Effect of acetic acid solutions on regenerated fibers from rennet-treated casein micelles

Abstract

Fibers made from rennet casein micelles promise a wide range of new applications in food-grade products. Understanding the influence of environmental conditions such as pH on the water binding and swelling properties is a crucial factor for embedding them in hydrated matrices in the future. The expansion of the fibers in dilute acetic acids always takes place in two steps, as previously observed in citric acid. Model analyses showed that the rates of the swelling steps decreased with increasing acetic acid strength. In contrast, the simulated plateau values of both swelling steps increased. Differences to swelling in citric acid are discussed for the second swelling step on the basis of the pH value of the swelling media, while different calcium affinities are assumed for the first swelling step.