Effects of milk protein-fat substitution on structure, texture and storage properties of model cake system.

摘要

Milk proteins are used commercially as fat replacers or as an ingredient of fat replacer systems in the food industry. This makes it important to understand their basic functionality in model food systems in order to utilize milk proteins efficiently as fat replacers.; In this study, whey protein isolate and {dollar}beta{dollar}-casein were used as fat-substitutes in model cake system. These samples are compared to regular and no-protein, no-fat substituted samples as controls. Milk proteins were substituted in batter at two levels as 100% and 50% of the fat 100% substitution was at two different protein concentrations. Denatured protein samples were also used to substitute for fat. Differential scanning calorimetry (DSC), texture analyzer (TA), dynamic mechanical thermal analyzer (DMTA) and dynamic differential scanning calorimetry (DDSC) were used to investigate long term storage effects (staling), toughness and structural relaxations of the model cake formulations with fat-substitution. Overall quality characteristics like air incorporation to the batter and volume expansion were also observed.; DSC analysis of batter samples after mixing were done. After DSC scanning, the same samples were stored for 7 and 30 days in DSC pans and amylopectin recrystallization was observed. Texture measurements by TA were done at day 1 and 3 of storage for the cake samples. Structural relaxations of the cake samples equilibrated at 0. 11 to 0.76 A{dollar}sb{lcub}rm W{rcub}{dollar} were also determined by using DMTA and DDSC. WPI but not {dollar}beta{dollar}-casein fat-substitution decreased amylopectin recrystallization compared to regular cakes. The extent of amylopectin recrystallization changed with formulation. Control and the 50% WPI and {dollar}beta{dollar}-casein substituted cakes were softer than the other cakes. Structural relaxations as observed with DMTA indicated that the glass transition curve for regular cake samples was higher than the rest of the control and WPI substituted cakes. The state diagrams obtained based on DMTA and DDSC analysis indicated differences for the same cake formulations stored for 7 and 30 days.; Results indicated that use of milk proteins as fat replacers change component interactions which leads to textural and structural differences. Milk protein-fat substitution improves the textural and storage quality of low fat cakes.