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Bile salt hydrolase (BSH) is an enzyme produced by the intestinal microflora that catalyzes the deconjugation of glycine-or taurine-linked bile salts. The crystal structure of BSH reported here from Bifidobacterium longum reveals that it is a member of N-terminal nucleophil hydrolase structural superfamily possessing the characteristic ␣␤␤␣ tetra-lamellar tertiary structure arrangement. Site-directed mutagenesis of the catalytic nucleophil residue, however, shows that it has no role in zymogen processing into its corresponding active form. Substrate specificity was studied using Michaelis-Menten and inhibition kinetics and fluorescence spectroscopy. These data were compared with the specificity profile of BSH from Clostridium perfrigens and pencillin V acylase from Bacillus sphaericus, for both of which the three-dimensional structures are available. Comparative analysis shows a gradation in activity toward common substrates, throwing light on a possible common route toward the evolution of pencillin V acylase and BSH.

The aim of the study was to evaluate the changes in the antioxidant properties of Cheddar cheese at different stages of ripening using different assays: 2, 2¢-azinobis (3 ethyl benzothiazoline)-6-sulphonic acid, 2, 2-diphenyl 1, picryl hydrazyl and superoxide radical scavenging activity. Cheddar cheese was prepared with Lactobacillus casei ssp. casei 300 and Lactobacillus paracasei ssp. paracasei 22 and without adjunct cultures. The antioxidant activity of water-soluble extracts of Cheddar cheese was dependent on the ripening period. The changes in the antioxidant activity were related to the rate of formation of soluble peptides (proteolysis) in all the samples of cheeses up to fourth month of ripening.

The purpose of the present study was to evaluate the anti-hypercholesterolaemic effects of two putative probiotic bile salt hydrolase (Bsh)-producing Lactobacillus plantarum strains, i.e. Lp91 and Lp21, in rats. L. plantarum Lp91 exhibited excellent tolerance to low pH and high bile salt concentrations as well as showed potential Bsh activity, cholesterol assimilation and cholesterol co-precipitation ability along with L. plantarum Lp21 and NCDO82 strains. Furthermore, the potential effect of L. plantarum Lp91 on plasma cholesterol level was evaluated in Sprague -Dawley rats. Five treatment groups of rats (n 6) were fed experimental diets: normal diet, hypercholesterolaemic diet (HD), HD plus L. plantarum Lp91 (HD91) at $ 1·0 £ 10 8 colony-forming units (cfu)/g, HD plus microencapsulated L. plantarum Lp91 (HDCap91) at $ 1·0 £ 10 8 cfu/g and HD plus L. plantarum Lp21 (HD21) at $ 1·0 £ 10 8 cfu/g for 3 weeks. Feed intake and feed efficiency differed significantly among the five groups. After 21 d of dietary treatment, comparative analysis revealed 23·26, 15·71 and 15·01 % reduction in total cholesterol, 21·09, 18·77 and 18·17 % reduction in TAG, 38·13, 23·22 and 21·42 % reduction in LDL-cholesterol, and the corresponding HDL-cholesterol values increased at the rate of 18·94, 10·30 and 7·78 % in treated groups HD91, HDCap91 and HD21, respectively. Faecal excretion of cholic acid and faecal lactobacilli counts were significantly higher in the probiotic treatment groups than in the control groups. In conclusion, these results suggest that the indigenous L. plantarum Lp91 strain has the potential to be explored as a probiotic in the management of hypercholesterolaemia.Key words: Lactobacillus plantarum: Microencapsulation: Bile salt hydrolase: Plasma lipids An elevated serum cholesterol level is considered to be one of the major risk factors associated with atherosclerosis and CHD (1,2) -the major cause of morbidity and mortality around the world (3,4) . The WHO predicts that by the year 2020, up to 40 % of all deaths will be related to CVD. Although drug-based therapy (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors or drugs) is currently being used to treat this condition (5) , it is often suboptimal, expensive and suffers from unwanted side effects (6 -8) .Another natural cost-effective and safe alternative approach recently being explored to manage cholesterolrelated problems is based on probiotic intervention. Probiotics particularly belonging to the genera Lactobacillus and Bifidobacterium as biotherapeutics have been investigated for reducing the level of cholesterol in the serum by virtue of bile salt hydrolase (Bsh) activity through direct impact on host bile salt metabolism (9 -12) . Bsh-producing lactobacilli have the selective advantage of surviving and colonising the lower small intestine where the enterohepatic cycle takes place and, therefore, Bsh activity could be considered as one of the important colonisation factors (13) . Bile salts are secreted as bile into the duodenum in the...

The aim of the present study was to evaluate the antioxidant activity of flavoured milk enriched with antioxidative whey protein hydrolysates (WPHs) by radical scavenging method. Whey protein concentrate (WPC) was hydrolyzed by using three commercial proteases; flavouzyme, alcalase and corolase PP and these WPHs were analyzed for degree of hydrolysis and antioxidant activity. The antioxidant activities of these WPHs were evaluated using ABTS method. Trolox equivalent antioxidant activity of all the hydrolysates i.e. flavourzyme (0.81 ± 0.04), alcalase (1.16 ± 0.05) and corolase (1.42 ± 0.12) was higher than the WPC (0.19 ± 0.01). Among these, whey protein hydrolysates prepared using corolase showed maximum antioxidant activity. Total 15 β-lactoglobulin, 1 α-lactoalbumin, and 6 β-casein derived peptide fragments were identified in the WPHs by LC-MS/MS. Due to their size and characteristic amino acid composition, all the identified peptides may contribute for the antioxidant activity. The strawberry and chocolate flavoured milk was supplemented with WPC and WPHs and 2 % addition has shown increase in antioxidant activity upto 42 %. The result suggests that WPH could be used as natural biofunctional ingredients in enhancing antioxidant properties of food products.

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