Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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Review Citation - WoS: 41Citation - Scopus: 43Electrochemical Sensors in the Food Sector: a Review(American Chemical Society, 2024) Ghaani, Masoud; Azimzadeh, Mostafa; Büyüktaş, Duygu; Carullo, Daniele; Farris, StefanoIn a world that is becoming increasingly concerned with health, safety, and the sustainability of food supply chains, the control and assurance of food quality have become of utmost importance. This review examines the application and potential of electrochemical sensors in the dynamic field of food science to meet these expanding demands. The article introduces electrochemical sensors and describes their operational mechanics and the components contributing to their function. A summary of the most prevalent electrochemical methods outlines the diverse food analysis techniques available. The review shifts to discussing the food science applications of these sensors, highlighting their crucial role in detecting compounds in food samples like meat, fish, juice, and milk for contemporary quality control. This paper showcases electrochemical sensors' utility in food analysis, underscoring their significance as powerful, efficient tools for maintaining food safety and how they could transform our approach to global food quality control and assurance.Article Citation - WoS: 10Citation - Scopus: 11Enzymatic Hydrolysis of Organosolv-Pretreated Corncob and Succinic Acid Production by Actinobacillus Succinogenes(Elsevier, 2024) Buyukoztekin, Gulperi Karanfil; Buyukkileci, Ali OguzIn this study, the conversion of organosolv-treated corncob into monosaccharides through enzymatic sacchari-fication was investigated, with the resulting monosaccharides being utilized as a carbon source to produce succinic acid. The synergy between the cellulase and xylanase provided 76% cellulose and 64% xylan di-gestibility at 50 degrees C and pH 5.2. In separate hydrolysis and fermentation (SHF), Actinobacillus succinogenes pro-duced 12.7 g/L of succinic acid from the hydrolysate with 0.12 g/g yield based on the pretreated corncob. Simultaneous saccharification and fermentation (SSF) demonstrated better performance with 16 g/L succinic acid titer and 0.24 g/g yield, though SHF provided a higher production rate. The condition in the SSF (37 degrees C and pH near neutral) was suboptimal for the enzymes, thus the succinic acid production was limited by the saccharification step. These findings emphasize the potential of organosolv-treated corncob to serve as an enzymatic hydrolysis substrate without neutralization and detoxification, supplying glucose and xylose for succinic acid production by A. succinogenes.Article Citation - Scopus: 11Chemical Composition and Biological Activities of Cypriot Propolis(Taylor and Francis Ltd., 2022) Nalbantsoy, A.; Sarıkahya, N.B.; Özverel, C.S.; Barlas, A.B.; Kırcı, D.; Akgün, İ.H.; Yalçın, Tansel; Düven, GamzePropolis compositions are highly variable, depending on the geographic region and the season of collection. In this study, propolis samples from seven different regions of Cyprus were studied for the first time by means of chemical content and biological activities. Secondary metabolite composition was determined by LC-HRMS. While the major flavonoids found were isosakuranetin, naringenin, rhamnocitrin, diosmetin, chrysin and acacetin, interestingly verbascoside, a phenylethanoid glycoside, and chlorogenic acid were identified as the major compounds in the ethanol-water extracts. α-Pinene was detected as the major compound of propolis extracts according to the volatile compositions via GC-MS. Karaoglanoglu and Tirmen extracts, presenting different chemical profiles, exerted enormous cytotoxic activity by MTT assay (IC50: 2.36–11.56 µg/mL; 1.44–9.33 µg/mL, respectively). The highest iNOS inhibition potential was detected in the Karpaz extract (IC50:2.6 µg/mL) in LPS induced RAW 264.7 cells whereas the Guzelyurt sample demonstrated remarkable antioxidant (88.82 ± 0.10%) and antimicrobial activities (with a MIC value of 31.2 μg/mL against S. aureus, S. epidermidis, E. faecium, and E. faecalis). © 2021 International Bee Research Association.Article Citation - WoS: 69Citation - Scopus: 88Shelf Life Extension of Strawberry Juice by Equivalent Ultrasound, High Pressure, and Pulsed Electric Fields Processes(Elsevier, 2021) Yıldız, Semanur; Pokhrel, Prashant Raj; Ünlütürk, Sevcan; Barbosa-Canovas, Gustavo V.Nonthermal