Effect of harvest time on physicochemical quality parameters, oxidation stability, and volatile compounds of extra virgin olive oil

The aim of this study was to determine the changes in some physicochemical properties of olives (fruit weight, water content and oil content) and olive oils (total chlorophyll, carotenoid, pheophytin a, peroxide value and free acidity), and in the chemical properties (fatty acids, tocopherols, phenolics, oxidation stability and volatile profiles) of oils during ripening.Ripening indices (RI) of olive samples were 1.93 (unripe), 4.28 (ripe) and 5.89 (overripe). Most of the mentioned features changed with ripening. During ripening there was a sharp decrease in total chlorophyll, carotenoid and pheophytin a contents. An increase in oleic and linoleic acids and a decrease in palmitic acid were found in the fatty acid composition. Olive oils showed strong relations among oxidation stability, tocopherol content, total phenols content, and antiradical actvity of phenol extracts and these parameters decreased with maturation. Nevertheless, higher amounts of trans-2-hexenal were found in the oil from ripe olives than from unripe and overripe olives. On the other hand, the highest concentration of hexanal was found in the oil from overripe olives.In general, significant differences were observed in fruit weight, pigments, free acidity, fatty acid, tocopherol, and total phenolics contents, radical scavenger activity, oxidation stability, phenolic profile and volatile profile between the olive oils from the Gemlik cultivar at different stages of maturation

Synthesis of axially disubstituted silicon phthalocyanines and investigation of their in vitro cytotoxic/phototoxic anticancer activities

In this study, two SiPcs have been selected and the photodynamic therapy potentials were evaluated of the Pcs. Synthesis of Axially 2-decyn-1-oxy disubstituted Es-SiPc-2 was newly synthesized by the reaction of SiPcCl2 with 2-decyn-1-ol in the presence of NaH in toluene. Furthermore, their nuclear imaging potentials were evaluated in human colon adenocarcinoma (HT-29) and human lung fibroblast cell (WI-38) cell lines. The uptake results have indicated that Es-SiPc labeled with 131I radionuclide (131I-Es-SiPc) was approximately 2-fold higher in the HT-29 cell line than the WI-38 cell line. In other words, the target/non-target tissue ratio is defined as two in the HT-29/WI-38 cell lines. Besides, the uptake values of 131I-Es-SiPc were found to be higher than 131I-Es-SiPc-2. 131I-Es-SiPc and 131I-Es-SiPc-2 are promising for imaging or treating colon adenocarcinoma. In vitro photodynamic therapy (PDT) studies have shown that both compounds are suitable and can be used in this field. Also, Es-SiPc has been shown to have higher phototoxicity than Es-SiPc-2. © 2020 World Scientific Publishing Company

I-based hybrid electrode

We experimentally demonstrate that oriented assembly of red algal photosystem I (PSI) reaction centers on a plasmonically active Silver Island Film (SIF) leads to strong enhancement of both the fluorescence intensity and photocurrent generated upon illumination. PSI complexes were specifically attached to a monolayer of graphene deposited on the SIF layer. The results of comprehensive fluorescence microscopy point to the critical role of the SIF layer in enhancing the optical response of PSI, as we observe increased emission intensity. Hence, importantly, the strong increase of photocurrent generation demonstrated for the biohybrid electrodes can be directly associated with the plasmonic enhancement of the optical and electrochemical functionalities of PSI. The results also indicate that the graphene layer is not diminishing the influence of the plasmonic excitations in SIF on the absorption and emission of PSI.C1 [Szalkowski, Marcin; Mackowski, Sebastian; Kowalska, Dorota] Nicolaus Copernicus Univ, Fac Phys Astron & Informat, Inst Phys, Grudziadzka 5, PL-87100 Torun, Poland.[Szalkowski, Marcin] Polish Acad Sci, Inst Low Temp & Struct Res, Okolna 2, PL-50422 Wroclaw, Poland.[Harputlu, Ersan; Ocakoglu, Kasim] Tarsus Univ, Fac Technol, Dept Energy Syst Engn, TR-33400 Tarsus, Turkey.[Kiliszek, Malgorzata; Kargul, Joanna] Univ Warsaw, Ctr New Technol, Solar Fuels Lab, Banacha 2C, PL-02097 Warsaw, Poland.[Unlu, C. Gokhan] Pamukkale Univ, Dept Biomed Engn, TR-20070 Denizli, Turkey

