RESUMEN
The effect of the UV-C treatment on the physico-chemical characteristics, pectin methylesterase activity (PME) as well as microbial quality of orange juice, compared to fresh juice, was studied. The juice samples were UV-C (254â nm) irradiated for different exposure times (15, 30, 45 and 60â min) and stored at 4 ± 1 °C for 30 days. UV-C treatment didn't significantly (p ≤ 0.05) affect pH values, titratable acidity, TSS (%), ascorbic acid content and PME activity in both fresh and stored samples. Increasing the exposure time from 5 to 60â min. showed no significant effect (p ≤ 0.05) on L* and a* values for both the fresh and the stored samples. On the contrary, negative relationship was observed between UV-C exposure time and b* values. Total bacterial counts were significantly (p ≤ 0.05) reduced from 2.69 to 0.93 log10 CFU/mL when the exposure time was increased from 0 to 60â min. The UV-C treatment showed similar trend on yeast and mold counts but to a lesser extend due to their resistance to UV. The sensory characteristics, i.e. odour, colour, taste, consistency and overall acceptability didn't change (p ≤ 0.05) as a result of UV-C treatment at any tested exposure times.
Asunto(s)
Citrus sinensis , Jugos de Frutas y Vegetales , Ácido Ascórbico/análisis , Levaduras , HongosRESUMEN
A passive haemagglutination technique was used to measure the E. coli antibody response in children with acute and chronic urinary tract infections with or without renal involvement. The E. coli antibody titre was also determined in sera of control normal children. In acute infections with renal involvement there was markedly high antibody response whereas in acute infections without renal involvement the rise in the antibody response to E. coli was only slight. In patients with chronic pyelonephritis the titres were also markedly high. E. coli antigens from 3 different sources were used in an attempt to find a substitute antigen for cases with negative urinary cultures. The 3 antigens used were urinary strains (only in patients with positive urinary cultures), patient's faecal strain and a polyvalent standard E. coli antigen. The faecal antigens gave results similar to the urinary ones in only 52% while the polyvalent antigen was found to be a more valuable substitute antigen giving equal titres to those with the urinary antigens in about 63% of the cases.