Effects of an inoculation dose of Issatchenkia terricola WJL-G4 on physicochemical properties, active substances, and antioxidant capacity of black, red, and white currant juice.

BACKGROUND: Due to the high level of organic acids - primarily citric acid - black, red, and white currants have an excessively sour taste, making taste adjustment during processing challenging. This study investigated and evaluated the effects of an inoculation dose of the acid-reducing yeast Issatchenkia terricola WJL-G4 on several aspect such as physicochemical properties, chromaticity, active substances, and antioxidant capacity. A sensory evaluation was also conducted. RESULTS: The results indicated that, when the inoculation dose increased from 2% to 12%, the total phenol, total flavonoid, and total anthocyanin content, and antioxidant capacity in currant juice decreased. A low inoculation dose (2-4%) was beneficial for preserving the total phenol and total flavonoid content. Although the levels of most phenolic compounds decreased, the concentrations of caffeic acid, p-coumaric acid, ferulic acid, rutin, and epicatechin were significantly higher than the control after fermentation. Overall acceptability and taste scores of fermented currants improved compared with those of the control group. CONCLUSION: This experiment provided an effective solution, with a theoretical basis, to the problems of the sour taste and harsh flavor of currant juice. © 2024 Society of Chemical Industry.

Extraction, physicochemical properties, and antioxidant activity of natural melanin from Auricularia heimuer fermentation.

Introduction: Natural melanin from Auricularia heimuer have numerous beneficial biological properties, which were used as a safe and healthy colorant in several industries. Methods: In this study, single-factor experiments, Box-Behnken design (BBD), and response surface methodology (RSM) were employed to investigate the effects of alkali-soluble pH, acid precipitation pH, and microwave time on the extraction yield of Auricularia heimuer melanin (AHM) from fermentation. Ultraviolet-visible spectrum (UV-Vis), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM), and high-performance liquid chromatography (HPLC) were used to analyze the extracted AHM. The solubility, stability, and antioxidant activities of AHM were also measured. Results: The results showed that alkali-soluble pH, acid precipitation pH, and microwave time significantly affected the AHM yield, with the following optimized microwave-assisted extraction conditions: alkali-soluble pH of 12.3, acid precipitation pH of 3.1, and microwave time of 53 min, resulting in an AHM extraction yield of 0.4042%. AHM exhibited a strong absorption at 210 nm, similar to melanin from other sources. FT-IR spectroscopy also revealed that AHM exhibited the three characteristic absorption peaks of natural melanin. The HPLC chromatogram profile of AHM showed a single symmetrical elution peak with a 2.435 min retention time. AHM was highly soluble in alkali solution, insoluble in distilled water and organic solvents, and demonstrated strong DPPH, OH, and ABTS free radical scavenging activities. Discussion: This study provides technical support to optimize AHM extraction for use in the medical and food industries.

Comparative study of the properties of lutein nanoliposomes coated with chitosan/(-)-epigallocatechin- 3-gallate (EGCG) complexes.

