The Role of Heating Treatments on Bioactive Compounds, Fatty Acid Compositions, Phenolic Compounds and Mineral Contents of Peanut Kernels

In this study, the role of boiling and roasting on chemical properties, fatty acid compositions, polyphenols and mineral contents of peanut kernels provided from Mersin (Silifke) province in Turkey was investigated. The oil yields of peanut kernels treated were specified between 48.92% (boiled) and 52.93% (oven roasting). While total phenolic quantities of raw, boiled and roasted-peanut kernels were assessed between 71.98% (boiled) and 178.81 mgGAE/100 g ( raw(control)), total flavonoid quantities of treated-peanut kernels were found to be between 120.36 (boiled) and 530.36 mgQE/100 g (control). The antioxidant activities of peanut kernels ranged from 2.66 (microwave roasting) to 3.90 mmolTE/ kg ( control). The phenolic constituents of peanut kernels are sensitivities to heat treatment. The maximum reduction in the phenolic compounds of peanut kernels was determined in the peanut kernels roasted in the microwave and oven roasting systems, and followed by the boiled process in decreasing order. Also, while oleic acid quantities of raw, boiled and roasted-peanut kernel oils are determined between 54.06% (boiled) and 57.22% (microwave roasting), the linoleic acid quantities of the oils of peanut kernels treated were specified between 25.18% (microwave roasting) and 27.33% (boiled). The composition of the oil of the peanut kernels roasted in microwave has highly increased (except palmitic and linoleic acids) according to the control. The macro elements found at the highest amounts in raw, boiled and roasted-peanut kernels were P, K, Ca, Mg, S and Na. The most available as micro element has been Fe and Zn. Heat treatments such as roasting and boiling not only change the visible rawness of peanuts, but they can also subsequently cause chemical changes in peanut kernels.