Oil extraction from vegetable fried snack waste: technical evaluation for second-generation biodiesel production

Abstract

Sustainable biodiesel production requires raw material sources that do not compete with the food chain. This study evaluated the technical feasibility of recovering sunflower oil from the waste products of fried vegetable snacks (potato, corn, and plantain) for use as an input in biodiesel production. The process was developed in two stages: (i) solid-liquid extraction with 96% ethanol at the laboratory level to determine the lipid content, and (ii) scale-up to pilot scale to evaluate yields and process stability. The results showed oil contents between 18.1% and 23.0% in the laboratory, depending on the type of snack. The pilot scale demonstrated equal or higher yields (up to 30% for potato chips), validating the efficiency of the process at a larger scale. The recovered oil, characterized as frying crude, has characteristics compatible with conventional transesterification routes (alkaline or acid) for biodiesel production. It is estimated that 100 kg of waste can generate approximately 25.5–28 kg of biodiesel, considering a conversion efficiency of 85%. This work positions the waste from fried snacks as a viable and scalable source of oil for second-generation biodiesel, contributing to the circular economy through the valorization of industrial waste.