to improvement in photocurrent generation

We report the fabrication of an oriented bioelectrode of photosystem I (PSI) on single-layer graphene (SLG). This bioelectrode demonstrates improved photocurrent generation, which can be directly attributed to the molecular conductive interface formed by cytochrome c(553) (cyt c(553)) promoting the uniform orientation of PSI with its donor side towards the electrode. The conductive interface between PSI-cyt c(553) and SLG is facilitated by a monolayer composed of pi-pi-stacked pyrene functionalized with the Ni-NTA moiety, which binds the His6-tagged cyt c(553). The surface uniformity of the PSI protein orientation in the electrode structure is evidenced by cross-sectional scanning electron microscopy and fluorescence microscopy, with the latter also proving the efficient electronic coupling between majority of the PSI complexes and graphene. With the uniform organization of the biological photoactive layer, photocurrents are generated at the open circuit potential, which can be further increased when a negative potential is applied. Indeed, at the highest applied negative potential (-0.3 V), over 5-fold increase in the cathodic photocurrent for the PSI complexes conjugated via cyt c(553) to the SLG substrate is observed compared with that obtained for the randomly oriented structure where PSI is physisorbed on graphene. These results indicate the key role of a strictly defined orientation of photoactive proteins on electrodes for proper electron transfer and substantial improvement in photocurrent generation in the present or similar bioelectrode architectures

Characterization of Aegean olive oils by their minor compounds

This study presents combined approach of establishing cultivar difference between Aegean olive oils, obtained from economically important olive oil producing cultivars (cv..Ayvalık and Memecik), based on chemometric evaluation of their content and in particular composition of minor compounds. Evaluation of minor compounds with principal component analysis (PCA) and linear discriminant analysis (LDA) indicated differentiation according to the cultivars. LDA produced a 100 % correct group classification. Moreover, stigmasterol, apparent β-sitosterol and total sterols were found to have the highest discriminating power. Memecik oils were characterized by the highest content of antioxidant compounds (α-tocopherol, phenolic compounds and total phenolic compounds). On the other hand, Ayvalık oil had the highest level of total sterols. The data were analyzed statistically to evaluate the differences according to variety and crop season. The minor compounds of Ayvalık and Memecik oils presented statistically significant differences (p < 0.01) according to variety, except for the hydroxytyrosol and clerosterol content. The amount of α-tocopherol, total phenolic compounds, apparent β-sitosterol and total sterols varied with respect to crop season. A good correlation was observed between the amount of α-tocopherol, total phenolic compounds, apparent β-sitosterol and total sterols and some climatic variables

LC-ESI-MS characterization of phenolic profiles Turkish olive oils as influenced by geographic origin and harvest year

The purpose of this investigation was to evaluate and compare the differences in the phenolic fractions and antioxidant properties of virgin olive oils from the Nizip yaglik and Kilis yaglik olive varieties cultivated in native and different olive growing areas of Turkey. The phenolic composition of olive oils was carried out by HPLC-DAD and identifications were made by LC-MS. Fourteen phenolic compounds were identified and among these compounds elenolic acid, tyrosol and hydroxytyrosol were the most dominant. Based on the results, there was no difference in distribution of phenolic compounds, but the total phenolic content in oil from native regions was higher than in oil from Bornova regions. The antioxidant capacity of olive oil extracts was determined by two different methods, including DPPH and ABTS. In both methods, antioxidant capacity values were higher in oil from native regions. © 2013 AOCS.110O602, ZF-2010-D24Acknowledgments The authors thank the Scientific and Technical Research Council of Turkey (TUBITAK) and Cukurova University Research Fund (ZF-2010-D24) for financial support for this research project (Project No. 110O602)