Evaluation of virgin olive oil bitterness by total phenol content analysis

Bitterness is an important sensory attribute of virgin olive oil (VOO). It is usually assessed by tasting, which is a time-consuming method and needs trained tasters. Bitterness is related to the phenolic compounds and can be estimated by the measurement of the specific absorbance at 225 nm (K-225). This paper proposes to evaluate oil bitterness intensity as estimated from the K-225 values measuring the phenol content. A significant relationship between phenol content and K-225 as well as a prediction model for bitterness intensity estimation from the phenol content was obtained. Classification of oil bitterness was based on the phenol content. Furthermore, when 12 VOO samples were classified by their bitterness intensities as estimated by the prediction model and by sensory analysis, more than 92% of the oil samples were correctly classified. Therefore, by measuring the phenol content, the bitterness intensity can be estimated and oils can be classified by their bitterness. This model may represent an easy method to evaluate the bitterness intensity without any sensory assessment.