Geographical origin impact on volatile composition and some quality parameters of virgin olive oils extracted from the “Ayvalık” variety

Abstract

"Ayvalık" is one of the prominent olive cultivar used for producing virgin olive oil (VOO) in Turkey. In this study, 215 olive samples of "Ayvalık" were harvested from 14 different locations in North Aegean Region of Anatolia by hand-picking during three consecutive crop seasons. The early harvested cold press VOO samples were produced at lab-scale and the quality indices (free acidity, peroxide value and spectral absorption at 232, 266, 270 and 274 nm), induction time, colour values, fatty acid and volatile profiles were determined in order to examine changes on composition of the "Ayvalık" olive oils based on their growing area. Characteristically, it was found that volatile fraction of "Ayvalık" VOOs composed of aldehydes (29.72), terpene (12.68), alcohol (11.65), benzene ringed compound (4.71), ketone (3.49), organic acid (2.87), ester (1.84), furan (0.96) compounds on average percentage. It was highlighted with this research 61.84–87.36% of aldehydes, 0.00–91.11% of ketones, 0.00–46.11% of esters, and 34.53–92.06% of alcohols were generated only by lipoxygenase pathway. As a conclusion, Ayvalık VOOs had different chemical composition based on geographic origin. Therefore, it was considered that this work is so promising to directly accelerate that the number of geographic indicated VOOs linked to "Ayvalık" cultivar.

Food science; Virgin olive oil; Food analysis; Volatile compounds; Oxidative stability; Fatty acid composition; Agriculture; Ayvalik olive cultivar; Natural product chemistry

1. Introduction

The consumption of virgin olive oil (VOO) all over the world has reached a rising trend due to its high nutritional value and functional compounds such as monounsaturated fatty acid, tocopherols, phenolics and sterols. The presence of these bioactive constituents in VOO is directly influence on its oxidative stability, shelf life and sensory properties (Hernáez et al., 2019; Sanaeifar and Jafari, 2019). Numerous epidemiological and clinical studies approved that Mediterranean diet covering regular consumption of VOO reduce the incidence of metabolic disorders such as heart disease, stroke and Type-II diabetes (Corominas-Faja et al., 2018; Soto-Alarcon et al., 2018; Tsartsou et al., 2019).

The olive oils, extracted from Olea europaea L. fruit, can be classified as extra virgin olive oil (EVOO), virgin olive oil (VOO) and lampant olive oil (LOO) depending on its chemical (i.e. free acidity, peroxide value, UV absorptions) and sensorial (i.e. odor, taste, color, appearance) quality according to the European Union regulations (EEC, 2016).

Turkey is the third olive producer of the world (FAOSTAT, 2020). "Ayvalık" (Edremit Yağlık) is the eminent olive cultivar (cv.) which utilized for oil production in Turkey. Ayvalık cv. is a quarter of the olive trees in Aegean Region (TURKPATENT, 2020). However, this cultivar is more widespread in North Aegean Region; it was started to grown in other parts of Anatolia such as Antalya, Mersin, and Adana recently (Naskali, 2016). Therefore, several researchers focused on "Ayvalık" oils quality and purity parameters. Classifying geographic origins of "Ayvalık" VOOs topic was examined before several researchers based on fatty acid profile (Dıraman et al., 2011; Oğraş et al., 2016; Ucuncuoglu, 2019) and phenolic profiles (Alkan et al., 2012). To the best of current knowledge, there was no research about geographical discrimination based on volatile profile and quality parameters of "Ayvalık" VOOs in Turkey.

Sensorial profile (aroma) is a crucial quality parameter for EVOO and depends on volatile and semi-volatile fractions. The volatile fraction of VOO is principally generated from the degradation pathways of linoleic and linolenic acids by various enzymes, mainly lipoxygenase. These reactions release when malaxation starts after crushing. Generally, positive notes and desired volatiles occur by this pathway. The other volatiles can be formed by direct fatty acid metabolism, as well as by sugar fermentations or amino acid conversion. The former reactions produce linear acids (i.e. acetic acid), alcohols (i.e. ethyl alcohol), esters (i.e. ethyl acetate) and ketones (i.e. propanone). The latters can generate branched esters, aldehydes, alcohols and acids etc. The desirable aroma compounds are attributed to C6 and C5 volatiles, including aldehydes, esters, alcohols, hydrocarbons, furan and ketones. There are some other volatile generation pathways caused from lipid oxidation mechanisms, microbial fermentation reactions or damaged olive fruit, which gives defective or off-flavours to VOO ketones (Kalua et al., 2007; Boskou, 2012).

The volatile profile of VOO and its sensorial descriptions affects the consumer preferences and so rural economy. Therefore, volatile compounds previously used for registering "Geographical Indications" such as Protected Designation of Origin (PDO) and Protected Geographical Indications (PGI) by several authorities (Barbieri et al., 2019). A geographical indication is a quality-sign correspond with a specific producing method, and its quality characteristics linked with its geographical origin or growing area. Regarding olive oils, the EU Regulation has made a labelling with geographical origin information compulsory (Likudis, 2016). The main goal of this study was to contribute to the creation of a comprehensive "Ayvalık" VOOs database via examining chemical composition of VOOs harvested from 14 different growing areas in Northern Aegean region during three consecutive crop seasons. The graphical abstract was shown at Figure 1.

Figure 1.

Graphical abstract.

2. Materials and methods

2.1. Materials and sample modelling

The olive samples belongs to "Ayvalık" cv. (n: 215) were harvested from 14 different geographic origins of North Aegean Region at early stages (4th week of October-1st week of November) of maturation during three consecutive harvest year by hand-picking. The number of sample at first harvest on-year was 76, at second harvest off-year was 37 and at third harvest on-year was 102.

Edremit (GO1), Gömeç (GO2), Ayvalık (GO3), Havran (GO4) and Burhaniye (GO5) were the sub-locations from Balıkesir; Ayvacık (GO6), Merkez (GO7) and Ezine (GO8) were the sub-locations from Çanakkale; Bergama (GO9), Bornova (GO10) and Dikili (GO11) were the sub-locations from İzmir, and finally, Akhisar (GO12), Kırkağaç (GO13) and Saruhanlı (GO14) were the sub-locations from Manisa cities. Geographic origins of monocultivar olives and number of samples were detailed in Table 1 and shown at Figure 2. The mathematical coordinates of the investigated geographic area was between 26-27° East Longitudes and 38–40° North Latitudes.

Table 1.

Geographic origins and sample numbers of monocultivar olives (Ayvalık cv.).

