Cheddar whey processing and source: I. Effect on composition and functional properties of whey protein concentrates

Cheddar whey (RW), from either a Jersey (J) or a mixed herd (M), was used to observe the effect of source (WSr) on the composition and functionality of whey products. To observe the effect of whey processing, J- and M-RW were dehydrated by four processes (WPr): (i) UF and vacuum-evaporation (VE) followed by lactose crystallization (C) and spray-drying (SD); (ii) VE followed by C and SD; (iii) UF and VE followed by SD without C and (iv) UF followed by SD without C. Moisture, crude fat, ash, calcium and crude protein were analysed. The emulsifying activity index (EAI), emulsion stability (ES), thermostability, oil-holding capacity and solubility (SO) were determined. Both WPr and WSr affected these properties of whey and whey protein concentrate (WPC). Mean EAIs of J- and M-RW were similar but significantly increased by UFVECSD and UFVESD treatment, respectively, to 171 and 174 m(2) g(-1) for J, and to 107 and 143 m(2) g(-1) for M. The ES of RW and pasteurized whey was significantly different based on WSr. Jersey whey showed better SO than M whey. Thermostability of WPCs was significantly increased when VE was a component of WPr. The J-whey apparently had higher ash content, although this was decreased by UF treatment, calcium content was significantly increased. Moisture content of WPC was also WPr dependent, being more than twice higher for UF-treated WPC compared to VE-treated WPC. Though both parameters influenced powder functionality, WPr appeared to have a dominant affect in terms of SO and TS, and appeared crucial for EAI and ES.