Cheddar whey processing and source: II. Effect on non-fat ice cream and yoghurt

Cheddar whey obtained from milk from either a Jersey (J) or a mixed (M) herd was used to observe the effect of whey source (WSr) and whey processing (WPr) on dairy product quality. These were (i) ultrafiltered, vacuum-evaporated and spray-dried after lactose crystallization (UFVECSD) and (ii) vacuum-evaporated and spray-dried after lactose crystallization (VECSD). These were used to replace non-fat dry milk (NDM) in vanilla-flavoured non-fat yoghurt and non-fat ice cream at 20, 60, 80 and 90% (w/w solids). Physicochemical and sensory properties of products were assessed on days 1, 15 and 30. In yoghurt, regardless of WSr, pH and titrable acidity were similar in treatments compared to control. All whey protein concentrates (WPCs) decreased apparent viscosity and syneresis. Conversely, penetration increased with increased WPC usage. All, except 20% VECSD, detrimentally affected texture. Syneresis was improved by both WSr and WPr but was better improved by WPr; UFVECSD was the best with regard to syneresis reduction. Yoghurt flavour appeared WSr dependent with J-WPCs improving it most. On the contrary, texture appeared WPr dependent with all VECSDs markedly improving this parameter. In non-fat ice cream, all WPCs decreased mix pH and increased centrifugal drainage. Jersey VECSD decreased apparent viscosity at >60% usage. Both UFVECSDs at 60% usage level improved melting resistance. Body and texture were improved by all VECSDs showing significant influence of WPr. Data indicated that both WSr and WPr impacted different attributes of dairy product quality.