Code	Geographic Origins	First Harvest Year (On-Year)	Second Harvest Year (Off-Year)	Third Harvest Year (On-Year)	Total
GO1	Balıkesir-Edremit	9	19	15	43
GO2	Balıkesir-Gömeç	6	3	9	18
GO3	Balıkesir-Ayvalık	9	2	9	20
GO4	Balıkesir-Havran	8	1	5	14
GO5	Balıkesir-Burhaniye	9	3	8	20
GO6	Çanakkale-Ayvacık	9	-	11	20
GO7	Çanakkale-Merkez	-	2	-	2
GO8	Çanakkale-Ezine	9	2	9	20
GO9	Izmir-Bergama	-	-	6	6
GO10	Izmir-Bornova	-	-	3	3
GO11	Izmir-Dikili	6	3	13	22
GO12	Manisa-Akhisar	11	2	5	18
GO13	Manisa-Kırkağaç	-	-	3	3
GO14	Manisa-Saruhanlı	-	-	6	6
Total		76	37	102	215

Edremit (GO1), Gömeç (GO2), Ayvalık (GO3), Havran (GO4) and Burhaniye (GO5) were the sub-locations from Balıkesir; Ayvacık (GO6), Merkez (GO7) and Ezine (GO8) were the sub-locations from Çanakkale; Bergama (GO9), Bornova (GO10) and Dikili (GO11) were the sub-locations from İzmir, and finally, Akhisar (GO12), Kırkağaç (GO13) and Saruhanlı (GO14) were the sub-locations from Manisa cities.

Figure 2.

Geographic origins of monocultivar (Ayvalık cv.) olives. GPS Coordinates: 38°1′17.73″-40°10′9.06″ North Latitudes and 26°10′49.96″-27°58′16.10″ East Longitudes.

Approximately 5 kg olives were harvested and were immediately transported to the laboratory in the mesh-bags. The leaves were removed and the healthy olives were washed to obtain oil samples using a laboratory scale physical extraction unit (HAUS Centrifuge Technologies, Aydin, Turkey) including a crusher, a malaxer and a centrifuge without any delay. Malaxation process was performed for 30 min at 25 °C. A vertical centrifuge (3000 rpm, 2 min) was used for solid-liquid phase separation. Samples were passed through cotton filter and stored at + 4 °C till analysis.

Every VOO sample was divided into three amber bottles (50 ml) without any headspace on each. The first bottle was used for only volatile and fatty acid profile analysis; the second was used for other chemical analyses. The last bottle was kept in the fridge to be used if necessary.

2.2. Methods for determining quality parameters

Free acidity (as % oleic acid), peroxide value (as meq active O₂/kg oil), K₂₃₂ and K₂₇₀ values were determined according to IOC (2015a, 2015b; 2016). Fatty acid profile was determined according to IOC method. Fatty acids methyl esters (FAMEs) were prepared according to COI/T.20/Doc. No. 24 (IOC, 2001) and they were analysed by gas chromatography (Thermo Scientific, Trace™ Ultra Gas Chromatograph, Waltham, USA) equipped with a 100 m long capillary column (0.25 mm id, 0.20 μm film thickness) and a flame ionization detector (FID).

2.3. Methods for determining colour indices and oxidative stability

L, a∗ and b∗ values were measured with Minolta Spectrophotometer (CM-3600d, Japan) as lightness, red-green and blue-yellow colour. Induction period was measured with the Rancimat 743 (Metrohm, Basel, Switzerland) apparatus at 120 °C with a continuous airflow of 20 L.h⁻¹ passing through the oil samples. Induction time (as hour) is defined at the point of rapid change in the rate of oxidation resulting in a sharp inflection point on the oxidation curve.

2.4. Method for determining volatile profile

Volatile compounds were determined using 50/30μm thickness DVB/CAR/PDMS three-phase fiber (2 cm) with DHS-SPME (Supelco Co., Bellefonte, CA, USA), GC-MS (Thermo Scientific GC, DSQ II Series Single Quadruple GC/MS, Waltham, MA, USA). TR Wax MS 60 capillary column (60 m × 0.32 mm i.d. × 0.5 μm thickness) was coupled to GC. 4-methyl-2-pentanol (Aldrich, Germany) was used as an internal standard. VOO (3 g) was added to a 15 ml vial with 1.5 ppm internal standard. The vial was then closed with a polytetrafluoro ethylene (PTFE) septum. The fibre was exposed for 30 min at 40 °C, after 30 min at 40 °C for equilibration time. Thermal desorption time was 5 min for injection. The temperature was set at 40 °C for 10 min, followed by an increase of 3 °C min-1 up to 240 °C, and then held for 15 min. The injector was kept at 240 °C. Helium was used as carrier gas (1.0 mL.min⁻¹). The scanning mass range varied from 50 to 550 m/z. Mass spectra were recorded at 70 eV. All measurements were triplicated. Before use, the fiber was conditioned at 260 °C for 1 h. Moreover, a blank test (both empty vial and fiber) was carried out before every run-day to prevent the release of undesirable compounds. The identification of volatile compounds was performed by comparing their retention time with NIST and Wiley library tools, and by checking mass isotope distributions.

2.5. Data processing

Statistical analysis was performed by SPSS (version 23, IBM SPSS Statistics Inc. Chicago, IL) statistical software using One-way ANOVA method. Differences among all groups were determined by Duncan test at 95% confidence level.

3. Results and discussion

3.1. Quality parameters, colour indices & oxidative stability

It was determined that free acidity values were altered between 0.3% and 0.6%; peroxide values 3.0 and 10.1; K₂₃₂ values 1.6 and 2.1; and, K₂₇₀ values 0.1 and 0.2 among the samples (Table 2). Quality parameters data obviously suggested that all investigated samples in this study were "extra virgin" category according to IOC (2015a). GO2 and GO11 were significantly different in terms of free acidity; GO4 and GO14 in terms of peroxide value; GO11 in terms of K₂₃₂; GO8, and GO11 & GO14 in terms of K₂₇₀ (P ≤ 0.05).

Table 2.

Quality parameters, color indices & oxidative stability (induction period) of Ayvalık VOOs.

