RESUMO
Strawberry contains many bioactive compounds such as vitamin C and polyphenols as well as folate, a vitamin that is especially important for women of childbearing age. We investigated the effects of the acute consumption of strawberry on the serum levels of vitamin C and folate, and on the antioxidant potential of low-density lipoprotein (LDL). In a randomised, placebo-controlled, double-blind, crossover study, twenty-three healthy female volunteers (age 22â 5 ± 1â 4 years) ingested 500 g of a strawberry purée beverage or a sugar content-matched placebo beverage. Blood samples were collected at fasting and at 0â 5, 1, 2 and 4 h post-ingestion. The serum concentrations of vitamin C and folate were significantly elevated from 0â 5 to 4 h after the strawberry beverage ingestion (P < 0â 001); the levels peaked at 2 h, with peak levels of 15â 0 ± 2â 5 µg/ml for vitamin C and 14â 4 ± 7â 0 ng/ml for folate. Notably, at 1 h after the strawberry beverage ingestion, the LDL oxidation lag time was significantly prolonged (P < 0â 05), suggesting that the antioxidant potential of LDL was increased. After the ingestion of either beverage, the serum levels of glucose and insulin reached a peak at 0â 5 h and then quickly returned to baseline levels. These results suggest that strawberries are a useful source of vitamin C and folate and may help enhance the antioxidant potential of LDL in healthy young women.
Assuntos
Antioxidantes , Fragaria , Humanos , Feminino , Pré-Escolar , Ácido Ascórbico , Glicemia , Ácido Fólico , Estudos Cross-Over , VitaminasRESUMO
Neosartorya and Talaromyces are typical fungi capable of producing heat resistant ascospores responsible for the spoilage of processed fruit products. In this study, the heat activation rates of Neosartorya and Talaromyces ascospores were investigated in several suspending media at various heating temperatures. Ascospores were dispersed in pH 3.5 McIlvain buffer, organic acid/alcohol-supplemented McIlvain buffer and grape juice (pH 3.5, 5.0 degrees Brix) prior to heat treatments. In McIlvain buffer, the number of germinating ascospores increased logarithmically with longer exposure to heating at an test temperatures. Heat activation rates (k values) accelerated with increasing temperature. The calculated activation energy (Ea) values were similar among ascospores from the same genus, but the Ea of the test Neosartorya spp. were greater than that of the test Talaromyces spp. Greater k values were calculated from acetate-supplemented McIlvain buffer and grape juice. Similarly, normal- and branched-chain fatty acids were shown to enhance the heat activation rate of the ascospores in McIlvain buffer systems. These results could assist the food industry in designing adequate thermal processes for food products against the heat resistant fungi.
Assuntos
Microbiologia de Alimentos , Neosartorya/patogenicidade , Esporos Fúngicos/patogenicidade , Talaromyces/patogenicidade , Ácidos/farmacologia , Contagem de Colônia Microbiana , Manipulação de Alimentos , Temperatura Alta , Concentração de Íons de Hidrogênio , Microscopia Eletrônica de Varredura , Neosartorya/efeitos dos fármacos , Neosartorya/isolamento & purificação , Microbiologia do Solo , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/isolamento & purificação , Talaromyces/efeitos dos fármacos , Talaromyces/isolamento & purificação , Talaromyces/ultraestruturaRESUMO
This study dealt with the isolation, characterization, and identification of the fungal microflora of frozen blueberries imported from Canada. The thermal inactivation rates of the rarely studied isolated heat-resistant molds, Devriesia spp. and Hamigera striata, in naturally and artificially contaminated blueberry slurries were also determined. The D-values of naturally contaminating Devriesia spp. at 70, 80, 85, and 90 degrees C were 714, 114, 44.4, and 14.1 min, respectively. The D-values of H. striata at 70, 80, 85, and 90 degrees C were 909, 286, 42.6, and 10.3 min, respectively. The z-values calculated from the thermal death time curves were 11.0 and 6.9 degrees C for Devriesia spp. and H. striata, respectively. Results also showed that in both test mold species, the naturally occurring molds had significantly higher thermal resistance than did the artificially contaminated counterparts. The results established by this study may be used by blueberry processors to prevent losses due to spoilage caused by the heat-resistant microorganisms.