Yazar "Ayvaz, Huseyin" seçeneğine göre listele
Listeleniyor 1 - 20 / 30
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Adulteration detection technologies used for halal/kosher food products: an overview(Springernature, 2022) Mortas, Mustafa; Awad, Nour; Ayvaz, HuseyinIn the Islamic and Jewish religions, there are various restrictions that should be followed in order for food products to be acceptable. Some food items like pork or dog meat are banned to be consumed by the followers of the mentioned religions. However, illegally, some food producers in various countries use either the meat or the fat of the banned animals during food production without being mentioned in the label on the final products, and this considers as food adulteration. Nowadays, halal or kosher labeled food products have a high economic value, therefore deceiving the consumers by producing adulterated food is an illegal business that could make large gains. On the other hand, there is an insistent need from the consumers for getting reliable products that comply with their conditions. One of the main challenges is that the detection of food adulteration and the presence of any of the banned ingredients is usually unnoticeable and cannot be determined by the naked eye. As a result, scientists strove to develop very sensitive and precise analytical techniques. The most widely utilized techniques for the detection and determination of halal/kosher food adulterations can be listed as High-Pressure Liquid Chromatography (HPLC), Capillary Electrophoresis (CE), Gas Chromatography (GC), Electronic Nose (EN), Polymerase Chain Reaction (PCR), Enzyme-linked Immuno Sorbent Assay (ELISA), Differential Scanning Calorimetry (DSC), Nuclear Magnetic Resonance (NMR), Near-infrared (NIR) Spectroscopy, Laser-induced Breakdown Spectroscopy (LIBS), Fluorescent Light Spectroscopy, Fourier Transform Infrared (FTIR) Spectroscopy and Raman Spectroscopy (RS). All of the above-mentioned techniques were evaluated in terms of their detection capabilities, equipment and analysis costs, accuracy, mobility, and needed sample volume. As a result, the main purposes of the present review are to identify the most often used detection approaches and to get a better knowledge of the existing halal/kosher detection methods from a literature perspective.Öğe Anthocyanins, Vibrant Color Pigments, and Their Role in Skin Cancer Prevention(Mdpi, 2020) Diaconeasa, Zorita; Stirbu, Ioana; Xiao, Jianbo; Leopold, Nicolae; Ayvaz, Zayde; Danciu, Corina; Ayvaz, HuseyinUntil today, numerous studies evaluated the topic of anthocyanins and various types of cancer, regarding the anthocyanins' preventative and inhibitory effects, underlying molecular mechanisms, and such. However, there is no targeted review available regarding the anticarcinogenic effects of dietary anthocyanins on skin cancers. If diagnosed at the early stages, the survival rate of skin cancer is quite high. Nevertheless, the metastatic form has a short prognosis. In fact, the incidence of melanoma skin cancer, the type with high mortality, has increased exponentially over the last 30 years, causing the majority of skin cancer deaths. Malignant melanoma is considered a highly destructive type of skin cancer due to its particular capacity to grow and spread faster than any other type of cancers. Plants, in general, have been used in disease treatment for a long time, and medicinal plants are commonly a part of anticancer drugs on the market. Accordingly, this work primarily aims to emphasize the most recent improvements on the anticarcinogenic effects of anthocyanins from different plant sources, with an in-depth emphasis on melanoma skin cancer. We also briefly summarized the anthocyanin chemistry, their rich dietary sources in flowers, fruits, and vegetables, as well as their associated potential health benefits. Additionally, the importance of anthocyanins in topical applications such as their use in cosmetics is also given.