Agronomic and Technological Factors Affecting Tunisian Olive Oil Quality

Abstract

Olive oil is a very versatile product. It has distinctive virtues in the fields of health and nutrition. For this reason olive oil quality has attracted attention and become the focus of many studies. Olive oil quality depends on several factors such as ripening, extraction method, soil type, climatic conditions, harvesting time, varieties and storage conditions. Quality assessment of olive oil is linked to an important series of physicochemical parameters including free fatty acid content, peroxide value and sensory evaluation. The main objective of this study is to investigate using statistical analysis, the main factors influencing the quality of Tunisian olive oils. Physicochemical analysis of 89 samples of olive oil produced in the region of the Sahel and central Tunisia. This study demonstrates that the main factors influencing Tunisian olive oil quality are: olive ripening, harvesting methods, olive pre-processing storage, olive washing, leaf removing, mixing, separation systems and crushing time. The data also shows that the commercial qualitative parameters of virgin olive oil such as free fatty acids, peroxide value, specific spectrophotometric absorptions in the UV region and sensorial assessment depend on the cultivar and quality of olives before processing. The application of good olive-growing practices complemented by studies similar to this would improve the quality of olive oil produced in Tunisia. This will contribute to the promotion and value of these oils as a regional product.

Effect of Maturity and Environmental Conditions on Chemical Composition of Olive Oils of Introduced Cultivars in Morocco

“…e evolution of the maturity index was similar between cultivars during the two studied years in the both sites of our study. According to Gharbi et al [32], maturity index may depend on the evolution of genetic factor (the cultivar), the cultivation zone, the climatic conditions, and the cultivation practices.…”

Variations in fatty acid composition and antioxidant content in olive fruits as a result of the application of phytoregulators to the olive tree (Olea europaeaL.)

“…The quality of olive oil depends on a number of factors (Ghabi et al, 2015). However, one of the most relevant factors is the delay in olive processing and, as a consequence, the need for fruit storage after harvesting (Spika, Olivera Koprivnjak, Skevin, Zanetic, & Katalinic, 2015).…”

Pre-and post-harvest factors and their impact on oil composition and quality of olive fruit

“…Olive washing ensures safety and hygienic that helps to maintain the natural quality of oil (Di Giovacchino et al, 2002). Free fatty acid percentage increases if leaves are not removed and/or the olive fruit is not washed (Gharbi et al, 2015).…”

“…Prolonged crushing time may degrade the quality of the olive oil. The recommended olive crushing time is 20-30 minutes because crushing the fruit within this time window produces less peroxide (Gharbi et al, 2015). The milling system has an impact on the oil quality as well as the organoleptic properties (Caporaso, 2016).…”

“…Temperature influences the peroxidase, polyphenol oxidase, and lipoxygenase oxidative enzymes, which are responsible for the quality of volatile compounds of olive oil (Angerosa, 2002). Researchers should follow the rotation, speed 15-20 rpm and have to avoid addition of water in lieu of adjuvants during malaxation of paste (Gharbi et al, 2015). Shorter malaxation is better than longer one.…”