Effect of addition of gelatin on the rheological and microstructural properties of acid milk protein gels

Abstract

6To gain an understanding of the gelation mechanism of mixtures of milk proteins and gelatin, 7 rheological and microstructural properties of the mixtures were characterized following four stages. 8During the acidification stage (at 45 °C), the presence of gelatin at sufficient concentration (higher 9 than 1%) led to a lower storage modulus (G′) than that of the pure milk protein gels and a more 10 heterogenous microstructure with larger milk protein clusters was formed. During the cooling (from 11 45 to 10 °C) and annealing stage s (at 10 °C), the G′ of the gels increased because of both milk gel 12 enhancement and gelatin gelation. Higher concentrations of gelatin led to earlier formation of strand-13 like structures, seen in the micrographs. The gelation of gelatin changed the microstructure of whey 14 protein isolate (WPI) gel dramatically, while gels of milk protein concentrate (MPC) and skim milk 15 powder (SMP) maintained the typical milk gel network and gelatin formed strands and films without 16 destroying the existing gels. During the heating stage (from 10 to 45 °C), gelatin strands were melted 17 and the G′ of the mixed gels tended to revert to the value at the end of the acidification stage, 18indicating that the changes caused by gelatin in the microstructure of milk protein gels after 19 acidification are reversible. Additionally, gelatin enhanced the water holding capacity (WHC) of the 20 gels (no serum expulsion was observed for gels containing ≥1% gelatin), without increasing gel 21 firmness significantly. 22

The effect of filler particles on the texture of food gels

“…As an example, several studies have looked at the addition of small amounts of gelatin (e.g., 1%) to milk protein gels. This significantly improves the water-holding capacity of the resulting milk product (e.g., yoghurt), while only inducing small changes in gel firmness, depending on gelatin concentration (Pang et al, 2015;Fiszman et al, 1999). Another example is the addition of galactomannans (such as locust bean gum), which can affect the mechanical properties of gels made from several gelling agents.…”

Development of rheological and sensory properties of combinations of milk proteins and gelling polysaccharides as potential gelatin replacements in the manufacture of stirred acid milk gels and yogurt

“…Among the stabilizers used, gelatin is preferred 28 due to its unique properties (Kumar & Mishra, 2004). As explored in our previous study, gelatin 29 showed gelling and melting properties below body temperature in acid milk gels and it increased 30 the water holding capacity (WHC) of the gels (Pang et al, 2015b). However, finding alternatives to 31 gelatin has gained considerable attention in recent years due to religious beliefs and vegetarian 32 lifestyle choices (Karim & Bhat, 2008).…”

“…Dynamic oscillatory rheology 93 The dynamic oscillatory rheology was carried out on the samples according to the method reported 94 previously (Pang et al, 2015b iii. Microstructure…”

Effects of Hot‐Pressure Extraction Time on Composition and Gelatin Properties of Chicken Bone Extracts

“…Micrographs of gelatins made from chicken bone extracts were performed using an inverted microscope equipped with an Ar/Kr laser (Lecia TCS SL, Heidelberg, Germany). Confocal laser scanning microscopy was conducted according to the slightly‐modified method of Pang and others (). Briefly, rhodamine B (0.1%, w/w) was added to the gelatin solutions in order to dye the proteins (20 μL/mL chicken bone extracts).…”