5564 tester

Color of external and internal surfaces of the cheeses of the cheeses was assessed by a Minolta Chroma Meter CR300 (Minolta, Osaka, Japan) using the illuminant C; measurements of lightness (L*, from 0 = black, to 100 = white), redness (a*, from red = +a, to green = −a) and yellowness (b*, from yellow = +b, to blue = −b) were performed according to the CIE L* a* b* system [21 ].
The maximum resistance to compression (compressive stress, N/mm²) of samples (2 cm × 2 cm × 2 cm) kept at room temperature (22 °C) was measured, as index of cheese hardness, with an Instron 5564 tester (Instron, Trezzano sul Naviglio, Milan, Italy).
The freeze-dried cheese samples were analyzed for the content of dry matter (DM), fat, protein (N × 6.38) and ash as reported by Bonanno et al. [22 (link)].
The products of secondary lipid oxidation were determined as thiobarbituric acid-reactive substances (TBARS), expressed as μg malonylaldehyde (MDA)/kg DM, as reported by Bonanno et al. [22 (link)]. Each physicochemical determination was assessed in duplicate.

Cheeses were sampled at 48 h and evaluated for their physical traits. Cheese colour was assessed in duplicate on internal and external surfaces measuring, by a Minolta Chroma Meter CR-300 (Minolta, Osaka, Japan), the values of lightness (L*, from 0 = black to 100 = white), redness (a*, from green = −a to red = +a) and yellowness (b*, from blue = −b to yellow = +b), according to the CIE L*a*b* system [31 ]. Cheeses hardness was evaluated measuring the maximum resistance to compression (compressive stress, N/mm²) of samples (2 × 2 × 2 cm) kept at room temperature (22°C), with an Instron 5564 tester (Instron, Trezzano sul Naviglio, Milano, Italy).

Cheeses after 15 d of refrigerate storage were assessed for external and internal color, measured in duplicate by a Minolta Chroma Meter CR300 (Minolta, Osaka, Japan) using the illuminant C; results are expressed as lightness (L*, from 0 = black, to 100 = white), redness (a*, from red = +a, to green = −a), and yellowness (b*, from yellow = +b, to blue = −b), according to the CIE L* a* b* system. Cheese hardness was evaluated with an Instron 5564 tester (Instron, Trezzano sul Naviglio, Milan, Italy) measuring the maximum resistance to compression (compressive stress, N/mm²) of samples (2 cm × 2 cm × 2 cm) kept at room temperature (22 °C).
Cheese samples were freeze-dried and analyzed using standard methods of the International Dairy Federation for dry matter (DM) (IDF, 4A:1982) [22 ], fat (IDF, 5B:1986) [23 ], protein (N × 6.38) (IDF, 25:1964a) [24 ], and ash (IDF, 27:1964b) [25 ] content. In addition, the products of secondary lipid oxidation were assessed in duplicate on freeze-dried samples by determining the thiobarbituric acid-reactive substances (TBARs), expressed as μg malonylaldehyde (MDA)/kg DM, as described by Bonanno et al. [26 (link)].