Fac-simile Scheda Linee di Ricerca - Federalimentare

Parole chiave- glicosidasi- vino- aroma- resveratrolo- qualità sensoriale e salutisticaDati pubblicati inerenti il tema di ricerca:1. Barbagallo R.N., Spagna G.., Palmeri R., Restuccia C., Giudici P. (2004). Selection, characterizationand comparison of β-glucosidase from mold and yeasts for oenological applications.Enzyme Microb. Technol. 32 , 58-66.A comparison has been made of the main physicochemical and kinetic parameters of the β-glucosidase(βG,EC3.2.1.21) of a commercial preparation from Aspergillus niger chosen for its high activity and that of 463yeast strains, isolated and screened from Sicilian musts and wines. A higher percentage of βG-positive strains(30%) was found on Yeast Carbon Base + lysine compared to 18% on Sabouraud + ethanol + SO 2 and just 8%on Sabouraud medium. The positive strains with the highest βG activity were subsequently identified andcomparedwith the purified commercial preparation. Optimum pH values were found to be 4.5 for A. niger βG, withrelative activity of about 87% at pH 3.5, that is close to that of wine, whilst amongst the yeasts, AL 41 was thestrain with optimum pH closest to that of wine.Optimum temperatures were found to be about 62 and 20–25 ◦C for A. niger and yeast βG, respectively. Withinthe latter temperature range, that is potentially the most suitable for the use of the enzymes in enology, mould βGrelative activity was found to be 40–50%.Enzyme stability in wine model solution (at 20 ◦C) was 12 days for mould activity and at least 35-45 for thatfrom yeasts. Finally, the V max values were ranged from 1.75 to 6.94 Umg -1 of protein for the yeasts, while the K mvalues were 0.61–2.53 mM. The behaviour of βG from A. niger could not be explained by the Michaelis–Mentenequation. The case was ascribable to the typical behaviour of an unproductive bond with substrate concentrationexceeding saturation point and incorrect positioning at the enzyme’s active site. The enzyme from mould wouldbe useful during the final stages of alcoholic fermentation, whilst some yeast strains (AL 112 and AL 41) couldbe directly added during fermentation in order to enhance wine aroma.2. Palmeri R., Spagna G. (2007). β-Glucosidase in cellular and acellular form for winemakingapplication: A minireview. Enzyme Microb. Technol. 40: 3, 382-389.β-Glucosidase (βG, EC 3.2.1.21) is one of the most interesting glycosidases, especially for hydrolysis of glycoconjugatedprecursors, in musts and wines, and the release of active aromatic compounds. We summarize the researchon the use of commercial preparations selected yeasts and malolactic bacteria, as source of glycosidaseactivities, βG in particular. We illustrate our results on a new simple purification process and the physicochemicalcharacteristics of the β-d-glucosidase (βG) from acellular and cellular origin. The βG from a commercial enzymepreparation chosen for its high activity and three yeast strains with the highest βG activity have been selectedand characterized: Y8 (Hanseniaspora uvarum); AL 41 (Saccharomyces cerevisiae); AL 112 (Pichiaanomala). An Oenococcus oeni strains (DSTVR 10) has been chosen among 10, it was isolated from wines ofthe ValpolicellaSISTAL - SOCIETA’ ITALIANA DI SCIENZE E TECNOLOGIE ALIMENTARIDipartimento di Scienze e Tecnologie Agroalimentari, Università degli Studi della TusciaVia San Camillo de Lellis, 01100 ViterboTel.: 0761- 35 74 94/7 , Fax: 0761- 35 74 98, e-mail: mmoresi@unitus.it91