Effect of water content and sugars on the glass transition of casein and sodium caseinate

Abstract

Summary The glass transitions of casein and sodium caseinate were studied as a function of water content, using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), a mechanical three point bend test, solid state 13 C nuclear magnetic resonance (NMR) spectroscopy and X‐ray diffraction. Glucose and lactose at 10% mass ratio of anhydrous casein had no effect on the glass transition of casein as a function of water content, although at 50% mass ratio there was some increase in glass transition temperature (Tg), i.e. an anti‐plasticizing effect, with glucose. In contrast, with 50% fructose in sodium caseinate, there was some plasticizing effect. These results are compared with previous results for amylopectin and glutensugar mixtures.