A kiwi juice aqueous solution as coagulant of bovine milk and its potential in Mozzarella cheese manufacture

• The kiwi fruit aqueous extract exhibits milk-clotting activity.
• Mozzarella cheese was manufactured using the kiwi extract as plant coagulant.
• No flavor defects were detected in fresh mozzarella cheese made with kiwi extract.
• The extract maintains its properties after storage for 20 days at −20 °C.

In this work a kiwi juice aqueous solution was prepared and used as coagulant enzyme in the manufacturing process of mozzarella cheese. The aqueous solution does exhibit high levels of milk-clotting activity probably due to the presence of the clotting enzyme actinidin in mixture with other kiwi fruit proteolityc enzymes. The mozzarella cheese was manufactured from bovine milk with a yield of 10.6% being in the range of that routinely obtained during cheese manufacture. A preliminary evaluation of the cheeses flavor showed positive results and lack of bitterness. Finally, in view of a future marketing of the kiwi juice aqueous solution as plant coagulant, it is shown that the aqueous solution stored for 20 days at −20 °C maintains both the clotting and proteolytic activities unaffected. Due to its properties as well as to the accessibility of the primary source for the preparation of the aqueous solution, it might represent a good candidate for calf rennet substitution, provided that further research on cheese properties will be carried out.