Discrimination of extra virgin olive oil with chemometric methods according to their aroma profiles

Bu çalışmada, ülkemizin kalite ve ekonomik açıdan en önemli yağlık zeytin çeşitleri olan Ayvalık ve Memecik tipi zeytinlerinden elde edilen naturel sızma zeytinyağlarının aroma bileşenlerine göre karakterizasyonu ve sınıflandırılması kemometrik tekniklerden PCA (temel bileşen analizi) ve LDA (doğrusal ayırma analizi) yardımıyla gerçekleştirilmiştir. Zeytinyağlarında, lipoksigenaz metabolik yolu ile meydana gelen hekzanal, E-2-hekzenal, hekzanol, Z-3-hekzenol ve E-2-hekzenol bileşenlerinin aroma profilini oluşturan başlıca uçucu bileşenler olduğu saptanmıştır. Ayvalık tipi zeytinyağlarında terpenlerden limonen ve undekan tespit edilirken Memecik tipi zeytinyağlarında α-kopaen tespit edilmiştir. Ayvalık ve Memecik tipi zeytinyağlarının, hekzanal, E-2-hekzenal, E-2-hekzenol, 3-etil-1,5-oktadien ve linolenik asitten meydana gelen C6 bileşikleri toplamı pik alanı yüzdeleri arasındaki fark istatistiksel olarak önemli bulunmuştur. İki hasat sezonundan alınan örnekler ile yapılan çalışmada, hasat sezonları arasında E-2-hekzenal, Z-3-hekzenol, Z-3-hekzenil asetat, hekzil asetat ve linolenik asitten meydana gelen C6 bileşikleri toplamı pik alanı yüzdeleri arasındaki farklılıkların istatistiksel olarak önemli olduğu saptanmıştır. Memecik tipi zeytinyağlarının C6 bileşiklerinden E-2-hekzenal, hekzanol ve E-2-hekzenol pik alanı yüzdelerinin Ayvalık tipi zeytinyağlarına göre daha yüksek olduğu tespit edilmiştir. Temel bileşen skor grafiğinde, Ayvalık ve Memecik tipi zeytinyağlarının iki ayrı grup oluşturduğu gözlenmiştir. Doğrusal ayırma analizi sonuçlarına göre zeytinyağlarının doğru gruplara atanma oranı % 100 olarak bulunmuştur.  Anahtar Kelimeler: Zeytinyağı, aroma, Ayvalık zeytinyağı, Memecik zeytinyağı, kemometrik analiz.Olive oil is obtained from the fruits of olive trees (Olea europaea L.) by mechanical procedures. In terms of value, it accounts for 30 % of the world trade in edible vegetable oils. Mediterranean members of the EU produce approximately 75 % of the world’s olive oil. Turkey, not member of EU, is the world’s 5th largest producer of olive oil (% 5). The consumption of olive oil, the main component of the Mediterranean diet, is increasing because of its nutritional quality and health effects. The beneficial effects of olive oil are attributed to its high content of monounsaturated fatty acids and antioxidants. Olive oil consists of triacylglycerols (98 %) and minor compounds (2 %). Tocopherols, phenols, sterols, hydrocarbon and flavor compounds are minor compounds found in olive oil.The quality of monovarietal olive oil varies on environmental (climate and soil), agronomic (irrigation and fertilization), cultivation (harvest and ripeness) and technological (storage and extraction) factors.The EU allows labelling of food products with growing areas, which could claim a typical quality based on geographical origin of product. Oils are certified with Protected Designation of Origin (PDO) label improving the commercial value of products. Since PDO olive oils have a much higher market price, they are subjected to frauds. To prevent frauds, the reference database are needed. Therefore, characterization of olive oils with respect to cultivar and geographical origin becomes more important in olive oil industry. The chemometric methods such as principal component analysis (PCA) and linear discriminant analysis (LDA) are the methods utilized for the characterization and discrimination of olive oils according to the cultivar and geographic origin. In recent years, the numerous studies have conducted on the chemometric characterization of olive oils using physical and chemical parameters such as fatty acids, sterols, phenols and volatiles. Aegean Region, Marmara Region, Mediterranean Region and Southeasth Region are the olive growing region in Turkey. Aegeon region provides around 75-80 % of total olive oil production. Memecik and Ayvalık are the major cultivars grown in Aegean Region. In literature, the number of studies regarding the characterization of Turkish olive oils are limited. Only few chemical parameters (fatty acids and sterols etc.) were evaluated. Moreover, the chemometric classification of Turkish olive oils were performed only with respect to fatty acid composition.The characteristic aroma of olive oil depends on the volatile compounds. The C6 compounds (aldehydes, alcohols and esters) are enzimatically produced from linoleic and linolenic acids through the so-called lipoxygenase (LOX) pathway. Hexanal, hexanol and hexyl acetate derive from linoleic acid, whereas Z-3-hexenal, E-2-hexenal, Z-3-hexenol and Z-3-hexenyl acetate derive from linolenic acid. The C6 compounds are responsible for the “green” note. The profile of volatiles varies according to the enzymatic activity, which depends on the external factors such as environmental, cultivation and technological ones. To evaluate olive oil aroma, several methods are developed. Solid phase microextraction (SPME) is simple, fast and solvent-free technique integrating sampling, extraction and sample introduction into a single run. A short, thin, solid rod of fused silica, coated with adsorbent polymer is called SPME fiber, which is the same type of chemically inert fused silica used to make capillary GC columns.Various studies have been carried out on the characterization of volatile profile of virgin olive oils. Previous studies were mainly done on Spanish, Italian and French cultivars. However, there is a lack of data defining the volatile profile of Turkish olive oils. The aim of this study was to characterize the profile of volatiles of Turkish olive oils obtained from Ayvalık and Memecik cultivars. The objective of this study was also to classify olive oils with respect to cultivar using chemometric methods. Keywords : Olive oil, aroma, Ayvalık olive oil, Memecik olive oil, chemometric analysis

