Use of exopolysaccharide-producing cultures to improve the functionality of low fat cheese

Lactic acid bacteria may produce exopolysaccharide (EPS) that is tightly associated with the bacterial cell wall (capsular EPS) or liberated into the growth medium (ropy EPS). Because EPS have viscosity enhancing and stabilizing properties. exopolysaccharide-producing (EPS+) starter cultures are commonly used to enhance water binding and viscosity in yogurt and fermented milks. Previous work has shown that low fat Mozzarella cheese manufactured with an EPS(+)starter pair, Streptococcus thermophilus MR-1C and Lactobacillus delbrueckii subsp. bulgaricus MR-1R, contained significantly more moisture and had better melt properties than cheese made with a control starter pair. Genetic studies demonstrated that this effect was due to the MR-1C capsular EPS, and industrial cheese trials confirmed that MR-1C can effect a 1.5% moisture increase in part-skim Mozzarella. Because EPS accumulation in cheese whey may retard whey protein concentration and drying efficiency, the effect of capsular and ropy S. thermophilus starter bacteria on Mozzarella cheese and whey was also compared. Moisture and melt properties were improved in cheeses made with either EPS+ S. thermophilus, but 5 x concentrated whey from the ropy S. thermophilus was significantly more viscous than concentrated wheys from capsule-producing or non-EPS-producing S, thermophilus. These data indicate that encapsulated. but not ropy, EPS+ S. thermophilus can be used to increase moisture content and improve melt in Mozzarella cheese, without deleteriously affecting whey viscosity. (C) 2001 Elsevier Science Ltd. All rights reserved.