Characterization of Turkish Extra Virgin Olive Oils and Classification Based on Their Growth Regions Coupled with Multivariate Analysis

Proximate analysis and fatty acid, mineral and soluble carbohydrate profiles of some brown macroalgae collected from Türkiye coasts

In this study, the fatty acid, carbohydrate, and mineral profiles and proximate composition of Halopteris scoparia, Padina pavonica, Zanardinia typus, Cladostephus spongiosum, Sargassum vulgare, and Sargassum acinarium brown macroalgae collected from Türkiye seas were determined. According to the results, the ash and total carbohydrate contents of all macroalgae ranged from 20.79 to 53.49% in dry weight (dw) and from 15.32 to 55.13% dw, respectively. Their protein, lipid and crude fiber contents changed between 4.22 and 9.89% dw, 0.25 and 0.90% dw, and 12.28 and 16.01% dw, respectively. Palmitic acid (29.36-48.55% dw) and oleic acid (8.92-20.92% dw) were at the highest levels in all brown macroalgae. In addition, they included prominent levels of saturated fatty acids (51.87-69.56% dw of total fatty acid content). Magnesium (6.97-18.78 mg/kg dw), potassium (1.34-3.78 mg/kg dw), iron (1.27-8.24 mg/kg dw), and manganese (63.10-252.23 μg/kg dw) were found to be the major minerals. The main soluble carbohydrates of macroalgae were found to be mannitol (1149.99-8676.31 mg/kg dw), glucose (368.78-1305.59 mg/kg dw), myo-inositol (225.96-956.78 mg/kg dw), fructose (137.05-689.21 mg/kg dw), and sucrose (189.55-328.06 mg/kg dw). This study revealed that brown macroalgae are particularly rich in potassium, magnesium, iron, manganese, and zinc and they may have potential for use in the food industry.

Characterization and Comparison of Extra Virgin Olive Oils of Turkish Olive Cultivars

Extra virgin olive oils (EVOOs) obtained from five Turkish olive cultivars widely produced in the Aegean and Marmara regions were investigated based on their total antioxidant capacity (TAC), total phenolic content (TPC), pigment contents, fatty acid (FA) profiles, phenolic compounds (PC), volatile compounds (VC), and sensory properties. The results showed that all properties of EVOO samples were significantly affected by the olive cultivar used. The pigment contents in Ayvalık (9.90 mg·kg^-1) and Uslu (9.00 mg·kg^-1) oils were higher than the others (p < 0.05). The greatest values for oleic acid (74.13%) and TPC (350.6 mg·kg^-1) were observed in Gemlik and Domat oils, respectively (p < 0.05). Edincik oil showed the maximum hydroxytyrosol content (48.022 mg·kg^-1) and TAC value (515.36 mg TE·kg^-1) (p < 0.05). The Edincik, Domat, and Uslu oils were significantly not different for the total content of C6 compounds derived by lipoxygenase, which are the main volatiles responsible for the typical aroma of EVOOs (p > 0.05). Domat oil also exhibited the highest scores for bitterness and pungency perceptions (p < 0.05). The fruitiness scores of the oil samples (except for Ayvalık oil) were close to each other, even if they were statistically different (p < 0.05). Principal component analysis (PCA) indicated that the Ayvalık oil was separated from the others due to its poor-quality characteristics. As a result, it can be stated that Domat olive oil has better quality than the others.

