Use of a combined autochthonous starter to ferment Peranzana Alta Daunia table olives

The use of starter cultures for table olives fermentation is highly recommended, since it may reduce spoilage, inhibit the growth of pathogens and help to achieve a controlled process. Despite these benefits, most of the olive varieties are still processed without starter addition. “Peranzana Alta Daunia” is an olive cultivar used to produce an excellent table olive prepared by the Greek style through a spontaneous fermentation in brine without any preliminary treatment. However, spontaneous fermentation is often unpredictable, thus the use of a suitable starter could be an important way to standardize production and provide a correct fermentation course.

The purpose of this study was to evaluate the use of a multiple strain cocktail as starter culture for “Peranzana Alta Daunia” olives; in particular, the effect of the ripening degree (veraison) of drupes (violet or green olives) and of the salt concentration in the brine (6 or 8%) on the acidification kinetic was analysed by using a 2^k Factorial Design. A combined starter cocktail including three autochthonous strains (Lactiplantibacillus plantarum, Candida norvegica and Wickeramomyces anomalus) was used.

The acidification was affected by all the variables tested with the verasoin degree as the most significant one; namely, the pH values decreased with the increase of the fruit ripening underlining that the fruit maturity may exert a strong effect on the fermentation course. In fact, neither the brine salt concentration nor the presence of the starter culture were able to improve the acidification kinetic when unripe fruits were used.