Effect of duration of olive storage on the quality of olive oil produced in west Libya

Abstract

Olive oil is known for its health benefits due to its richness in monounsaturated fats, antioxidants like polyphenols, and vitamin E. Regular consumption lowers risks of cardiovascular diseases, inflammation, and certain cancers, benefiting public health in Libya. Olive oil quality is influenced by factors such as the time from harvest to processing. This research aimed to study the effect of olive storage duration on the oil's chemical composition. Therefore, ten samples of olive fruits were collected from different regions of the Libyan coast and western mountain regions during October 2018 to evaluate the quality of the olive oil by conducting analyses of acidity, peroxide values and absorption coefficients, as well as estimating the content of phenolic compounds. The results showed that the acidity percentage in the Zliten Azdo oil samples which were stored for 2 months and the Nalut sample which were stored for 3 months exceeded the values specified by International Olive Oil Council (3%), while the acid number and peroxide number for all samples were within international standard limits (17) and (20) respectively. The results from this study demonstrated a range of K232 and K270 values across different olive oil samples, highlighting the influence of storage conditions on oil quality. Delaying the pressing of olives after harvesting increases free acidity, and raises the peroxide index.

This study provides guidelines to minimize the storage duration from harvesting to processing, aiming to preserve both the chemical and sensory quality of the oil throughout its shelf life.