Fermentation of Milk and Soymilk byLactobacillus bulgaricusandLactobacillus acidophilusEnhances Functionality for Potential Dietary Management of Hyperglycemia and Hypertension

Cultivar evaluation and effect of fermentation on antioxidant capacity and in vitro inhibition of α-amylase and α-glucosidase by highbush blueberry (Vaccinium corombosum)

The berry fruits of highbush blueberry (Vaccinium corymbosum) contain bioactive compounds with potential health benefits. The objective was to evaluate blueberries grown in southern Illinois as well as the effect of fermentation, at two different temperatures, on chemical and physical parameters. Fruits from fifteen blueberry cultivars were analyzed. Fruit diameter ranged from 12.8 mm to 18.7 mm, pH from 2.6 to 3.7, reducing sugars from 6.4% to 15.2%, total sugars from 13.9% to 21.6%, total polyphenols from 0.39 to 1.00 mg gallic acid equivalents (GAE)/g blueberry and antioxidant capacity from 5.8 to 10.9 μM Trolox equivalents (TE)/g. In vitro α-amylase and α-glucosidase inhibitory capacity relative to the positive control acarbose, a known anti-diabetic drug, showed a range from 91.8 to 103.3% for α-amylase and from 103.2% to 190.8% for α-glucosidase. Wines prepared from several of these blueberry cultivars were analyzed throughout fermentation and compared at room temperature and cold temperature fermentation for pH (3.5 to 6.3), °Brix (13.6 to 29.7), total polyphenols (375.4 to 657.1 μg GAE/mL wine), and antioxidant capacity (4.5 to 25.1 mM TE). The wines were also tested for their in vitro capacity to inhibit α-amylase and α-glucosidase and maintained similar inhibitory action as the berries. Highbush blueberry cultivars and their fermented beverages are good natural sources of antioxidants and starch-degrading enzyme inhibitors important for type 2 diabetes management.

Inhibitory potential of tea polyphenolics and influence of extraction time against Helicobacter pylori and lack of inhibition of beneficial lactic acid bacteria

Tea polyphenolics such as catechins are known to have the potential to inhibit many bacterial pathogens. Helicobacter pylori has been identified as an etiologic agent in the development of gastric ulcer, peptic ulcer, gastritis, and many other stomach-related diseases. In this study, we investigated the effect of 9 tea extracts--3 different brands representing 4 different processed types (white, green, oolong, and black)--on the inhibition of H. pylori. Extraction times of 2 and 5 minutes were compared. Most 5-minute extracts showed H. pylori inhibition, whereas 2-minute extracts only of Choice darjeeling black and Tazo white showed inhibition. No recovery was observed after the addition of 0.5 and 5 mM proline, indicating that tea polyphenols do not inhibit H. pylori by inhibition of proline oxidation via proline dehydrogenase. Extracts that showed inhibition were further evaluated for their effect on beneficial lactic acid bacteria. None of the samples showed inhibition, suggesting that tea might be able to inhibit H. pylori without affecting the beneficial lactic acid bacteria. High-performance liquid chromatography indicated the presence of gallic acid, quercetin, caffeine, and tea catechins (including catechin, epicatechin, and epigallocatechin) in all the tea samples. Our study indicates that tea can be potentially used as a low-cost dietary support to combat H. pylori-linked gastric diseases without affecting the beneficial intestinal bacteria.