processing technologies have focused on the production of safe, fresh-like and high quality food products very much in line with current consumer demands. It is a high priority to maintain the quality attributes of the food during its shelf life. In this study; microbial stability, physicochemical properties and phytochemical characteristics of strawberry juice (SJ) pasteurized by ultrasonication (US) (55 degrees C, 0.29 W/mL acoustic energy density, 120 mu m amplitude, 3 min), high pressure processing (HPP) (300 MPa, 1 min), and pulsed electric fields (PEF) (35 kV/cm, 27 mu s) were evaluated during 42 days of storage at 4.C in comparison with conventional thermal pasteurization as a reference treatment (72 degrees C, 15 s). The nonthermal processes were equivalent in terms of E. coli inactivation since the selected processing conditions previously led to almost identical inactivation level (at least 5-log) of inoculated E. coli. Thus, the current study demonstrates how these equivalent US, HPP, and PEF treatments differ from each other in terms of their effect on SJ natural microbiota and quality characteristics during refrigerated storage. Results showed that US, HPP, and heat treatment ensured the microbial stability of SJ for at least 42 days while PEF extended the shelf life of SJ by at least 28 days based on the natural microbiota. No significant difference was found for the total soluble solids of the processed samples (p > 0.05) whereas acidity and pH of the samples varied during the storage period (p < 0.05). Immediately after processing, the total phenolic contents and antioxidant activities of SJ were better retained by HPP and PEF compared to thermal pasteurization. Furthermore, HPP and PEF significantly increased total anthocyanin content of SJ by 15 and 17% with respect to untreated SJ (p < 0.05). Phytochemical characteristics of processed SJ started to decrease after 7 days of storage irrespective of treatment type. HPP treated juices showed significantly higher levels of total anthocyanin and antioxidant activity at the final day of storage. Principal component and cluster analysis showed that the processed SJ samples had higher similarity to the untreated fresh SJ during storage up to 14 days, while the samples beyond this storage period clustered together and discriminated from the rest indicating a decreased similarity to the fresh juice. This study rendered simultaneous evaluation of several quality characteristics during storage of pasteurized strawberry juice based on the equivalent processing approach and multivariate data analysis. Under the selected processing conditions, HPP was the best option to extend the shelf life of SJ and enhance its phytochemical characteristics.Review Citation - WoS: 10Citation - Scopus: 10Authentication of Vinegars With Targeted and Non-Targeted Methods(Taylor & Francis, 2023) Çavdaroğlu, Çağrı; Çavdaroğlu, Çağrı; Özen, Banu; Özen, Fatma BanuThere has been a growing interest in vinegar, especially after the increasing reports about its beneficial health effects. Bioactive compounds of vinegar are associated with its antimicrobial, antioxidant, antidiabetic, antitumor, and anti-obesity types of activities. Quality of vinegar is related with the authenticity of the product besides the amounts of bioactive compounds in its composition. Addition of cheaper substitutes to higher quality vinegars and false labeling are some common authentication problems for this product. There are various examples of the use of targeted and untargeted methods in authentication studies for vinegars. Specific constituents and properties of vinegars such as molecular isotope ratios and individual volatile compounds were used to detect adulteration with targeted methods. On the other hand, untargeted methods, mostly in the form of the application of spectroscopic techniques, such as infrared and fluorescence spectroscopy in combination with chemometrics, provide an overall measurement. This review mainly focuses on adulteration types and elaborates on different targeted and non-targeted methods used to authenticate vinegars.Article Citation - WoS: 7Citation - Scopus: 11Chemical Composition and Biological Activities of Cypriot Propolis(Taylor and Francis Ltd., 2021) Nalbantsoy, Ayşe; Sarıkahya, Nazlı Böke; Özverel, Cenk Serhan; Barlas, Ayşe Berçin; Kırcı, Damla; Akgün, İsmail Hakkı; Yalçın, Tansel; Güven, Gamze; Kışla, Duygu; Demirci, Betül; Topçu, Gülaçtı; Gören, Ahmet CeyhanPropolis compositions are