Avocado-Soybean Unsaponifiables: A Panoply of Potentialities to Be Exploited

Avocado and soybean unsaponifiables (ASU) constitute vegetable extracts made from fruits and seeds of avocado and soybean oil. Characterized by its potent anti-inflammatory effects, this ASU mixture is recommended to act as an adjuvant treatment for osteoarthritic pain and slow-acting symptomatic treatment of hip and knee osteoarthritis; autoimmune diseases; diffuse scleroderma and scleroderma-like states (e.g., morphea, sclerodactyly, scleroderma in bands). Besides, it was reported that it can improve the mood and quality of life of postmenopausal women in reducing menopause-related symptoms. This article aims to summarize the studies on biological effects of the avocado-soybean unsaponifiable, its chemical composition, pharmacotherapy as well as applications in auto-immune, osteoarticular and menopausal disorders. Finally, we will also discuss on its safety, toxicological and regulatory practices

Glycyrrhiza Genus: enlightening phytochemical components for pharmacological and health-promoting abilities

The Glycyrrhiza genus, generally well-known as licorice, is broadly used for food and medicinal purposes around the globe. The genus encompasses a rich pool of bioactive molecules including triterpene saponins (e.g., glycyrrhizin) and flavonoids (e.g., liquiritigenin, liquiritin). This genus is being increasingly exploited for its biological effects such as antioxidant, antibacterial, antifungal, anti-inflammatory, antiproliferative, and cytotoxic activities. The species Glycyrrhiza glabra L. and the compound glycyrrhizin (glycyrrhizic acid) have been studied immensely for their effect on humans. The efficacy of the compound has been reported to be significantly higher on viral hepatitis and immune deficiency syndrome. This review provides up-to-date data on the most widely investigated Glycyrrhiza species for food and medicinal purposes, with special emphasis on secondary metabolites’ composition and bioactive effects

Antioxidative Effect Of Rosemary Antioxidants On Improvement Of Shelf Life Of Hazelnut Puree

