Comparative Evaluation of Cold and Heat Pressing on the Quality Characteristics of Olive Oil Extracted from Black Olives (Picual Cultivar).

Abstract

This study evaluates the effect of cold pressing and heat pressing methods on the quality of olive oil extracted from black olives (Picual cultivar). A total of 50 kg of olives were divided into two groups and processed using cold and hot extraction methods for comparison. The fruits showed good production characteristics, including a high oil content (23%) and high phenolic compounds (1025 mg/100 g). Results indicated that cold-pressed oil had lower acidity (0.14%) compared to heat-pressed oil (0.17%). Cold-pressed oil also showed lower oxidation values such as peroxide value compared to heat-pressed oil. Heat treatment increased oxidation indicators such as K232 and K270, indicating oil quality deterioration. Phenolic content decreased in heat-pressed oil, negatively affecting oxidative stability. Cold-pressed oil retained a higher proportion of oleic acid, improving stability and nutritional quality. In contrast, polyunsaturated fatty acids increased in heat-pressed oil, which reduces stability. DPPH results showed that antioxidant activity varied depending on the extraction method despite changes in phenolic.