Locations	Free Acidity	Peroxide Value	K232	K270	L∗	a∗	b∗	Induction Period
GO1	0.5 ± 0.02 abc	9.2 ± 0.60 ab	2.0 ± 0.06 a	0.2 ± 0.01 abc	32.9 ± 0.41 b	1.2 ± 0.07 a	8.2 ± 0.40 abc	7.2 ± 0.34 ab
GO2	0.6 ± 0.04 a	8.7 ± 0.60 abc	2.0 ± 0.10 a	0.2 ± 0.01 abc	32.5 ± 0.77 b	1.2 ± 0.17 a	7.5 ± 0.91 bc	6.1 ± 0.39 b
GO3	0.4 ± 0.04 bcde	7.8 ± 0.53 abc	2.1 ± 0.05 a	0.1 ± 0.01 bcd	33.2 ± 0.58 b	0.8 ± 0.10 ab	9.8 ± 0.80 ab	6.8 ± 0.68 ab
GO4	0.3 ± 0.03 de	10.1 ± 0.75 a	2.0 ± 0.06 a	0.2 ± 0.01 abc	32.8 ± 0.42 b	0.8 ± 0.14 ab	7.8 ± 0.75 abc	7.0 ± 0.44 ab
GO5	0.4 ± 0.04 abcde	8.7 ± 0.58 abc	2.1 ± 0.10 a	0.2 ± 0.01 ab	33.6 ± 0.51 b	1.0 ± 0.15 ab	8.8 ± 0.58 abc	8.3 ± 0.60 ab
GO6	0.4 ± 0.03 cde	8.4 ± 0.77 abc	1.8 ± 0.07 ab	0.1 ± 0.01 bcd	31.6 ± 0.60 b	0.7 ± 0.10 ab	6.9 ± 0.68 bc	8.4 ± 0.99 ab
GO7	0.4 ± 0.03 abcd	8.9 ± 0.86 ab	2.1 ± 0.19 a	0.1 ± 0.01 bcd	32.1 ± 0.54 b	1.0 ± 0.08 ab	8.6 ± 0.56 abc	5.8 ± 0.56 b
GO8	0.6 ± 0.04 ab	9.1 ± 1.29 ab	2.0 ± 0.00 a	0.2 ± 0.00 a	36.1 ± 0.10 a	0.6 ± 0.04 b	10.9 ± 0.54 a	5.7 ± 0.68 b
GO9	0.3 ± 0.02 de	9.0 ± 0.50 ab	1.9 ± 0.08 a	0.1 ± 0.01 cd	32.4 ± 0.62 b	1.1 ± 0.11 ab	8.6 ± 0.66 abc	7.2 ± 0.62 ab
GO10	0.5 ± 0.05 abc	6.0 ± 0.72 bcd	2.0 ± 0.08 a	0.1 ± 0.01 bcd	31.3 ± 0.58 b	0.9 ± 0.13 ab	8.3 ± 1.10 abc	7.3 ± 0.39 ab
GO11	0.3 ± 0.07 e	6.0 ± 0.72 bcd	1.6 ± 0.02 b	0.1 ± 0.01 d	28.8 ± 0.82 c	0.6 ± 0.08 b	3.9 ± 1.39 d	7.4 ± 1.30 ab
GO12	0.4 ± 0.03 abcde	8.0 ± 0.67 abc	2.0 ± 0.09 a	0.2 ± 0.01 abc	33.3 ± 0.46 b	0.8 ± 0.12 ab	8.9 ± 0.56 abc	8.1 ± 0.29 ab
GO13	0.5 ± 0.04 abc	5.5 ± 0.75 cd	2.1 ± 0.07 a	0.1 ± 0.01 cd	31.4 ± 0.74 b	1.0 ± 0.16 ab	6.5 ± 1.13 cd	8.4 ± 1.79 ab
GO14	0.3 ± 0.04 de	3.0 ± 0.73 d	1.8 ± 0.05 ab	0.1 ± 0.01 d	32.2 ± 0.26 b	1.1 ± 0.15 ab	11.0 ± 0.54 a	9.5 ± 1.12 a

The values were expressed as mean ± standard deviations. Means within a column with different letters are significantly different (P ≤ 0.05). Free acidity was given as % g oleic acid; peroxide value as meq active O2/kg oil; induction period as hour, respectively.

Induction period, is an indicator of oxidative stability, changed in a wide range from 5.7 to 9.5 h and GO2, GO7, GO8 and GO14 had different oxidative stability (P ≤ 0.05). The lowest induction period was measured at GO8 and the highest was at GO14. GO7 and GO8 were classified with lower induction period from the other geographic origins (Table 2).

L∗ values (lightness) were changed from 28.8 to 36.1, a∗ values (redness) 0.6 to 1.2, and b∗ values (yellowness) 3.9 to 11.0 indicating that colours altered from green to light yellow. GO8 and GO11 were differed in terms of L∗ values, GO1 & GO2 and GO8 & GO11 in terms of a∗ values, GO8 & GO14, and GO11 in terms of b∗ values (Table 2). Even though colour is not regarded as an important quality characteristic for VOOs, it has a great effect on consumer acceptance. Our results were in agreement with both regulations for EVOO and reported studies (Kıralan and Bayrak, 2013; Toker et al., 2016; Guclu et al., 2016) before related to "Ayvalık" EVOOs except b∗ values.

In this study, it was found that the major fatty acids were oleic (61–70%), palmitic (12–16%), linoleic (10–16%), stearic (2–4%) and palmitoleic (1–3%) acids, respectively. Previously reported researches (Andjelkovic et al., 2009; Gurdeniz et al., 2010; Dıraman et al., 2011) showed that Ayvalık VOOs had 60–77% oleic, 10–19% palmitic, 8–17% linoleic, 2–4% stearic and 0.5–2% palmitoleic acids, respectively. According to C18:1 content, it was observed that two main cluster, one of them includes GO3, GO9, GO10, GO11, GO13 and GO14 origins which had 67–69% oleic acid. The other group was heavily contained 61–64% oleic acid. The most distinct origins were GO5 and GO14 by palmitic acid. GO10 had the lowest and GO8 had the highest linoleic acid percentage. GO1, GO2, GO9 and GO10 origins were significantly distinguished among others in terms of palmitoleic acid content (P ≤ 0.05). Fatty acid compositions of "Ayvalık" VOOs were presented in Table 3. It was shown a good (P ≤ 0.05) statistic description concerning each geographical origin (Table 3). For example, among Balıkesir sub-locations, GO1 and GO2 were characterized by the lowest C16:1 and the highest C18:0 contents. Moreover, GO3 was separated from the others based on the lowest saturated fatty acids such as C16.0 (12.5%) and C18:0 (2.3%), and the highest C18:1 (67.5%) and C18:3 (0.9%) contents. GO6 origin was the only different sub-location among Çanakkale based on both arachidic and eicosanoic fatty acids. Among Izmir sub-locations, GO10 was distinguished by myristic and eicosanoic acids, and GO11 by palmitoleic and margaric acids statistically. GO12 was also statistically varied among Manisa sub-locations in terms of C16:0, C17:1, C18:1 and C18:2.

