Effect of egg yolk substitution by sweet whey protein isolate on texture, stability and colour of Gelato-style vanilla ice cream

Gelato samples were made with two levels of egg-yolk (4.5 and 9%). For each level, samples were prepared with and without whey protein isolate (WPI). Texture and melting rates values were significantly (P < 0.05) higher in 9% egg-yolk samples over the storage period than in samples containing 4.5%. Increasing WPI led to a significant increase in hardness at both levels of egg-yolk. Gelato with added WPI in 9% samples had slightly higher whiteness (L) and yellowness (b) values than 4.5% samples. A significant effect of fat content was observed in all physical properties measured. Results suggest that this approach can deliver functionality at a lower cost and can produce a good quality Gelato.