Changes in the phenolic content and free radical-scavenging activity of vacuum packed walnut kernels during storage

In this study, the effects of storage temperature, O2 permeability of packaging materials and variety on phenolic content and free radical-scavenging activity of vacuum-packaged walnut kernels were studied over a 12 months storage period. Methyl gallate (23.70 . 93.75 mg/kg), ellagic acid (137.95 . 569.22 mg/kg), and an ellagic acid pentoside (270.59 . 637.17 mg ellagic acid equivalent/kg) were identified in walnut varieties. While a slight decrease in the amount of ellagic acid was observed during 12 months storage, decreases in the amount of ellagic acid pentoside, total phenolic content and free radical-scavenging activity were severe. The present study concluded that it is possible to protect the phenolic content and antiradical activity of walnut kernels by packaging in Polyamide/Polyethylene laminate pouches having an oxygen permeability lower than 63.40±0.40 (mL/m2/24h at 23°C) under vacuum at 20°C up to twelve months

Nitrite in Nature: Determination with Polymeric Materials

Nitrogen compounds being important for the vital activities of living things are produced by the nitrification process and occurred spontaneously in the nitrogen cycle. Human vital activities are also responsible for the extra nitrogen released into the atmosphere. So, both human and environmental healths are negatively affected by the increasing nitrate and nitrate amounts in water and soil. For this reason, it is aimed to ensure regular control of nitrates and nitrites at certain levels in order to protect the universe and all living things. Their precise and selective determination by various methods is very important. Their determinations can usually be made by using electrochemical, spectrophotometric, chromatographic and titrimetric methods. Nowadays instead of these techniques, sensors are preferred in determining nitrate and nitrite due to their easy, fast, selective and sensitive application properties. Furthermore, polymeric materials have shown great promise for different sensing applications such as gas, humidity, explosive and water pollutants. Sensors, which are developed by polymerization, have very high quality for the determination of nitrite. The highly sensitive results of optical and electrochemical sensors attract the attention of researchers. In this review, different detection methods for nitrite ions and various studies on the preparation of polymeric sensors that can selectively capture the nitrite ions in complex matrices are examined

METİLEN MAVİSİ VE ALİZARİN’İN LÜMİNESANS SPEKTROMETRESİ İLE ASİTLİK SABİTLERİNİN TAYİNİ VE BAZI METAL DUYARLILIKLARININ İNCELENMESİ

Organik boyar maddeler endüstride renklendirme amaçlı kullanılmalarının yanı sıra indikatör ve/veya sensör olarak da kullanılabilen önemli hammaddelerdir. Birçoğu metal ve proton iyonlarına duyarlı olduğunda indikatör özelliği kazanır. Ayrıca metal iyonlarına karşı aktif olan birçok boya da sensör kabiliyeti sergilemektedir. Bu araştırmada, Metilen mavisi ve Alizarin boyar maddelerinin sulu çözeltilerinin çalışma pH aralıkları ile asitlik sabitlerinin (pKa) hesaplanması ve metal duyarlılıklarının incelenmesi üzerinde çalışılmıştır. Bu amaçla, Luminesans Spektrometre cihazıyla her iki boyar maddenin de taze hazırlanmış 10-3M’ lık sulu çözeltilerinde uyarma ve emisyon spektrumları ayrı ayrı alınmıştır. Emisyon spektrumlarından faydalanılarak Metilen mavisi ve Alizarin’ in çalışma pH aralıklarının sırasıyla 2-6 ve 2-9 olduğu tespit edilmiştir. Yapılan hesaplamalardan Metilen mavisi için pKa değeri 4,97 olarak bulunurken Alizarin için bu değer 3,70 olarak hesaplanmıştır. İlaveten Metilen mavisi’ nin IB ve IIB grubu-d blok geçiş elementlerinin iyonları olan Cu2+ ve Zn2+ iyonları ile kompleks yapabildikleri gözlenmiştir. Benzer biçimde, Alizarin’ in 3A grubu ve IB ile VIIIB grubu-d blok geçiş elementlerinin iyonları olan Al3+, Cu2+, Co2+, Ni2+ iyonları ile kompleksleşebildiği tespit edilmiştir.

