Microstructural transformations in anisotropy and melt-stretch properties of low moisture part skim mozzarella cheese

Abstract

Mozzarella cheese is primarily consumed in its melted form due to its desirable melt and stretch characteristics when heated. Understanding the relationship between the anisotropic structure and melt-stretch properties is critical for controlling functionality. A novel ex situ sample extraction system was developed to produce melted and stretched mozzarella. New structure analytics were established to reveal transient changes during deformation of mozzarella under dynamic heat-shear conditions. Transformations in anisotropy were examined using various microscopy techniques coupled with image analysis. Coalescence of milk fat aggregates into large droplets upon heating caused loss of anisotropy. However, fat droplets broke down into channels on stretching, comprising agglomerates of smaller droplets, and anisotropy was regained. When stretched further, adhesion between agglomerated fat droplets was broken by forces exerted from the contracted protein fibres. Large fat droplets are necessary as they act as shock absorbers that enable protein fibres to become pliable, allowing greater stretch.