Total polar compounds of PSO were slightly affected by thermal stress, accounting for 5.71, 6.35, and 9.53% (w/w) in the unheated, heated at mild temperature (50 ☌, 2 h), and heated at frying temperature (170 ☌, 4 h) PSO, respectively. In contrast, triacylglycerol-bound punicic acid in PSO was unchanged by simulated gastric conditions and was degraded by 5−7% by severe heating (up to 170 ☌ for 4 h), as herein assessed by gas chromatography, attenuated total reflectance−Fourier transform infrared spectroscopy, 1 H and 13 C NMR, and high-resolution electrospray ionization mass spectrometry. As a free fatty acid, punicic acid is rapidly oxidized in air and extensively isomerizes upon acid-catalyzed methylation at 90 ☌. The fatty acid composition of pomegranate (Punica granatum L.) seed oil (PSO) is dominated by punicic acid, a conjugated linolenic acid (18:3ω-5). Due to these physicochemical and thermal properties, CSO is an excellent source of essential fatty acids for food industries. CSO remained stable up to 300 ☌ with negligible degradation. Melting point and melting enthalpy of CSO were À34 ☌ and 77.48 J/g, respectively. This CSO contained twelve triacylglycerols (TAGs) out of which trilinolenin (aLnaLnaLn) was the most abundant comprising 33.2% of total TAG. a-linolenic acid is the most abundant fatty acid comprising (64.39% of total oil) followed by linoleic acid (21.46%), while saturated fatty acid content is less than 10%. The acid, peroxide, saponification and iodine values and unsaponifiable matter content of CSO were 2.54 g KOH/kg oil, 4.33 meq O 2 /kg oil, 197 g KOH/kg oil, 204 g I 2 /kg oil and 1.12%, respectively. The specific gravity, viscosity and refractive index of CSO at ambient temperature were 0.93, 43.2 mPa.s and 1.48, respectively. Physicochemical and thermal characteristics of Australian chia seed oil (CSO) were studied.
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