Table 3.

Fatty acid composition of Ayvalık VOOs.

Locations	C14:0	C16:0	C16:1	C17:0	C17:1	C18:0	C18:1	C18:2	C18:3	C20:0	C20:1	C24:0
GO1	0.0 ± 0.00bcd	15.2 ± 0.28ab	1.4 ± 0.21b	0.1 ± 0.01ab	0.2 ± 0.01ab	3.7 ± 0.21ab	62.8 ± 0.52c	15.0 ± 0.25ab	0.6 ± 0.03bc	0.4 ± 0.01bcd	0.3 ± 0.01bc	0.1 ± 0.01ab
GO2	0.0 ± 0.01a	15.1 ± 0.14ab	1.2 ± 0.20b	0.2 ± 0.01a	0.2 ± 0.00a	4.2 ± 0.07a	62.9 ± 0.54c	14.7 ± 0.29abc	0.5 ± 0.03bc	0.4 ± 0.00bcd	0.3 ± 0.01ab	0.1 ± 0.00abc
GO3	0.0 ± 0.00d	12.5 ± 0.02d	2.1 ± 0.00a	0.1 ± 0.00c	0.1 ± 0.00f	2.3 ± 0.01e	67.5 ± 0.06a	13.6 ± 0.03bcde	0.9 ± 0.02a	0.4 ± 0.01d	0.3 ± 0.00ab	0.1 ± 0.00d
GO4	0.0 ± 0.00bcd	14.7 ± 0.31bc	2.1 ± 0.08a	0.1 ± 0.00bc	0.1 ± 0.00def	2.7 ± 0.09de	64.3 ± 0.46bc	14.4 ± 0.26abcd	0.6 ± 0.02bc	0.4 ± 0.01bcd	0.3 ± 0.00ab	0.1 ± 0.00cd
GO5	0.0 ± 0.00bc	16.2 ± 0.38a	2.4 ± 0.11a	0.2 ± 0.01ab	0.2 ± 0.01bcd	2.3 ± 0.03e	62.3 ± 0.28c	14.8 ± 0.33abc	0.6 ± 0.04bc	0.4 ± 0.02bcd	0.3 ± 0.01ab	0.1 ± 0.00abcd
GO6	0.0 ± 0.01b	14.9 ± 0.26ab	2.2 ± 0.17a	0.1 ± 0.01bc	0.1 ± 0.01def	3.6 ± 0.18ab	63.0 ± 0.59c	14.7 ± 0.45abc	0.5 ± 0.03bc	0.4 ± 0.02cd	0.2 ± 0.01d	0.1 ± 0.01bcd
GO7	0.0 ± 0.00bcd	15.9 ± 0.27ab	2.1 ± 0.24a	0.1 ± 0.01c	0.1 ± 0.01cde	3.4 ± 0.13bc	61.2 ± 0.44c	15.4 ± 0.52ab	0.7 ± 0.04b	0.4 ± 0.02ab	0.3 ± 0.02ab	0.1 ± 0.01bcd
GO8	0.0 ± 0.00cd	15.4 ± 0.13ab	2.2 ± 0.15a	0.1 ± 0.00bc	0.2 ± 0.01abcd	3.5 ± 0.15ab	61.2 ± 0.44c	15.9 ± 0.34a	0.5 ± 0.03bc	0.5 ± 0.01ab	0.3 ± 0.01ab	0.1 ± 0.00abcd
GO9	0.0 ± 0.00bc	14.5 ± 0.14bc	1.4 ± 0.14b	0.1 ± 0.00bc	0.1 ± 0.00cde	2.5 ± 0.20e	67.0 ± 0.94ab	12.7 ± 0.50defg	0.6 ± 0.02bc	0.4 ± 0.02abc	0.2 ± 0.01d	0.1 ± 0.01abcd
GO10	0.0 ± 0.00d	13.4 ± 0.01cd	1.1 ± 0.01b	0.1 ± 0.00bc	0.2 ± 0.00bcd	3.3 ± 0.02bcd	69.4 ± 0.36a	10.8 ± 0.34g	0.6 ± 0.01b	0.5 ± 0.00a	0.3 ± 0.00a	0.1 ± 0.00abc
GO11	0.0 ± 0.01bc	12.6 ± 0.25d	2.7 ± 0.06a	0.2 ± 0.00a	0.2 ± 0.04abcd	2.7 ± 0.26de	67.1 ± 1.02ab	13.0 ± 0.80cdef	0.6 ± 0.08b	0.5 ± 0.04a	0.2 ± 0.01cd	0.1 ± 0.01abcd
GO12	0.0 ± 0.00bcd	14.5 ± 0.43bc	1.4 ± 0.21a	0.1 ± 0.00bc	0.2 ± 0.01abc	3.4 ± 0.12bcd	63.9 ± 1.04c	14.3 ± 0.64abcd	0.6 ± 0.05bc	0.4 ± 0.01bcd	0.3 ± 0.01ab	0.1 ± 0.01abcd
GO13	0.0 ± 0.00bc	12.8 ± 0.02d	1.4 ± 0.21a	0.1 ± 0.00c	0.1 ± 0.00ef	2.8 ± 0.02cde	68.8 ± 0.20a	11.5 ± 0.17fg	0.5 ± 0.01bc	0.4 ± 0.00cd	0.3 ± 0.00bc	0.1 ± 0.00a
GO14	0.0 ± 0.01bcd	12.2 ± 0.01d	1.4 ± 0.21a	0.1 ± 0.00bc	0.1 ± 0.01def	3.6 ± 0.06ab	67.9 ± 0.01a	12.0 ± 0.03efg	0.5 ± 0.01c	0.4 ± 0.01bcd	0.3 ± 0.00ab	0.1 ± 0.01ab

C14:0 (myristic acid), C16:0 (palmitic acid), C16:1 (palmitoleic acid), C17:0 (margaric acid), C17:1 (margoleic acid), C18:0 (stearic acid), cis-C18:1 (oleic acid), C18:2 (linoleic acid), C18:3 (linolenic acid), C20:0 (arachidic acid), C20:1 (eicosanoic acid), C22:0 (behenic acid), C24:0 (lignoceric acid). The values were expressed as mean ± standard deviations. Means within a column with different letters are significantly different (P ≤ 0.05). trans-C18:1 & C22:0 are not given at table due to statistically meaningless difference (P > 0.05).