Öğe Antiproliferative Activity of Anthocyanins Pure Extracts from Mulberries and Raspberries on HeLa and A2780 Human Cancer Cell Lines(Univ Agricultural Sciences & Veterinary Medicine Cluj-Napoca, 2018) Nistor, Madalina; Ghiman, Raluca; Ayvaz, Huseyin; Rugina, Dumitrita; Mada, Diana; Stanila, Andreea; Socaciu, CarmenRed berries are important sources of bioactive compounds and they are known to provide unique health benefits. Lately, it has been proved that anthocyanins have health benefits against degenerative diseases such as cardiovascular disease, cancer or diabetes. Accordingly, the aim of this study was to characterize the anthocyanin content of anthocyanins pure extracts (APEs) obtained from raspberries (Rubus sp.) and mulberries (Morus sp.) and to evaluate their antiproliferative effect in vitro. Upon chromatographic analysis, three anthocyanins were identified in purified extracts of mulberries (M-APEs), with cyanidin-3-O-glucoside being more abundant. On the other hand, purified extracts of raspberries (R-APEs) contained 2 anthocyanins, both identified as cyanidinderivatives. The in vitro test demonstrated that APEs decreased the proliferation on both HeLa and A2780 human cancer cell lines in a dose dependent manner, demonstrating that these two different berries are both rich sources of anthocyanins and are able to exert antiproliferative proprieties toward cervical and ovarian cancer.Öğe Antiproliferative and Antioxidant Properties of Anthocyanin Rich Extracts from Blueberry and Blackcurrant Juice(Mdpi, 2015) Diaconeasa, Zorita; Leopold, Loredana; Rugina, Dumitrita; Ayvaz, Huseyin; Socaciu, CarmenThe present study was aimed at evaluating the antiproliferative potential of anthocyanin-rich fractions (ARFs) obtained from two commercially available juices (blueberry and blackcurrant juices) on three tumor cell lines; B16F10 (murine melanoma), A2780 (ovarian cancer) and HeLa (cervical cancer). Individual anthocyanin determination, identification and quantification were done using HPLC-MS. Antioxidant activity of the juices was determined through different mechanism methods such as DPPH and ORAC. For biological testing, the juices were purified through C-18 cartridges in order to obtain fractions rich in anthocyanins. The major anthocyanins identified were glycosylated cyanidin derivatives. The antiproliferative activity of the fractions was tested using the MTT assay. The antiproliferative potential of ARF was found to be associated with those bioactive molecules, anthocyanins due to their antioxidant potential. The results obtained indicated that both blueberry and blackcurrants are rich sources of antioxidants including anthocyanins and therefore these fruits are highly recommended for daily consumption to prevent numerous degenerative diseases.Öğe Application of a Portable Infrared Instrument for Simultaneous Analysis of Sugars, Asparagine and Glutamine Levels in Raw Potato Tubers(Springer, 2015) Ayvaz, Huseyin; Santos, Alejandra M.; Moyseenko, Jennifer; Kleinhenz, Matthew; Rodriguez-Saona, Luis E.The level of reducing sugars and asparagine in raw potatoes is critical for potato breeders and the food industry for production of commonly consumed food products including potato chips and French fries. Our objective was to evaluate the use of a portable infrared instrument for the rapid quantitation of major sugars and amino acids in raw potato tubers using single-bounce attenuated total reflectance (ATR) and dial path accessories as an alternative to time-consuming chromatographic techniques. Samples representing a total of 84 experimental and commercial potato varieties harvested in two consecutive growing seasons (2012 and 2013) were used in this study. Samples had wide ranges of sugars determined by HPLC-RID (non-detectable (ND)-7.7 mg glucose, ND-9.4 mg fructose and 0.4-5.4 mg sucrose per 1 g fresh weight), and asparagine and glutamine levels determined by GC-FID (0.7-2.9 mg and 0.3-1.7 mg per 1 g fresh weight). Infrared spectra collected from 64 varieties were used to create partial least squares regression (PLSR) calibration models that predicted the sugar and amino acid levels in an independent set of 16 validation potato varieties. Excellent linear correlations between infrared predicted and reference values were obtained. PLSR models had a high correlation coefficient of prediction (rPred > 0.95) and residual predictive deviation (RPD) values ranging between 3.1 and 5.5. Overall, the results indicated that the models could be used to simultaneously predict sugars, free asparagine and glutamine levels in the raw tubers, significantly benefiting potato breeding, certain aspects of crop management, crop production and research.