Non-alcoholic beer (NAB) or low alcoholic beer (LAB) are taking over the market with a growing sale. Sus-tainable recycling and valorization of exhausted brewer’s spent grains (BSG) coming from craft beer is a relevant issue in brewing process. In this work, recycled BSG and BSG+GJ (supplemented with 10% grape juice) were used as wort-substrate to inoculate already selected non-conventional yeasts to produce NABLAB craft beer. Results showed that wort composed by only recycled BSG produced appreciate NAB beers (ethanol from 0.12% to 0.54 % v/v) while the addition of 10% of grape juice made LAB beers (ethanol from 0.82 to 1.66 % v/v). As expected, volatile compounds production was highest with the addition of grape juice. Lachancea thermotolerans confirmed the lactic acid production and, as Saccharomyces cerevisiae, is characterized by (in both worts) ethyl butyrate and isoamyl acetate, while Torulaspora delbrueckii produced relevant amounts of exanol, phenylethyl acetate and β-phenyl ethanol (wort added with grape juice). Wickeramhomyces anomalus and Pichia kluyvery showed consistent volatile production but only in wort with grape juice addition where a fermentation activity was exhibited. The overall results indicated that reused BSGs, non-conventional yeasts and grape juice is a suitable strategy for specialty NABLAB beer.

Fermented food matrices, including beverages, can be defined as the result of the activity of complex microbial ecosystems where different microorganisms interact according to different biotic and abiotic factors. Certainly, in industrial production the technological processes aim to control the fermentation to place safe foods on the market. Therefore, if food safety is the essential prerogative, consumers are increasingly oriented towards a healthy and conscious diet driving the production and consequently the applied research towards natural processes. In this regard, the aim to guarantee safety, quality and diversify of products should be reached limiting or avoiding the addition of antimicrobials or synthetic additives using the biological approach. In this paper, following the recent re-evaluation of non-Saccharomyces yeasts (NSYs) has been re-viewed the bio-protectant and biocontrol activity with a particular focus on their antimicrobial power, probiotic features and promoting functional aspects. In this review, the authors would underline the contribution of NSYs in all food production chain and its role in the technological and fermentative features for their practical and useful use as biocontrol agent in food preparations.

Torulaspora delbrueckii showed renewed interest in recent years in the fermentation of wine, for its biotechnological potential linked to the ability to enhance flavor and aroma and it probably is the non-Saccharomyces yeast currently widely used in winemaking. On the base of this, sequential fermentations with a selected native strain of T. delbrueckii (DiSVA 130) and low sulfite native strain of Saccharomyces cerevisiae (DiSVA 709) were carried out to establish their contribution in biocontrol and aroma profile. A first set trials, carried out in winery, were set up to establish the effect of the sulfur dioxide addition on pure and T. debrueckii/S. cerevisiae sequential fermentations. A second set of sequential fermentations without SO₂ addition were conducted in the same conditions, to evaluate the biocontrol and aromatic effectiveness of the T. delbrueckii native strain and a commercial one. The effective biocontrol action of native T. delbrueckii inoculated in sequential fermentation was shown, indeed without SO₂ addition the presence of native T. delbrueckii revealed an effective fungistatic action in the first two days of fermentation. Moreover, the native T. delbrueckii strain seems to have fermentative performances comparable to those of T. delbrueckii commercial strain showing a more evident biocontrol action (wild yeasts reduced by c.a. 1 Log at 2^nd day) and its presence did not negatively affect S. cerevisiae fermentation activity. Finally, the combination of both native and commercial T. delbrueckii/S. cerevisiae trials led distinctive aromatic profile of wines with a significant enhancement of isoamyl acetate, phenyl ethyl acetate, supported by positive appreciations, from the tasters, for ripe and tropical fruits, citrus and balance. The whole results indicate that the proposed strain could be a potential biocontrol tool toward wild yeasts in the first phase of fermentation also contributing to improve and differentiate the final aroma wine.