José M A Empis

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Two Gram-negative bacterial strains capable of using lupanine, the predominant quinolizidine alkaloid in Lupinus albus, as a sole carbon source were isolated from soil in which L. albus and L. luteus had been grown [Santana, F. M. et al. J. Ind. Microbiol. 1996, 17, 110-115]. In the present study, we present results suggesting that these isolates are of(More)
The use of natural colourings in food products presents nutritional advantages, and certain pigments are associated with functional properties, e.g. antioxidant effects. This can be very advantageous in food products with high fat contents like mayonnaises. The aim of this work was to study the effect of adding natural pigments, lutein and phycocyanin, to(More)
Apparent digestibility, deposition and retention of carotenoids in the muscle of rainbow trout, Oncorhynchus mykiss, were investigated comparing the feeding of pigments from Chlorella vulgaris against commercially available pigments at two different total lipid contents (15% and 20% lipid). Algal biomass (ALG) was included in rainbow trout diets and muscle(More)
The feasibility of using apparent viscosity (eta a) as a method for detecting the occurrence of previous irradiation of pepper was studied. Apparent viscosity of heat-treated suspensions of white and black pepper, nonirradiated or irradiated with different doses of ionising radiation (gamma), was measured under different "shear rates". Results of previous(More)
The inclusion compounds of carvone enantiomers in cylcomaltoheptaose (beta-cyclodextrin, betaCD) are studied at defined temperatures above room temperature and in relation to H-->D and D-->H exchanges. Loss of water molecules and release of carvone molecules from the betaCD cavity are caused by increase of temperature above room temperature and are measured(More)
The influence of water content, additives, pH and substrate concentration on the thermostability of α-chymotrypsin entrapped in a reversed micellar system of the cationic surfactant TTAB/heptane/ chloroform, was studied. Increasing the water level inside the reversed micelles diminishes the enzyme stability. Enzyme stability enhancement was achieved with(More)
The stability and proteolytic activity of papain were studied in reverse micellar systems, and in aqueous media. In reverse micelles the maximum activity obtained was 80% of the enzyme activity in aqueous solution. Higher papain stability was found in reverse micellar systems compared with that in aqueous solution with half-lives of 24 and 10 days(More)
The influence of five different N-terminal protecting groups (For, Ac, Boc, Z, and Fmoc) and reaction conditions (temperature and dimethylformamide content) on the alpha-chymotrypsin-catalyzed synthesis of the dipeptide derivative X-Phe-Leu-NH(2) was studied. Groups such as For, Ac, Boc, and Z always rendered good peptide yields (82% to 85%) at low reaction(More)
Seven Gram-negative bacterial strains, capable of using lupanine, the predominant quinolizidine alkaloid in white lupin, as sole carbon and energy source, were isolated from soil in whichLupinus albus andL. luteus had been grown. A metabolic profile system (BIOLOG) identified only three of the seven isolates, two asXanthomonas oryzae pvoryzae E and one(More)