highly variable, depending on the geographic region and the season of collection. In this study, propolis samples from seven different regions of Cyprus were studied for the first time by means of chemical content and biological activities. Secondary metabolite composition was determined by LC-HRMS. While the major flavonoids found were isosakuranetin, naringenin, rhamnocitrin, diosmetin, chrysin and acacetin, interestingly verbascoside, a phenylethanoid glycoside, and chlorogenic acid were identified as the major compounds in the ethanol-water extracts. alpha-Pinene was detected as the major compound of propolis extracts according to the volatile compositions via GC-MS. Karaoglanoglu and Tirmen extracts, presenting different chemical profiles, exerted enormous cytotoxic activity by MTT assay (IC50: 2.36-11.56 mu g/mL; 1.44-9.33 mu g/mL, respectively). The highest iNOS inhibition potential was detected in the Karpaz extract (IC50:2.6 mu g/mL) in LPS induced RAW 264.7 cells whereas the Guzelyurt sample demonstrated remarkable antioxidant (88.82 +/- 0.10%) and antimicrobial activities (with a MIC value of 31.2 mu g/mL against S. aureus, S. epidermidis, E. faecium, and E. faecalis).Article Citation - WoS: 19Citation - Scopus: 20Processing of Hazelnut (corylus Avellana L.) Shell Autohydrolysis Liquor for Production of Low Molecular Weight Xylooligosaccharides by Aureobasidium Pullulans Nrrl Y-2311 Xylanase(Elsevier, 2021) Sürek, Ece; Büyükkileci, Ali Oğuz; Yeğin, SırmaIn this study, a versatile process for the production of xylooligosaccharides (XOS) with a low degree of polymerization (DP 2-6) from hazelnut shells was designed. This process included autohydrolysis integrated with sequential enzymatic hydrolysis by crude xylanase produced with Aureobasidium pullulans NRRL Y-2311-1 from wheat bran. Autohydrolysis of hazelnut shells was carried out at a solid:liquid ratio of 1:6 (w/w) and 190 degrees C nonisothermally. The effects of several parameters on enzymatic hydrolysis of the autohydrolysis liquor were determined. The maximum XOS (DP 2-6) production was 22.5 g/L which was obtained at pH 5.0 and 40 degrees C using enzyme concentration of 240 U/g XOS and substrate concentration of 72 g/L. Under these conditions, 31.29 % of the substrate (total XOS) was converted to low-DP-XOS; xylobiose and xylotriose are being the major oligomers. This is the first study on the application of A. pullulans xylanase in production of xylooligomers from hazelnut shells.Article Citation - WoS: 41Citation - Scopus: 43Changes in Quality Characteristics of Strawberry Juice After Equivalent High Pressure, Ultrasound, and Pulsed Electric Fields Processes(Springer Verlag, 2020) Yıldız, Semanur; Pokhrel, Prashant Raj; Ünlütürk, Sevcan; Barbosa-Canovas, Gustavo V.Understanding the efficacy of viable emerging technologies in preserving overall quality attributes and antioxidant characteristics of fruit juices is of great interest. This study aimed to evaluate the effect of high pressure (HP), ultrasound (US), and pulsed electric fields (PEF) processes on natural microbiota inactivation, as well as changes in physicochemical attributes and phytochemical content of strawberry juice (SJ). HP at 300 MPa (1 min), US at 55 degrees C (3 min) and 517.1 mW/mL acoustic energy density, and PEF at 35 kV/cm (27 mu s) using monopolar square pulses with 2 mu s pulse width were applied, and then compared with a conventional thermal pasteurization treatment (72 degrees C, 15 s). The nonthermal processes were equivalent in terms ofEscherichia coli(E. coli) inactivation since the selected processing conditions led to almost identical inactivation level (at least 5-log) of inoculatedE. coli. The current study analyzes why these equivalent processes had different effect on SJ quality. All treatments significantly reduced the initial natural microbiota (i.e., total mesophilic aerobic bacteria and yeast-molds) below 2 log CFU/mL. No significant changes were observed on the total soluble solid content (7.83-8.00 degrees Brix), titratable acidity (0.79-0.84 g/100 mL), and pH (3.45-3.50; except in sonication) between SJ processed samples and the untreated ones (p > 0.05). HPP and PEF significantly promoted higher retention of total phenolic content (TPC) and radical scavenging activity (RSA) than thermal pasteurization, and significantly enhanced total anthocyanin content (TAC) compared with unprocessed SJ. HPP and PEF increased the TPC (4-5%), RSA (18-19%), and TAC (15-17%) in comparison with