Search

The antimicrobial and antioxidant activities and the composition of the essential oil and of the supercritical extracts of Xanthium strumarium were studied. The best yields were observed in the supercritical extracts (SFE). The composition of the extracts obtained by SFE and by hydrodistillation presented little qualitative difference, but they did differ quantitatively. The essential oil contained a high content of β-guaiene (79.6%) while as the major compounds in the supercritical extracts were unidentifiable compound with Kovats Index of 2303 and xanthinin. All the X. strumarium extracts showed strong antimicrobial activity against Staphylococcus aureus, Escherichia coli, Salmonella thyphimurium, Pseudomonas aeruginosa and Clostridium perfringens, however no differences were observed between the extracts. Poor antioxidant activity was found for all the Xanthium strumarium extracts. [ABSTRACT FROM AUTHOR]

Fermented dairy beverages supplemented with the probiotics Lactobacillus acidophilus and Bifidobacterium lactis containing different concentrations of whey in their formulas (0, 20, 35, 50, 65, and 80%, vol/vol) were processed and checked for pH; proteolysis; levels of glucose, lactose, ethanol, acetic acid, lactic acid, diacetyl, and acetaldehyde; and lactic bacteria and probiotic counts. The results allowed the effect of whey concentration on the dairy beverages to be observed for each of the different parameters analyzed. The degree to which the whey concentration was useful for the microbial cultures, particularly probiotic cultures, appeared to have a limit. In general, dairy beverages processed with different levels of whey in their formulation exhibited good potential as a food matrix for supplementation with probiotic bacteria, with production of characteristic compounds of fermented milk products, such as volatiles and organic acids. [ABSTRACT FROM AUTHOR]

We investigated the effect of increased glucose oxidase concentration as a technological option to decrease oxidative stress during the processing of probiotic yogurts. Probiotic yogurts were produced with increased concentrations of glucose oxidase (0, 250, 500, 750, or 1,000 mg/kg) and submitted to physicochemical and microbiological analysis at 1, 15, and 30 d of refrigerated storage. Higher concentrations of glucose oxidase (750 and 1,000 mg/kg) and a longer storage time were found to have an influence on the characteristics of the probiotic yogurt, contributing to more extensive post-acidification, an increase in the dissolved oxygen level, and higher proteolysis. In addition, increased production of aroma compounds (diacetyl and acetaldehyde) and organic acids (mainly lactic acid) and a decrease in the probiotic bacteria count were reported. The use of glucose oxidase was a feasible option to minimize oxidative stress in probiotic yogurts. However, supplementation with excessive amounts of the enzyme may be ineffective, because insufficient substrate (glucose) is present for its action. Consumer tests should be performed to evaluate changes in the sensory attributes of the probiotic yogurts with increased supplementation of glucose oxidase. In addition, packaging systems with different permeability to oxygen should be evaluated. [ABSTRACT FROM AUTHOR]

Six sample lots of loquat commercialized in Campinas, Brazil were analyzed for their carotenoid composition beta-carotene (7.8 micrograms/g), zeta-carotene (0.1 micrograms/g), neurosporene (1.1 micrograms/g), beta-cryptoxanthin (4.8 micrograms/g), 5,6-monoepoxy-beta-cryptoxanthin (0.6 micrograms/g), violaxanthin (1.6 micrograms/g), (0.8 micrograms/g) and auroxanthin (0.9 micrograms/g) were identified beta-Carotene and beta-cryptoxanthin were the principal pigments, being responsible for 44% and 27%, respectively, of the total carotenoid content (17.6 micrograms/g). Both were also the principal contributors to the vitamin A value of 175 RE/100g. The carotenoid composition of the Brazilian loquat resembles that of the Japanese loquat variety Tanaka.