Quality analysis of walnut oil extracted by cold press and solvent methods for in vitro phytochemicals, antioxidant activity and GCMS analysis

• While solvent extraction increased oil output at the expense of slight phytochemical degradation, cold press extraction produced less oil while preserving higher quantities of beneficial chemicals. • Major bioactive components were identified, such as tocopherols, oleic acid, and linoleic acid, with different volatile and non-volatile chemicals according on the extraction technique. • Cold-pressed oil demonstrated a richer polyphenolic and unsaturated fatty acid profile, making it more suitable for functional food applications, while solvent-extracted oil showed enhanced extraction efficiency for industrial applications . Walnut oil was obtained by using two different extraction methods (cold press and solvent extraction). The cold pressing process yield (48.0±0.1%) was clearly lower than the solvent extraction (66.0 ±0.3%). There were no significant differences in oil density between the two extractions methods used in this study. The oil extracted using the CP method had the highest viscosity (81.08±0.0310 −3 xPas), acid value (0.35±0.03%), and peroxide value (0.83±0.04 meq x kg) than SE walnut oil. A total number of 60 compounds were found in cold pressed walnut oil. However, only 43 compounds were found in solvent extracted oil. The prominent bioactive compounds detected in cold press walnut oil were pentadecanoic acid, 9,12-octadecadieno, 9-hexadecenoic acid, gamma-sitosterol, delta-tocopherol, heneicosanoic acid, gamma-tocopherol, nonanoic acid, camphor while in case of solvent extracted walnut oil, the prominent compounds found were palmitic acid, linolenic acid, oleic acid, alpha-linolenic acid, eicosanoic acid, 9,12-octadecadieno, 2-linoleoylglycerol, monolinolein. Considering the aforementioned factors, cold press walnut oil has potential uses in food, cosmetics, and healthcare. .