Changes in Physicochemical Properties of Oils Obtained from Pastes of Three Groundnut Varieties in Côte d’ivoire under Two Storage Conditions

Abstract

In Côte d’Ivoire, peanut paste represents one of the main forms of peanut consumption, particularly in the northern part of the country. However, its storage raises significant concerns related to the deterioration of oil quality. This study aims to evaluate the impact of two storage conditions (ambient temperature and cold storage) on the physicochemical parameters of oils extracted from pastes produced from three local peanut varieties: large striped shell (Gcs), medium striped shell (Mcs), and small smooth shell (Pcl). After processing the kernels into paste and subsequently into oil, analyses were conducted to monitor changes in acid value, peroxide value, iodine value, saponification value, and refractive index over a twelve-month storage period. The results revealed a significant increase (p < 0.05) in acid value (from 0.08 ± 0.00 to 1.19 ± 0.01 mg KOH/g oil), peroxide value (from 0.15 ± 0.01 to 1.38 ± 0.01 meq O₂/kg), iodine value (from 87.68 ± 0.11 to 99.75 ± 0.01 g I₂/100 g oil), and saponification value (from 185.28 ± 0.30 to 200.19 ± 0.02 mg KOH/g) throughout the storage period, regardless of paste type. Conversely, the refractive index showed a significant decrease at the 5% significance level, with values ranging from 1.46 ± 0.02 to 0.70 ± 0.02 at 20 °C ± 1. These findings highlight the influence of storage conditions on the stability of oils derived from peanut pastes and provide insights for optimizing storage and processing conditions.