Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
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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: 2Citation - Scopus: 2Enhanced Reducing Sugar Production and Extraction for Chlorella Vulgaris in Mixotrophic Cultivation Using High Hydrostatic Pressure Processing and Ultrasound(Taylor & Francis, 2023) Uzuner, Sibel; Kurhan, Şebnem; Akdemir Evrendilek, GülsünAlthough extraction of polysaccharides to convert reducing sugars (RS) from microalgae by acid or alkali pretreatments and enzymatic hydrolysis has been extensively studied, few reports exploring the use of high hydrostatic pressure processing (HHP) and ultrasonication (US) as emerging technologies for the extraction of sugars from microalgae biomass exist. Thus, the present study was conducted to determine the effects of mixotrophic growth and stress conditions (NaNO3 and CO2 concentration and light intensity) on RS and protein accumulation in the unicellular green alga Chlorella vulgaris in addition to optimization of the effectiveness of the sequential applications of HHP and US with dilute acid as well as simultaneous enzymatic saccharification on the production of RS from microalga cells. High light intensity, high CO2 concentration and limited nitrogen concentration promoted RS production. The maximum protein content (0.0683 mg g(-1)) was achieved at 0.3 g l(-1) NaNO3 concentration, 7000 mu mol photons m(-2) s(-1) and 6 l min(-1) CO2 concentration. The highest RS content of C. vulgaris after 48 h enzymatic saccharification (583.86 +/- 13.23 mg g(-1)) was obtained at 1% (w/w) acid concentration and 80% amplitude for 30 min with 79.4% RS yield. Combined US-assisted dilute acid pretreatment and enzymatic hydrolysis were also found to be more effective than HHP assisted dilute acid pretreatment and enzymatic saccharification. Therefore, microalgal biomass can be considered a suitable renewable feedstock used in fermentation. Highlights center dot The cultivation period of Chlorella vulgaris was reduced from 25 days to 14 days using mixotrophic growing conditions.center dot Mixotrophic conditions enhanced reducing sugar productivity.center dot Novel extraction techniques enhanced the extraction of reducing sugar from microalgae.Article Enhanced Production of 3-Phenyllactic Acid From Novel Non-Axenic Coculture: Adaptive Evolution and Statistical Fermentation Studies(Springer Heidelberg, 2024) Meruvu, HarithaThis research pivots around screening of idoneous lactic acid bacteria (LAB) from cow milk and subjecting them to adaptive evolution experiments to aid superior growth/robustness necessary for 3-phenyllactic acid (3-PLA) production. Conventional and statistical fermentation studies were conducted at batch scale using a non-axenic coculture of three novel LAB strains: Lactiplantibacillus plantarum str. nov. plantharim, Lactobacillus delbrueckki str. nov. delharim, and Pediococcus pentasaceous str. nov. pentharim. Statistically optimized fermentation using Box Behnken technique resulted in 1225 mg/L 3-PLA production using the growth medium: cheese whey-MRS medium mixture (5:2 ratio), phenylalanine (2.69% w/v), and glucose (9.6% w/v). Statistical optimization of fermentation parameters resulted in a substantial increase (17 times higher) compared to the non-optimized fermentation conditions (72 mg/L). Monad growth kinetics of the cow milk whey (CMW) coculture were calculated and estimated as: mu(max)=0.336 h(-1), K-s=11.64 mg/mL, Y-x/s=0.835 mg/g, Y-P/S=1.66 mg/g, Y-X/P=0.112 mg/mg. The purified 3-PLA (1.93 mg/mL) showed antimicrobial activity with pathogenic bacteria like Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus, with a minimum inhibitory concentration of 12 mg/mL.Review Citation - WoS: 25Citation - Scopus: 27Bacillus Cereus: a Review of “fried Rice Syndrome” Causative Agents(Academic Press, 2023) Leong, Sui Sien; King, Jie Hung; Korel, Figen“Fried rice syndrome” originated from the first exposure to a fried rice dish contaminated with Bacillus cereus. This review compiles available data on the prevalence of B. cereus outbreak cases that occurred between 1984 and 2019. The outcome of B. cereus illness varies dramatically depending on the pathogenic strain encounter and the host's immune system. B. cereus causes a self-limiting, diarrheal illness caused by heat-resistant enterotoxin proteins, and an emetic illness caused by the deadly toxin named cereulide. The toxins together with their extrinsic factors are discussed. The possibility of more contamination of B. cereus in protein-rich food has also been shown. Therefore, the aim of this review is to summarize the available data, focusing mainly on B. cereus physiology as the causative agent for “fried rice syndrome.” This review emphasizes the prevalence of B. cereus in starchy food contamination and outbreak cases reported, the virulence of both enterotoxins and emetic toxins produced, and the possibility of contaminated in protein-rich food. The impact of emetic or enterotoxin-producing B. cereus on public health cannot be neglected. Thus, it is essential to constantly monitor for B. cereus contamination during food handling and