Impact of roasting level on fatty acid composition, oil and polycyclic aromatic hydrocarbon contents of various dried nuts

Abstract

Herein, the effects of roasting levels (rare, medium, and well) on the fatty acid composition, oil and polycyclic aromatic hydrocarbon (PAH) contents of various dried nuts (almonds, hazelnuts, peanuts, and cashews) were investigated. The roasting level affected the moisture and total oil contents, as well as the fatty acid composition. The roasting level had no significant effect (P > 0.05) on saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) contents of the dried nuts, while it had a significant effect (P < 0.05) on polyunsaturated fatty acid (PUFA). In raw and dry roasted nut, the most common SFA, MUFA, and PUFA were palmitic, oleic, and linoleic acid, respectively. The amounts of linoleic acid and ΣPUFA, as well as ΣPUFA/ΣSFA ratio were the lowest in the well roasted samples. Additionally, the types of dried nut had a significant effect (P < 0.01) on the amounts of total oil and fatty acid compositions. The highest total oil amount (62.15%) was found in hazelnuts, while the lowest PUFA content (7.54%) was also determined in hazelnuts. From the nutritional perspective of view, the highest ΣPUFA / ΣSFA ratio (2.40) belonged to almonds. Although the recovery rates of PAH standards varied between 70.14%-85.10%, none of the heavy PAH compounds could be detected in raw and roasted samples.