Structural Characterization and Antioxidant Activity of Exopolysaccharide from Soybean Whey Fermented by Lacticaseibacillus plantarum 70810

Antioxidant Activity of Auricularia auricula Polysaccharides with Different Molecular Weights and Cytotoxicity Difference of Polysaccharides Regulated CaOx to HK-2 Cells

Objective

This study aimed to investigate the growth of calcium oxalate (CaOx) crystals regulated by Auricularia auricular polysaccharides (AAPs) with different viscosity-average molecular weights (Mv), the toxicity of AAP-regulated CaOx crystals toward HK-2 cells, and the prevention and treatment capabilities of AAPs for CaOx stones.

Methods

The scavenging capability and reducing capacity of four kinds of AAPs (Mv of 31.52, 11.82, 5.86, and 3.34 kDa) on hydroxyl, ABTS, and DPPH free radicals and their capability to chelate divalent iron ions were detected. AAP-regulated CaOx crystals were evaluated by using zeta potential, thermogravimetric analysis, X-ray diffraction, and scanning electron microscopy. The cytotoxicity of AAP-regulated crystals was evaluated through examination of cell viability, cell death, malondialdehyde (MDA) content, and cell surface hyaluronic acid (HA) expression.

Results

The in vitro antioxidant activities of the four AAPs were observed in the following order: AAP0 < AAP1 < AAP2 < AAP3. Thus, AAP3, which had the smallest Mv, had the strongest antioxidant activity. AAPs can inhibit the growth of CaOx monohydrate (COM), induce the formation of CaOx dihydrate (COD), and reduce the degree of crystal aggregation, with AAP3 exhibiting the strongest capability. Cell experiments showed the lowest cytotoxicity in AAP3-regulated CaOx crystals, along with the lowest MDA content, HA expression, and cell mortality. In addition, COD presented less cytotoxicity than COM. Meanwhile, the cytotoxicity of blunt crystals was less than that of sharp crystals.

Conclusion

AAPs, particularly AAP3, showed an excellent antioxidative capability in vitro, and AAP3-regulated CaOx crystals presented minimal cytotoxicity.

Optimization of Extraction Process, Preliminary Characterization and Safety Study of Crude Polysaccharides from Morindae Officinalis Radix

In this study, the hot water extraction process of crude polysaccharides from Morindae officinalis radix (cMORP) was conducted and optimized through a single-factor test and orthogonal experimental design. With the optimal extraction process (extraction temperature of 80 °C, extraction time of 2 h, liquid/solid ratio of 15 mL/g, and number of extraction of 1), the cMORP was obtained by the ethanol precipitation method. The chemical properties and preliminary characterization of the cMORP were analyzed by chemical or instrumental methods. Furthermore, to indicate a preliminary study on safety, a single oral dose of 5000 mg/kg body weight (BW) was administered orally to Kunming (KM) mice for acute toxicity, and the cMORP was administered orally to KM mice once a day at doses of 25, 50, and 100 mg/kg BW for 30 days. General behaviors, body weight variations, histopathology, relative organ weights, and hematological and serum biochemical parameters were observed and recorded. The results suggested there were no toxicologically significant changes. Based on the safety study, cMORP can be initially considered non-toxic with no acute oral toxicity up to 5000 mg/kg BW and safe at up to 100 mg/kg BW in KM mice for 30 days.

Study on the fermentation effect of Rhodotorula glutinis utilizing tofu whey wastewater and the influence of Rhodotorula glutinis on laying hens

Background

Tofu whey wastewater (TWW) is the wastewater of tofu processing, which is rich in a variety of nutrients. Rhodotorula glutinis can make full use of TWW to ferment and reproduce yeast cells, produce carotenoids and other nutrients, improve the utilization value of TWW, and reduce environmental pollution and resource waste.

Methods

In this study, the nutrient composition changes of TWW treated by Rhodotorula glutinis were analyzed to reformulate TWW medium, and the optimal composition and proportion of TWW medium that can improve the biomass and carotenoids production of Rhodotorula glutinis were explored. Meanwhile, the Rhodotorula glutinis liquid obtained under these conditions was used to prepare biological feed for laying hens, and the effect of Rhodotorula glutinis growing on TWW as substrate on laying performance and egg quality of laying hens were verified.

Results

The results showed that the zinc content of TWW after Rhodotorula glutinis fermentation increased by 62.30%, the phosphorus content decreased by 42.31%, and the contents of vitamin B1, B2 and B6 increased to varying degrees. The optimal fermentation conditions of Rhodotorula glutinis in the TWW medium were as follow: the initial pH was 6.40, the amount of soybean oil, glucose and zinc ions was 0.80 ml/L, 16.32 g/L, and 20.52 mg/L, respectively. Under this condition, the biomass of Rhodotorula glutinis reached 2.23 g/L, the carotenoids production was 832.86 μg/g, and the number of effective viable yeast count was 7.08 × 10⁷ cfu/ml. In addition, the laying performance and egg quality of laying hens fed Rhodotorula glutinis biological feed were improved.

Discussion

In this study, we analyzed the composition changes of TWW, optimized the fermentation conditions of Rhodotorula glutinis in TWW medium, explored the influence of Rhodotorula glutinis utilizing TWW on laying layers, and provided a new idea for the efficient utilization of TWW.

