The Effect of Added Lipase Enzyme on Lipolysis Development and Microbiological Characteristics of Traditional (White brined) Cheese & Ultra Filtered Feta Cheese

Subject Areas : Microbiology

صدیقه Yazdanpanah ¹ , محمد رضا Ehsani ² , مریم Mizani ³

1 - دانشجوی دکتری دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، گروه علوم و صنایع غذایی، تهران، ایران
2 - استاد دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، گروه علوم و صنایع غذایی، تهران، ایران
3 - دانشیار دانشگاه آزاد اسلامی، واحد علوم و تحقیقات تهران، گروه علوم و صنایع غذایی، تهران، ایران

Received: 2013-10-28 Accepted : 2015-03-06 Published : 2014-09-23

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Abstract :

Introduction: Lipolysis during cheese ripening is one of the main biochemical reactions. In pasteurization natural lipase present in milk becomes inactive. Therefore lipolysis occurs in Iranian cheeses at low level. The aim of this study is to accelerate the ripening of traditional and ultra-filtered Feta cheeses by lipolysis and evaluate the effect on the microbiological characteristics of the cheeses. Materials and Methods: Aspergillus niger encapsulated lipase was prepared according to Sol-Gel method. For producing cheeses after milk fat standardization where the pasteurization was carried out at 75 °C for 15 s, the milk was cooled and the starter, rennet  and lipase were added in three forms of encapsulated, encapsulated with arabic gum and non- encapsulated to the traditional and UF-Feta cheeses. The amount of added lipase to curd or retentate was 4 g/100kg. The lipolysis development and evaluations of chemical, microbial and sensory characteristics were performed during the 60 days of ripening. Results: On the 15th day of ripening period the lipolysis development and chemical compounds observed had significant differences at the P< 0.05 between the traditional and UF- Feta cheeses. The microbial counts were negative after 15 th day.Encapsulated lipase treatment of UF-Feta cheeses had the highest sensory score. Conclusion: Accelerated lipolysis in cheese might be regarded as a ripening indicator.  Production of free fatty acid and hygroscopic additive like arabic gum had prevention effect on microbial counts in the final product and improved the sensory properties.