Estimation of Avocado Oil (Persea americana Mill., Greek “Zutano” Variety) Volatile Fraction over Ripening by Classical and Ultrasound Extraction Using HS-SPME–GC–MS

Abstract

The study of flavors and fragrances is a topic of rising interest from both marketing and scientific perspectives. Over the last few years, the cultivation of avocados has accelerated in Greece, with production levels elevated by 300%. There has been increasing attention from a number of growers and consumers on avocado oil, the volatiles of which form a key part of consumers’ purchase decisions. A previously unevaluated Zutano cultivar was chosen for this study. Extraction of the pulp oil was performed during three phases of ripening using Soxhlet and ultrasound techniques. Headspace-solid-phase microextraction (HS-SPME) and gas chromatography–mass spectrometry (GC–MS) were utilized in order to analyze the isolated volatile fraction. At least 44 compounds, including mainly terpenoids (61.7%) and non-terpenoid hydrocarbons (35.9%), presented in the Zutano variety, while (1S,6S,7S,8S)-1,3-dimethyl-8-propan-2-yltricyclo[4.4.0.02,7]dec-3-ene (a-copaene) and (1R,9S,Z)-4,11,11-trimethyl-8-methylenebicyclo[7.2.0]undec-4-ene (β-caryophyllene) were in higher abundance. The composition of the volatiles was unaffected by the extraction techniques but was influenced by the ripening stage. Thus, during maturation, the volatile fraction fluctuates, with a significantly higher abundance of terpenoids during the fourth day of the ripe stage, whilst it decreases during over-ripening. These findings demonstrate that the Zutano variety can be used to produce an aromatic oil and hence could be used, among others, as an ingredient in cosmetic products.