Assessment of volatile compound profiles and the deduced sensory significance of virgin olive oils from the progeny of Picual×Arbequina cultivars

Abstract

Volatile compounds are responsible for most of the sensory qualities of virgin olive oil and they are synthesized when enzymes and substrates come together as olive fruit is crushed during the industrial process to obtain the oil. Here we have studied the variability among the major volatile compounds in virgin olive oil prepared from the progeny of a cross of Picual and Arbequina olive cultivars (Olea europaea L.). The volatile compounds were isolated by SPME, and analyzed by HRGC-MS and HRGC-FID. Most of the volatile compounds found in the progeny's oil are produced by the enzymes in the so-called lipoxygenase pathway, and they may be clustered into different groups according to their chain length and polyunsaturated fatty acid origin (linoleic and linolenic acids). In addition, a group of compounds derived from amino acid metabolism and two terpenes also contributed significantly to the volatile fraction, some of which had significant odor values in most of the genotypes evaluated. The volatile compound content of the progeny was very varied, widely transgressing the progenitor levels, suggesting that in breeding programs it might be more effective to consider a larger number of individuals within the same cross than using different crosses with fewer individuals. Multivariate analysis allowed genotypes with particularly interesting volatile compositions to be identified and their flavor quality deduced.

Natural Variation of Volatile Compounds in Virgin Olive Oil Analyzed by HS-SPME/GC-MS-FID

“…Volatile esters are the main compounds responsible for these odor notes, especially LOX esters. Their content in the olive collection subset was 1844 ng/g oil on average, and is present in a range of 14-15,369 ng/g oil, much higher than those values found in a progeny of the cross of cultivars Picual and Arbequina [29]. Only a few accessions (3%) had (E)-hex-2-en-1-yl acetate contents that contribute to their aroma (OAV > 1, Table 2).…”

“…They are thought to be produced in the same branch of the LOX pathway as the rest of the C5 compounds [33]. The pentene dimers represented 82% of the C5/LnA content on average (Figure 1), but seem to have a quite low or negligible sensory contribution to the VOO aroma, according to the estimated odor thresholds for these compounds [29]. The rest of the C5/LnA compounds seem to contribute to VOO aroma according to their OAVs (Table 2).…”

“…The odor of this compound is considered unpleasant [9], while the aroma of pent-2-en-1-ol is pleasant, green-fruity. Most of the olive cultivars (90%) presented (E)-pent-2-en-1-ol contents above its odor threshold [29] (Table 2). On the contrary, (Z)-pent-2-en-1-ol contents suggest that this compound is of little relevance to VOO aroma, as it was present below its threshold concentration in the oils.…”

“…The mean content of (E)-hex-2-enal in the oils was 27.19 µg/g oil, ranging from 4.70 to 65.03 µg/g oil. The large amount, and the relatively low odor threshold [32], of this C6/LnA compound make it one of the main contributors to the aromas of the oils, which seems to be typical of oils from the olive species [29,31]. Table 1. C5/LnA compounds showed contents close to those of the C6/LnA compounds.…”

“…Analysis of volatile compounds was carried out according to Pérez et al [29]. Olive oil samples (0.5 g) were prepared in 10-mL vials and placed in a vial heater at 40 • C for a 10 min equilibration time.…”