Gc fid 6890n

FAMEs were determined using the method described by [38 (link)]. The equipment used was: GC- FID (6890N, Agilent Technologies, Santa Clara, CA, USA), equipped with a SP2380 capillary column (30 m × 0.25 mm i.d., 0.20 µm film thickness). Helium was used as carrier gas (1 mL/min). The temperature program was: 50 °C (2 min), ramp to 250 °C, 4 °C/min and 1 min maintenance. Injector and detector temperatures were 260 and 280 °C, respectively.

The fat content of the cheese samples was extracted using a mixture of hexane:methanol (2:1 v/v) and methylated, as explained in Yaman et al. (19 (link)). Methylated samples were analyzed through a GC-FID (6890N, Agilent Technologies, Santa Clara, CA, USA). The separation of the fatty acids was achieved in an HP-88 capillary column (100 m × 0.25 mm × 0.2 μm) (Agilent Technologies, Santa Clara, CA, USA). Fatty acids’ identification was verified by comparing the sample peak retention times and percentage with reference standards (Supelco 37 Component FAME Mix, Sigma-Aldrich, St. Louis, MO, USA). The fatty acid concentrations were determined as percent fatty acid. All the reference analyses were performed in duplicate. Short-chain fatty acid content was calculated by adding the content of fatty acids, including Butyric acid, Caproic acid, Caprylic acid, and Capric acid.

A method described by Norazlina et al. [18 (link)] using a gas chromatography-flame ionisation detector (GC-FID 6890N, Agilent, Wilmington, DE, USA) was used to determine the fatty acid composition of the formulated fat samples. First, the fatty acid for the blends was transformed into fatty acid methyl ester (FAMEs) before being injected into the BPX70 column (30 m × 0.25 μm × ID 0.25, SGE, Courtaboeuf, France). Approximately 0.5 g of the melted fat blends was mixed with 2.5 mL of n-hexane and 0.5 mL of methanolic potassium hydroxide (2N). Then, the extracted upper layer of FAMEs was used for the fatty acid determination. The fatty acid composition for the blended fat was identified based on the elution of the FAME standard and reported as % concentration. Analysis was performed using the following condition: oven temperature was set at 90 °C (held for 5 min) and was then increased to 185 °C (8 °C/min; held for 1 min), 200 °C (at 8 °C/min), and to the final temperature of 250 °C (2 °C/min; held for 5 min). The injector (split mode, 1:20) and detector were set at 250 °C, and the helium gas was set at 1 mL/min.