Karolina Brkić. Institute of Agriculture and Tourism of Croatia.

The aroma of virgin olive oil is one of the most important properties of this product and plays a major role in consumer choice. The unique and pleasant aroma of virgin olive oil is attributed to the volatile compounds that are formed during and after the extraction of the oil from the olive fruits. During the past decades, various volatile compounds that contribute to the positive and negative odours of olive oil have been identified. The virgin olive oil aroma is a complex mixture of volatile compounds, which includes aldehydes, alcohols, ketones, hydrocarbons, esters, terpenes, furans and volatile phenols. Depending on the odour detection thresholds of particular volatile compounds, some of them contribute directly to the aroma of virgin olive oil or they can contribute in the synergy with other volatile compounds. In the present lecture, the most relevant volatiles found in virgin olive oil will be presented. The sensorial character of the volatile compounds and their contribution to the virgin olive oil aroma will be discussed.

It is highly important to understand the path of formation of volatile compounds that cause certain desirable and undesirable sensory characteristics of olive oils. Volatile compounds from virgin olive oil are mostly formed during the oxidation of fatty acids. It is known that endogenous plant enzymes participating in the lipoxygenase pathway are responsible for the formation of volatile compounds associated with the positive odour properties of virgin olive oils, while chemical oxidation and exogenous microorganism enzymes are associated with the formation of volatile compounds that cause negative odour properties. Therefore, in this lecture origin and formation of volatile compounds that influence the positive and negative sensory properties of virgin olive oil will be displayed. Moreover, this presentation will integrate current knowledge on the impact of several agronomical and technological factors, such as olive fruit characteristics, processing conditions, storage, etc., which could influence the volatile formation and sensory properties of virgin olive oils. In this overview, special attention will be given to the most important factors influencing virgin olive oil aroma.

Sensory analysis is an analytical procedure that uses people's senses as detectors. It is still the most effective way to identify virgin olive oil sensory properties because provides complete information about odour and taste and takes into account the interaction of taste and odour compounds. Although a complete description of the sensory characteristics of virgin olive oil can be obtained only by sensory analysis, the analytical methods for determination of the composition and concentration of volatile compounds can provide useful information about the quality of the product. In the last two decades, several analytical approaches for virgin olive oil volatiles determination were developed. In the present lecture, the most widely used and the most promising methods in terms of supporting sensory analysis will be discussed.