Effects of the Autochthonous Probiotic Bacteria Lactobacillus plantarum B and Lactococcus lactis Subsp. lactis S1 on the Proteolysis of Croatian Cheese Ripened in a Lambskin Sack (Sir iz Mišine)

Abstract

This study aims to determine the effects of the autochthonous probiotic bacteria Lactobacillus plantarum B (currently Lactiplantibacillus plantarum) and Lactococcus lactis subsp. lactis S1 on proteolysis during the ripening of Sir iz mišine—a Croatian cheese which ripens in a lambskin sack. Sir iz mišine was produced in four different variants: (1) from raw milk without starter cultures, and from pasteurized milk with added (2) Lactococcus lactis ssp. lactis S1, (3) Lactobacillus plantarum B, or (4) a starter culture consisting of a mixture of Lactococcus lactis ssp. lactis S1 and Lactobacillus plantarum B (1:1). The addition of Lactobacillus plantarum B alone or in combination with Lactococcus lactis subsp. lactis S1 noticeably increased the alpha and beta indices because of the synergistic activity between the enzymes responsible for primary proteolysis and added autochthonous bacteria. Cheese produced from raw milk had the lowest (12.16%) content of WSN%TN. The highest WSN%TN content was found in cheese produced with combined probiotic bacteria (30.40%) and Lactococcus lactis ssp. lactis S1 (29.74%). Cheese with added combined probiotic bacteria had a noticeably higher content of TCA-SN%TN, indicating a synergistic performance among autochthonous probiotic bacteria. In conclusion, autochthonous probiotic bacteria, in addition to having a functional value, can improve the ripening properties of cheese.