3.2. The profile of volatile aroma compounds

LOX pathway includes hydroperoxide lyase, alcohol dehydrogenase, alcohol acyltransferase and isomerase enzymes which causes C5 and C6 compounds generation, in particular. Moreover, hexanal, hexan-1-ol and hexyl acetate were formed by 13-hydroperoxides of linoleic acid; cis-3-hexenal, cis-3-hexen-1-ol, cis-3-hexenyl acetate, trans-2-hexenal and trans-2-hexen-1-ol were formed by 13-hydroperoxides of linolenic acid; 2-pentanal, 2-penten-1-ol, 1-penten-3-ol, 1-penten-3-one and some other pentenyl radicals were occurred by 13-alkoxy radicals during LOX pathway. These specific compounds can be chemically grouped as aldehydes, ketones, esters and alcohols. Furthermore, these LOX products can be heavily attributed with green and fruity aroma of VOOs. Green and fruity (positive notes) odour descriptions could characterize the early stage harvesting, fresh-high quality olive fruit, and well-processing and storing conditions. The other fatty acids (both saturated and unsaturated) and nitrogen contained compounds catabolism, and biodegradation reactions linked autoxidation, thermal oxidation or microbial fermentation could be create negative notes, such as waxy, oily, winey, vinegary, musty, fermented, creamy, soapy, tallow, fried, cheesy, ethereal or mushroom-like. In this study, volatile compounds identified and quantified for "Ayvalık" VOOs. GC-MS data showed the presence of total 125 different volatile constituents in the samples. Table 4 cited that the chemical formula and generation mechanisms of volatiles, which were categorized as aldehydes, alcohols, acids, esters, ketones, terpenes, benzenoids, furans and hydrocarbons in Table 5, and their odour/flavour descriptions (Ridolfi et al., 2002; Kalua et al., 2007; Boskou, 2012; Kesen et al., 2013; Zhu et al., 2016; Song and Liu, 2018; Aparicio-Ruiz et al., 2018; Genovese et al., 2018; Abbatangelo et al., 2019; flavornet.org; pubchem.ncbi.nlm.nih.gov, The Good Scents Company Information System TGSC, 2020).

Table 4.

Isolated volatile compounds from Ayvalık VOOs, generation pathways and sensorial descriptions.

