Effect of Lactobacillus spp. strains on the microbiological, biochemical, and organoleptic properties of Moroccan goat’s cheese during ripening

Abstract

The aim of the present work was to investigate the effect of adding autochthonous lactic acid bacteria strains (LAB) to Moroccan goat’s milk cheese, focusing on its microbiological and biochemical evolution during the ripening process, as well as on the product’s sensorial properties. We prepared three types of cheese: (i) a control cheese (CNT) made by adding a starter culture composed of a strain of Lactococcus lactis subsp. lactis var. diacetylactis and a strain of Lactobacillus lactis subsp. lactis; (ii) a cheese (“LP”) made with the same lactococcal starter culture, and adding a strain of Lactobacillus plantarum as an adjunct culture, and (iii) a cheese (“LPC”) made with the same lactococcal starter culture, and adding Lactobacillus paracasei as an adjunct culture. The counts of most bacterial groups decreased as the cheeses matured, except for lactic acid bacteria, which increased during ripening. Throughout the ripening period, LP cheese showed the highest values for total nitrogen, soluble nitrogen, and soluble nitrogen in 12% TCA. On the 60th day of ripening, the highest contents of diacetyl and acetoin were recorded in LPC cheese. A significant difference in FFA was observed among the LP, LPC, and CNT cheeses, thus indicating a change in lipolysis extension (C4:0-C18:3 FFA) that might be influenced by the starter employed. These suggested that both adjunct strains could produce high-quality Moroccan goat cheese. However, the addition of Lactobacillus paracasei culture had the particular advantage of improving aroma intensity and overall cheese quality. Moreover, the lipolysis process increased continually until the end of the ripening period, thereby confirming that the ripening phase is the main factor that affects these cheeses’ sensory properties. The cheeses made with adjunct cultures had the typical taste of Moroccan goat cheese, presented an acceptable flavour, and fulfilled the usual sensory requirements.