Tez (Doktora) -- İstanbul Teknik Üniversitesi, Fen Bilimleri Enstitüsü, 2000Thesis (PhD) -- İstanbul Technical University, Institute of Science and Technology, 2000Bu çalışmada önemli ihracat ürünlerimizden birisi olan fındık füresinin raf ömrünün uzatılmasında biberiye bitkisi (Rosmarinus officinalis) antioksidanlarının (BAE) etkinliğinin incelenmesi amaçlanmıştır. Bu amaçla biberiye antioksidan ekstraktı (BAE), füre yağına konularak, Ransimat, Diferansiyel Taramalı Kalorimetre (DTK) ve Fırın Testi olmak üzere üç farklı hızlandırılmış test yöntemi ile, fındık füresi yağındaki (FFY) Antioksidatif Aktivitesi ve Koruma Faktörü saptanmıştır. Ayrıca BAE' nin füre yağının Q10 değeri ile aktivasyon enerjisi üzerine etkisi de araştırılmıştır . Bunların yanısıra, BHA, BHT, ?-tokoferol gibi sentetik antioksidanların da FFY üzerindeki antioksidatif etkileri belirlenerek, BAE ile sinerjistik etkileri incelenmiştir. Sonuç olarak BAE' nin füre yağında antioksidatif etki göstererek raf ömrünün artmasında etkili olduğu, fakat BAE' nin fındık füresi yağında sentetik antioksidanlarla sinerjistik etki göstermediği görülmüştür. DTK cihazının füre yağının oksidatif indüksiyon süresinin hesaplanmasında kullanılması mümkündür.In this study it was aimed to investigate the effectiveness of rosemary antioxidants on improvement of shelf life of hazelnut puree. For this purpose, antioxidant extract of rosemary (RAE) was added into hazelnut puree oil (HPO) using three different Accelerated Shelf Life tests ;Rancimat, Differantial Scanning Calorimetry (DSC) and Schaal Oven Test to determine the antioxidative activity and Protection Factor of RAE on hazelnut puree oil. Moreover, the effect of RAE on Q10 values and Activation energies of (HPO) were also determined. Furthermore, antioxidative activities of some synthetic antioxidants (BHA, BHT, ?-tocopherol) were determined and their synergistic effects with RAE were also calculated. In conclusion, it was shown that RAE has a significant prolonging efect on the shelf-life of hazelnut puree but RAE has not any synergistic effect with other synergistic antioxidants used. It was also possibile to use DSC for determining the oxidative ınductıon periods.DoktoraPh

Development of affordable 3D food printer with an exchangeable syringe-pump mechanism

The technique of additive manufacturing has increasing popularity in food research area as well as other scientific fields. However, 3D food printers are expensive options compared to 3D polymer printers. Scientists, that require laboratory scale production capacities, resemble the syringe-pump systems that available in open source and free hardware designs. Present study aimed to develop an exchangeable syringe-pump mechanism (SPM) to demonstrate transformation of conventional 3D printer from polymer to food extrusion. The SPM can print a variety of materials, including miscellaneous foods, pastes, hydrogels and even biopolymers. The complete mechanism relies mostly on 3D printed parts and costs approximately 72$. Therefore, it allows users to obtain a 3D food printer inexpensively and does not require large amounts of technical labor. The SPM uses big volume (60 ml) luer lock syringe and blunt tip needles for greater versatility and user-friendliness. It could also be extended with cooling mechanism, so that the proposed system gains unique attribute among its counterparts. Finally, a standard polymer-printing 3D-Printer was converted into a laboratory-scale food printer, and edible ink was successfully printed in the desired shape

A novel antioxidant source: evaluation of in vitro bioaccessibility, antioxidant activity and polyphenol profile of phenolic extract from black radish peel wastes (Raphanus sativus L. var. niger) during simulated gastrointestinal digestion

Yücetepe, Aysun ( Aksaray, Yazar )The aim of this study was to evaluate the potency of polyphenolic extract from black radish (Raphanus sativus L. var. niger) root peel waste (PEBRRP) as an antioxidant food additive. PEBRRP was found a powerful antioxidant extract, in which had 172.9 +/- 11.5, 462.72 +/- 3.05, and 796.51 +/- 10.4 mg TE per g dw of total antioxidant capacity (TAC) by CUPRAC, DPPH, and FRAP assays, respectively. The total phenolic content (TPC) and total flavonoid content (TFC) of PEBRRP were found as 305.51 +/- 5.2 mg GAE per g dw and 171.58 +/- 6.2 mg CAE per g dw, respectively. The ferulic acid (28.02 +/- 4.5 mg per g dw) and epicatechin (19.82 +/- 3.6 mg per g dw) were identified as the main polyphenols in undigested PEBRRP. The bioaccessibility of total phenolic and total flavonoid compounds of PEBRRP was found approximately 5%, and the antioxidant capacity of bioaccessible PEBRPP fraction was determined 6% in CUPRAC, 36% in DPPH and 47% in FRAP methods