Acid coagulation behavior of homogenized milk: effect of interacting and non-interacting droplets observed by rheology and diffusing wave spectroscopy

Abstract

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. Abstract This study analyzes the early stages of the acid coagulation behavior of milk containing homogenized fat globules. By addition of Tween 20 to homogenized milk, it was possible to create two similar colloidal systems with completely different interfacial properties. Control experiments using skim milk demonstrated that the presence of Tween did not overly affect the acid coagulation behavior of the casein micelles. The initial stages of aggregation were also similar for the two homogenized milk systems, indicating that the casein micelles were the main driving force behind early gel formation. For the case of homogenized milk without Tween, the fat globules were fully incorporated in the network. The stiffness of the gel was higher than the control and the overall spatial distribution of the fat droplets was not largely affected by the developing gel matrix. In contrast, the homogenized milk with added surfactant contained fat globules which did not interact directly with the casein micelles but rather became trapped inside the pores of the ensuing network. This gel showed a lower elastic modulus than the homogenized milk case and freediffusing fat globules. Although the presence of interacting and non-interacting droplets did not overly affect the coagulation kinetics of the casein micelles, the acid gels did show different final properties which fully reflected the presence of "active" or "inert" fillers. The knowledge derived from this work will be the first step towards developing novel textures for dairy gels, modulating the extent of the interactions between the fat globules and the protein network.

Combination effect of sodium carboxymethyl cellulose and soybean soluble polysaccharides on stability of acidified skimmed milk drinks

“…2a, ASMDs showed a higher viscosity (3.73±0.17 mPa.s) on the sample with SSPS concentration of 2 g.L −1 . This abnormal increase is related to the small aggregation of casein micelles within the sample as this concentration was not enough to fully adsorb on casein micelles (Tuinier et al 2002;Ion Titapiccolo et al 2011). The viscosity of the samples stabilized by SSPS showed no significant increase (P<0.05) in all treatments contrary to the viscosity of the samples stabilized with CMC where the viscosity increased with increased concentration of CMC in the system.…”

The surface properties of milk fat globules govern their interactions with the caseins: Role of homogenization and pH probed by AFM force spectroscopy

“…Moreover, the yield stress of the homogenized milk gels was higher than that of the native milk gel (2.70 ± 0.04 versus 0.5 ± 0.2 Pa, respectively; not shown). Therefore, homogenized milks formed stiffer acid gels compared to native milks [36,37].…”

Effect of 2 types of resistant starches on the quality of yogurt

“…Casein gel, the main constituent of yogurt structure, is dynamic by nature, and excessive rearrangements of particles making up the gel network before and during gelation are responsible for the fermentation process (Titapiccolo et al, 2011). In this study, the evolution of parameters EI, MVI, and SLB by multispeckle diffusing wave spectroscopy was used to monitor the gelation process of yogurt with or without addition of different RS and sucrose.…”