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Featured researches published by Hamza Bozkir.


Chemistry of Natural Compounds | 2015

HPLC DETERMINATION OF CAROTENOID, ORGANIC ACID, AND SUGAR CONTENT IN PEPINO (Solanum muricatum) FRUIT DURING THE RIPENING PERIOD

Osman Kola; Merve Simsek; Hüseyin Duran; Hamza Bozkir

Pepino, Solanum muricatum, is a herbaceous plant of South American origin [1, 2]. Currently, several commercial varieties are being developed in New Zealand and Australia through selection and breeding (e.g., Suma, Miski, Lincoln Long, Golden Litestripe, etc.), while other cultivars (e.g., El Camino and Schmidt) are direct introductions of material grown in Chile [3]. The pepino (Solanum muricatum Aiton, Solanaceae) is a little-known crop from the tropical and subtropical Andes esteemed for its edible fruits, which are aromatic, juicy, scented, mildly sweet, and greatly varying in size, shape, and color depending on the cultivar [1, 2]. The fruit matures 30 to 80 days after pollination. Its color starts with green and during ripening changes to golden yellow covered with purple stripes [4]. El-Zeftawi et al. [5] reported that the fruit often fails to ripen normally and thus fails to develop its characteristic flavor after harvest. Hence, appropriate harvesting of pepino fruit is essential for high pepino quality [6–8]. The pepino is said to have medicinal properties. It is a good antiscorbutic since it contains vitamin C (25–70 mg/100 mL) at higher levels than normally found in most fruits [9–11]. This work is a first step to identify and quantify organic acids and sugars and some properties in pepino fruits and fruit juices (cv. Miski) from Turkey using HPLC methods. The overall objective of the study was to determine the quality characteristics of pepino fruits during the maturation period and to identify objective indices of the properties of both the fruit and the juice. Pepino fruits (cv. Miski) were harvested at three stages (green, strapped green, mature) from December 2009 to February 2010 at Akyazi and Antalya, Turkey. Pepino fruits were harvested and kept at a temperature of 5 C until analysis. All chemicals and solvents were obtained from Sigma Chemical Co. (St Louis, MO, USA) and Merck (Darmstadt, Germany). Pepino fruits (cv. Miski) were 168.2–258.2 g/fruit weight, 6.50–8.78 cm in diameter, and 8.17–9.32 cm long. The juice yield (%) of pepino samples varied from 43.0 to 51.0% (Table 1). During the maturation period a small increase in fruit weight, fruit width, and fruit length was detected. Antalya pepinos were approximately 10% more massive than Akyazi pepinos at the mature stage. The chemical properties of pepino juice samples are given in Table 1. In this study, the total acidity (%) in pepino fruits was determined as ranging from 0.06 to 0.08, the Brix (total soluble solids, SSC) from 4.00 to 7.10, and pH values from 4.89 to 5.84. The total soluble solids content of the two different pepinos increased during the maturation period. Gonzalez et al. [7] found pH values ranging from 4.74–5.40 and 4.89–5.14 in the sweet round and sweet long kinds. In their study on the quality and physiological behavior of pepinos, Lizana and Levano [12] reported that typical Chilean pepinos had 8.5% soluble solids when ripe. De Arriola et al. [9] also reported a total acidity of 0.06%, a Brix (total soluble solids) of 9.5%, total sugars of 4.06 g/100 g, and ascorbic acid of 34.25 mg/100 g in ripe pepino fruits of a local selection.


GIDA / THE JOURNAL OF FOOD | 2018

KIRMIZI BİBER PÜRESİNİN VERİM VE KALİTESİNE MİKRODALGA ISITMANIN ETKİSİ

Hamza Bozkir; Ahsen Rayman Ergün; Özge Taştan; Taner Baysal

Bu calismada kirmizi biber puresinin verim ve kalitesi uzerine konvansiyonel isitma teknigine alternatif olarak mikrodalga isitma teknigi uygulanmistir. Mikrodalga isitma uygulamasi verim ve cikis sicakligi cevap olacak sekilde yanit yuzey metodu ile optimize edilmistir. Mikrodalga isitma uygulamasinin yanit yuzey metodu ile optimum kosullari 900 W guc ve 6.52 rpm akis hizi olarak saptanmistir. Bu optimum calisma kosullarinda verim ve cikis sicakligi %76.76 ve 95 °C olarak bulunmustur. Konvansiyonel isitma uygulamasi da mikrodalga isitmada ulasilan ayni sicaklik derecesinde 95°C ve 9 dk olarak yurutulmustur. Sonuc olarak mikrodalga isitma uygulamasi ile verimde %8.07, pektin iceriginde %17.75, C vitamin iceriginde %20.6 artis saptanmistir.Bu calismada kirmizi biber puresinin verim ve kalitesi uzerine konvansiyonel isitma teknigine alternatif olarak mikrodalga isitma teknigi uygulanmistir. Mikrodalga isitma uygulamasi verim ve cikis sicakligi cevap olacak sekilde yanit yuzey metodu ile optimize edilmistir. Mikrodalga isitma uygulamasinin yanit yuzey metodu ile optimum kosullari 900 W guc ve 6.52 rpm akis hizi olarak saptanmistir. Bu optimum calisma kosullarinda verim ve cikis sicakligi %76.76 ve 95 °C olarak bulunmustur. Konvansiyonel isitma uygulamasi da mikrodalga isitmada ulasilan ayni sicaklik derecesinde 95°C ve 9 dk olarak yurutulmustur. Sonuc olarak mikrodalga isitma uygulamasi ile verimde %8.07, pektin iceriginde %17.75, C vitamin iceriginde %20.6 artis saptanmistir.