Öğe Determination of pesticide residual levels in strawberry (Fragaria) by near-infrared spectroscopy(Wiley, 2020) Yazici, Arzu; Tiryaki, Gulgun Yildiz; Ayvaz, HuseyinBACKGROUND In this study, an infrared-based prediction method was developed for easy, fast and non-destructive detection of pesticide residue levels measured by reference analysis in strawberry (Fragaria x ananassa Duch, cv. Albion) samples using near-infrared spectroscopy and demonstrating its potential alternative or complementary use instead of traditional pesticide determination methods. Strawberries of Albion variety, which were supplied directly from greenhouses, were used as the study material. A total of 60 batch sample groups, each consisting of eight strawberries, was formed, and each group was treated with a commercial pesticide at different concentrations (26.7% boscalid + 6.7% pyraclostrobin) and varying residual levels were obtained in strawberry batches. The strawberry samples with pesticide residuals were used both to collect near-infrared spectra and to determine reference pesticide levels, applying QuEChERS (quick, easy, cheap, rugged, safe) extraction, followed by liquid chromatographic-mass spectrometric analysis. RESULTS AND CONCLUSION Partial least squares regression (PLSR) models were developed for boscalid and pyraclostrobin active substances. During model development, the samples were randomly divided into two groups as calibration (n = 48) and validation (n = 12) sets. A calibration model was developed for each active substance, and then the models were validated using cross-validation and external sets. Performance evaluation of the PLSR models was evaluated based on the residual predictive deviation (RPD) of each model. An RPD of 2.28 was obtained for boscalid, while it was 2.31 for pyraclostrobin. These results indicate that the developed models have reasonable predictive power. (c) 2019 Society of Chemical IndustryÖğe High Pressure Effects on Packaging Materials(Springer, 2016) Ayvaz, Huseyin; Balasubramaniam, V. M.; Koutchma, TatianaDuring high pressure processing, the prepackaged food material is pasteurized or sterilized by subjecting it to combined pressure-thermal treatment of different intensity. This chapter summarizes the impact of pressure-thermal treatment on moisture and gas barrier properties, seal and mechanical strength, as well as migration characteristics of the packaging polymer. Packaging also play important role in preserving quality of pressure treated foods during extended storage life. Some of the recommended future research needs in the development of novel packaging material for high pressure processing are summarized.Öğe Improving the screening of potato breeding lines for specific nutritional traits using portable mid-infrared spectroscopy and multivariate analysis(Elsevier Sci Ltd, 2016) Ayvaz, Huseyin; Bozdogan, Adnan; Giusti, M. Monica; Mortas, Mustafa; Gomez, Rene; Rodriguez-Saona, Luis E.Efficient selection of potato varieties with enhanced nutritional quality requires simple, accurate and cost effective assays to obtain tuber chemical composition information. In this study, 75 Andean native potato samples from 7 Solanum species with different colors were characterized and quantified for their anthocyanin, phenolics and sugar content using traditional reference methods. IR (infrared) spectra of potato extracts were collected using a portable infrared system and partial least squares regression (PLSR) calibration models were developed. These models were validated using both full cross-validation and an independent sample set giving strong linear correlation coefficients of prediction (rPred) > 0.91 and standard error of prediction (SEP) of 24 mg/100 g phenolics, 7 mg/100 g monomeric anthocyanins, 0.1 g/100 g reducing sugars and 0.12 g/100 g sucrose. Overall, portable infrared system with PLSR showed great potential to facilitate potato breeding and certain aspects of crop management, material selection for potato processing and related research by providing alternative prediction models. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Infrared spectroscopy combined with chemometrics as a convenient method to detect adulterations in cooking/stretching process in commercial cheese(Elsevier Sci Ltd, 2022) Ozturk, Mustafa; Dogan, Muhammed Ali; Menevseoglu, Ahmed; Ayvaz, HuseyinStretching and kneading of the curd during fresh Kashar cheese manufacturing must take place in hot water; dry cooking/stretching of the curd with the assistance of emulsifying salts is not allowed. However, some producers in recent years tend to label their processed cheese as Kashar cheese resulting in unfair economic gain and consumer deception. Near-infrared (NIR) diffuse reflectance and mid-infrared (MIR) attenuated total reflectance (ATR) spectroscopy were assessed for the fast and convenient identification of these two types of cheese. Soft independent modeling of class analogy (SIMCA) models of both NIR and MIR-ATR spectra were developed; the latter gave superior separation due to the greater inter-class distance originating from better-resolved peaks associated with phosphates (6.7 for MIR-ATR versus 3.2 for NIR). Information Theory determined two and three variables were enough for MIR and NIR spectral data classification, respectively; quadratic discriminant and support vector machine provided 100% accuracy for class prediction. (C) 2021 Published by Elsevier Ltd.