Introduction: Ultrafiltered (UF) Iranian white cheese has the highest per capita consumptionin Iran. Optimizing the formulation of transglutaminase -treated ultrafiltered milk makes itpossible to develop a low-fat UF cheese with desired textural and sensory properties.However, persistence of active transglutaminase in cross-linking the cheese proteins duringstorage may adversely affect the product quality before it reaches the consumer. Thus, thepresent study aimed to monitor the changes in rheological and sensory properties oftransglutaminase –treated low-fat UF cheese during shelf-life.Materials and Methods: A control full-fat (16% fat), a control low-fat (5.95% fat) and anenzyme-treated low-fat (5.95% fat, 0.56 U transglutaminase/g protein, 8.79% retentatereplacement with whey protein concentrate) ultrafiltered cheese were produced and theirphysicochemical, rheological and sensory properties were studied after 3, 20, 40 and 60 daysResults: Throughout the storage period, the lowest hardness parameters (fracture stress andYoung’s, storage and lost moduli) belonged to the control full-fat sample, followed by theenzyme-treated and the control low-fat cheese samples. Hardness indices increasedcontinuously during storage for all the samples among which the enzyme-treated cheeseshowed the highest rate of firming. This in turn led to significant difference (P<0.05) betweenthe control full-fat and the enzyme-treated low-fat cheese samples after 40 days of storage interms of hardness parameters. Increased texture hardness during storage was accompanied bysignificant reduction (P<0.05) in consumer acceptance of enzyme-treated low-fat cheese but itwas still significantly more appreciated by consumers than the control low-fat sample.Conclusion: Transglutaminase treatment of ultrafiltered milk results increase in hardness andthus decrease in texture desirability of the resultant low-fat cheese during storage.
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