Effects of in vitro digestion on protein degradation, phenolic compound release, and bioactivity of black bean tempeh

The nutritional value and bioactivity of black beans are enhanced when fermented as tempeh, but their bioaccessibility and bioactivity after ingestion remain unclear. In this study, black bean tempeh and unfermented black beans were digested in vitro and changes in protein degradation, phenolic compound release, angiotensin I-converting enzyme (ACE)-inhibitory activity, and antioxidant activity between the two groups were compared. We observed that the soluble protein content of digested black bean tempeh was generally significantly higher than that of digested unfermented black beans at the same digestion stage (P < 0.05). The degree of protein hydrolysis and the content of <10 kDa peptides were also significantly higher in the digested black bean tempeh than in digested unfermented black beans (P < 0.05). SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and reversed-phase high-performance liquid chromatography (RP-HPLC) analysis showed that most macromolecular proteins in tempeh had been degraded during fermentation and more of the small peptides were released from black bean tempeh during digestion, respectively. Compared to that of the unfermented black beans, the level of ACE inhibition of black bean tempeh was lower, but this significantly increased to 82.51% following digestion, closing the gap with unfermented black beans. In addition, the total respective levels of phenolics, flavonoids, and proanthocyanidins released from black bean tempeh were 1.21, 1.40, and 1.55 times those of unfermented black beans following in vitro digestion, respectively. Antioxidant activity was also significantly higher in digested black bean tempeh than in digested unfermented black beans and showed a positive correlation with phenolic compound contents (P < 0.05). The results of this study proved that, compared to unfermented black beans, black bean tempeh retained protein and phenolic compound bioaccessibility and antioxidant activity and showed an improved ACE-inhibitory activity even after consumption.

Structural Characteristics, Antioxidant, and Immunostimulatory Activities of an Acidic Polysaccharide from Raspberry Pulp

The extraction and characterization of new bioactive plant-derived polysaccharides with the potential for use as functional foods and medicine have attracted much attention. In the present study, A novel acidic polysaccharide (RPP-3a) with a weight-average molecular weight (Mw) of 88,997 Da was isolated from the raspberry pulp. RPP-3a was composed of rhamnose, arabinose, galactose, glucose, mannose, and galacturonic acid at a molar ratio of 13.1:28.6:16.8:1.4:6.2:33.9. Structural analysis suggested that the RPP-3a backbone was composed of repeating units of →4)-β-Galp-(1→3,4)-α-Rhap-(1→[4)-α-GalAp-(1→4)-α-GalAp-(1→]_n with branches at the C-4 position of rhamnose. The side chain of RPP-3a, containing two branch levels, was comprised of α-Araf-(1→, →5)-α-Araf-(1→, →3,5)-α-Araf-(1→, →3)-β-Galp-(1→, →3,6)-β-Galp-(1→, →4)-β-Glcp-(1→, and →2,6)-α-Manp-1→ residues. RPP-3a exhibited moderate reducing power and strong hydroxyl and superoxide anion radical scavenging abilities. RPP-3a significantly promoted the viability of RAW264.7 macrophages by increasing the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) at both the expression and transcriptional levels. In summary, the immunostimulatory and antioxidant activities make RPP-3a a viable candidate as a health-beneficial functional dietary supplement.

Biological Functions of Exopolysaccharides from Lactic Acid Bacteria and Their Potential Benefits for Humans and Farmed Animals

Lactic acid bacteria (LAB) synthesize exopolysaccharides (EPS), which are structurally diverse biopolymers with a broad range of technological properties and bioactivities. There is scientific evidence that these polymers have health-promoting properties. Most commercialized probiotic microorganisms for consumption by humans and farmed animals are LAB and some of them are EPS-producers indicating that some of their beneficial properties could be due to these polymers. Probiotic LAB are currently used to improve human health and for the prevention and treatment of specific pathologic conditions. They are also used in food-producing animal husbandry, mainly due to their abilities to promote growth and inhibit pathogens via different mechanisms, among which the production of EPS could be involved. Thus, the aim of this review is to discuss the current knowledge of the characteristics, usage and biological role of EPS from LAB, as well as their postbiotic action in humans and animals, and to predict the future contribution that they could have on the diet of food animals to improve productivity, animal health status and impact on public health.

Antioxidant Content and Antioxidant Capacity of the Protein-Rich Powdered Beverages Enriched with Flax Seeds Gum

Powdered beverages produced from dried fruit and vegetables are new products whose properties may be tailored by adding efficient nutrients and functional ingredients. The analyses of low-molecular antioxidants and antioxidant properties as well as nutrient content and digestibility were tested in beverages enriched with lentil proteins (AGF) and flaxseed gum (FSG). A replacement of sprouted lentil flour with the AGF deteriorated the phenolic content. As a main source of phenolics and vitamin C, lyophilized parsley leaves and broccoli sprouts were recognized. (There was no clear effect of the FGS.) The highest content of phenolics was determined in the beverages with these additives without the AGS (c.a. 125 μg/g). The AGF significantly improved the ability to quench ABTS radicals and reduce power. The best results were for the beverages without the FSG. (The effect was enhanced by lyophilized fruit and green vegetables.) The lowest chelating power and ability to quench hydroxyl radicals were in the beverages based on the AGF (improvement by the FSG and green vegetables). The tailoring of beverages' recipes significantly increased protein content and did not affect nutrient digestibility. The modifications allow obtaining the beverages exhibiting multidirectional antioxidant properties, being a source of easily bioaccessible starch and proteins.