Influence of Sumac Extract on the Physico-chemical Properties and Oxidative Stability of Some Cold Pressed Citrus Seed Oils

Abstract

The acidity values changed between 1.03 mgKOH/100g (control) and 1.11 mgKOH/100g (0.1% extract) for orange oil, 1.06 mgKOH/100g (0.5% extract) and 1.13 mgKOH/100g (0.1% extract) and 1.25 mgKOH/100g (0.5% extract) and 1.31 mgKOH/100g (control) for mandarin oil. The peroxide values were determined between1.37 meqO₂/kg (0.5% extract) and 1.43 meqO₂/kg (0.1% extract) for orange oil, between 1.24 meqO₂/kg (control) and 1.27 meqO₂/kg (0.1% extract) for lemon and 1.60 meqO₂/kg (0.5% extract) and 1.71 meqO₂/kg (control) in mandarin oil samples. The viscosity values of samples changed between 0.051 Pa.S (control) and 0.065 Pa.S (0.5% extract) for orange, 0.051 Pa.S (control) and 0.067 Pa.S (0.5% extract) lemon and 0.044 Pa.S (control) and 0.057 Pa.S (0.5% extract) in mandarin oil samples. At the end of storage study (28^th day), the acidity values significantly changed, and their values ranged between 2.28 mgKOH/100g (0.5% extract) and 3.64 mgKOH/100g (control) in orange, 1.67 mgKOH/100g (0.5% extract) and 2.28 mgKOH/100g (control) in lemon and 1.74 mgKOH/100g (0.5% extract) and 2.36 mgKOH/100g (control) in mandarin oil samples. While peroxide values vary between 11.68 meqO₂/kg (0.5% extract) and 32.57 meqO₂/kg (control) for orange, 12.55 meqO₂/kg (0.5% extract) and 34.63 meqO₂/kg (control) for lemon and between 17.56 meqO₂/kg (0.5% extract) and 37.81 meqO₂/kg (control) for mandarin oils, viscosity values after 28 day storage changed between 0.123 Pa.S (0.5% extract) and 0.675 Pa.S (control) in orange, 0.257 Pa.S (0.5% extract) and 0.697 Pa.S (control) in lemon and 0.215 Pa.S (0.5% extract) and 0.728 Pa.S (control) in mandarin oil samples.

Keywords: citrus oils; cold press; oxidative stability; storage; sumac extract; viscosity.