Application of preheated whey protein polymers in low fat beef frankfurters

Functionality (water binding ability) of preheated whey protein isolate (WPI) in comminuted meat products was determined in this research project. The impact of adding preheated WPI on comminuted meat product attributes (textural properties and sensory attributes) was also investigated. The overall goal of this project was to investigate the applicability of preheated WPI in comminuted meat products. To achieve this goal, three separate studies were conducted.; Study I utilized response surface methodology in a beta-lactoglobulin (LG) model system to determine the effect of heat denatured LG aggregate (HDLG) size on rheological properties and microstructure of LG gels. Response surface graphs predicted that LG gels with high gel hardness and low gel point could be produced by preheating LG solution at 90°C, 40 min, pH 7.0. While larger HDLG aggregates produced LG gel with higher gel hardness, HDLG aggregates size did not affect microstructure of LG gels.; Study II focused on further investigating the effects of various preheating conditions on WPI in comminuted meat products and its effects on the functional properties of high added water, fat and standard meat emulsions. Three preheating conditions were chosen: 95°C, 10 min, 95°C, 40 min, and 85°C, 80 min, and WPI was preheated at 8%, pH 7.0. Emulsion stability of high added fat, water emulsions prepared with the three preheated WPIs was higher than those prepared with unheated WPI (p < 0.05). Increasing WPI amount from 3.5 to 7.0% also increased emulsion stability of high added fat and high added water emulsions (p < 0.05). Among the three preheated WPIs, emulsions prepared with WPI preheated at 95°C for 40 min had the best emulsion stability in both high added fat and high added water emulsions (p < 0.05). While all beef meat emulsions were able to bind fat better, preheated WPI was a better water binder.; Study III verified the efficacy of preheated WPI in comminuted meat products. Whey protein isolate was preheated at 8% (w/w), 95°C, 40 min, pH 7.0. Low fat (4%) beef frankfurters were manufactured with 35, 40 and 45% water, and preheated WPI was added at 3.5 and 7.0% level. At 40% added water level and 7.0% added WPI level, beef frankfurters prepared with preheated WPI had higher cooking yields with lower expressible moisture than those prepared with unheated WPI (p < 0.05). Not only were cooking yields improved, but the textural properties of beef frankfurters prepared with preheated WPI had higher hardness, gumminess and chewiness values than those prepared with unheated WPI (p < 0.05). During 56 days of refrigerated storage, beef frankfurters prepared with preheated WPI had less purge loss than those prepared with unheated WPI (p < 0.05). Preheating of WPI was proven to be an effective method to improve functionality of WPI in comminuted meat products.