Browsing by Author "Alpas H."

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Effect of high hydrostatic pressure on seed germination, microbial quality, anatomy-morphology and physiological characteristics of garden cress (Lepidium sativum) seedlings
(2013-06-01) Işlek C.; Altuner E.M.; Çeter T.; Alpas H.
High hydrostatic pressure is a non-thermal food processing technology that is found to increase the percentage of germination, decrease the germination time and improve the microbial quality of seeds. In this study, pressures of 100-400 MPa for 10 min at 30°C are used to compare the percentage of germination, the microbial quality of seeds, chlorophyll a and b, and total phenolic compounds concentrations in seedlings, and the anatomy-morphology characteristics of garden cress. Enhanced reductions of total aerobic mesophilic bacteria, total and fecal coliforms, and yeast and mould populations in seeds were observed, especially at 300 MPa. In addition, the percentage of germination, chlorophyll content and phenolic compounds concentrations, fresh and dry weights, and hypocotyl lengths of the seedlings are higher than those of all samples, where the percentage of germination is equal to controls but higher than other samples, and radicula length is lower than controls but higher than others. © 2013 Copyright Taylor and Francis Group, LLC.
Effect of high hydrostatic pressure on the profile of proteins extracted from Betula pendula pollens
(2014-10-02) Altuner E.; Çeter T.; Alpas H.
High hydrostatic pressure (HHP) has high success potential in pollen protein extraction, but its effect on pollen protein profiles has not been studied yet. The aim of this study is to put forward whether HHP processing causes a change in the protein profiles extracted from pollens or not. In this study, proteins extracted from Betula pendula pollens were studied at 100, 200 and 300MPa at room temperature for 5min. In addition, the efficiency of three different extraction solvents, namely phosphate buffer saline (PBS) buffer pH 7.5, trichloroacetic acid-acetone and Tris-HCl buffer pH 8.8, was also observed, and the results were compared with the conventional pollen protein extraction procedure. As a result, it is concluded that 200MPa for 5min has extracted similar amounts of protein compared with the conventional extraction method which lasted for 24h, which lasted for 24 h. On the other hand, the application time for 200 MPa for 5 min is extremely shorter when it is compared to the conventional extraction method.
High hydrostatic pressure processing: A method having high success potential in pollen protein extraction
(2012-06-01) Altuner E.; Çeter T.; Alpas H.
Even a single peptide that is present in the pollen wall and cytoplasm could cause pollen allergy. To produce skin-prick test kits, the first step is the extraction of these molecules. In this study, Cedrus atlantica pollens were subjected to 220 and 330MPa for 10 and 30min in order to extract these molecules. After high hydrostatic pressure processing (HHPP), the total amounts of proteins (TAPs) are measured and compared with the results of the conventional extraction method (CEM). As a result, the TAPs extracted by HHPP is 18.0210 μg/mL at 220MPa for 10min, 22.5770 μg/mL at 220MPa for 30min, 23.3810 μg/mL at 330MPa for 10min and 25.9270 μg/mL at 330MPa for 30min, while this is 1.9460 μg/mL in 24h by the CEM. In addition to these results, visual pollen deformation and eruption, pollen wall and surface damage have also been observed. © 2012 Taylor & Francis.
Predictive modeling for 5-hydroxymethylfurfural formation by some application conditions of high hydrostatic pressure, namely glucose concentration and application temperature, in high glucose containing model beverages
(2018-11-01) Altuner E.; Alpas H.
High hydrostatic pressure (HHP) is a nonthermal food processing technology. Many studies have shown that HHP may be used as a process to increase the shelf life of beverages, which are inherently containing glucose or subsequently glucose added. Depending on food processing technologies and storage conditions 5-hydroxymethylfurfural (5-HMF) formation from glucose in foods occurs. There are some limitations about the amount of the 5-HMF present in foods based on World Health Organization and various International Standards, such as European Commission Directive 2007/196/EC. The aim of this study is to present the effect of glucose concentration and HHP in 5-HMF formation in model beverages with different glucose concentrations (10, 40, and 70 g/200 mL). A strong positive correlation was observed between 5-HMF formation and glucose concentration (R = 0.6055) and application temperature (R = 0.6774). Also a predictive analysis model was fitted to the 5-HMF formation response by response surface model (RSM). Practical applications: The equation obtained as a model in this study can be used to calculate the formation of 5-HMF for a glucose containing beverages processed by HHP as a response of glucose concentration and application temperature within the conditions of the study. The model was calibrated and validated on glucose containing model beverages, which are representatives of some high glucose containing beverages. HMF content is an important parameter and should be included as one of the quality parameters for commercial beverages. Because of that, this equation has an importance especially for the beverage producers, who process their product by HHP, to predict 5-HMF formation by controlling glucose concentration and HHP treatment conditions. Moreover, developed model can easily be adapted to the standard procedures of academic and industrial applications.
The effect of high hydrostatic pressure on the physiological and biochemical properties of pepper (Capsicum annuum L.) seedlings
(2015-10-02) Işlek C.; Altuner E.M.; Alpas H.
High hydrostatic pressure is a non-thermal food processing technology, which also has several successful applications in different areas besides food processing. In this study, Capsicum annuum L. (pepper) seeds are subjected to 50, 100, 200 and 300 MPa pressure for 5 min at 25°C and the seedlings of HHP processed seeds are used to compare percentage of seed germination and biochemical properties such as chlorophyll a, b and a/b, proline content, total protein, carotenoid, malondialdehyde, glucose, fructose and phenolic compounds concentrations. As a result of the study, it was observed that there are remarkable changes in terms of biochemical properties especially for seedlings, whose seeds were pressurized at 200 and 300 MPa. More detailed studies are needed to put forward the mechanism behind the changes in biochemical properties.
Using high hydrostatic pressure as an abiotic elicitor strategy for improving capsaicin production in free and immobilized cell suspension cultures of Capsicum annuum L.
(2021-01-01) İşlek C.; Koç E.; Altuner E.M.; Alpas H.
In this study, the effects of immobilization and high hydrostatic pressure (HHP) on capsaicin production in cell suspension culture of pepper seeds at different application times were investigated. Callus cultures were obtained from in vitro germinated hypocotyl explants of pepper seedlings and cell suspensions were prepared from calluses. Immobilized cell suspension cultures with calcium alginate and free cell suspension cultures were obtained by using these cell suspensions. 50, 100, 200, 300 and 400 MPa were applied to both free and immobilized cell suspensions as an elicitor. When all the results were compared, the highest amount of capsaicin was achieved in immobilized cell suspensions on the tenth day as 293.187 µg/g f.w at 400 MPa pressure. As a result, it can be concluded that the combined application of immobilization and elicitor (HHP) caused significant increases (p <.05) in the amount of capsaicin.