Compound	Chemical Formula	Flavour/ Odour Description	Generation Pathway/Source
ethanol	C2H6O	winey, vinegaryc,d	Anaerobic fermentationd
1-hexen-3-ol	C6H14O	woody, green planth	Plant metabolitek
1-penten-3-ol	C5H10O	wet soilb	13-alkoxy radicalsk
1-butanol	C4H10O	solventk	microbial fermentation through the butanoate metabolic pathwayk
1-heptanol	C7H16O	fragrantk	Nature of some essential oilsk
1-pentanol	C5H12O	green-fruityb	Plant metabolitek
trans-2-penten-1-ol	C5H10O	pungent, bitterb	13-alkoxy radicals and isomerisationk
cis-2-penten-1-ol	C5H10O	green-fruityb	13-alkoxy radicalsk
cyclopentanol	C5H10O	unpleasant notesd	Hydroxyl pathwayk
6-methylhepten-5-en-2-ol	C8H16O	Sweet, oily, green, corianderk	Plant metabolitek
1-hexanol	C6H14O	green-appleb; fruity, pungent, bitterd; grass, floral, aromaticf	13-hydroperoxides, LA metabolism, LOX ADH activity on C6 aldehydesd
trans-3-hexen-1-ol	C6H12O	fruity, softb; astringent, bittere	Isomerisationd,k
cis-3-hexen-1-ol	C6H12O	greenb	13-hydroperoxides, LnA metabolism, LOXd
trans-2-hexen-1-ol	C6H12O	green-bananab	α-LnA metabolism, Isomerisation, LOXd
cis-2-hexen-1-ol	C6H12O	Green, leafy, fruityk	Isomerisationd,k
1-octene-3-ol	C8H16O	mushrooma; moistness-humidityd; mouldye	Derivation from oct-1-en-3-one and short chain fatty acidsd
3-methylheptan-1-ol	C8H18O	citrusk	Plant metabolitek
1-octanol	C8H18O	Waxy, green, citrus, aldehydic and floral with a sweet, fatty, coconut nuancek	Plant metabolitek
benzene methanol	C7H8O	Sweet, floral, fruity with chemical nuancesk	Plant metabolitek
benzeneethanol	C8H10O	Sweet, floral, fresh and bready with a rosey honey nuancek	Plant metabolite; An antimicrobial, antiseptic and disinfectantk
1-hexadecanol	C16H34O	Waxy, clean, greasy, floral, oilyk	reduction of palmitic acidk
butyraldehyde	C4H8O	Pungent, cocoa, greenk	reductase using p-nitrobenzaldehydek
2-methyl propanal	C4H8O	Fresh, aldehydic, floral, green, pungentk	Saccharomyces cerevisiae metabolitek
2-propenal	C3H4O	fruity, almond, cherryk	xenobiotic metabolite and a herbicidek
2-methyl butanal	C5H10O	unpleasant notesd; musty, rummy, nutty, cereal, caramellic, fruityk	plant metabolite, Saccharomyces cerevisiae metabolitek
3-methylbutanal	C5H10O	unpleasant notesd; fruity dry green chocolate nutty leafy cocoak	plant metabolite, Saccharomyces cerevisiae metabolitek
pentanal	C5H10O	almond, malte; winey, fermentedk	Protein kinase catalytic activityk
hexanal	C6H12O	green, appleb,e; fruity, pungent, bitterd; grasse	HPL activity on 13-hydroperoxides, LA metabolism, LOXd
trans-2-pentenal	C5H8O	unpleasant notesd; green plant, grassyh	Autoxidationd; 13-alkoxy radicalsk
cis-3-hexenal	C6H10O	fresh, green, herba,g	HPL activity on 13-hydroperoxides, LnA metabolism, LOXd
heptanal	C7H14O	citrus, fatty, rancide; green, grassy, clover cilantrok	lipid oxidationk
trans-2-hexenal	C6H10O	fruity, pungent, bitterd; green, apple-like, almond, cut-grassf	α-LnA metabolism, Isomerisation, LOXd
octanal	C8H16O	lemon, fatty, greene; waxy, citrus, fruityk	plant metabolitek
trans-2-heptenal	C7H12O	unpleasant notesd; soap, fat, almonde	monounsaturated fatty acid catabolism with -oxo groupk
nonanal	C9H18O	fat, citrus, greene; fatty, waxy, pungentg	reduction of the carboxy group of nonanoic acidk
trans, trans-2,4-hexadienal	C6H8O	ripe-fruitb; Sweet, green, waxy, aldehydic with fresh melon nuancesk	polyunsaturated fatty acid catabolismk
trans, 2-octenal	C8H14O	unpleasant notesd; fatty, citrus, peel, spicy, cucumberk	antifungal agent
trans, trans-2,4-heptadienal	C7H10O	unpleasant notesd; fatty, green, oily, greasyk	Autoxidationd
decanal	C10H20O	fatty, soapyh; orange, peel, soap, tallowj	reduction of the carboxy group of capric acid (decanoic acid)k
trans, 2-nonenal	C9H16O	unpleasant notesd; tallowj; Green, cucumber, aldehydic, fatty with a citrus nuancek	monounsaturated fatty acid catabolism with -oxo groupk
trans, 2-tridecenal	C13H24O	Aldehydic, citrus-Iike fatty, green and creamyk	plant metabolitek
cis/trans, 2-decenal	C10H18O	soapy, fattyh; tallowj; waxy, fatty, earthy, coriander, mushroom, green with a pork fat nuancek	Nature of some essential oilsk
trans, trans, 2,4-nonadienal	C9H14O	unpleasant notesd fattyh; melon, waxyk	Lipid oxidationk
2-undecenal	C11H20O	olive, fattyh; roasted, mango, waxy, citrus peel,k	Lipid oxidationk
trans, trans, 2,4-decadienal	C10H16O	unpleasant notesd; fatty, solventh; fried, waxy, oilyj,k	Lipid oxidationk
methyl benzene	C7H8	-	environmental pollution indicator & from insecticidesk
ethyl benzene	C8H10	-	environmental pollution indicator & from insecticidesk
xylene	C8H10	Plastic, geraniumk	from insecticides and pharmaceuticalsk
propyl benzene	C9H12	-	Simple form of phenylpropanoid lignin skeletonk
1,2,3-trimethyl benzene	C9H12	-	a neurotoxin and a plant metabolite; methylation of toluene and xylenesk
1,2,4-trimethyl benzene	C9H12	-	a neurotoxin and a plant metabolite; methylation of toluene and xylenesk
styrene	C8H8	Sweet, balsamic, floral, plastick	a plant metabolite and a mouse metabolite, an acyclic olefink
1,2,5-trimethyl benzene	C9H12	-	derivatization of benzene ring; oxidation of methyl groupsk
vanillin	C8H8O3	Vanilla, sweet, spicy, phenolick	a plant metabolite, an antioxidant and an anticonvulsantk
trans-α-bergamotene	C15H24	woody, warmk	a plant metabolitek
ethyl acetate	C4H8O2	winey, vinegaryc,d; sticky, sweetf	Anaerobic fermentationd
butyl acetate	C6H12O2	sweet, ripe banana, tutti frutti, tropical and candy-like with green nuancesk	Derivation of butan-1-olk
ethyl propionate	C5H10O2	fruityc; etherial, fruity, sweet, winey, bubble gum, apple and grape nuancesk	Derivation of ethanolk
hexyl acetate	C8H16O2	fruityc	13-hydroperoxides, LA metabolism, LOXd
methyl heptanoate	C8H16O2	pepper, sweet, fruit, green, orris, waxy, floral, berryk	methylation of heptadecanoic acidk
methyl octanoate	C9H18O2	waxy, green, sweet, orange, aldehydic, vegetable, herbalk	Formal condensation of the carboxy group of octanoic acid with the hydroxyl group of methanolk
octyl formate	C9H18O2	fruity, rose, orange, waxy, cucumberk	Derivation of octan-1-olk
ethyl octadecanoate	C20H40O2	waxyk	Formal condensation between the carboxy group of octadecanoic (stearic) acid and the ydroxyl group of ethanol; a plant metabolitek
methyl nonanoate	C10H20O2	winey, waxy, green celery and pear, with an unripe fruit nuancek	formal condensation of methanol and nonanoic acidk
2-hydroxy methyl benzoate	C8H8O3	Sweet, creamy, vanilla-like, spicy, woodyi	Nature of fruiti
cis-3-hexene-1-ol acetate	C8H14O2	banana-like, green, fruity, floral, esterf	13-hydroperoxides, LnA metabolism, LOX, AAT activity on C6 alcoholsd
Hexanoic acid, 1-methylethyl ester	C9H18O2	fruity, pineapple, berryk	a plant metabolitek
2-pentyl furan	C9H14O	fruity, green, earthy, beany, vegetablek	Aspergillus fumigatus infections; catabolic reactionsk
2-ethyl furan	C6H8O	sweet, burnt, earthy, maltyk	a constituent of numerous plant speciesk
octane	C8H18	gasolinei	Xenobiotici
1,1-dimethyl-2-(2-methyl-2-propenyl)-cyclopropane	C9H16	-	fragmentationk
decane	C10H22	-	fragmentationk
2-ethyl, 6-methyl, 1,5-heptadiene	C10H18	-	fragmentationk
3-ethyl, 1,5-octadiene	C10H18	-	a plant metabolitek
4,8-dimethyl, 1,7-nonadiene	C11H20	-	a constituent of aromatic oilsk
4,5-dimethyl, 2,6-octadiene	C10H18	-	fragmentationk
2-methyl, 6-methylene, 2-octene	C10H18	-	fragmentationk
trans-3-octadecene	C18H36	-	fragmentationk
3-carene	C10H16	Citrus, sweet, terpenic, fir needlek	Dimerization of C5 moleculesd; a plant metabolitek
docosane	C22H46	waxyk	a plant metabolite k
tetracosane	C24H50	-	a plant metabolite k
squalene	C30H50	floralk	olive metabolitek
pentacosane	C25H52	waxyk	a plant metabolite k
galangin	C15H10O5	bitterk	7-hydroxyflavonol with additional hydroxy groups; an antimicrobial agent; a plant metabolitek
2-propanone	C3H6O	solvent, ethereal, apple, peark	occurs naturally in plants, trees, forest fires, vehicle exhaustk
2-butanone	C4H8O	ethereal, fruity, camphoraceousk	a bacterial metabolitek
2-pentanone	C5H10O	Sweet, fruity, ethereal, wine, banana, woodyk	a plant metabolite k
3-pentanone	C5H10O	sweetb; ethereal, acetonek	Triatoma brasiliensis, Triatoma infestans infections
4-methyl, 2-pentanone	C6H12O	Sharp, solvent-like with green, herbal, fruity and dairy nuancesk	-
1-penten-3-one	C5H8O	sweet, strawberry, pungency, metallicb,c,d; green, strawberry, sharpf	Prolonged contact with metal surfaced; 13-alcoxy radicalsk
2-heptanone	C7H14O	wet soilc	Fungal activityc
2-octanone	C8H16O	unpleasant notesd; musty, ketonic, cheesy, earthy, dairy	Lipid oxidationd
2-pentadecanone	C15H30O	Fatty, spicy, floralk	a plant metabolite k
5-ethyl-(5h)-furan-2-one	C6H8O2	Spicyk	a plant metabolite k
6-methyl, 5-heptene-2-one	C8H14O	green-fruity, grasse	a plant metabolite k
5-methyl, 4-hexene-3-one	C7H12O	-	a plant metabolitek
acetic acid	C2H4O2	winey-vinegaryc,d	Anaerobic fermentationd
propanoic acid	C3H6O2	unpleasant notesd; rancid, soya, pungente	Anaerobic fermentationd
butanoic acid	C4H8O2	unpleasant notesd rancid, soya, pungente	Anaerobic fermentationd
hexanoic acid	C6H12O2	oilyh	Caproic acid is found naturally in various plantk
heptanoic acid	C7H14O2	Cheesy, waxy, sweaty, fermented, pineapple, fruityk	a C7, straight-chain fatty acid that contributes to the odour of some rancid oilsk
octanoic acid	C8H16O2	Fatty, waxy, rancid, oily, cheesyk	an antibacterial agent; a conjugate acid of an octanoatek
nonanoic acid	C9H18O2	Waxy, dirty and cheesy with a cultured dairy nuancek	herbicide; antifungalk
octadecanoic acid	C18H36O2	Odourless, mild, fatty, waxyk	Nature of some essential oilsk
6-octadecenoic acid	C18H34O2	-	Nature of some essential oilsk
cis-9-octadecenoic acid	C18H34O2	Fatty, vegetable oilk	Nature of some essential oilsk
trans-9-octadecenoic acid	C18H34O2	-	Nature of some essential oilsk
α-copaene	C15H24	sweet, fruityh; woody, spicy, honeyk	a plant metabolitek
zingiberene	C15H24	floralh; spicy, fresh, sharpk	a plant metabolitek
δ-curcumene	C15H24	herbal k	a plant metabolitek
α-Sesquiphellandrene	C15H24	floralh	a plant metabolitek
trans- caryophyllene	C15H24	wood, oak, drya	a plant metabolitek
funebrene	C15H24	cedarwood, woodyk	a plant metabolitek
β- himachalene	C15H24	-	a plant metabolitek
valencene	C15H24	mint, orange blossomh	a plant metabolitek
α-muurolene	C15H24	Herbal, woody, spicyk	a plant metabolitek
α-farnesene	C15H24	floral, green plant, herbh	Natural coating material of fruits for defencing against to fungal attacki
cadidene	C15H24	wood, fragrant, flowerya	a plant metabolitek
bisabolene	C15H24	balsamic, woodyk	a plant metabolitek
α-pinene	C10H16	pine, fragrant, fresha; woody, herbal, spicy, tropicalk	Dimerization of C5 moleculesd; a plant metabolitek
β-myrcene	C10H16	balsamica	Dimerization of C5 moleculesd; a plant metabolitek
limonene	C10H16	sweet, citrusa	Dimerization of C5 moleculesd; a plant metabolitek
trans-ocimene	C10H16	herba	Dimerization of C5 moleculesd; a plant metabolitek
α-terpinene	C10H16	lemon, wooda	Dimerization of C5 moleculesd; a plant metabolitek
linalool	C10H18O	lilac, lavenderf	Phenolic-protein interactionsf

