Impact of UV-light irradiation on sensory properties, volatile, fatty acid, and tocopherol composition of peanuts (Arachis hypogaea L.)

Shelf life of peanuts is determined by their susceptibility to lipid oxidation. However, oxidation stability tests require accelerated conditions to speed up oxidation processes. This work aimed to test the use of UV radiation to accelerate the oxidation in peanuts. Shelled and fried peanuts were irradiated for 3 and 7 days, respectively with a UV lamp. The content of fatty acids, tocopherols, and volatile compounds was determined followed by colour and sensory properties of samples. Obtained results were compared with samples heated for 2 months at 70 °C in an oven. Tocopherol content showed oxidation process had just started after 3 days of UV irradiation. Moreover, aldehydes content increased 8.40 times and 11.77 times at 3 days and 7 days, respectively. Aroma, odour, sweetness scores, and a* value of peanuts were lower and permanency and rancity scores were higher after the oxidation process. Thermal treatment showed an increase in colour and b* value and a reduction in a crunchiness score highlighting temperature possible causes chemical changes which are not related to the oxidation process. Acceleration of oxidation with UV radiation can be used to study peanuts oxidation with less impact on sample colour and crunchiness when the sensorial analysis was performed.