hygiene practices for food product preparation. © 2023 Elsevier LtdArticle Citation - WoS: 2Citation - Scopus: 2Golden Thistle (scolymus Hispanicus L.) Hydromethanolic Extracts Ameliorated Glucose Absorption and Inflammatory Markers in Vitro(Wiley, 2023) Özel Taşcı, Cansu; Güleç, ŞükrüGolden thistle (GT, Scolymus hispanicus L.) is an edible plant native to the Mediterranean. Several activities have been reported for the GT, as it is used for traditional medicinal purposes in some cultures. In this study, we aimed to investigate the effects of GT crude extract on phenolic bioavailability, antidiabetic, and anti-inflammatory activities by using colonic epithelium (CaCo-2) and murine macrophage (RAW 264.7) cell lines. The CaCo-2 cells were grown on the bicameral membrane system for intestinal bioavailability and glucose efflux. Lipopolysaccharide (LPS, 0.5 mu g/mL) was used to induce systemic inflammation on RAW 264.7. The inflammatory medium of RAW 264.7 cells was given to Caco-2 cells to mimic colonic inflammation. Our results showed that 5-o-caffeoylquinic acid had an apparent permeability of (1.82 +/- 0.07) x 10-6 cm/s after 6 h. The extract lowered the glucose efflux by 39.4%-42.6%, in addition to the reductions in relative GLUT2 mRNA expressions by 49%-66% in pre- and co-treatments (p < .05). Decreases in systemic inflammation markers of nitric oxide, tumor necrosis factor-alpha, and interleukin-6 (IL-6) were also detected in 30%-45% range after pre-treatments with the GT extract (p < .05). Lastly, colonic inflammation markers of IL-6 and IL-8 were reduced by 8.7%-19.5% as a result of GT pre-treatments (p < .05). Thus, an in vitro investigation of GT extract revealed promising results on antidiabetic and anti-inflammatory activities.Editorial Citation - WoS: 2Citation - Scopus: 2Editorial: Population Genomics and Adaptation To Novel Environments: Challenges and Opportunities(Frontiers Media S.A., 2023) Matur, Ferhat; Keskin, Emre; Sezgin, EfeUnderstanding how organisms adapt to novel environments is an active Research Topic in ecological and evolutionary studies. Most ecological and evolutionary studies focus on how organisms find food (utilization of ecological resources), how they avoid being the food (avoidance of predators), or form the next generation (reproductive strategies) in changing environmental conditions. Yet, some novel environments may present with extreme challenges that organisms may need to evolve novel metabolic pathways even just to exist. Population genomics methods can offer reliable estimates of basic population characteristics such as effective population size, inbreeding, demographic history, and population structure, all of which are also important for conservation efforts. Furthermore, population genomics studies can pinpoint specific genetic loci and variants that are under selection for a populations’ ability to evolve and adapt in response to environmental change and manage adaptive variation. The last 10 years have seen a rise in the study of population genetics of non-model organisms, and the findings of this research are increasingly being applied to the conservation and management of wildlife. To understand population genetics and adaptations, it is equally crucial to share and disseminate the research done using these techniques.Article Citation - WoS: 11Citation - Scopus: 10Molecular Evolution and Population Genetics of Glutamate Decarboxylase Acid Resistance Pathway in Lactic Acid Bacteria(Frontiers Media S.A., 2023) Sezgin, Efe; Tekin, BurcuGlutamate decarboxylase (GAD) pathway (GDP) is a major acid resistance mechanism enabling microorganisms’ survival in low pH environments. We aimed to study the molecular evolution and population genetics of GDP in Lactic Acid Bacteria (LAB) to understand evolutionary processes shaping adaptation to acidic environments comparing species where the GDP genes are organized in an operon structure (Levilactobacillus brevis) versus lack of an operon structure (Lactiplantibacillus plantarum). Within species molecular population genetic analyses of GDP genes in L. brevis and L. plantarum sampled from diverse fermented food and other environments showed abundant synonymous and non-synonymous nucleotide diversity, mostly driven by low frequency changes, distributed throughout the coding regions for all genes in both species. GAD genes showed higher level of replacement polymorphism compared to transporter genes (gadC and YjeM) for both species, and GAD genes that are outside of an operon structure showed even higher level of replacement polymorphism. Population genetic tests suggest negative selection against replacement changes in all genes. Molecular structure and amino acid characteristics analyses showed that in none of the GDP genes replacement changes alter 3D structure or charge distribution supporting negative selection against non-conservative amino acid changes. Phylogenetic and between species divergence analyses suggested adaptive protein evolution on GDP genes comparing phylogenetically distant species, but conservative evolution comparing closely related species. GDP genes within an operon structure showed slower molecular evolution