**3. Results**

#### *3.1. Technological Parameters*

The milk-clotting activity could only be assessed visually, as the r value could not be detected (higher than 30 min) either for BM-K or SM-K (Table 1).


**Table 1.** Technological parameters of the cheeses made with kiwi extract or calf rennet.

BMC, buffalo–calf rennet cheese; BMK, buffalo–kiwifruit cheese; SMC, sheep–calf rennet cheese; SMK, sheep–kiwifruit cheese; SEM, standard error medium; S, significance. \*, 0.01 < *P*< 0.05; \*\*, 0.01 < *P* < 0.001; \*\*\*, *P* < 0.001;ns:notsignificant;n.r.,notreactive;ne:not estimable.

The first appearance of solid material after adding the kiwifruit extract was observed after 20–22 min and 15–17 min in buffalo and sheep milk, respectively. These times were significantly higher than the milk with rennet calf (Table 1).

The kind of coagulant was a significant variation factor with respect to whey volume, and to initial cheese yield (Table 1). These differences became smaller after 24 h (rennet cheese weight decreased more than the kiwi extract) but the cheese yield was still significant.

#### *3.2. Physico-Chemical Composition*

The chemical compositions and colour characteristics of the cheeses are reported in Table 2. Dry matter was on average 40% similar to a typical fresh cheese. Buffalo cheeses showed a lower protein, fat and ash content than sheep cheeses.


**Table 2.** Physico-chemical composition of the cheeses made with kiwi extract or calf rennet.

BMC, buffalo–calf rennet cheese; BMK, buffalo–kiwifruit cheese; SMC, sheep–calf rennet cheese; SMK, sheep–kiwifruit cheese; ΔE between cheese from calf rennet—kiwifruit, ΔE\* = ((ΔL\*)2 + (Δa\*)2 + (Δb\*)2)1/2. Values are expressed as the mean ± standard deviation; SEM, standard error medium; S, significance. +, 0.01< *P*< 0.05; ++, 0.01 < *P* < 0.001; +++, *P* < 0.001; ns: not significant.

The kiwi extract produced a cheese with a higher dry matter, both in buffalo and sheep milk (Table 2), except for proteins, which were not affected by the different holding whey capacity.

Iron, magnesium, potassium and calcium were not affected by cheesemaking. The kind of coagulant affected the sodium content of the cheese. Cheeses produced with the kiwifruit extract had the lowest amount of sodium (-34% and -14% in buffalo and sheep cheese, respectively).

The kiwi extract significantly affected the colour of the cheese (Table 2), reducing the lightness both in sheep and buffalo cheese. The use of kiwi also increased the b\* value in buffalo cheese, but not in sheep cheese. Total colour differences (E) were less than 2.
