Milk Reactivity of Gum and Milk Protein Solutions

Milk reactivity, defined as the ability of a gum to produce significantly higher viscosity in milk than in water, was determined for three gums--carrageenan, guar, and xanthan-at .05, .1, and .2% in both NOM and whey protein concentrate (reconstituted to 11 % solids). Batch (69C for 30 min) and HTST (80C for 25 s) heat treatments were also studied. Milk reactivity was demonstrated in batch-heated solutions as follows. The apparent viscosities of carrageenan-NOM and carrageenan-whey protein concentrate solutions were higher than those of carrageenan-water solutions I;'t all three gum concentrations. Guar at .1 % was more viscous in whey protein concentrate than in water. For HTST, carrageenan exhibited milk reactivity with NOM and whey protein concentrate at .1 and .2%. Guar exhibited milk reactivity with NOM at .2% and with whey protein concentrate at all three gum concentrations. Xanthan exhibited milk reactivity with whey protein concentrate at .05%.