Texture characteristics and pizza bake properties of low-fat Mozzarella cheese as influenced by pre-acidification with citric acid and use of encapsulated and ropy exopolysaccharide producing cultures

Abstract

Low-fat Mozzarella cheeses containing 6% fat were made by pre-acidification of milk with citric acid to pH 6.1 and using encapsulated ropy or non-ropy exopolysaccharide (EPS) producing Streptococcus thermophilus. Moisture retention, changes in texture profile analysis (TPA), meltability and stretchability of cheese, and changes in colour, surface scorching and shred fusion were analysed after baking over 90 days (d). Control cheeses and those made from pre-acidified milk without EPS cultures had the lowest moisture content at 54.84% and 55.28%, respectively. Control cheeses were hardest and their meltability and stretchability were initially low. Hardness was reduced and the melt and stretch distances increased with time. When baked, control cheeses showed incomplete shred fusion. Pre-acidification reduced hardness and increased meltability. Capsular- and ropy-EPS were quantified at 30.42 and 30.55 mg g-1 of cheese, respectively, and increased moisture retention in pre-acidified cheese to 56.67% and 56.21%, respectively. These cheeses were softer and exhibited lower springiness. Greater meltability was observed initially but became similar to control cheeses after 90 d of storage. When baked after 45 d of storage, cheeses containing EPS producing cultures showed improved shred fusion, meltability and a reduction in surface scorching. © 2006 Elsevier Ltd. All rights reserved.