Abstract: Background.Microbial proteases are the most important enzymes in the industry, accounting for 60% of
total enzyme sales in the world. The proteases of lactic acid bacteria (LAB) have received special attention
because of their importance in the food and dairy industry.
Materials and methods.The crude extract and purified protease enzyme produced from an isolated bacterialstrain identified as Lactobacillus plantarumwere used in the ripening and flavor improvement of softwhite cheese (Domiati-type). The effect of protease enzyme on the chemical and sensory properties of Domiaticheese during the storage period was studied.
Results.The results showed that the pH value, moisture and protein contents of all Domiati cheese treatmentsdecreased by adding protease and increasing the storage period, whereas the soluble nitrogen, tyrosine andtryptophan and fat contents for all cheese treatments increased with protease addition as the storage periodadvanced compared to control. Moreover, most free fatty acids (FFA) contents were similar between thecontrol and protease cheese treatments during the storage period, whereas free amino acid (FAA) content increasedas the storage period for protease cheese treatments was increased. The predominated free fatty acidsin Domiati cheese at the end of the ripening were palmitic acid, followed by oleic acid, stearic and myristicacids. Free amino acids (glutamic acid, proline, leucine, aspartic, lysine, serine and valine) were present inhigher concentrations and represented more than 50% of total amino acids in all Domiati cheese samples atthe end of the ripening period. The results of sensory evaluation indicated that as the ripening period progressed,the flavor characteristics gradually increased, leading to an improvement in the organoleptic propertiescompared with the control. The results showed that at end of the storage period, the cheese treatment (T2)with 2% crude enzyme recorded the highest flavor score.
Publication year 2019
Pages 385–397
Availability location 1644-0730
Availability number 1898-9594
Organization Name
Author(s) from ARC
External authors (outside ARC)
    منال محمد ياسر قسم النبات والميكروبيولوجي- كلية العلوم – جامعة بني سويف
    صفاء صلاح الدين طه 1قسم بحوث الالبان- معهد بحوث تكنولوجيا الاغذية-مركز البحوث الزراعية
Publication Type Journal