## 2 Materials and Methods
### Determination of Fatty Acid Composition and Nutritional Indices  
Yoghurt samples that were collected on storage day 7 were frozen and stored for analysis, which was conducted within six months following collection. The samples were thawed overnight at 4 \({}^{\circ}\)C, and the following day, fatty acids were extracted according to the method of [PERSON] et al. [36]. Briefly, samples were thoroughly mixed with a spatula before transferring a portion into a screw-capped Pyrex tube. Aqueous potassium hydroxide solution and methanol containing t-butyl-hydroxytoluene (BHT) were added to prevent oxidation of unsaturated fatty acids. The tubes were heated in a water bath and periodically shaken to ensure proper mixing and hydrolysis. After cooling, aqueous sulfuric acid was added, and the mixture was gently inverted before reheating and shaking again. Once cooled, hexane was added, and the tubes were vortexed to complete the process. Following that, the upper hexane phase was filtered through a 0.45 \(\upmu\)m pore size PVDF syringe filter, transferred into amber GC vials, and stored at \(-20\)\({}^{\circ}\)C until analysed. Fatty acid methyl ester analysis was performed on an Agilent Technologies 6890N GC (Agilent Technologies, Inc., Santa Clara, CA, USA) equipped with a flame ionisation detector (FID) and a 60 m \(\times\) 0.25 mm i.d., 0.25 \(\upmu\)m film thickness DB-23 (50% cyanopropyl 50% dimethyl polysiloxane) capillary column (Model Number: Agilent 122 2362). The injector temperature was set at 250 \({}^{\circ}\)C. The oven temperature was programmed from 110 \({}^{\circ}\)C (held for 6 min), to 165 \({}^{\circ}\)C at 1 \({}^{\circ}\)C/min (held for 13 min), to 195 \({}^{\circ}\)C at 15 \({}^{\circ}\)C/min (held for 22 min) and to 230 \({}^{\circ}\)C at 7 \({}^{\circ}\)C/min (held for 7 min). The carrier gas was helium at 0.7 mL/min and the injection volume was set at 3 \(\upmu\)L and the E Split ratio was 1:50. The injection was performed using an Agilent 7683 Series auto-sampler. Fatty acids were identified using the information of the retention times of the three commercial standard mixtures: (a) 37 component FAME mix (Supelco(r), 47885-U, Sigma-Aldrich, Taufkirchen, Germany), (b) PUFA-2, Animal source (Supelco(r), 47015-U, Sigma-Aldrich, Taufkirchen, Germany), and (c) a mixture of cis- and trans-9,11- and -10,12-octadecanenoic acid methyl esters (Sigma, O5632, Sigma-Aldrich, Taufkirchen, Germany). Fatty acids were quantified by peak area measurement and the results are expressed as percent (%) of the total peak areas for all quantified acids. Fatty acids were grouped as saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), and unsaturated fatty acids (UFA). The fatty acid profile was used to determine the nutritional indices associated with healthy fat intake. The applied indices are those outlined in the recent review by [PERSON] and [PERSON] [37] for ruminant dairy products. These researchers systematically compiled information on fatty acid profiles published since 2000 to enhance the understanding of the implications and applications of diverse nutritional indices.