unprocessed SJ. Multivariate data analysis tools, i.e., principal component analysis (PCA) and hierarchical cluster analysis (HCA), were successfully applied for discrimination and classification of SJ samples based on the similarities or differences among physicochemical and phytochemical characteristics. PCA and HCA indicated that HPP- and PEF-treated samples had similar enhanced properties in terms of phytochemical content and were superior to sonicated, thermally pasteurized, and unprocessed samples. The multivariate data analysis methods were very useful to compare and classify SJ quality characteristics as a function of the processing technology. This study demonstrated that the application of the equivalent processing approach may reveal new opportunities to produce equivalent or even enhanced quality fruit juices.Article Citation - WoS: 13Citation - Scopus: 13Multi-Scale Benchtop 1h Nmr Spectroscopy for Milk Analysis(Academic Press, 2021) Söyler, Alper; Çıkrıkçı, Sevil; Çavdaroğlu, Çağrı; Bouillaud, Dylan; Farjon, Jonathan; Giraudeau, Patrick; Öztop, Mecit H.Benchtop NMR systems offers various advantages such as being easy to use, not requiring constant maintenance and being available at affordable prices. In this study, multiple aspects of benchtop NMR spectroscopy were explored to analyze milk in an industrial context, either regarding the quality of production or regarding the differentiation of the final product. The first part focuses on the production conditions of lactose hydrolysis in milk and quantitative online NMR spectroscopy was adapted to follow lactose hydrolysis in milk in continuous flow mode. The second part focuses on differentiating milk samples having different properties. 36 milk samples from France and Turkey were analysed and glycerol, fat and sugar contents were measured from the NMR spectra. Combination of spectroscopic data with a proposed Artificial Neural Network model enabled to classify milk of different origins and different properties. This study shows that benchtop NMR spectroscopy is a versatile non-destructive control method that can help controlling milk quality both during and after production. © 2020 Elsevier LtdArticle Citation - WoS: 42Citation - Scopus: 53Effects of Ultraviolet-Light Emitting Diodes (uv-Leds) on Microbial Inactivation and Quality Attributes of Mixed Beverage Made From Blend of Carrot, Carob, Ginger, Grape and Lemon Juice(Elsevier Ltd., 2021) Baykuş, Gökçen; Pelvan Akgün, Merve; Ünlütürk, SevcanEfficacy of ultraviolet light-emitting diodes (UV-LEDs) with peak and coupled emissions at 280, 365 and 280/365 nm on inactivation of E. coli K12 in mixed beverage (MB) was investigated. MB comprised of 31.6% carrot, 44.3% carob, 8.7% grape, 10.2% ginger, and 5.2% lemon juice. The impact of UV-LEDs on some physicochemical and phytochemical properties of MB was compared to that of heat treatment (70 °C, 120 s). While, UV-LED irradiation using coupled 280/365 nm for 40 min resulted in the highest inactivation of E. coli K12 (>4 log) out of tested wavelengths, the number of mesophilic bacteria (TAC), and yeast and molds (YM) in mixed beverage were reduced by 2.59 log CFU/mL (from 5.69 log CFU/mL of initial load), and 0.17 log CFU/mL (from 3.28 log CFU/mL of the initial load), respectively. Although, the color parameters slightly changed after irradiation, the color of MB did not show visual difference (?E = 0.94) compared to untreated samples. UV-LED treatment caused a significant increase in total phenolic compound (1.75-fold) and antioxidant capacity (4.60 fold) compared to heat-treated samples (p < 0.05). UV-LED treatment caused a decrease in carotenoid content (71.3%) lower than that of heat-treated samples (88.9%), indicating that UV-LED irradiation preserved the total carotenoid content better than the heat treatment. Industrial relevance: Light-emitting diodes (LEDs) are new sources of ultraviolet light utilized for non-thermal processing of foods. In this study, a static bench top unit was designed to investigate the efficacy of UV-LEDs with different treatment times and peak emissions by considering the inactivation of E. coli K12 in newly formulated mixed drink (MB). UV-LED irradiation of MB using coupled 280/365 nm for 40 min provided the highest microbial inactivation and preserved bioactive compounds better than the heat treatment. It can be proposed as an effective method for the processing of fruit juices which is rich in bioactive constituents. © 2020 Elsevier Ltd