LOX: lipoxygenase enzymatic pathway; LA: Linoleic acid; LnA: Linolenic acid. HPL: hydroperoxide lyase; ADH: Alcohol dehydrogenase; AAT: alcohol acetyl transferase. ^aSong and Liu (2018); ^bRidolfi et al. (2002); ^cFEMA (2020); ^dBoskou (2012); ^eAparicio-Ruiz et al. (2018); ^fGenovese et al. (2018); ^gKalua et al. (2007); ^hKesen et al. (2013); ⁱAbbatangelo et al. (2019); ^jZhu et al. (2016); ^k web sites (flavornet.org; pubchem.ncbi.nlm.nih.gov; TGSC Information System).

Table 5.

Volatile profiles of Ayvalık VOOs, %.

Codes	Aldehydes		Ketones		Esters		Alcohols		Organic Acid	Terpene	Benzene Ringed	Furan Ringed	Hydrocarbons
	Total	by LOX	Total	by LOX	Total	by LOX	Total	by LOX
GO1	28.40 h	78.14 H	4.03 d	46.17 H	0.71 j	46.11 A	15.01 c	62.64 F	3.21 e	8.53 h	2.36 m	0.73 h	37.02 e
GO2	30.03 g	84.82 C	3.57 e	43.59 J	1.28 g	2.91 L	13.76 e	62.61 F	3.29 d	11.15 g	2.79 i	1.35 c	32.78 g
GO3	31.19 e	76.32 I	3.10 f	34.09 L	0.82 i	42.46 C	13.72 f	60.92 G	6.61 b	5.70 k	10.40 a	1.25 d	27.22 h
GO4	23.94 j	81.32 G	9.48 a	33.04 M	0.31 k	23.08 D	26.71 a	57.78 H	2.81 f	6.89 i	10.30 b	0.54 j	19.03 i
GO5	23.28 k	78.12 H	2.51 j	42.18 K	0.85 i	4.54 I	15.20 b	48.63 K	2.55 g	14.58 d	7.76 c	0.53 j	32.74 g
GO6	31.19 e	61.84 L	3.11 f	52.28 F	0.69 j	6.55 H	12.86 g	62.94 E	2.79 f	4.15 l	2.46 l	1.14 e	41.61 d
GO7	35.00 d	72.89 J	2.31 k	73.95 C	2.50 c	4.32 J	13.99 d	52.24 I	8.54 a	12.99 e	2.67 j	3.75 a	18.23 j
GO8	7.50 m	83.41 E	0.43 m	0.00 N	0.02 l	0.00 N	8.05 k	65.92 D	0.70 i	0.32 n	2.56 k	0.09 k	80.32 a
GO9	27.62 i	83.51 D	1.87 l	74.32 B	0.92 h	3.01 K	12.20 h	38.73 L	2.00 h	2.51 m	4.53 f	1.06 f	47.30 b
GO10	35.77 c	65.87 K	3.02 g	44.21 I	2.04 d	11.86 F	5.80 l	85.42 B	4.52 c	32.48 b	4.45 g	0.01 l	11.90 l
GO11	21.20 l	87.36 A	2.61 i	68.85 D	1.37 f	1.47 M	2.24 n	50.28 J	0.28 j	38.14 a	1.10 n	0.00 l	33.06 f
GO12	30.90 f	82.44 F	2.69 h	55.87 E	1.78 e	44.98 B	10.13 i	34.53 M	2.08 h	6.14 j	3.58 h	0.67 i	42.04 c
GO13	47.45 a	86.66 B	5.31 b	46.97 G	6.04 b	10.84 G	8.22 j	76.11 C	0.00 k	12.45 f	5.24 e	0.87 g	14.41 k
GO14	42.65 b	83.43 E	4.85 c	91.11 A	6.49 a	12.66 E	5.18 m	92.06 A	0.74 i	21.53 c	5.67 d	1.48 b	11.42 m