BACKGROUND: Numerous positive effects have been attributed to lutein, a lipophilic nutrient, including resisting ultraviolet radiation and protecting retinal pigment epithelial (RPE) cells against blue light damage. It also has preventive effects against cardiovascular disease and cancer. However, its use could be limited by its poor stability and low bioaccessibility in the human digestive system. An encapsulation delivery system was therefore developed to resolve these limitations. In this study, chitosan-modified lutein nanoliposomes (CS-LNLs), chitosan-EGCG covalently modified lutein nanoliposomes (C-CS-EGCG-LNLs), and chitosan-EGCG noncovalently modified lutein nanoliposomes (non-C-CS-EGCG-LNLs) were designed. The average particle size, ζ-potential, and retention of lutein during storage were measured to indicate the physicochemical stability of the modified lutein nanoliposomes. The bioaccessibility of modified lutein nanoliposomes was also investigated to demonstrate the availability of lutein in the human digestive system. RESULTS: First, Fourier-transform infrared spectroscopy (FTIR) verified that covalent bonds between chitosan and EGCG were formed. Subsequently, ζ-potential results revealed that C-CS-EGCG-LNLs had a relatively stable structure in comparison with lutein nanoliposomes (LNLs). The retention rate of lutein in CS-LNLs, C-CS-EGCG-LNLs, and non-C-CS-EGCG-LNLs was improved, especially in C-CS-EGCG-LNLs (at around 70% of lutein in initial system). An in vitro digestion experiment illustrated that CS-LNLs, C-CS-EGCG-LNLs, and non-C-CS-EGCG-LNLs presented relatively higher bioaccessibility, especially in C-CS-EGCG-LNLs (at around 33% of luein in initial system), which increased 2.5 and 1.65 times in comparison with free lutein and LNLs, respectively. CONCLUSION: Overall, the results showed that C-CS-EGCG-LNLs presented greater physicochemical stability and bioaccessibility than LNLs, CS-LNLs, and non-C-CS-EGCG-LNLs. © 2023 Society of Chemical Industry.

Construction of vitamin D delivery system based on pine nut oil Pickering emulsion: effect of phenols.

BACKGROUND: The food industry has begun to develop foods fortified with unsaturated fatty acids; however, the susceptibility of pine nut oil to oxidation and other properties limits its use in food production. Researchers often inhibit the oxidation of oil by adding antioxidants. After the combination of polyphenols and proteins, the complex formed can improve or enhance the performance of the emulsion when it stabilizes the emulsion. Encapsulating, protecting, and controlling the release behavior of vitamin D (VD ) during digestion through an emulsion delivery system can effectively overcome limitations such as easy degradation during processing and storage. This research uses tannic acid, gallic acid, tea polyphenol, and vanillic acid to prepare Pickering emulsions, and the type of phenolic compound is explored by multi-dimensional characterization and the amount of emulsion. RESULTS: The influence of traits, microstructure, stability, VD load application, and effect on the emulsion matrix's encapsulation rate and bioaccessibility is studied. A method was investigated to enhance the oxidative stability of whey protein isolate-stabilized emulsions by introducing phenol. Pickering emulsions could be obtained in the presence of phenol, while the type of phenol played a relatively important role, probably because the mechanism involved interactions between particles. Viscosity and creaming stability of emulsions increased with crosslinking of phenol in emulsions. In addition, the presence of phenol in emulsions significantly increased the bioaccessibility of encapsulated VD after in vitro digestion. CONCLUSION: The method presented in this study was important for improving the oxidative stability of pine nut oil emulsions, expanding the application of pine nut oil in the food industry, and providing the theoretical and application basis of application and active substance emulsion delivery systems. © 2022 Society of Chemical Industry.

Development of a novel functional yogurt rich in lycopene by Bacillus subtilis.

Functional lycopene-rich yogurt displays attractive nutritious and health-promoting benefits among existing functional dairy products, owing to supplement with lycopene which could enhance immunity, prevent cancer, and cardiovascular diseases. Due to poor stability and fat-solubility of lycopene, its incorporation into yogurt is challengeable. In this study, carotenoid genes for lycopene synthesis were co-introduced into probiotic Bacillus subtilis for efficient lycopene production. Further engineered B. subtilis was applied as adjunct starter culture for achieving lycopene-rich yogurt. Developed yogurt exhibited desirable physiochemical characteristics compared with plain yogurt. Moreover, lycopene-rich yogurt was endowed with significantly high antioxidant capacity. More importantly, this functionalized yogurt had attractive sensorial attributes for quality-assured food to facilitate consumer acceptance. As the first report of fortifying yogurt of lycopene using B. subtilis with improved functional properties, this study offers a new and facile clue to enrich bioactive lycopene and probiotic B. subtilis in yogurt for healthy and nutritional food development.

Concurrent Production of α- and ß-Carotenes with Different Stoichiometries Displaying Diverse Antioxidative Activities via Lycopene Cyclases-Based Rational System.

