibited the melanin synthesis of B16 cells in a dose-dependent manner from 100-1000 μg/mL, and rFIP-glu at 500 μg/mL (p ≤ 0.01) exhibited the highest intracellular melanin amount reduction of 16.8%. Furthermore, a mechanism analysis showed that rFIP-glu inhibited tyrosinase (TYR) activity by up-regulating the expression of the microphthalmia-associated transcription factor (MITF) and down-regulating the gene expression of TYR and tyrosinase-related protein-1 (TYRP-1), thus inhibiting melanin synthesis. The data implied that rFIP-glu had significant antioxidant activity and whitening potency. It should be used as raw materials for cosmeceutical applications.

Silver Carp (Hypophthalmichthys molitrix) Scales Collagen Peptides (SCPs): Preparation, Whitening Activity Screening and Characterization

This study involves the preparation of scale collagen peptides (SCPs) with whitening activity from silver carp (Hypophthalmichthys molitrix) and their characterization and peptide sequence identification. In this article, scanning electron microscopy (SEM) was used to observe structure changes of sliver carp scales; enzymatic hydrolysis was optimized through protease screening and response surface optimization. The ultrafiltration was used to separate SCPs and the whitening activity was comprehensively evaluated using radical scavenging rate and tyrosinase-inhibiting activity, among others. An optimal component was characterized and identified using various modern spectral analysis techniques. The results showed that the surface of silver carp scales after decalcification was smooth and clear. The pepsin had the highest peptide yield and tyrosinase-inhibiting activity (90.01% and 82.25%, respectively). The optimal enzymatic hydrolysis conditions were an enzyme dosage of 16.1%, a solid-liquid ratio of 1:15.6 and a time of 4.9 h. The proportions of hydrophobic and basic amino acids in the peptide composition were 32.15% and 13.12%, respectively. Compared with SCPs2, SCPs1 (6096.68-9513.70 Da) showed better ·OH scavenging ability, tyrosinase-inhibiting activity and moisture absorption. SCPs1 was a macromolecular fragment of type I collagen with a triple helix structure, containing three peptide sequences with the potential for tyrosinase activity inhibition (AGPPGADGQTGQRGE, SGPAGIAGPAGPRGPAGPNGPPGKD and KRGSTGEQGSTGPLGMRGPRGAA). These results show that SCPs1 is a collagen peptide product with whitening potential.

Development and properties evaluation of multi-strain probiotic with cholesterol-lowering potential in vitro.

Probiotics have a cholesterol-lowering effect. Multi-strain probiotics (MSPs) outperformed single-strain probiotics due to the interaction of strains. Hence, we expect to develop a high-efficiency MSP for lowering cholesterol. Three strains, including Lactobacillus caseiS1, Enterococcus faeciumS4, and L. harbinensisS6, were used to develop the MSPs. To evaluate their effect, gastrointestinal tolerance, bile salt hydrolase (BSH) activity, cholesterol-lowering rate, antioxidant ability, gamma-aminobutyric acid (GABA) production, and antibiotic sensitivity were determined. The triple lactic acid bacteria probiotic (TLP) was the most efficient one. After 24h treatment with artificial gastric fluid, 47.88% of TLP survived. TLP exhibited the highest BSH activity (149.40 U·ml-1) and cholesterol-lowering rate (75.05%) in vitro, with co-precipitation reducing the majority of cholesterol. The reducing power and superoxide radical scavenging rate of the cell-free supernatant and the hydroxyl radical scavenging rate in viable cells were 1.52, 85.03%, and 89.66%, respectively, and the GABA production was 0.67mg·ml-1, which enhanced the health benefit effects. By fuzzy mathematical analysis, TLP was the optimal probiotic and was competitive with commercial probiotics. The three strains were susceptible to 13 antibiotics. Therefore, TLP has the potential to develop into a cholesterol-lowering probiotic preparation.