LOX: lipoxygenase enzymatic pathway, Standard Deviations ≤0.2.

Means within a column with different letters are significantly different (P ≤ 0.05).

Aldehydes were found the most abundant volatiles in "Ayvalık" VOOs. The aldehyde compounds (n:24) were detected with a total concentration of 11.77 ppm. The terpenes (n:18) were detected in a total amount of 8.08 ppm. So, terpenes were determined as the second abundant volatile group of "Ayvalık" VOOs. The alcohols (n:21) were isolated; however not all of them was generated by LOX reactions. Their concentration was 7.07 ppm. The benzene ringed compounds (n:10) were identified with a total amount of 2.83 ppm. 11 ketone, 11 acid, 12 ester, and 3 furan compounds were defined by approximately 1.63, 1.74, 0.71 and 0.23 ppm, respectively. Guclu et al. (2016) reported for Ayvalık VOOs obtained from different growing area (Mersin province) in Turkey that 6.3 ppm aldehyde, 6.2 ppm alcohol, 2.3 ppm terpene, 0.2 ppm ester, 0.002 ppm butanoic acid presence.

With another perspective, isolated organic volatile compounds namely, aldehydes, ketones, esters, alcohols, acids, terpenes, benzene and furan ringed contents, and straight hydrocarbons were totally found in this study that 100.38 ppm for GO1, 57.43 ppm for GO2, 81.62 ppm for GO3, 18.6 ppm for GO4, 135.09 ppm for GO5, 36.36 ppm for GO6, 41.39 ppm for GO7, 55.43 ppm for GO8, 50.67 ppm for GO9, 86.67 ppm for GO10, 42.92 ppm for GO11, 20.57 ppm for GO12, 13.74 ppm for GO13 and 12.17 ppm for GO14 growing areas, respectively. For "Ayvalık" VOOs, it could be seen from Figure 3a that aldehydes and alcohols were the most detected volatile group generated by LOX. At the same time, ester and ketone concentration were obviously varied between geographical origins. C5 and C6 aldehydes, ketones, alcohols and esters produced by LOX pathway gains to VOO fresh-green notes (cut grass, unripe fruit, almond), green-fruity notes (green, sweet, strawberry, herbal), green-fruity notes (leaf, grass, bitter, banana), fruity-floral notes (sweet, banana-tomato, flowery, species), respectively (Table 4).

Figure 3.

Volatile profiles of Ayvalık VOOs; a) total amount (ppm) of volatiles b) total percentage of volatiles generated via LOX pathway.

As also shown at Figure 3b, GO1 and GO3 had well-balanced odour based on LOX volatiles. There were no ketone and ester compounds in volatile fraction of GO8 formed by LOX even any harvest year. Moreover, a little ester content was isolated from GO2, GO9 and GO11. The highest content of aldehydes was detected at GO11, the highest content of ketones at GO14, the highest content of esters at GO1, the highest content of alcohols at GO14 geographical origin. Most of terpene compounds stem from olive fruit as a plant metabolite (Table 4). In this study, the highest terpene contents were defined at GO11 and GO10 respectively (Table 5). These volatile compounds attributed with woody, herbal, spicy, sharp and floral odours (Table 4). It was characteristically found that "Ayvalık" VOOs contains 7.50–47.45% aldehydes, 0.32–38.14% terpenes, 2.24–26.71% alcohols, 1.10–10.40% benzene ringed compounds, 0.43–9.48% ketones, 0.00–8.54% organic acids, 0.02–6.49% esters, 0.00–3.75% furans. The rest of those had contained straight chain-hydrocarbons and some other fragmentation products. It was also observed that 61.84–87.36% of aldehydes, 0.00–91.11% of ketones, 0.00–46.11% of esters and 34.53–92.06% of alcohols were generated only by LOX pathway among investigated harvest seasons (Table 5).

4. Conclusions

A notable and comprehensive data set was generated including quality indices, oxidative properties, fatty acid and volatile profiles of “Ayvalık” VOOs by this presented research. 125 different volatile compounds were isolated and amounts were calculated. Their generation mechanisms were chemically defined. Aldehydes, terpenes and alcohols were found the most three abundant volatile groups. Overall high-quality “Ayvalık” VOOs can be described as full of positive attributes such as fresh, green, fruity, flowery notes. The major fatty acids were oleic, palmitic, linoleic, stearic and palmitoleic acids, respectively. Quality parameters and profile of fatty acids and volatiles isolated from “Ayvalık” EVOO showed a strong link with its geographical roots. It was expected that by this way, a rapid acceleration in the number of new geographical registrations, which is one of the most competitive economic strategies for value-added VOOs, linked “Ayvalık” variety.

Declarations

Author contribution statement

Didar Üçüncüoğlu: Conceived and designed the experiments; Performed the experiments; Analyzed and interpreted the data; Contributed reagents, materials, analysis tools or data; Wrote the paper.

Dilek Sivri-Özay: Conceived and designed the experiments; Contributed reagents, materials, analysis tools or data; Wrote the paper.

Funding statement

This work was financially supported by the Republic of Turkey, Ministry of Agriculture and Forestry, General Directorate of Agricultural Research and Policies (TAGEM,) Research & Development Project (R&D 12–26), Turkey. The volatile analysis were funded by Hacettepe University Scientific Research Projects Coordination Unit (Project, 1933), Turkey.

Competing interest statement

The authors declare no conflict of interest.

Additional information

No additional information is available for this paper.