Ultrasound-assisted extraction and (U)HPLC-DAD-ESI-MSn analysis of phenolic compounds from black chokeberries cultivated in Turkey

Phenolic compounds from two black chokeberry cultivars 'Viking' and 'Nero' grown in Turkey were analyzed by high performance liquid chromatography-diode array detection-electrospray ionization-multistage mass spectrometry (HPLC-DAD-ESI-MSn). In the first step, five different solvents were compared to efficiently isolate phenolic compounds by ultrasound-assisted extraction. Three sequential extraction cycles using methanol/formic acid (95:5, v/v) sufficed for exhaustive extraction of anthocyanins, hydroxycinnamic acid derivatives, and flavonol glycosides from black chokeberry within merely 60 sec. A total of four cyanidin glycosides, two hydroxycinnamic acids, and five quercetin mono- and diglycosides were detected in both cultivars. Total anthocyanins (425-438 mg/100 g of fresh weight, FW), hydroxycinnamic acids (173-179 mg/100 g of FW), and flavonols (37 mg/100 g of FW) were determined in a similar range for both cultivars. Complementary, a rapid ultra-high performance liquid chromatography (UHPLC)-DAD method was developed, permitting a high throughput screening of chokeberry phenolics. The established methods were validated considering extraction recoveries, intra- and inter-day repeatability, calibration linearity, limit of detection (LOD), and limit of quantitation (LOQ). UHPLC provided a 2.3 times faster compound separation (30 min) and less solvent consumption than HPLC (68 min)

Effects of Clarification and Storage on Anthocyanins and Color of Pomegranate Juice Concentrates

Whole pomegranates with rinds were processed into juice and then concentrate. Effects of cold clarification and storage temperatures (-23C, 5C, 12C and 20C) on anthocyanins (ACNs), ACN composition and color were determined. Major ACNs in pomegranate juice concentrate (PJC) were identified as cyanidin-3,5-diglucoside (47.9%), delphinidin-3,5-diglucoside (23.2%) and cyanidin-3-glucoside (18.5%). Diglucosides were more stable than monoglucosides during storage. ACN degradation and polymeric color formation were fitted to first-order reaction models. Higher storage temperatures increased the rate of ACN degradation and polymeric color formation in PJCs. Good correlation (r=-0.988) was found between ACN degradation and polymeric color formation during storage. Rate of ACN degradation and polymeric color formation were slower in the PJC obtained from unclarified juice than PJC obtained from clarified juice during storage. © 2012 Wiley Periodicals, Inc

Transcanal Endoscopic Type 1 Cartilage Tympanoplasty in Children

Objective:Transcanal endoscopic type 1 tympanoplasty is a minimally invasive procedure that enables better visualization of deep and narrow spaces compared to conventional microscopic methods. In our study, we aimed to evaluate air-bone gap difference, graft success, and hearing gain according to the perforation size and location in pediatric patients who underwent transcanal endoscopic type 1 cartilage tympanoplasty.Methods:Fifty pediatric patients who underwent transcanal endoscopic type 1 cartilage tympanoplasty for chronic otitis media were included in the study. Tragal cartilage grafts were used in all patients. Air conduction pure tone audiometry hearing results (500, 1000, 2000, and 4000 Hz), mean air-bone gap levels, operating times, postoperative gap closure, and graft success rates were evaluated.Results:Mean operating time was 43.34±8.56 minutes. Overall graft success was 94% (47/50). Mean hearing levels at all frequencies (500, 1000, 2000, and 4000 Hz) were found to have significantly improved after the operation (p<0.001). Mean preoperative air conduction pure tone threshold and mean air–bone gap had statistically significantly improved by the 6th postoperative month (p<0.001).Conclusion:Transcanal endoscopic type 1 cartilage tympanoplasty was found to be a minimally traumatic, easy and safe method with a low complication rate. In pediatric patients, this method allows for high rates of anatomic and functional recovery with optimal surgery time regardless of the location and the size of the perforation

Furfural Synthesis from d-Xylose in the Presence of Sodium Chloride: Microwave versus Conventional Heating

We investigate the existence of specific/nonthermal microwave effects for the dehydration reaction of xylose to furfural in the presence of NaCl. Such effects are reported for sugars dehydration reactions in several literature reports. To this end, we adopted three approaches that compare microwave-assisted experiments with a) conventional heating experiments from the literature; b) simulated conventional heating experiments using microwave-irradiated silicon carbide (SiC) vials; and at c) different power levels but the same temperature by using forced cooling. No significant differences in the reaction kinetics are observed using any of these methods. However, microwave heating still proves advantageous as it requires 30 % less forward power compared to conventional heating (SiC vial) to achieve the same furfural yield at a laboratory scale

Microwave-assisted hydrothermal treatments for biomass valorisation : a critical review

