Immobilised native plant cysteine proteases: packed-bed reactor for white wine protein stabilisation.

This research presents a feasibility study of using a continuous packed-bed reactor (PBR), containing immobilised native plant cysteine proteases, as a specific and mild alternative technique relative to the usual bentonite fining for white wine protein stabilisation. The operational parameters for a PBR containing immobilised bromelain (PBR-br) or immobilised papain (PBR-pa) were optimised using model wine fortified with synthetic substrate (Bz-Phe-Val-Arg-pNA). The effectiveness of PBR-br, both in terms of hazing potential and total protein decrease, was significantly higher than PBR-pa, in all the seven unfined, white wines used. Among the wines tested, Sauvignon Blanc, given its total protein content as well as its very high intrinsic instability, was selected as a control wine to evaluate the effect of the treatment on wine as to its soluble protein profile, phenolic composition, mineral component, and sensory properties. The treatment in a PBR containing immobilised bromelain appeared effective in decreasing both wine hazing potential and total protein amount, while it did not significantly affect the phenol compounds, the mineral component nor the sensory quality of wine. The enzymatic treatment in PBR was shown to be a specific and mild technique for use as an alternative to bentonite fining for white wine protein stabilisation.

Descriptive sensory analysis of Aceto Balsamico Tradizionale di Modena DOP and Aceto Balsamico Tradizionale di Reggio Emilia DOP.

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.