Thesis (M.Sc)-Cairo University, 2025.

Bibliography: pages 125-151.

This study was designed to produce Cheddar cheese rich in bioactive peptides
(BAPs) and γ-aminobutyric acid (GABA). Firstly, the most important types of ripened
cheese were collected from the local market and include very hard types (parmesan),
hard types (Cheddar-Emmental-Ras), semi-hard types (Gouda-Edam-Kashkaval-
Roquefort) and soft types (Camembert) to determine their content of BAPs and
GABA. Cheddar cheese showed a low content of BAPs where it was one of the lowest
in proteolytic activity and its content of angiotensin converting enzyme (ACE)
inhibitory peptides. Also, it did not appear to have any anticancer and antimicrobial
activity. Consequently, Cheddar cheese was selected to improve its content of BAPs
where it is one of the most produced and consumed types of ripened cheeses all over
the world. In addition, ten classical and adjunct cheese starters were evaluated for
their ability to produce BAPs under cheese ripening conditions where these starters
considered one of the most effective factors for BAPs production particularly at
elevated ripening temperature. The results showed that proteolytic, antioxidant and
ACE-I activity increased during storage period, and the rate of increase was the
highest at 15ºC compared with 10℃. Lb. helveticus (Lh-B02), Lb. acidophilus
probiotic (La-5), Lb. paracasei and Lb. rhamnosus (Fresh Q4), and Lc. lactis subsp.
lactis and Lc. lactis subsp. cremoris (MO-30) cultures had high proteolytic activity
and BAPs production. Consequently, these starters were selected for Cheddar cheese
manufacturing, where MO-30 was used as a classical Cheddar cheese starter for all
treatments, while probiotic La-5, Lh-B02 and Fresh Q4 cultures were used as adjunct
starter cultures. MO-30 culture was used alone as a control (B1), while in batches B2,
B3 and B4 probiotic La-5, Lh-B02 and Fresh Q4 cultures were used, respectively,
whereas in B5, La-5, Lh-B02 and Fresh Q4 were used as co-cultures. As the result of
using adjunct starter cultures with elevated ripening temperature (12℃), all
treatments exhibited the highest levels of BAPs compared to the control (B1). After
120 days of ripening B2, B3, and B5 showed the highest proteolytic, antioxidant,
ACE-I activity, whereas B2, B4, and B5 had a high concentration of GABA. As for
anticancer activity, B2 and B4 had the most pronounced effects, and all treatments
exhibited antimicrobial activity against Proteus vulgaris. Regarding organoleptic
assessment, adjunct cultures improved firmness and decreased crumbliness as well as
declined significantly the bitterness of Cheddar cheese. In general, panelists preferred
cheese made by Lh-B02, Fresh Q4, and co-cultures, respectively.

هدفت هذه الدراسة إلى إنتاج جبن تشيدر غني بالمركبات النشطة حيويا. ولتحقيق ذلك، تم تحليل أنواع مختلفة من الجبن المسواة في السوق المحلي لتحديد محتواها من هذه المركبات، حيث أظهرت النتائج أن جبن التشيدر كان الأقل في محتواه من هذه المركبات. وبناءً على ذلك تم إختياره. أظهرت بادئات Lh-B02 وLa-5 و Fresh Q4 قدرة عالية على إنتاج المركبات الحيوية تحت ظروف التسوية. ولذا تم استخدامها في تصنيع أكثر من معاملة من جبن التشيدر. أظهرت النتائج تفوق المعاملات المحتوية على البادئات المساعدة من حيث النشاط المضاد للأكسدة والمثبط لإنزيم ACE ونمو الميكروبات.

Issues also as CD.

Text in English and abstract in Arabic & English.