Microbial profile of a kefir sample preparations: grains in natura and lyophilized and fermented suspension

Probiotics are supplementary foods developed by microbial strains that improve animal health beyond basic nutrition. Probiotics are consumed orally, regardless of being considered as normal inhabitants of the intestines, able to survive in enzimatic and biliary secretions. Kefir is a probiotic originated from the old continent, fermented by several bacteria and yeasts, encapsulated in a polyssacharide matrix, and resembles jelly grains. Kefir is also presented as its sourish product both in sugary or milky suspensions containing vitamins, aminoacids, peptides, carbohydrates, ethanol, and volatile compounds. Kefir is known to have a diverse microbial content depending on the country and fermentative substrates, which cause distinct probiotic effects. In this sense, the purpose of this work was to isolate, identify, and quantify the microbial content of a native sugary kefir sample (fermented suspension and lyophilized natural grains). Serial dilutions were plated on Rogosa agar (AR) and De Man, Rogosa and Sharpe (MRS), for Lactobacillus; Brain Heart Infusion (BHI), for total bacteria; Sabouraud-Dextrose-Agar (SDA), for yeasts and filamentous fungi; Thioglycolate Agar (TA), for Streptococcus, Acetobacteria and Leuconostoc; and Coconut Water Agar (CWA), and CWA supplemented with yeast extract (CWAY), for various genera. Genera and species for all strains were identified through biochemical reactions and specific API systems. The microbial profile of kefir was different from other sources of grains despite the presence of similar microorganisms and others which have not been reported yet. The data obtained with the CWA and CWAE media suggest that both substrates are alternative and salutary media for culture of kefir strains.

Flavonoids, total phenolics and antioxidant capacity: comparison between commercial green tea preparations

The potential health benefits attributed to green tea and its catechins such as antioxidant effects, cancer chemoprevention, and weight loss have led to a huge increase of green tea products in the food market. The objectives of this work were to analyze and compare these products in terms of phenolic contents and in vitro antioxidant capacity including tea bags, dehydrated leaves, and ready-to-drink preparations after standardization of the infusion preparation procedure. Total phenolics content in 1 cup of the different teas varied from 90 to 341 mg of catechin equivalents, and the highest and the lowest values were both those of the ready-to-drink products. Infusions prepared from tea bags had contents varying from 96 to 201 mg.200 mL-1, and there were no significant differences among batches. The DPPH radical scavenging and the Oxygen Radical Absorbing Capacities (ORAC) varied largely among the different tea preparations, from 23 to 131 mmoles of Trolox Equivalents (TE).200 mL-1 (DPPH), and from 1.2 to 5.1 mmoles of TE.200 mL-1 (ORAC), but again there were no differences among infusions or ready-to-drink commercial preparations. However, the antioxidant capacity of ready-to-drink products was partially due to the presence of other non-phenolic compounds such as ascorbic acid

Quantification of catechins and caffeine from green tea (Camellia sinensis) infusions, extract, and ready-to-drink beverages

This study aimed to quantify the levels of catechins and caffeine in various forms of presentation of green tea: infusion tea bags, extract, and ready-to-drink beverage and, based on their content, identify the most suitable for consumption. High Performance Liquid Chromatography (HPLC) analytical method was used for the quantification of catechins and caffeine. The tea bags had the highest concentration of total catechins with 5 to 9.5% followed by the extract with 3.64 to 4.88%, and ready-to-drink green tea beverage showed low levels of catechins, from 0.14 to 0.26%. As for caffeine content, green tea extract had higher concentration (1.96 to 3.54%) compared to the tea bags (1.39 to 1.57%). Tea bags were found the most suitable for consumption because it contains higher amounts of catechins and smaller amounts of caffeine.

Prevention of contrast induced nephropathy with sodium bicarbonate (the PROMEC study)

Introduction: Contrast-induced nephropathy is a common complication of radiographic procedures. Different measures have been used to avoid this damage, but the evidence is controversial. New investigations are required to clarify it. We investigated the efficacy and safety of sodium bicarbonate solution compared with sodium chloride solution to prevent contrast induced nephropathy in patients with or at risk of renal dysfunction. Methods: A prospective, single-center, randomized clinical trial conducted from May 1, 2007 to February 8, 2008. Inpatients in a tertiary center, scheduled to undergo a procedure with the nonionic radiographic contrast agent iohexol. There were 220 patients with serum creatinine levels of at least 1.2 mg/dL (106.1 µmol/L) and/or type 2 diabetics, who were randomized to receive an infusion of sodium chloride (n = 113) or sodium bicarbonate (n = 107) before and after contrast dye administration. The intervention were "A" group received 1 ml/kg/hour of normal saline solution, starting 12 hours before and continuing 12 hours after iohexol contrast. "B" group received 3 ml/kg of sodium bicarbonate solution (150 mEq/L) one hour prior to procedure and then drip rate was decreased to 1 ml/kg/hour until 6 hours post procedure. Our main outcome measure was change in serum creatinine. Results: The mean creatinine value after the procedure was 1.26 mg/dL in the saline group and 1.22 mg/dL in the bicarbonate group (mean difference: 0.036; CI 95%: -0.16 to 0.23, p = 0.865). The diagnosis of contrast-induced nephropathy, defined by increase in serum creatinine on 25% or more within 2 days after administration of radiographic contrast, was done in twelve patients (12%) in the bicarbonate group and eighth patients (7.1%) in the saline group (RR: 1.68, CI 95%: 0.72 to 3.94). Conclusion: Our investigation showed that there were no differences between normal saline solution (extended infusion) vs. bicarbonate solution for nephroprotection.