Öğe Infrared spectroscopy-based rapid determination of adulteration in commercial sheep's milk cheese via n-hexane and ethanolic extraction(Elsevier Sci Ltd, 2023) Menevseoglu, Ahmed; Gumus-Bonacina, Cansu Ekin; Gunes, Nurhan; Ayvaz, Huseyin; Dogan, Muhammed AliThis study aimed to authenticate a commercial cheese using FT-IR spectroscopy combined with che-mometrics via ethanol and n-hexane extraction. Erzincan Tulum cheese (ETC) is one of the most pro-duced and consumed cheeses in Turkiye. With an increase in production and consumption, adulteration has become a concern. Authentic ETC (n = 24) and non-authentic cheese samples (n = 22) were pur-chased from local markets. Ethanol and n-hexane extracts of the ETC were used for FT-IR analysis. Ali-quots of the extracts were placed on a zinc selenide crystal, dried, and scanned in the mid-infrared region (4000-650 cm-1). Partial least squares-discriminant analysis (PLS-DA), soft independent modelling of class analogy (SIMCA), and conditional entropy (CE) were used as chemometric tools. PLS-DA and SIMCA provided 99% accuracy, followed by CE as low as 93.5%. Despite some disadvantages, overall, FT-IR spectroscopy with chemometrics is simple, rapid, and an inexpensive tool to detect cheese adulteration.(c) 2022 Elsevier Ltd. All rights reserved.Öğe Kinetic modeling of ascorbic acid degradation of pineapple juice subjected to combined pressure-thermal treatment(Elsevier Sci Ltd, 2018) Dhakal, Santosh; Balasubramaniam, V. M.; Ayvaz, Huseyin; Rodriguez-Saona, Luis E.A study was conducted to investigate and model kinetic degradation of ascorbic acid in freshly prepared pineapple juice subjected to various pressure (0.1, 300,450 and 600 MPa)-thermal (30, 75, 85 and 95 degrees C) treatment combinations. Experiments were conducted using a semi-custom made high pressure kinetic tester as well as an aluminum thermal kinetic tester. Thermal degradation of ascorbic acid was described with simple first order kinetics. The thermal rate constants (k (75 _95 degrees c, 0.1 MPa)) and activation energy (E-a) for ascorbic acid degradation reaction varied in the range of 0.004-0.006 per min and 14.22-29.78 kJ/mol, respectively. Within the experimental conditions of the study (300-600 MPa at 30 degrees C for holding times up to 15 min) high pressure processing did not alter ascorbic acid content (535.5-564.5 mg/kg). Combined pressure-thermal treatment (300-600 MPa at 75-95 degrees C) degraded ascorbic acid with increasing thermal intensity and was modeled using first order fractional conversion kinetics model. The lower asymptote value ([A](infinity)/[A](0))rate constants (k(75 _95 degrees c, 0.1 MPa)) and Ea were in the range of 77-85%, 0.108 to 0.138 per min and 17.4-43.8 kJ/mol, respectively. Similarly, pressure sensitivity (Delta V-not equal) was similar to 0 and -2.99 cm(3)/mol at 30 and 95 degrees C, respectively. Knowledge gained from the study can be useful for food processors to optimize high pressure treatment conditions for pineapple juice products. (C) 2017 Elsevier Ltd. All rights reserved.Öğe Laser-induced breakdown spectroscopy as a reliable analytical method for classifying commercial cheese samples based on their cooking/stretching process(Elsevier Sci Ltd, 2022) Sezer, Banu; Ozturk, Mustafa; Ayvaz, Huseyin; Apaydin, Hakan; Boyaci, Ismail HakkiThe present work evaluates the possibility of using laser-induced breakdown spectroscopy (LIBS) coupled with chemometric methods to classify cheese samples (namely Kashar cheese and processed cheese) based on their cooking/stretching process. Chemometric analysis of the data provided by LIBS and ICP-OES/AAS analyses made it possible to discriminate between the two cheese types regarding their elemental profiles. The principal component analysis model was able to discriminate the Kashar cheese with an explained variance of 97.02%. Furthermore, the partial least squares discriminant analysis model perfectly classified the Kashar samples with a prediction ability of 100%. Furthermore, calibration and validation models for Mg, Ca, Na, P, Zn, and K elements for both Kashar and processed cheese samples were developed using partial least square regression yielding high correlation coefficients and low root mean square errors. Overall, this study indicates that LIBS with chemometrics can be an easy-to-use and rapid monitoring system for cheese classification.