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Two white wines produced industrially, originating from the V. vinifera cultivars Asyrtiko and Chardonnay, were monitored with regard to the evolution of selected phenolic acids, during “on lees” ageing in oak casks for a period of 197 days. Four benzoic acid derivatives, namely p-hydroxybenzoic acid, protocatechuic acid, vanillic acid and syringic acid, and their corresponding hydroxycinnamate analogues p-coumaric acid, caffeic acid, ferulic acid and sinapic acid, were considered. The most abundant benzoate and hydroxycinnamate derivatives were protocatechuic acid and caffeic acid, with concentrations varying from 0.31 to 0.42 μg mL−1 and 1.71 to 2.47 μg mL−1, respectively, while the profile of both phenolic categories was essentially the same in both wines. The evolution pattern of benzoates showed that maximum concentration of protocatechuic acid was achieved after approximately 100 days (0.45–0.48 μg mL−1) of ageing for both samples, whereas all other compounds exhibited an increasing trend towards the end of the examination period. The concentration of all hydroxycinnamates increased at the end of ageing, from 49.4% (caffeic acid) to 123% (p-coumaric acid), to the exception of sinapic acid which underwent practically no changes.

Background European legislators and wine producers still debate on the requirement for labeling of wines fined with potentially allergenic food proteins (casein, egg white or fish-derived isinglass). We investigated whether wines fined with known concentrations of these proteins have the potential to provoke clinical allergic reactions in relevant patients. Methods In-house wines were produced for the study, fined with different concentrations of casein (n = 7), egg albumin (n = 1) and isinglass (n = 3). ELISA and PCR kits specific for the respective proteins were used to identify the fining agents. Skin prick tests and basophil activation tests were performed in patients with confirmed IgE-mediated relevant food allergies (n = 24). A wine consumption questionnaire and detailed history on possible reactions to wine was obtained in a multinational cohort of milk, egg or fish allergic patients (n = 53) and patients allergic to irrelevant foods as controls (n = 13). Results Fining agents were not detectable in wines with the available laboratory methods. Nevertheless, positive skin prick test reactions and basophil activation to the relevant wines were observed in the majority of patients with allergy to milk, egg or fish, correlating with the concentration of the fining agent. Among patients consuming wine, reported reactions were few and mild and similar with the ones reported from the control group. Conclusion Casein, isinglass or egg, remaining in traces in wine after fining, present a very low risk for the respective food allergic consumers. Physician and patient awareness campaigns may be more suitable than generalized labeling to address this issue, as the latter may have negative impact on both non-allergic and allergic consumers.