α- and ß-carotenes belong to the most essential carotenoids in the human body and display remarkable pharmacological value for health due to their beneficial antioxidant activities. Distinct high α-/ß-carotene stoichiometries have gained increasing attention for their effective preventions of Alzheimer's disease, cardiovascular disease, and cancer. However, it is extremely difficult to obtain α-carotene in nature, impeding the accumulations of high α-/ß-carotene stoichiometries and excavation of their antioxidant activities. Herein, we developed a dynamically operable strategy based on lycopene cyclases (LCYB and LCYE) for concurrently enriching α- and ß-carotenes along with high stoichiometries in E. coli. Membrane-targeted and promoter-centered approaches were firstly implemented to spatially enhance catalytic efficiency and temporally boost expression of TeLCYE to address its low competitivity at the starting stage. Dynamically temperature-dependent regulation of TeLCYE and TeLCYB was then performed to finally achieve α-/ß-carotene stoichiometries of 4.71 at 37 °C, 1.65 at 30 °C, and 1.06 at 25 °C, respectively. In the meantime, these α-/ß-carotene ratios were confirmed to result in diverse antioxidative activities. According to our knowledge, this is the first time that both the widest range and antioxidant activities of high α/ß-carotene stoichiometries were reported in any organism. Our work provides attractive potentials for obtaining natural products with competitivity and a new insight on the protective potentials of α-/ß-carotenes with high ratios for health supply.

Effect of phenolic compounds and hydroxyl content on the physicochemical properties of pine nut oil Pickering emulsions.

BACKGROUND: For decades, pine nut oil Pickering emulsions have been stabilized using a covalent composite of two phenolic chemicals (tannic acid, TA; and gallic acid, GA) and whey protein isolate (WPI) following alkali treatment. Based on covalent composite particles being excellent sources of high-quality stabilizers, this research explored the influence of phenolic addition and hydroxyl content on stability, rheological parameters and characterization of Pickering emulsions. RESULTS: Tannic acid was more effective in reducing the average particle size of the emulsion, which decreased from 479.4 ± 2.1 nm without addition to between 187.6 ± 5.9 and 368.2 ± 16.8 nm (P < 0.05). The potential values of all the emulsions were between -30 and -50 mV (except for the gallic acid addition of 2.5 g kg-1 ). When the phenolic addition was 7.5 g kg-1 , emulsions demonstrated the best emulsification ability. Pickering emulsion stabilized by WPI-TA and WPI-GA particles were successfully generated, according to confocal laser scanning microscopy. Rheological results showed that the increase of phenolic addition contributed to larger elastic modulus (G'), viscosity modulus (G″) and viscosity of emulsions, which was beneficial to the stability of emulsions. CONCLUSION: Both phenolic compounds significantly improved the physicochemical stability of the emulsions (P < 0.05) and their oxidative stability. Covalently crosslinking phenolic compounds to proteins is a better method to prepare stable emulsions. It is more prominent that TA shows a more significant improvement in emulsion stability due to the number of hydroxyl groups it can provide. This research might serve as a theoretical foundation for enhancing the quality of pine nut oil-related products. © 2022 Society of Chemical Industry.

Hypoglycemic effects and modulation of gut microbiota of diabetic mice by saponin from Polygonatum sibiricum.

