*4.4. Colour*

Colour (L \*, a \*, b \*, and c \*) was evaluated daily for 7 d. Measurements were taken thrice in MAP raw meat with a colorimeter (Minolta ® Konica Minolta Camera, Tokyo, Japan), 8 mm Illuminant C. Standard observer, C: Y = 94.2, x = 0.3130 and y = 0.3190following the methodology of the Commission Internationale l'Eclairage with the CIELAB scale [101].

#### *4.5. Fatty Acids (FA) Profile Analysis*

Fatty acid profile analysis was carried out in the steaks without simulated retail display. Lipid extraction was carried out following Bligh and Dyer [102,103]. FA derivatization was obtained by saponification, methylation, and esterification [104]. FA were analysed by gas chromatography (Claurus 400 Perkin Elmer, Waltham, MA, USA), with a polar column (100 m × 0.25 mm × 0.20 μm; Sigma, Bellfonte, PA, USA). Peak identification was achieved by comparing the retention times of the unknowns with the standard SupelcoTM 37 Component FAME mix (Sigma).

#### *4.6. Analysis of Data*

Variables measured only once (TBARs values, compression values, fatty acid, and concentrations) were analysed with a one-way ANOVA, where diet (5 treatments) was the independent variable. If the treatments were significantly di fferent (*p* < 0.05), means were compared with a Tukey test. The e ffect of diet on colour (L \*, a \*, b\*, an c \*) was analysed with a general linear mixed model, considering the day of the storage as random variable and diet (5 treatments) as a fixed e ffect. All analyses were performed using the 'R' statistical software version 3.6.0 [105].