Öğe Melanoma Inhibition by Anthocyanins Is Associated with the Reduction of Oxidative Stress Biomarkers and Changes in Mitochondrial Membrane Potential(Springer, 2017) Diaconeasa, Zorita; Ayvaz, Huseyin; Rugina, Dumitrita; Leopold, Loredana; Stanila, Andreea; Socaciu, Carmen; Tabaran, FlaviuAnthocyanins are water soluble pigments which have been proved to exhibit health benefits. Several studies have investigated their effects on several types of cancer, but little attention has been given to melanoma. The phytochemical content of nine different berry samples was assessed by liquid chromatography followed by electrospray ionization mass spectrometry (LC-ESI+-MS). Twenty-six anthocyanins were identified, after a previous C-18 Sep-pak clean-up procedure. Chokeberry and red grape anthocyanins rich extracts (C-ARE and RG-ARE) were selected to be tested on normal and melanoma cell lines, due to their different chemical pattern. C-ARE composition consists of cyanidin aglycone glycosylated with different sugars; while RG-ARE contains glucosylated derivatives of five different aglycones. Both C-ARE and RG-ARE anthocyanins reduced proliferation, increased oxidative stress biomarkers and diminished mitochondrial membrane potential in melanoma cells, having no negative influence on normal cells. A synergistic response may be attributed to the five different aglycones present in RG-ARE, which proved to exert greater effects on melanoma cells than the mixture of cyanidin derivatives with different sugars (C-ARE). In conclusion, C-ARE and RG-ARE anthocyanins may inhibit melanoma cell proliferation and increase the level of oxidative stress, with opposite effect on normal cells. Therefore, anthocyanins might be recommended as active ingredients for cosmetic and nutraceutical industry.Öğe Monitoring multicomponent quality traits in tomato juice using portable mid-infrared (MIR) spectroscopy and multivariate analysis(Elsevier Sci Ltd, 2016) Ayvaz, Huseyin; Sierra-Cadavid, Andrea; Aykas, Didem P.; Mulqueeney, Brett; Sullivan, Scott; Rodriguez-Saona, Luis E.In this study, a novel portable infrared spectrometer was evaluated for rapid and simultaneous determination of glucose, fructose, total reducing sugars, soluble solids (degrees Brix), serum viscosity, Bostwick consistency, predicted paste Bostwick value and pH. A total of 350 hot-break juices from two consecutive years (2013 and 2014) including 66 different varieties grown in 6 counties of California, USA, were used in this study. Duplicate spectra for each tomato juice were collected using the transmission accessory of the portable infrared spectrometer at 50 gm fixed path length. Samples were randomly divided into calibration (n = 280) and external validation (n = 70) sets and partial least squares (PLS) regression was used to develop calibration models to predict all the variables (quality traits) in the validation samples based on the tomato juice spectral data (r(pred) > 0.82). Overall, our validated chemometric models allowed rapidly (-2 min) predicting all the quality traits in tomato juice samples with no sample preparation. (C) 2016 Elsevier Ltd. All rights reserved.Öğe Multiparametric analysis of cheese using single spectrum of laser-induced breakdown spectroscopy(Elsevier Sci Ltd, 2019) Ayvaz, Huseyin; Sezer, Banu; Dogan, Muhammed Ali; Bilge, Gonca; Atan, Mustafa; Boyaci, Ismail HakkiThe potential of using laser-induced breakdown spectroscopy (LIBS) for prediction of chemical quality/control parameters in a cheese matrix was investigated. Traditional methods are usually time-consuming and require complex pre-treatments, the use of toxic chemicals and laboratories and personnel equipped with these analytical skills. In this study, 11 different chemical analyses commonly performed on cheese samples were conducted using traditional methods on 82 full-fat, white pickled and ripened cheese samples. Additionally, these parameters of interest were correlated with multi-elemental spectra of LIBS using partial least squares regression. The results obtained for moisture, dry matter, salt, total ash, total protein, pH, fat, acidity, water soluble nitrogen, trichloroacetic acid soluble nitrogen, and phosphotungstic acid soluble nitrogen (R-cal(2) = 0.964, 0.959, 0.970, 0.973, 0.952, 0.971, 0.733, 0.762, 0.714, 0.633, and 0.707, respectively) indicated that LIBS could be used as an alternative or complementary method in quality control of cheese. (C) 2018 Elsevier Ltd. All rights reserved.