Phenolic Constituents, Antioxidant and Antimicrobial Activity and Clustering Analysis of Propolis Samples Based on PCA from Different Regions of Anatolia

This study aimed to evaluate the biochemical composition and biological activity of propolis samples from different regions of Türkiye to characterize and classify 24 Anatolian propolis samples according to their geographical origin. Chemometric techniques, namely, principal component analysis (PCA) and a hierarchical clustering algorithm (HCA), were applied for the first time to all data, including antioxidant capacity, individual phenolic constituents, and the antimicrobial activity of propolis to reveal the possible clustering of Anatolian propolis samples according to their geographical origin. As a result, the total phenolic content (TPC) of the propolis samples varied from 16.73 to 125.83 mg gallic acid equivalent per gram (GAE/g) sample, while the number of total flavonoids varied from 57.98 to 327.38 mg quercetin equivalent per gram (QE/g) sample. The identified constituents of propolis were phenolic/aromatic acids (chlorogenic acid, caffeic acid, p-coumaric acid, ferulic acid, and trans-cinnamic acid), phenolic aldehyde (vanillin), and flavonoids (pinocembrin, kaempferol, pinobanksin, and apigenin). This study has shown that the application of the PCA chemometric method to the biochemical composition and biological activity of propolis allows for the successful clustering of Anatolian propolis samples from different regions of Türkiye, except for samples from the Black Sea region.

Fatty Acid and Sterol Compositions of Turkish Monovarietal Olive Oils with Regard to Olive Ripening

This study was conducted in crop season of 2018 and the olive fruits from three Turkish varieties Saurani, Karamani and Halhalı under the same pedoclimatic conditions (with no irrigation and no fertilization) were assessed. Oil content, fatty acid, and sterol compositions of three monovarietal 'Halhalı', 'Karamani', and 'Saurani' virgin olive oils were examined at green, spotted and ripe olives. The oil content of olives ranges between 23.77-34.77% and the highest oil yield was observed in the ripe Karamani variety. In terms of fatty acids, the lowest oleic acid values were found in the ripe period of Karamani variety (59.78%), and the highest oleic acid values in the green period of Halhalı variety (69.97%). The oleic and palmitic acid contents decreased, while linoleic and stearic acid contents increased with olive ripening. Total sterol amounts of olive oils varied between 946-1782 mg/kg and showed a significant increase with ripening (p < 0.05). The highest β-sitosterol amount was detected in the green period of Saurani variety (91.66%), and the lowest β-sitosterol amount in the spotted period of Halhalı variety (86.16%). The highest ∆⁵-avenasterol amounts were detected in the ripe period of Saurani variety (6.54%), the lowest ∆⁵-avenasterol amounts were detected in the green period of Halhalı variety (2.36%). Total β-sitosterol, stigmasterol and erythrodiol+uvaol contents of olive oils are changed with ripening. Accordingly, these results showed that fatty acid and sterol compositions can be used as indicators of variety and ripening degree among monovarietal virgin olive oils.

Genome-wide exploration of oil biosynthesis genes in cultivated olive tree varieties (Olea europaea): insights into regulation of oil biosynthesis

Genome-wide oil biosynthesis was explored by de novo sequencing two cultivated olive tree (Olea europaea) varieties (cv. Ayvalik and Picual). This is the first report of the former variety sequencing. As outgroups, raw reads of cv. Leccino and scaffold-level assembly of cv. Farga were also retrieved. Each of these four cultivars was chromosome-scale assembled into 23 pseudochromosomes, with 1.31 Gbp (Farga), 0.93 Gbp (Ayvalik), 0.7 Gbp (Picual), and 0.54 Gbp (Leccino) in size. Ab initio gene finding was performed on these assemblies, using wild olive tree (oleaster)-trained parameters. High numbers of gene models were predicted and anchored to the pseudochromosomes: 69,028 (Ayvalik), 55,073 (Picual), 63,785 (Farga), and 40,449 (Leccino). Using previously reported oil biosynthesis genes from wild olive tree genome project, the following homologous sequences were identified: 1,355 (Ayvalik), 1,269 (Farga), 812 (Leccino), and 774 (Picual). Of these, 358 sequences were commonly shared by all cultivars. Besides, some sequences were cultivar unique: Ayvalik (126), Farga (118), Leccino (46), and Picual (52). These putative sequences were assigned to various GO terms, ranging from lipid metabolism to stress tolerance, from signal transactions to development, and to many others, implicating that oil biosynthesis is synergistically regulated with involvement of various other pathways.