Sourdough is the result of a fermentation process involving mainly LAB and yeasts. The present microbiota increase acidification, leavening and flavour. Moreover, consumers demand for more nutritious, healthy and clean-label products, has increased the use of sourdough in bread-making. Generally, LAB rapidly acidify the sourdough medium due to organic acids production (lactic and acetic acid, mostly). Nevertheless, different process parameters may influence sourdough microbiota, inducing changes in both sourdough and the resulting bread. Finally, sourdough fermentation involving probiotics can provide extra health benefits to its consumers. Also, long fermentations can reduce FODMAPs and phytate content, besides lowering the glycemic index.

Food safety can be compromised by some bioactive compounds such as biogenic amines that can be specially found in fermented foods due to the bacterial decarboxylation of some amino acids by fermentative or spoilage bacteria. Cava lees are a winery by-product rich in fiber and phenolic compounds and previous works have raised their revalorization from a food safety point of view. The aim of the current work was to investigate whether the use of cava lees can help to control biogenic amine formation in bread and fermented sausages. In bread, only very low levels of biogenic amines (putrescine, cadaverine, and/or spermidine) were found, whose content did not vary with the addition of different amounts of lees. However, the addition of lees in fermented sausages significantly reduced the formation of tyramine and cadaverine. In sausages spontaneously fermented and inoculated with Salmonella spp., the presence of cadaverine and putrescine diminished by 62 and 78%, respectively, due to the addition of cava lees. The addition of cava lees phenolic extract also showed an anti-aminogenic effect (21% for cadaverine and 40% for putrescine), although in a lesser extent than cava lees. Cava lees and their phenolic extract were shown to be an effective strategy to control the undesirable accumulation of high levels of biogenic amines during the production of fermented products.

Interest in some non-Saccharomyces yeasts has increased recently, because they have been associated with an improvement in wine quality. Nevertheless, little attention has been paid to the effect that the use of these yeasts may have on malolactic fermentation (MLF). In this study, the strains Torulaspora delbrueckii Biodiva and Metschnikowia pulcherrima Flavia were evaluated by co-inoculation and sequential fermentation with S. cerevisiae QA23. A fermentation with S. cerevisiae as a single starter was also performed as a control, then MLF was performed inoculating Oenococcus oeni PSU-1 in all wines. Finally, the wines obtained after alcoholic fermentation and MLF were characterised. The results of the coinoculated fermentations were similar to those of the S. cerevisiae control fermentations. Nevertheless, significant differences were observed in sequential fermentations in terms of lower content of acetic, L-malic and succinic acids. These differences were particularly noticeable in fermentations carried out with T. delbrueckii.

Wine lees are a by-product that represents a 25% of the total winery waste. Although lees are rich in antioxidant compounds and dietary fiber, they have no added value and are considered a residue. The aim of this study was to evaluate the effect of Cava lees (0 and 5% w/w) on microbial populations during sourdough and bread fermentation and the volatile fraction of the final bread. The results showed that 5% Cava lees promoted the growth of both lactic acid bacteria (LAB) and yeast in short fermentations (bread) but did not improve microbial growth in long fermentations (sourdough). Regarding volatile compounds, the addition of Cava lees increased the concentration of volatiles typically found in those products. Also, some compounds reported in sparkling wines were also identified in samples with Cava lees adsorbed on their surface. To sum up, the addition of Cava lees to sourdough and, especially, bread formulation may be a new strategy to revalorize such by-product.

Cava lees are a sparkling wine by-product formed of dead microorganisms, tartaric acid and other inorganic compounds, with a potential for enhancing microbial growth. Lees are rich in antioxidant compounds as well as β-glucans and mannoproteins. The aim of this study was to evaluate the effect of different concentrations of cava lees (0–2% w/w) on the microbiota (LAB and yeasts) responsible for sourdough fermentation (8 days) to revalorize this by-product of the wine industry. The results showed that 2% cava lees promoted microbial growth and survival in both wheat and rye sourdoughs, except for yeast growth in rye, which stopped at day 3 of fermentation. Moreover, sourdough with lees achieved lower pH values as well as higher concentrations of organic acids, especially lactic and acetic acids (p < 0.05). To sum up, the use of cava lees in sourdough formulation promotes the growth and survival of microorganisms, which, in consequence, promotes a lower pH and greater amounts of organic acids. This could lead to microbial stability as well as changes in bread flavor.

Cava is a sparkling wine produced using a traditional method that must be aged in contact with lees for a minimum period of nine months. The contact between wine and lees improves the quality of the final product, and aroma is one of the most important qualitative parameters of a wine. The aim of the work was to study the role of lees in the ageing of Spanish sparkling wine (Cava), by sampling at industrial scale the bottles, from 9 to 30 months of ageing, jointly with the winery and in real time. The volatile profile of Cava during biological ageing and commercial storage, after disgorging, was evaluated by Headspace-Solid Phase Microextraction coupled to gas chromatography–mass spectrometry. More than 60 compounds were identified from several chemical classes including esters, alcohols, terpenes, furans, norisoprenoids, and fatty acids. A reduction in volatile components was observed when the disgorging step took place. When the behaviour of aroma over time was assessed, the principal factor that discriminated between samples was the type of ageing i.e. with or without lees. Evaluation of volatiles over time revealed that furans showed a significant relationship with ageing, indicating that some components of this family could be possible markers of ageing.