Archive | 2017

Concentration of apple juice by vacuum microwave evaporator and in comparison to rotary evaporator

Hamza Bozkir; Taner Baysal

A consumers are increasingly concerned about the impact of beef on health, the studies about beef contents are becoming popular recently. Oleic acid, the main components of Korean native beef (Hanwoo) fat, is usually known as beneficial material in reducing cardiovascular disease. Therefore, we studied the effects of oleic acid on lipid metabolism of rats, and then tried to see the possible effects on humans. To each twenty rats, 5% of olive oil, 10% of olive oil or 10% of coconut oil (control) in diet was added at a total feed amount of 30g/day. After 4 or/and 8 weeks, the rats feeding the oleic acid were increased oleic acid concentration in blood (P=0.001). In adipose tissue, there was a significant difference in C18-long chain fatty acid in the group fed with olive oil compared with control. Especially, cis-9 C18:1 contents had a big difference (P<0.0001). There was an increase in C18-long chain fatty acid, arachidonic acid(C20:4) and docosahexaenoic acid(C22:6) when fed with olive oil, but there was no effect of olive oil on adipose tissue except for C18 long chain fatty acid. Based on these results, followed experiment were conducted for finding the effects of Hanwoo fat, which is higher oleic acid than the other American beef (Angus) fat, on lipid metabolism of blood and adipose tissues of rats. The content of unsaturated fatty acid in blood was higher in the rats fed with diet including 7% of Hanwoo fat (HF) than the group fed with 7% of Angus fat (AF) (P<0.0001). High density lipoprotein was also higher in HF (P=0.005). However, AF was higher trans-type oleic acid in adipose tissue (P<0.0001). From these results, we have predicted that Hanwoo fat (high oleic acid) will have a positive effect on index of cardiovascular disease.E of physical treatments with mild heating and freezing (H: heating at onset gelatinization temperatures-T0 for 1hr; HC: heating at T0 for 1hr and then cooling at 4oC for 12hr; HFT: heating at T0 for 1hr, freezing at -20oC for 12hr and then thawing at 25oC for 1 hr; HCFT: heating at T0 for 1hr, cooling at 4oC for 12hrs freezing at -20 ̊C for 12hrs and then thawing at 25oC for 1hr) on normal corn, waxy corn, potato, and tapioca starches were investigated. After the treatments, starches recovered by centrifugation and drying were examined in their pasting/thermal properties and microstructure. Comparing with H, HC and HFT treatments, HCFT significantly modified the granule structure, crystalline properties, and pasting properties. HCFT-treated potato starch increased its final viscosity and onset gelatinization temperature for crystal melting, from 2773 to 3930cP and 60.2o to 66.0oC, respectively. However, the breakdown and setback in viscogram decreased. The change in gelatinization enthalpy was more significant than that of other HCFT-treated starches. No significant change could be observed in waxy corn starch, possibly due to the absence of amylose. Overall, B-type starches (potato and tapioca) were more significantly modified than A-type starches (normal corn and waxy corn), resulting in more changes in pasting properties and microstructure. Heating at T0 is the first key step to increase the amylose leaching and seduce more water molecules, while cooling treatment as a preparatory and necessary work to improve the effects of followed FT treatment and during FT-treatment the mechanical force was produced which acts as a final key step in this study. The physical treatment using mild heating and freezing (HCFT) could be utilized to modify granule structure of starches which may replace some of chemical modification processes.


