Phyto-chemical and bioactive compounds of pumpkin seed oil as affected by different extraction methods

Pumpkin (Cucurbita moschata Duch.) seeds of KH (Kashi Harit) cultivar were chosen for oil extraction by three different methods cold press extraction (CPE), soxhlet extraction (SE) and mechanical shaking extraction (MSE) method. SE method showed highest oil yield (38.03%) followed by CPE (33.25%) and MSE (26.36%) methods. Peroxide and acid value were found to be least in the CPE pumpkin seed oil (PSO) whereas oil stability index was highest in this oil. PSO is a good source of essential fatty acids as it contains significant amount (p < 0.05) of linoleic acid in the range of 44.38–44.47%. PSO also contains major sterols like campesterol, stigmasterol, β-sitosterol, ∆7,22,25-Stigmastratrienol, ∆7,25-Stigmastadienol, ∆5-Avenasterol, etc. CPE oil showed higher values for tocopherols (α, β, γ and δ) (4.01, 0.77, 12.51 and 6.42 mg/100 g, respectively), β-carotene (3.86 mg/kg), TPC (19.26 mg GAE/g), DPPH (46.35%) and squalene (352.63 mg/100 g). Thermal analysis of all oil samples revealed that no endothermic reaction occurred beyond 27.5 °C and remains at liquid state at room temperature. 1HNMR fingerprinting of PSO was carried out to determine the composition of major and minor oil constituents like mono and di-glycerides, aliphatic chains and fatty acids