Rheological and physical properties of camel and cow milk gels enriched with phosphate and calcium during acid-induced gelation

Abstract

The rheological properties of acid-induced coagulation of camel and cow milk gels following the addition of calcium chloride (CaCl 2 ) and hydrogen phosphate dehydrate (Na 2 HPO 4 *2H 2 O) were investigated using a dynamic low amplitude oscillatory rheology. For a considered condition, the final values of storage modulus (G 0 ) and loss modulus (G 00 ) of camel milk gels were significantly lower than those of cow milk gels. The increase of the added CaCl 2 levels improved significantly the gelation properties of camel and cow milk gels, since a reduction in the gelation time and an increase in the gel firmness were observed. Following the addition of Na 2 HPO 4 *2H 2 O at 10 and 20 mM, no significant effect on the gelation rate and the firmness of camel milk gels was observed, while, a significant decrease in the gelation rate and firmness were observed for cow milk gels.

Physico-chemical, microstructural and rheological properties of camel-milk yogurt as enhanced by microbial transglutaminase

“…The significant increase in the viscosity when b-lg was added to camel milk, as its ratio in bovine milk, confirmed this assumption. Compared with bovine milk, the remarkable differences of camel-milk casein micelle i.e., the micelle size and the relative distribution of individual caseins especially for b-and j-caseins (Al haj and Al Kanhal 2010; Kamal et al 2017) as well the different behavior of camel-milk casein during acidification (Kherouatou et al 2003) could be other reasons for the pseudo curd from camel milk.…”

“…The fermented camel milk products have a watery consistency and have a fragile and poor structure (Abdel Rahman et al 2009). This behavior is probably more due to the large size of casein micelles (Kamal et al 2017), the relative distribution of casein fractions (Al haj and Al Kanhal 2010) andthe absence of b-lg in camel milk (ElAgamy et al 2009) compared with bovine milk. The small size of camel fat globule might be another cause for the poor structure in fermented camel milk (El-Zeini 2006).Because yogurt texture is an important characteristic that affects its quality and consumer acceptance, many attempts were conducted to solve the problems related to poor texture of fermented camel milk and to produce a settype yogurt from this milk.…”

Rheological and Structural Properties of Camel Milk/Sweet Potato Starch Gel

“…Some obvious characteristics of fermented camel milk products include watery texture and weak and poor structure [5]. is characteristic is due to the large size and distribution of casein micelles and the absence of b-lg casein protein [2,6,7]. Camel milk casein has high beta-casein compared to cow milk (65% versus 39%), low alpha-casein (22% versus 38%), and low kappa-casein (3.5% versus 13%) [8].…”

“…is difference could be attributed to the variation in their physicochemical composition [6,11]. Camel milk composed of 2.2-6.1% fat, 3.2-5.6% lactose, 3.0-3.9 protein, 0.6-1.0 ash, and specific weight between 1.026 and 1.036, whereas cow milk has higher specific gravity [12].…”

“…e storage modulus (G′) and loss modulus (G″) of camel milk gels are significantly lower than those of cow milk gels. Gelation properties of camel milk can be improved by adding CaCl 2 or sodium phosphate as indicated by the higher gel firmness and gelation time [6].…”