Aspartic proteinases from Mucor spp. in cheese manufacturing.

Filamentous fungi belonging to the order of Mucorales are well known as producers of aspartic proteinases depicting milk-clotting activity. The biosynthesis level, the biochemical characteristics, and the technological properties of the resulting proteinases are affected by the producer strain and the mode of cultivation. While the milk-clotting enzymes produced by the Rhizomucor spp. have been extensively studied in the past, much less is known on the properties and potential applications of the aspartic proteinases obtained for Mucor spp. Indeed, several Mucor spp. strains have been reported as a potential source of milk-clotting enzymes having unique technological properties. Both submerged fermentation and solid substrate cultivation are proven alternatives for the production of Mucor spp. aspartic proteinases. This review provides an overview on the bioprocessing routes to obtain large amounts of these enzymes, on their structural characteristics as related to their functional properties, and on their industrial applications with focus on cheese manufacturing.

Biosorption of cadmium and lead ions by ethanol treated waste baker's yeast biomass.

The biosorption of cadmium and lead ions from artificial aqueous solutions using waste baker's yeast biomass was investigated. The yeast cells were treated with caustic, ethanol and heat for increasing their biosorption capacity and the highest metal uptake values (15.63 and 17.49 mg g(-1) for Cd(2+) and Pb(2+), respectively) were obtained by ethanol treated yeast cells. The effect of initial metal concentration and pH on biosorption by ethanol treated yeast was studied. The Langmuir model and Freundlich equation were applied to the experimental data and the Langmuir model was found to be in better correlation with the experimental data. The maximum metal uptake values (qmax, mg g(-1)) were found as 31.75 and 60.24 for Cd(2+) and Pb(2+), respectively. Competitive biosorption experiments were performed with Cd(2+) and Pb(2+) together with Cu(2+) and the competitive biosorption capacities of the yeast biomass for all metal ions were found to be lower than in non-competitive conditions.

Protection capacity against low-density lipoprotein oxidation and antioxidant potential of some organic and non-organic wines.

Current research suggests that phenolics from wine may play a positive role against oxidation of low-density lipoprotein (LDL), which is a key step in the development of atherosclerosis. Considering the effects of different wine-making techniques on phenols and the wine consumption preference influencing the benefical effects of the product, organically and non-organically produced wines were obtained from the grapes of Vitis vinifera origin var: Carignan, Cabernet Sauvignon, Merlot, Grenache, Columbard and Semillon. Levels of total phenols [mg/l gallic acid equivalents (GAE)], antioxidant activity (%) and inhibition of LDL oxidation [%, inhibition of diene and malondialdehyde (MDA) formation] were determined. Some phenolic acids (gallic acid, p-hydroxybenzoic acid, syringic acid, 2,3-dihydroxybenzoic acid, ferulic acid, p-coumaric acid and vanillic acid) were quantified by high-performance liquid chromatography equipped with an electrochemical detection carried at +0.65 V (versus Ag/AgCl, 0.5 microA full scale). The highest concentrations of gallic, syringic and ferulic acids were found in organic Cabernet Sauvignon; 2,3-dihydroxybenzoic acid in organic Carignan and p-coumaric and vanillic acids in non-organic Merlot wine. High levels of antioxidant activity (AOA), inhibition of LDL oxidation and total phenol levels were found in non-organic Merlot (101.950% AOA; 88.570% LDL-diene; 41.000% LDL-MDA; 4700.000 mg/l GAE total phenol) and non-organic Cabernet Sauvignon (92.420% AOA; 91.430% LDL-diene; 67.000% LDL-MDA; 3500.000 mg/l GAE total phenol) grape varieties. Concentrations of some individual phenolic constituents (ferulic, p-coumaric, vanillic) are correlated with high antioxidant activity and inhibition of LDL oxidation. The best r value for all examined characteristics was determined for gallic acid, followed by 2,3-dihydroxybenzoic, syringic, ferulic and p-coumaric acids. Negative correlation of vanillic with MDA and p-hydroxybenzoic acid with LDL were confirmed by principal component analysis (PCA) analyses. Red wines display a higher antioxidant activity (81.110% AOA) than white ones (19.512% AOA). The average level of LDL inhibition capacity in red wine was determined as 87.072% and for the white as 54.867%.