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排序方式: 共有231条查询结果,搜索用时 15 毫秒
1.
Acetyl-salicylic acid (ASA) is a nonsteroidal antiinflammatory/analgesic drug, which may cause gastritis or stomach ulcers if intensively employed. Exopolysaccharide (EPS)-producing lactic acid bacteria have been claimed to induce immunostimulatory/antiulcer effects in the host. This study investigated the potential preventive effect of fermented milks (FM) with EPS-producing Streptococcus thermophilus strains (CRL 1190 and CRL 804) on an in vivo model of chronic gastritis. Fermented milks (2 EPS+ and 1 EPS−, separately) were fed to BALB/c mice for 7 d before inducing gastritis with ASA (400 mg/kg of body weight per day for 10 d; gastritis group, n = 5). Appropriate control groups (ASA administered but not given FM, n = 5; and ASA not administered but given FM) were included in this study. Gastric inflammatory activity was evaluated through the stomach's histology and the number of IFNγ+ and IL-10+ cytokine-producing cells in the gastric mucosa. Only mice preventively treated with the EPS-producing Strep. thermophilus CRL 1190 FM and later administered ASA did not develop gastritis, showing a conserved gastric mucosa structure similar to those of healthy mice. A marked decrease of IFNγ+- and increase of IL-10+-producing cells compared with the gastritis group mice were observed. Purified EPS from Strep. thermophilus CRL 1190 resuspended in autoclaved milk was also effective for gastritis prevention. The EPS-protein interaction might be responsible for the observed gastroprotective effect; such interactions may be affected by industrial manufacturing conditions. The results indicate that the FM with Strep. thermophilus CRL 1190 or its EPS could be used in novel functional foods for preventing chronic gastritis. 相似文献
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The objectives were to reduce bitterness in reduced-fat Cheddar cheese made with an exopolysaccharide (EPS)-producing culture and study relationships among ultra-filtration (UF), residual chymosin activity (RCA), and cheese bitterness. In previous studies, EPS-producing cultures improved the textural, melting, and viscoelastic properties of reduced-fat Cheddar cheese. However, the EPS-positive cheese developed bitterness after 2 to 3 mo of ripening due to increased RCA. We hypothesized that the reduced amount of chymosin needed to coagulate UF milk might result in reduced RCA and bitterness in cheese. Reduced-fat Cheddar cheeses were manufactured with EPS-producing and nonproducing cultures using skim milk or UF milk (1.2×) adjusted to a casein:fat ratio of 1.35. The EPS-producing culture increased moisture and RCA in reduced-fat Cheddar cheese. Lower RCA was found in cheese made from UF milk compared with that in cheese made from control milk. Ultrafiltration at a low concentration rate (1.2×) produced EPS-positive, reduced-fat cheese with similar RCA to that in the EPS-negative cheese. Slower proteolysis was observed in UF cheeses compared with non-UF cheeses. Panelists reported that UF EPS-positive cheese was less bitter than EPS-positive cheese made from control milk. This study showed that UF at a low concentration factor (1.2×) could successfully reduce bitterness in cheese containing a high moisture level. Because this technology reduced the RCA level (per g of protein) to a level similar to that in the control cheeses, the contribution of chymosin to cheese proteolysis would be similar in both cheeses. 相似文献
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Yu Zhang Xiaofei Dai Haonan Jin Chaoxin Man Yujun Jiang 《Journal of dairy science》2021,104(4):4023-4032
This study aimed to predict the optimal carbon source for higher production of exopolysaccharides (EPS) by Lactobacillus paracasei TD 062, and to evaluate the effect of this carbon source on the production and monosaccharide composition of EPS. We evaluated the EPS production capacity of 20 strains of L. paracasei under the same conditions. We further investigated L. paracasei TD 062, which showed the highest EPS-producing activity (0.609 g/L), by examining the associated biosynthesis pathways for EPS. Genomics revealed that fructose, mannose, trehalose, glucose, galactose, and lactose were carbon sources that L. paracasei TD 062 could use to produce EPS. We identified an EPS synthesis gene cluster that could participate in transport, export, and sugar chain synthesis, and generate 6 sugar nucleotides. Experimental results showed that the sugar content of the EPS produced using fermentation with the optimized carbon source (fructose, mannose, trehalose, glucose, galactose, and lactose) increased by 115%. Furthermore, use of the optimized carbon source changed the monosaccharide content of the associated EPS. The results of enzyme activity measurements showed significant increases in the activity of 2 key enzymes involved in the glycoside synthesis pathway. Our study revealed that optimizing the carbon source provided for fermentation not only increased the production of EPS, but also affected the composition of the monosaccharides by increasing enzyme activity in the underlying synthesis pathways, suggesting an important role for carbon source in the production of EPS by L. paracasei TD 062. 相似文献
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Bartosz Brzozowski Włodzimierz Bednarski Bartłomiej Dziuba 《Journal of the science of food and agriculture》2009,89(14):2467-2476
BACKGROUND: This study addressed the characteristics of metabolites synthesized by Lactobacillus acidophilus 5e2, with particular attention paid to exopolysaccharides, biosurfactants, proline peptidases and antibacterial compounds. RESULTS: The strain Lb. acidophilus 5e2 synthesizes low‐molecular‐mass polysaccharides (340 kDa) constituted by glucose, galactose and glucosamine at a ratio of 3.3:2.8:1.0, as well as biosurfactants with a molecular mass of 32 kDa built from a protein fraction, a polysaccharide fraction and phosphate groups. It additionally synthesizes extra‐ and intracellular proline peptidases, including prolyl endopeptidase and thermostable low‐molecular‐mass (<3.5 kDa) compounds with antimicrobiological activity against Escherichia coli strains. CONCLUSION: The strain Lb. acidophilus 5e2 may be applied to the production of functional food. Copyright © 2009 Society of Chemical Industry 相似文献
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Fat-reduced cheeses often suffer from undesirable texture, flavor, and cooking properties. Exopolysaccharides (EPS) produced by starter strains have been proposed as a mechanism to increase yield and to improve the texture and cooking properties of reduced-fat cheeses. The objective of this work was to assess the influence of an exopolysaccharide on the yield, texture, cooking properties, and quality of half-fat Cheddar cheese. Two pilot-scale half-fat Cheddar cheeses were manufactured using single starters of an isogenic strain of Lactococcus lactis ssp. cremoris (DPC6532 and DPC6533) that differed in their ability to produce exopolysaccharide. Consequently, any differences detected between the cheeses were attributed to the presence of the exopolysaccharide. The results indicated that cheeses made with the exopolysaccharide-producing starter had an 8.17% increase in actual cheese yield (per 100 kg of milk), a 9.49% increase in moisture content, increase in water activity and water desorption rate at relative humidities ≤90%, significant differences in the cheeses microstructure, and a significant improvement in both textural and cooking properties, without negatively affecting the flavor profiles of the cheeses. 相似文献
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Deproteinization was comparatively employed for the purification of crude exopolysaccharide (CEP) of Ganoderma sinense mycelium. Results showed that ammonium sulfate (70% saturation) salting out could remove 95% proteins of CEP, whereas 20% trichloroacetic acid precipitation was best with a polysaccharide loss less than 20%. Protein-bound polysaccharides could be removed by both methods, and polysaccharides with high molecular weight dominated in the lost polysaccharides. Through anion-exchange chromatography, a highly branched α-(1→6)-D-mannan and a protein-bound heteropolysaccharide were prepared from CEP. Both fractions could inhibit the in vitro proliferation of tumor cells BEL-7402, and induce TNF-α secretion of murine splenocytes. 相似文献
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