Polygonatum sibiricum is a medicinal and homologous plant grown in China, which is commercially available without the provision of medical prescription. Saponin is one of the biologically active components of Polygonatum sibiricum. This study aimed to extract saponin from Polygonatum sibiricum (PSS) and to investigate its hypoglycemic effect and effect on gut micorbiota in diabetic mice. Through single factor and orthogonal experiments, the extraction conditions of saponin were optimized, and the content of saponin in the extract was 3.07 ± 0.02 mg g-1. During the experiment evaluating the hypoglycemic ability, it was found that PSS could inhibit the activity of α-amylase and α-glucosidase at first. Then, HepG2 was used to observe the effect of the saponin on insulin resistance. The results showed that PSS could significantly improve the state of insulin resistance in IR-HepG2 cells, increase the glucose consumption and intracellular glycogen content of cells, and the activity of hexokinase (0.455 ± 0.007 µmol min-1 g-1) and pyruvate kinase (0.174 ± 0.038 U per g prot). Finally, it was found that PSS could alleviate the symptoms of polyphagia and polydipsia in diabetic mice, regulate the gut microbiota of diabetic mice, increase the number of probiotics, and reduce the number of harmful bacteria. In summary, PSS may play an important role in regulating diabetes and can be developed as a promising natural material for diabetes prevention and treatment.

Preparation of microcapsule antioxidative wall materials of pine nut oil by the Maillard reaction.

BACKGROUND: Maillard reaction products contribute to the amelioration of the biological functions or physical properties of foods and can be used to make dependable antioxidant wall materials for microcapsules of pine nut oil. The present study aimed to analyze the effects of temperature on the Maillard reaction of dry heat processes using gelatin/gum arabic (GE/GA) or gelatin/gum arabic/maltodextrin (GE/GA/MD) models and the products of the Maillard reaction as encapsulants to protect pine nut oil, as well as to evaluate the characteristics of the microcapsules. RESULTS: The grafting degree of the product increased with the temperature increments during the Maillard reaction. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the polysaccharide covalently linked to the protein. The antioxidant capability of the Maillard products at 80 °C was the highest. The 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity, lipid peroxidation-inhibiting activity and reducing power of the GE/GA/MD model were higher than those of the GE/GA model. With in vitro digestion of Maillard products, GE/GA/MD pine nut oil microcapsules exhibited greater oil release in artificial gastric and enteric juices. Microencapsulated pine nut oil had more stable oxygen, which protected the oil, compared to unencapsulated pine nut oil. CONCLUSION: Temperature affects the degree of the Maillard reaction on GE/GA and GE/GA/MD models. © 2018 Society of Chemical Industry.

Codonopsis lanceolata polysaccharide CLPS inhibits melanoma metastasis via regulating integrin signaling.

ß1 integrin-mediated migration plays a fundamental role in melanoma metastasis. Here, we evaluated the molecular mechanisms underlying the anti-metastatic capacity of a polysaccharide fraction (CLPS) from Codonopsis lanceolata. CLPS inhibited in vivo melanoma metastasis in a B16F10 pulmonary metastasis model, impaired ß1 integrin-mediated B16F10 melanoma cell migration in vitro evaluated by Transwell assay, reduced affinity between ß1 integrin and ligand protein GST-FNIII9-10. Also, CLPS attenuated the adhesion-dependent formation of focal adhesion and blocked ß1 integrin/FAK/paxillin signaling axis. These findings illustrate a better understanding underlying the anti-metastatic activity of CLPS, indicating a potential treatment strategy for melanoma metastasis.

Characteristics and antioxidant activity of water-soluble Maillard reaction products from interactions in a whey protein isolate and sugars system.

The objective of this study was to determine antioxidant activities of water-soluble MRPs (Maillard reaction products) from the reactions between whey protein isolate (WPI) and xylose (X), glucose (G), fructose (F), lactose (L), maltose (M) and sucrose (S) at different initial pH values (3, 4, 5, 6, 7, 8 and 9). MRPs derived from the WPI-X system with increasing of pH rendered the highest browning, reducing power and DPPH radical-scavenging activity. SDS-PAGE analyses indicated formation of cross-linked proteins of large molecular mass produced from WPI-X systems. Results of FT-IR analysis indicated that the amide I, II and III bands of WPI from the WPI-X and WPI-G systems were changed by the Maillard reaction. CD spectroscopy showed that ß-sheet, ß-turns and random coil were increased while the α-helix was decreased after the WPI-G and WPI-X system aqueous solutions were heated. In conclusion, MRPs obtained from the WPI-X system had high antioxidant activity.