3.2.5. Effect of gamma irradiation and storage period on saponification value of oil.
The saponification number is defined as the mg KOH required to saponify one gramme of fat. High saponification values show that more alkali would be required to affect the neutralization of the available free fatty acid librated by the oil, the process of breaking down a neutral fat into glycerol and fatty acids by treatment with alkali. The mean value in the non irradiated pistachio oils was 193.50 mg KOH g1 (Table 3) which was greater than that of almond oil (168.27 mg KOH g1) (Atsu Barku et al., 2012), but lower than saponification value for some vegetable oil cited in the literature. For instance, Kyari (2008) reported that SV for palm oil is 200 (mg KOH g1 samples) and for coconut 257 (mg KOH g1 samples).