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Protein haze formation in white wines during storage is considered the most important instability phenomenon of non-microbial origin. The use of proteolytic enzymes, covalently immobilized on solid supports, has recently proved to be a promising approach for reducing the haze potential of white wines. In this study, supports based on chitosan and nanoclays were produced by solvent casting technique, and investigated for use as a covalently linked bromelain carrier in wine-like medium. Various kinds of nanoclays were tested, including montmorillonite, sepiolite and bentonite, in different amounts (1–5% w/w with respect to chitosan). More specifically, unmodified and organically modified clays and an activated bentonite authorized for contact with food (i.e. OPTIGEL CK) were considered, and their effect on the final microstructural, thermal and mechanical properties of the obtained composite systems was investigated, on the basis of their different chemical composition, morphology, hydrophilicity/hydrophobicity and surface charge, resulting in different interactions with the polymeric matrix and a different enzyme loading. The nanocomposite films were used as innovative supports for the covalent immobilization of pineapple stem bromelain, selected as reference enzyme, and the kinetic parameters of the immobilized bromelain were analyzed. [ABSTRACT FROM AUTHOR]

BACKGROUND Aceto Balsamico Tradizionale ( ABT) is a typical Italian vinegar available in two different forms: Aceto Balsamico Tradizionale di Modena DOP ( ABTM) and Aceto Balsamico Tradizionale di Reggio Emilia DOP ( ABTRE). ABT is obtained by alcoholic fermentation and acetic bio-oxidation of cooked grape must and aged at least 12 years in wooden casks and is known and sold around the world. Despite this widespread recognition, data on sensory characteristics of these products are very scarce. Therefore a descriptive analysis was conducted to define a lexicon for the ABT sensory profile and to create a simple, stable and reproducible synthetic ABT for training panellists. RESULTS A lexicon of 20 sensory parameters was defined and validated and a synthetic ABT was prepared as standard reference. Simple standards for panellist training were also defined and the sensory profiles of ABTM and ABTRE were obtained. CONCLUSION The obtained results confirm that descriptive analysis can be used for the sensory characterisation of ABT and that the sensory profiles of ABTM and ABTRE are very different. Furthermore, the results demonstrate that a lexicon and proper standard references are essential for describing the sensory qualities of ABT both for technical purposes and to protect the product from commercial fraud. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]