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 NDM and whey protein concentrate (reconstituted to 11% solids). Batch (69°C for 30 min) and HTST (80°C for 25 s) heat treatments were also studied. Milk reactivity was demonstrated in batch-heated solutions as follows. The apparent viscosities of carrageenan-NDM and carrageenan-whey protein concentrate solutions were higher than those of carrageenan-water solutions et all three gum concentrations. Guar at .1% was more viscous in whey protein concentrate than in water. For HTST, carrageenan exhibited milk reactivity with NDM and whey protein concentrate at .1 and 2%. Guar exhibited milk reactivity with NDM at .2% and with whey protein concentrate at all three gum concentrations. Xanthan exhibited milk reactivity with whey protein concentrate at .05%.