Öğe Near- and Mid-Infrared Spectroscopy Combined with Machine Learning Algorithms to Determine Minerals and Antioxidant Activity in Commercial Cheese(2023) Menevşeoğlu, Ahmed; Güneş, Nurhan; Ayvaz, Huseyin; Sarıkaya, Sevim Beyza Öztürk; Zehiroğlu, CumaErzincan Tulum Cheese (ETC) holds a significant place among the most popular cheeses in Türkiye. It has been awarded Protected Geographical Indication status, which restricts the allowable milk species, its production area, and specific sheep breed used in its production. Mineral content and antioxidant activity of ETC were aimed to be predicted using conventional FT-NIR and a portable FT-MIR spectrometer combined with partial least square regression (PLSR) and machine learning algorithms based on conditional entropy. Seventy ETC samples were analyzed for their mineral (Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, and P) content using ICP-MS. The samples' antioxidant activity was measured using the DPPH•+ scavenging activity method. PLSR combined with FT-NIR spectral data correlated with antioxidant activity (r=0.89) and minerals (as low as r=0.83) except for Cr and Fe. FT-MIR data provided a good correlation for minerals (as low as r=0.82) except for Cr and Mn and a moderate correlation with antioxidant activity (r=0.64). Information theory was applied to select wavenumbers used in machine learning algorithms, and better results were obtained compared to PLSR. Overall, FT-NIR and FT-MIR spectroscopy provided rapid (~ 1 min), non-destructive, sensitive, and reliable output for mineral and antioxidant activity predictions in commercial cheese samples.Öğe Phytochemical Characterization of Commercial Processed Blueberry, Blackberry, Blackcurrant, Cranberry, and Raspberry and Their Antioxidant Activity(Mdpi, 2019) Diaconeasa, Zorita; Iuhas, Cristian I.; Ayvaz, Huseyin; Rugina, Dumitrita; Stanila, Andreea; Dulf, Francisc; Bunea, AndreaBeing delicious and containing strong disease-fighting agents, berries represent an increasing proportion of fruits consumed nowadays in our diet. However, berries are highly perishable as fresh and, therefore, they are usually processed into various products to extend their shelf-life and availability throughout the year. Among the fruit-containing products, jam is one of the most common due to its nourishing properties, its low production costs, and its accessibility for a lengthy period. Rather than home preparation, consumers nowadays increasingly prefer to purchase commercial jams from markets due to its convenience. Although fresh berries have been extensively studied for their phenolic compounds, a limited number of studies investigating commercially manufactured jams have been conducted so far. Considering this, the objective of this study was to assess the total phenolic, flavonoid, and anthocyanin content and the antioxidant activity of five commonly consumed commercial berry jams (blueberry (Vaccinium myrtillus), blackberry (Rubus fruticosus) and blackcurrant (Ribes nigrun) mixture, blackcurrant (Ribes nigrun), cranberry (Vaccinium macrocarpon) and raspberry (Rubus idaeus)) collected from the market. Even though a possible loss of phenolics, anthocyanins, and a decrease of radical scavenging activity may occur during jam processing and subsequent storage, our data indicated that the selected commercial jams remained good sources of nutritive molecules with antioxidant properties based on the high levels of total phenolics, flavonoids, anthocyanins, and elevated antioxidant activities determined in this study. Additionally, the samples were characterized by GC-MS for their volatile profiles, and terpenes were found to be the dominating class covering more than 74% of volatile compounds in the jams.Öğe Phytochemical Characterization of Five Edible Purple-Reddish Vegetables: Anthocyanins, Flavonoids, and Phenolic Acid Derivatives(Mdpi, 2019) Frond, Alexandra D.; Iuhas, Cristian I.; Stirbu, Ioana; Leopold, Loredana; Socaci, Sonia; Andreea, Stanila; Ayvaz, HuseyinVegetables comprise a significant portion of our daily diet with their high content in nutrients including fiber, vitamins, minerals, as well as phenolic compounds. Vegetable consumption has been shown to be positively associated with the prevention of several degenerative diseases thanks to their bioactive compounds. Accordingly, five selected vegetables, namely, red chicory, red onion, eggplant, purple sweet potato, and black carrot were thoroughly assessed for their phenolic content in this study. For this purpose, the total phenolic and flavonoid content of these five vegetables and