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In this study, a recombinant Saccharomyces cerevisiae strain EKD13 overproducing mannoproteins has been used to obtain Albariño white wines. The inoculated strain prevailed and produced complete fermentation of the must, as also occurred in the case of spontaneous (non-inoculated) fermentation and in the must inoculated with the S. cerevisiae EC1118 strain. The analytical study of the wines obtained showed that the most important chemical differences among the wines produced with EKD-13, corresponded to the high concentration of mannoproteins, 2-phenyl ethanol and tyrosol. These differences were attributed to the expression, during must fermentation, of genes modified in the recombinant EKD-13 strain. The results obtained imply that this strain could be potentially useful to produce wines rich in mannoproteins that have distinctive characteristics compared to other similar wines, modifying the sensorial and technological parameters of the wines obtained. © 2013 Elsevier Ltd. All rights reserved., This work was funded through Projects Bodega Terras Gauda LTD. Xunta de Galicia (PGIDIT04TAL035E), 2004-7-OE-242, AGL2006-02558, A36108900, ALIBIRD-CM-S-0505/AGR-0153, and CONSOLIDER INGENIO 2010 (CSD2007-00063FUN-C-FOOD).

The influence of some variables on the manufacturing process for sparkling and red wines on the angiotensin I-converting enzyme inhibitory (ACEI) activity has been studied. Ageing on lees significantly influenced the angiotensin I-converting enzyme inhibitor activity in sparkling wines. It reached maximum values at 9 months, decreasing afterwards. In red wines, the ACEI activity also increased in the wines aged on lees. In both wines, hydrophobic peptides were responsible for the ACEI activity. These peptides would make a much greater contribution to the total activity if present in higher proportions. It would therefore be advantageous to increase their concentrations in wines, either by using starting materials with high initial peptide contents or by using a highly autolytic yeast, giving a greater degree of hydrolysis of wine proteins, and higher concentrations of peptides with ACEI activity.

Reaction mixtures containing β-lactoglobulin and chitosan (1:4 weight ratio) were dry-heated at 40 °C and 79% relative humidity for 2 weeks. Absorbance measurements and SDS-PAGE analysis indicated the occurrence of the Maillard reaction and conjugate formation, respectively. Some β-lactoglobulin and chitosan properties were modified. For example, the emulsifying capacity at pH 4 and bactericidal activity against Escherichia coli of the Maillard reaction products (MRPs) increased with incubation period up to 2 days, after which these properties deteriorated. The latter was explained by MRPs degradation, which was confirmed by the increased appearance of degradation products in electrophoresis gels at longer incubation times. Data show that the Maillard reaction, under the studied conditions, can be successfully employed to generate MRPs from β-lactoglobulin and chitosan, which exhibit improved properties with respect to β–lactoglobulin alone.

When producing sparkling wines by the traditional method, a small amount of bentonite is added to the tirage solution to help with the flocculation of the yeast. This work studies the effect of this addition on the nitrogen composition and sensory quality of the sparkling wines. Two batches of sparkling wines were industrially produced, one with addition of bentonite to the tirage solution and the other without bentonite addition. Samples were taken at 20, 40, 90, 180, 270 and 365 days of aging with yeast. Total, free amino-, protein- and peptide-nitrogen concentrations were determined and foam properties and sensory quality were evaluated. It was observed that the bentonite retained part of the peptides and proteins and had an adverse effect on the sensory quality of the wine.