Cloud Point Extraction for the Recovery of Bioactive Compounds from Peanut Shells

Abstract

Peanuts (Arachis hypogaea L.) belong to the legume family and originated in South America. Over time, they have spread to various parts of the world, especially China, India, the United States, and Türkiye. According to 2019 data, about 48 million tons of peanuts are produced worldwide, with Turkey producing 169 thousand tons of this amount. Anatomically, peanuts consist of three parts: the shell, membrane, and kernel. These components differ in the bioactive compounds they contain. During processing, these parts are separated at various stages in the factory. However, these by-products are often not sufficiently valorized, leading to underutilization of their potential. In recent years, waste valorization has gained significant attention in the peanut industry. Peanut shells highlight their potential as a valuable and sustainable resource. Moreover, extracting bioactive compounds from these by-products using innovative methods has become a key focus of recent research. The aim of this study was to recover the bioactive potential of peanut shell waste using a cloud point extraction technique, employing lecithin as a surfactant. Different parameters were tested through single-factor analysis, one at a time. An increase in the bioactive potential of peanut shells was recorded when the surfactant concentration was 10% w/v, the phase separation temperature was 90 °C for 40 minutes, the salt concentration was 10% w/v, and the pH was 2. The cloud point extraction method is regarded as an advantageous technique for recovering the total phenolic and flavonoid potential of peanut shell waste.

Keywords: Peanut shell, bioactive compounds, cloud point extraction