Stability of Model Acid Milk Beverage: Effect of Pectin Concentration, Storage Temperature and Milk Heat Treatment

Abstract

Acid milk beverages were made by homogenizing and diluting acid milk gels made with glucono-b-lactone. A central composite experimental design and response suqace methodology were used. Colloidal stability was assessed by the amount of surface whey produced during storage, the flow behaviour and particle size distribution. Using regression analysis a second order polynomial model satisfactorily predicted the @ect of pectin concentration on whey separation (R' = 0.88). Whey separation was significantly decreased by pectin concentration and increased by the quadratic term for pectin concentration (P < 0.001). Neither of the other variables had a significant effect on any of the indices of colloidal stability. The prediction equations for the variables flow behaviour index and particle size distribution had much lower values (I 0.63). It is suggested that pectin prevented the aggregation of casein-gel fragments; evidence for this was also provided by confocal scanning laser micrographs of beverages made with various concentrations of pectin.

Functional properties of citric acid extracted mango peel pectin as related to its chemical structure

“…These observations were confirmed by turbidity measurement of the whey layer which was much higher for AMDs prepared with either pectins than for the control sample, and the turbidity was increased by the increase of pectin concentration. In literature, the turbidity of the whey layer was linked to its quantity, and higher turbidity corresponded to less whey separation (Lucey et al, 1999). The higher observed values for turbidity in case of AMDs with added pectin compared to control sample were probably related both to the soluble pectin present and remaining non sedimented proteins.…”

“…To assist the stabilization of casein particles by pectin (Lucey, Tamehana, Singh, & Munro, 1999), samples were homogenized using a high pressure homogenizer (Stansted Fluid Power, Pressure cell homogenizer, UK) at 20 MPa at 4 C. The samples were subsequently heated to 70 C in a shaking water bath, then re-homogenized at the same pressure, reheated to 70 C and incubated for 10 min. The AMD containing pectin were cooled down to room temperature and used for further analysis.…”

Optimization of Rabadi-like fermented milk beverage using pearl millet

“…While addition of pectin decreased wheying off at higher levels of 0.5 and 0.6% (Table 5). Lucey et al (1999) reported reduction in whey separation with the increase in the concentration of pectin in acid milk beverage.…”

Rheological behaviour and physicochemical properties of kefir with honey

“…Torre et al (2003) reported that viscosity values of set-type fermented milks made with different commercial probiotics were between 15.8 and 23.3 mPa s. Fermented milk beverages were found to be non-Newtonian fluids with shear thinning (Butlert and McNulty 1995;Kristensen et al 1997;Lucey et al Penna et al 2001;Koksoy and Kilic 2003). Consistency index (K) and flow behavior index (n) and correlation coefficients of these constants were shown in Table 3.…”