their antioxidant activities that are based on three common methods ABTS radical cation decolorization assay (ABTS), Cupric Ion Reducing Antioxidant Capacity (CUPRAC), and DPPH scavenging activity assay were determined. Additionally, HPLC-PDA/Electrospray ionization coupled with mass spectrometry (HPLC-PDA/-ESI+-MS)-based identification and quantification of the members belonging to polyphenols present in each vegetable were determined. Statistical correlations between antioxidant activities and the specific type of phenolic compounds, such as anthocyanins, flavonoids, anthocyanins, and phenolic acids were further elucidated. Phenolic acids (chlorogenic and syringic acids) were found to be the most abundant compounds that are present in all samples. Among the anthocyanins, cyaniding derivatives were present in all vegetables. In terms of their antioxidant activities, the analyzed vegetables were ranked as red chicory > purple sweet potato > black carrot > eggplant > red onion, in descending order. Superior antioxidant activities exhibited by red chicory and purple sweet potato were attributed to the high content of phenolic compounds, especially flavonols (quercetin-3,4-O-diglucoside) in red chicory and anthocyanins (peonidin-3-caffeoyl p-hydroxybenzoylsophoroside-5-glucoside) in purple sweet potato.Öğe Portable Infrared Spectrometer to Characterize and Differentiate Between Organic and Conventional Bovine Butter(Springer, 2015) Pujolras, Marcal Plans; Ayvaz, Huseyin; Shotts, Mei-Ling; Pittman, Richard A., Jr.; Herringshaw, Sarah; Rodriguez-Saona, Luis E.The performance of a portable infrared system combined with pattern recognition to discriminate between organically and conventionally produced bovine butter samples as well as to predict the levels of conjugated linoleic acid (CLA) were evaluated. Sixty butter (27 organic and 33 conventional) samples were used in this study. Bovine butter-fat were applied onto an attenuated total reflectance infrared (ATR-IR) accessory equipped with a five-bounce ZnSe crystal set at 65 A degrees C for spectral collection. In addition, ATR-IR spectra of bovine butter were directly collected at room temperature to avoid phase separation. The fatty acid profile and the levels of CLA were determined using reference FAME-GC-FID analysis. SIMCA models showed well separated clusters that discriminated between organic and conventional bovine butters due to C=C trans bending out of the plane vibration modes band at 967 cm(-1). Additionally, strong PLSR models were developed to predict CLA levels using butter-fat and bovine butter spectra with SEP of 0.05 % and RPD of 4.7, indicating that the models are suitable for quality control applications. Portable IR technology offers the ability for in situ analysis of butters that is much less time consuming than current analytical practices for authentication and quality control efforts by the industry.Öğe Quantification of soybean oil adulteration in extra virgin olive oil using portable raman spectroscopy(Springer, 2017) Tiryaki, Gulgun Yildiz; Ayvaz, HuseyinExtra virgin olive oil is produced through either a cold press procedure or a centrifugation with no thermal and chemical treatments and it is considered as the best quality oil under the category of olive oils. The superior properties of olive oil due to its rich in phenolic and antioxidant content and its contribution to prevent several health problems has increased the demand for olive oil over the years. Consequently, it is nowadays sold at remarkably higher price than regular vegetable oils in the market. Unfortunately, extra virgin olive oil (EVOO) has been adulterated with other cheap oils due to potential high commercial profit. Even though, there are methods available to detect the adulteration in EVOO (such as chromatographic methods and PCR),alternative simpler and faster methods are being studied. In this study, performance of portable Raman spectroscopy to quantify soybean oil (SO) adulteration [up to 25 % (w/w)] in EVOO has been evaluated. Partial Least Square Regression (PLSR) calibration models were developed and both internally (using cross-validation, leave-one-out approach) and externally (using an independent sample set) validated. The model gave standard error of prediction (SEP) of 1.34 % (w/w) SO in EVOO and correlation coefficient of prediction (rPred) of 0.99. Additionally, the residual predictive deviation (RPD) value calculated for the model was found to be 5.71, indicating that the model was considered as good and could be used for routine analysis and quality control applications.