Archive | 2017

Effect of vacuum microwave evaporation and conventional evaporation on the phenolic compounds of apple juice

Hamza Bozkir; Taner Baysal

A consumers are increasingly concerned about the impact of beef on health, the studies about beef contents are becoming popular recently. Oleic acid, the main components of Korean native beef (Hanwoo) fat, is usually known as beneficial material in reducing cardiovascular disease. Therefore, we studied the effects of oleic acid on lipid metabolism of rats, and then tried to see the possible effects on humans. To each twenty rats, 5% of olive oil, 10% of olive oil or 10% of coconut oil (control) in diet was added at a total feed amount of 30g/day. After 4 or/and 8 weeks, the rats feeding the oleic acid were increased oleic acid concentration in blood (P=0.001). In adipose tissue, there was a significant difference in C18-long chain fatty acid in the group fed with olive oil compared with control. Especially, cis-9 C18:1 contents had a big difference (P<0.0001). There was an increase in C18-long chain fatty acid, arachidonic acid(C20:4) and docosahexaenoic acid(C22:6) when fed with olive oil, but there was no effect of olive oil on adipose tissue except for C18 long chain fatty acid. Based on these results, followed experiment were conducted for finding the effects of Hanwoo fat, which is higher oleic acid than the other American beef (Angus) fat, on lipid metabolism of blood and adipose tissues of rats. The content of unsaturated fatty acid in blood was higher in the rats fed with diet including 7% of Hanwoo fat (HF) than the group fed with 7% of Angus fat (AF) (P<0.0001). High density lipoprotein was also higher in HF (P=0.005). However, AF was higher trans-type oleic acid in adipose tissue (P<0.0001). From these results, we have predicted that Hanwoo fat (high oleic acid) will have a positive effect on index of cardiovascular disease.E of physical treatments with mild heating and freezing (H: heating at onset gelatinization temperatures-T0 for 1hr; HC: heating at T0 for 1hr and then cooling at 4oC for 12hr; HFT: heating at T0 for 1hr, freezing at -20oC for 12hr and then thawing at 25oC for 1 hr; HCFT: heating at T0 for 1hr, cooling at 4oC for 12hrs freezing at -20 ̊C for 12hrs and then thawing at 25oC for 1hr) on normal corn, waxy corn, potato, and tapioca starches were investigated. After the treatments, starches recovered by centrifugation and drying were examined in their pasting/thermal properties and microstructure. Comparing with H, HC and HFT treatments, HCFT significantly modified the granule structure, crystalline properties, and pasting properties. HCFT-treated potato starch increased its final viscosity and onset gelatinization temperature for crystal melting, from 2773 to 3930cP and 60.2o to 66.0oC, respectively. However, the breakdown and setback in viscogram decreased. The change in gelatinization enthalpy was more significant than that of other HCFT-treated starches. No significant change could be observed in waxy corn starch, possibly due to the absence of amylose. Overall, B-type starches (potato and tapioca) were more significantly modified than A-type starches (normal corn and waxy corn), resulting in more changes in pasting properties and microstructure. Heating at T0 is the first key step to increase the amylose leaching and seduce more water molecules, while cooling treatment as a preparatory and necessary work to improve the effects of followed FT treatment and during FT-treatment the mechanical force was produced which acts as a final key step in this study. The physical treatment using mild heating and freezing (HCFT) could be utilized to modify granule structure of starches which may replace some of chemical modification processes.


International Journal of Food Engineering | 2015

Investigating the Effects of Current and Wave Form of Electrical Pre-treatments on the Yield and Quality of Tomato Juice

Yeliz Tekgül; Kemal Çağrı Özcan; Taner Baysal; Ahsen Rayman Ergün; Hamza Bozkir

Abstract In this study, the effects of different current and wave forms of electrical application by electroplasmolyzator on the production of tomato juice were investigated. The whole electrical design can be divided into three subtitles. The three subtitles are used for only auto-transformer outputs for “AC (alternative current) voltage”, and the AC rectification for “DC” (direct current) voltage and the gate drive of the switching devices for “square waves”. Yield, lycopene content and color values were compared for these different current and wave forms. As a result the yield increase was found mostly in the AC-treated group which has square wave form and bipolar single phase (100 V–90 s). Lycopene was also found mostly in the same group. Significant differences were found between the groups that are treated with different current and wave forms.


Lwt - Food Science and Technology | 2016

Effects of electrical and sonication pretreatments on the drying rate and quality of mushrooms

Ruken Şeyda Çakmak; Onur Tekeoğlu; Hamza Bozkir; Ahsen Rayman Ergün; Taner Baysal


Journal of Food Process Engineering | 2017

Concentration of apple juice using a vacuum microwave evaporator as a novel technique: Determination of quality characteristics

Hamza Bozkir; Taner Baysal


GIDA / THE JOURNAL OF FOOD | 2018

EFFECT OF MICROWAVE HEATING ON THE YIELD AND QUALITY OF RED BELL PEPPER PUREE

Hamza Bozkir; Ahsen Rayman Ergün; Özge Taştan; Taner Baysal


Food Science and Biotechnology | 2018

Ultrasound as pretreatment for drying garlic slices in microwave and convective dryer

Hamza Bozkir; Ahsen Rayman Ergün; Yeliz Tekgül; Taner Baysal


Turkish Journal of Agriculture: Food Science and Technology | 2017

Changes in the Quality of Black Mulberry and Blueberry Sherbets During Storage

Ahsen Rayman Ergün; Yeliz Tekgül; Hamza Bozkir; Taner Baysal

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Yeliz Tekgül

Adnan Menderes University

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