The sustainable conversion of biomass into biofuels, chemicals and biomaterials has gained increasing attention to ensure the well-being of present and future generations. Among the different technologies available to date for the valorisation of biomass, microwave-assisted hydrothermal conversion has recently appeared as a state-of-the-art technology, capable of furnishing a wide range of reaction products for the energy, pharmaceutical and chemistry sectors. This emerging technology combines the inherent benefits of microwave heating and the sustainable features of biomass hydrothermal valorisation. Herein, for the first time, this critical review summarises and analyses all the work conducted to date on the use of microwave-assisted hydrothermal processes (including microwave-assisted carbonisation, liquefaction and treatment/hydrolysis) for the conversion of biomass into hydrochar, bio-crude (bio-oil) and valuable chemicals. In particular, this work has put together vital information addressing the influences of the reaction conditions (temperature, time, amount and type of catalyst, biomass loading and type, and microwave power) on the yields and key properties of the reaction products. The relationships between these processing parameters and the chemical transformations involved in the processes (hydrolysis, dehydration, decarboxylation, condensation and re-polymerisation) have been described in detail, and reliable comparisons have also been established between microwave-assisted and conventional hydrothermal technologies when data were available. As a result, this critical review collects essential information on the use of this cutting-edge, recently appeared microwave-assisted hydrothermal technology, and paves the way for its expansion and future development and commercialisation

Determination of Acidity Constants of Methylene Blue and Alizarin with Luminescence Spectrometry and Investigation of Some Metal Sensitivities

Organik boyar maddeler endüstride renklendirme amaçlı kullanılmalarının yanı sıra indikatör ve/veya sensör olarak da kullanılabilen önemli hammaddelerdir. Birçoğu metal ve proton iyonlarına duyarlı olduğunda indikatör özelliği kazanır. Ayrıca metal iyonlarına karşı aktif olan birçok boya da sensör kabiliyeti sergilemektedir. Bu araştırmada, Metilen mavisi ve Alizarin boyar maddelerinin sulu çözeltilerinin çalışma pH aralıkları ile asitlik sabitlerinin (pKa) hesaplanması ve metal duyarlılıklarının incelenmesi üzerinde çalışılmıştır. Bu amaçla, Luminesans Spektrometre cihazıyla her iki boyar maddenin de taze hazırlanmış 10-3M’ lık sulu çözeltilerinde uyarma ve emisyon spektrumları ayrı ayrı alınmıştır. Emisyon spektrumlarından faydalanılarak Metilen mavisi ve Alizarin’ in çalışma pH aralıklarının sırasıyla 2-6 ve 2-9 olduğu tespit edilmiştir. Yapılan hesaplamalardan Metilen mavisi için pKa değeri 4,97 olarak bulunurken Alizarin için bu değer 3,70 olarak hesaplanmıştır. İlaveten Metilen mavisi’ nin IB ve IIB grubu-d blok geçiş elementlerinin iyonları olan Cu2+ ve Zn2+ iyonları ile kompleks yapabildikleri gözlenmiştir. Benzer biçimde, Alizarin’ in 3A grubu ve IB ile VIIIB grubu-d blok geçiş elementlerinin iyonları olan Al3+, Cu2+, Co2+, Ni2+ iyonları ile kompleksleşebildiği tespit edilmiştir. Metilen mavisi ve Alizarin’ in çalışma pH aralıklarına bağlı olarak pH sensörü olarak çalışabilecekleri ve seçilmiş metallerle kompleks oluşturabildikleri görülmüştür. Dahası, Alizarin’ in Metilen mavisine kıyasla daha çok metal iyonunu yakalayabildiği, daha düşük pKa değerine sahip olduğu ve buna bağlı olarak Cu2+ iyonlarıyla daha kolay kompleksleştiği sonucuna varılmıştır.Organic coloring materials are important raw materials which can be used as indicators and / or sensors other than being used for coloring purposes. Many of them gain indicator properties when they can be sensitive to metal and proton ions. Also, many dyes that are active against metal ions also exhibit sensor capability. In this study, the working pH ranges and acidity constants (pKa) of aqueous solutions of methylene blue and Alizarin dyes and also their metal sensitivities were investigated. For this purpose, excitation and emission spectra of freshly prepared 10-3M aqueous solutions of both dye materials were taken separately with Luminescence Spectrometer. Using the emission spectra, it was determined that the working pH ranges of Methylene blue and Alizarin are 2-6 and 2-9, respectively. The pKa value was calculated as 4,97 for Methylene blue and 3,70 for Alizarin. In addition, Cu2+ and Zn2+ ions, which are ions of IB and IIB groups-d block transition elements, are observed to be able to form complex with Methylene blue. Similarly, Al3+, Cu2+, Co2+, Ni2+ which are ions of the 3A group and IB and VIIIB groups-d block transition elements, are also observed to be able to form complex with Alizarin dyes. It has been shown that Methylene blue and Alizarin have been capable of working as pH sensors depending on the working pH ranges, and can form complexes with selected metals. Moreover, Alizarin is able to capture more metal ions than Methylene blue, has a lower pKa value, and consequently has been more easily complexed with Cu2+ ions