Effects Of Transglutaminase On Quality Of Cheddar Cheeses With Replacing Part Of Fat By Pectin Gel

In this manuscript, full-fat Cheddar cheeses and low-fat Cheddar cheeses withdifferent content of TGase and part fat replaced by pectin gel were the research object,the flavor compounds and mechanical properties were the main research target. Effectsof different contents of PFM and TGase on key flavor compounds evolution in Cheddarcheese during the fermentation process were discussed. Flavor model in differentmature period combined with electronic nose and electronic tongue was established.Through the tracking investigation of flavor compounds and their precursors at differentmature period, key flavor formation mechanism of partly defatted cheese wasspeculated. To explore the mechanism of the effects of transglutaminase on quality ofCheddar cheeses with replacing part of fat by pectin gel, with the texture properties,rheological properties, moisture distribution, protein hydrolysate, lipolysis and pHchanges during the fermentation of Cheddar Cheese were studied. The main resultswere as follows:The physicochemical results indicated that transglutaminase treatment significantlyimproved the cheese protein level and cheese yield; PFM treatment improved the cheesemoisture content; PFM had no significant effects on protein content and fat content.The FAA and FFA changes of cheese in storage period were tracked, researchesshowed that high concentrations of TGase could promote proteolysis; TGase increasedthe Asp, Thr, Glu, Gly, and Cys; PFM and TGase improved the contents of long chainpolyunsaturated fatty acid, such as C18:2.Mechanical properties, LF-NMR and microstructure showed that addition of TGaseimproved the Elasticity Index and Macroscopic Viscosity Index with the extension ofcurd time. TGase improved elastic modulus of cheese; PFM and TGase improved thehardness, springiness, adhesiveness and chewiness. LF-NMR showed that TGaseincreased the proportion of bound water; PFM increased the fluidity of bound water.PFM and TGase could improve the uniformity and compactness of low fat cheesestructure which were observed by SEM.When PFM and TGase were added to cheese, higher levels of alcohols, acids andmethyl ketones volatile compounds were obtained than from control cheese. Theelectronic nose, electronic tongue and organoleptic investigation indicated that the PFMand TGase improved the flavor defects of low-fat cheese. The Cheddar cheese wasadded20%PFM and15u/L TGase can better meet the flavor requirements.