High hydrostatic pressure modification of whey protein concentrate for improved body and texture of lowfat ice cream.

摘要

Whey protein concentrate (WPC) has many applications in the food industry and application of high hydrostatic pressure (HHP) can enhance viscosity, solubility, and foaming properties of whey proteins. The objective of this study was to use HHP to improve functional properties of WPC, compared with commercial WPC 35 powder, for ice cream applications. Fluid whey was ultrafiltered to make a WPC, and reconstituted to the same total solids 8.23% as reconstituted commercial WPC 35 powder. Solutions of WSU-WPC were treated with 300, 400 MPa (0 and 15 min holding time) and 600 MPa (0 min holding time) pressure. After HHP treatment, the solubility of the WPC was determined at both pH 4.6 and 7.0, using UDY and Bio-Rad protein assay methods. Overrun and foam stability were determined after solutions of WPC were whipped for 15 min. The protein solubility was higher at pH 7.0 than at pH 4.6, but solubility was not significantly altered by HHP. The maintenance of solubility properties after HHP indicates that HHP-treated WPC may be appropriate for applications in ice cream. Untreated fluid WPC had the lowest overrun, while highest overrun was obtained with WPC treated at 300 MPa for 15 min. However, WPC treated at 300 or 400 MPa for 15 min and 600 MPa for 0 min obtained significantly longer-lasting foam stability than commercial WPC 35. HHP treatment was beneficial to enhance foaming properties of WSU-WPC, showing promise for ice cream applications.;Three batches of lowfat ice cream mix were made to contain: WSU-WPC without HHP (A), WSU-WPC with HHP at 300 MPa for 15 min (B), and WPC 35 without HHP (C). All lowfat ice cream mixes contained 10% WSU-WPC or WPC 35. Overrun and foam stability of mixes were determined after whipping for 15 min. Ice creams were made using standard ice cream ingredients and processing. The hardness of ice creams was determined with a TA-XT2 texture analyzer. Sensory evaluation by balanced reference duo-trio tests was carried out with fifty-two volunteers. The mix with HHP-treated WSU-WPC exhibited greatest overrun and foam stability (p 0.05), confirming the effect of HHP on foaming properties in ice cream mix. Ice cream with HHP-treated WSU-WPC was significantly harder (p 0.05) than ice cream with untreated WSU-WPC or WPC 35. Panelists were only able to distinguish between ice cream with HHP-treated WSU-WPC and ice cream with untreated WPC 35. These results show that HHP alters WPC foaming properties significantly enough for differences to be noted in a final product even when the modified ingredient is used at levels as low as 10% in a formulation of ice cream. The impact of HHP on instrumental experiments was more pronounced than impact on sensory evaluations.