and higher conservation. All GAD and transporter genes showed high codon usage bias in examined LAB species suggesting high expression and utilization of acid resistance genes. Substantial discordances between species, GAD, and transporter gene tree topologies were observed suggesting molecular evolution of GDP genes do not follow speciation events. Distribution of operon structure on the species tree suggested multiple independent gain or loss of operon structure in LABs. In conclusion, GDP genes in LABs exhibit a dynamic molecular evolutionary history shaped by gene loss, gene transfer, negative and positive selection to maintain its active role in acid resistance mechanism, and enable organisms to thrive in acidic environments.Article Citation - WoS: 6Citation - Scopus: 6Organosolv Pretreatment of Corncob for Enzymatic Hydrolysis of Xylan(Springer, 2023) Büyükkileci, Ali Oğuz; Temelli, NuranXylan is a renewable polysaccharide, readily available in agricultural and forestry residues. It can be hydrolyzed to produce xylooligosaccharides (XOS) with prebiotic activity and xylose, a precursor for several industrial chemicals. Enzymatic hydrolysis of xylan in the lignocellulosic biomass to obtain xylose and XOS requires a pretreatment to facilitate xylanase activity. In this study, organosolv was evaluated for the delignification of corncob while retaining xylan in the pretreated biomass. The treatment at 170 °C for 1 h with 70% ethanol provided 50% lignin removal and 81% xylan recovery. Increasing temperatures and decreasing ethanol fractions decreased the pH and the xylan recovery. Loss of xylan in the organosolv at 190 °C and in the liquid hot water treatment could be prevented by the addition of 100 mM MgO, without compromising lignin removal. Pretreated corncob was suspended in citrate buffer and hydrolyzed by commercial xylanases. Accellerase XY (250 U/ml) at pH 5.5 and 55 °C and Econase XT (0.6 U/ml) at pH 6.0 and 70 °C provided around 65% xylan digestibility and generated xylose (9.8 g/l) and XOS (10.9 g/l), respectively. This approach could decrease xylan loss and degradation in the pretreatment step and yield clear hydrolysates composed of essentially xylose or XOS. Lignocellulosic biorefineries can benefit from the efficient utilization of xylan, increasing sustainability. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Article Citation - WoS: 9Citation - Scopus: 8Development of a New Electrochemical Sensor Based on Molecularly Imprinted Biopolymer for Determination of 4,4'-methylene Diphenyl Diamine(MDPI, 2023) Ghaani, Masoud; Büyüktaş, Duygu; Carullo, Daniele; Farris, StefanoA new molecularly imprinted electrochemical sensor was proposed to determine 4,4' methylene diphenyl diamine (MDA) using molecularly imprinted polymer-multiwalled carbon nanotubes modified glassy carbon electrode (MIP/MWCNTs/GCE). GCE was coated by MWCNTs (MWCNTs/GCE) because of their antifouling qualities and in order to improve the sensor sensitivity. To make the whole sensor, a polymeric film made up of chitosan nanoparticles was electrodeposited by the cyclic voltammetry method on the surface of MWCNTs/GCE in the presence of MDA as a template. Different parameters such as scan cycles, elution time, incubation time, molar ratio of template molecules to functional monomers, and pH were optimized to increase the performance of the MIP sensor. With a detection limit of 15 nM, a linear response to MDA was seen in the concentration range of 0.5-100 mu M. The imprinting factor (IF) of the proposed sensor was also calculated at around 3.66, demonstrating the extremely high recognition performance of a MIP/MWCNT-modified electrode. Moreover, the sensor exhibited good reproducibility and selectivity. Finally, the proposed sensor was efficiently used to determine MDA in real samples with satisfactory recoveries ranging from 94.10% to 106.76%.Article Citation - WoS: 9Citation - Scopus: 11Authentication of Pomegranate Juice in Binary and Ternary Mixtures With Spectroscopic Methods(Elsevier, 2023) Aykaç, Başak; Çavdaroğlu, Çağrı; Özen, BanuFruit juices are among the most commonly adulterated food products and especially pomegranate juice as a high value product is mixed with different adulterants for unfair economic profit. It was aimed to investigate the performances of UV–visible and Fourier-transform infrared (FTIR) spectroscopies combined with chemometric methods to determine adulteration of pomegranate juice with dark colored sour cherry and black carrot juices. Binary and ternary mixtures of pomegranate juice with 2 adulterants were prepared at 5–25% levels. After various data transformations, both spectroscopic data of authentic and adulterated samples were evaluated with different chemometric classification tools. Classification models with 97% correct classification rate for validation set were obtained both for UV–visible and FTIR spectral data. Accurate predictions of adulterant concentration were also achieved with chemometric models using both spectroscopic data. These spectroscopic techniques provide rapid and accurate prediction of pomegranate juice adulteration in binary and ternary mixtures with dark colored juices.