RESUMO
OBJECTIVE: To examine immobilization stress-induced antioxidant defense alterations in rat kidney and the antioxidant effects of aqueous garlic extract in pre and post stress extract treatments. METHODS: Albino rats were treated with aqueous extract of garlic both before and 6 h of immobilization stress. Pro-oxidant eminence of rat kidney was assessed by determining the levels of glutathione, thiobarbituric acid reactive substances, aspartate aminotransferase, alanine aminotransferase, glucose, uric acid, alkaline phosphatase and antioxidant enzymes activities. RESULTS: In response to 6 h of immobilization stress, a significant rise in the level of kidney enzymes was recorded. However, antioxidant enzyme activities showed a sharp decline. CONCLUSIONS: The extract treatment before and after the stress reverted the activities of above mentioned enzymes towards their control values. Hence, garlic extract can be given as nutritional supplement for scavenging the free radicals generated in rat kidney.
RESUMO
In this study, immobilization of partially purified almond [Amygdalus communis] beta-galactosidase on Con A layered calcium alginate-cellulose beads was investigated. Immobilized beta-galactosidase retained 72% of the initial activity after crosslinking by glutaraldehyde. Both soluble and immobilized enzyme exhibited the same pH and temperature optima at pH 5.5 and 50.C, respectively. However, the immobilized enzyme showed a remarkable broadening in pH and temperature-activity profiles as compared to the native enzyme. Immobilized enzyme was significantly more stable against thermal denaturation at 60.C. Immobilized beta-galactosidase exhibited 67% residual activity in the presence of 5% D-galactose while its soluble counterpart retained only 35% activity under identical conditions. Soluble enzyme showed 69% residual activity after exposure to pepsin [0.15 mg/ml] for 1 h whereas the immobilized beta-galactosidase was more stable and retained nearly 84% activity under identical experimental conditions. The activity of immobilized enzyme was enhanced to 156% whereas soluble beta-galactosidase showed an enhancement upto 134% when exposed to trypsin [0.1 mg/ml] for 1 h. Moreover, immobilized beta-galactosidase exhibited greater enhancement in enzyme activity against exposure to various ions present in milk such as Na+, K+, Ca+2, Mg+2 and citrate ions. The higher concentration of lactose was hydrolyzed from whey as compared to the hydrolysis from milk by immobilized enzyme at 50.C and 60.C in batch processes. Lactose was hydrolyzed to 86% and 78% after 20 days continuous operation of reactors at the flow rates of 20 ml/h and 30 ml/h, respectively. In view of its stability and utility in batch and continuous processes, such preparation could be exploited for the hydrolysis of lactose from milk and whey in a more convenient and cheaper way in dairy industries