Browsing by Author "Esmer O.K."

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    The effect of modified atmosphere and vacuum packaging on the physicochemical, microbiological, sensory and textural properties of Crottin de Chavignol cheese
    (2009) Esmer O.K.; Balkir P.; Seckin A.K.; Irkin R.
    In this work, it was aimed to determine the effect of packaging technique on some quality properties of "Crottin de Chavignol" type goat cheese packaged under vacuum (VP) and modified atmosphere (MAP) (%20 CO2 + %80 N2) during storage at + 4°C and also to compare these two packaging techniques to be able determine the more suitable packaging technique for "Crottin de Chavignol" type goat cheese. Sampling was carried out for physicochemical, microbiological, sensory and textural analyses at l st day, 3rd, 6th, 9th,l2 th and 15th weeks. Control cheeses which were packaged under atmospheric air were unacceptable sensorially at 3rd week due to their visible mould growth. Both modified atmosphere and vacuum packaging had favourable effects on physicochemical properties, microbiological properties, color, sensory attributes of Crottin de Chavignol type goat cheese to longer the shelf life of cheese. According to the results of our study, at 15th weeks mould growth increased to 2.3 log cfu/g and 3.8 log cfu/g at MAP and VP cheese samples respectively whereas the mould growth was > 1 log cfu/g at 1.day of storage. And the taste scores of VP cheese samples were below acceptability limit at 15th weeks because of formation of oxidized flavour. The packaging type whether MAP or VP didn't significantly affected the pH, dry matter, color and textural properties except hardness, chewiness and gumminess. Hardness, chewiness and gumminess values of VP cheeses were higher than MAP cheese samples.
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    Effect of freezing and packaging methods on the organic acid contents of goat cheeses during storage; [Utjecaj zamrzavanja i metoda ambalažiranja na udjel organskih kiselina kozjeg sira tijekom skladištenja]
    (2011) Kemal Seçkin A.; Esmer O.K.; Balkir P.; Ergönül P.G.
    Effects of freezing and packaging methods on organic acid content of goat cheese during 12 weeks of storage were determined. Goat cheese milk curds were divided into two parts and stored at 4°C refrigerated control sample and at -18°C for six months frozen experimental samples. After that, cheeses were packed in three different packaging methods: aerobic, vacuum or modified atmosphere. Citric, malic, fumaric, acetic, lactic, pyruvic and propionic acids were analyzed using HPLC method after 1 st, 3 rd, 6 th, 9 th and 12 th week of storage period. Lactic acid was the main organic acids while pyruvic acid had the lowest content in all cheese samples. Citric and fumaric acid levels of frozen samples increased during storage whereas malic, acetic, pyruvic and propionic acid amounts were decreased compared to the beginning of storage. Packaging methods and freezing process also effected lactic acid levels statistically (p<0.05). Fumaric, acetic and lactic acid concentration of refrigerated samples were increased but citric, malic and propionic acids decreased during storage. Pyruvic acid level did not change significantly. It was determined that organic acid concentrations were effected by freezing process, storage time and packaging methods significantly (p<0.05).
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    Effects of Green Extraction Methods on Antioxidant and Antimicrobial Properties of Artichoke (Cynara scolymus L.) Leaves
    (University of Zagreb, 2024) Turksever C.; Gurel D.B.; Sahiner A.; Çağındı O.; Esmer O.K.
    Research background. Artichoke leaves, an important waste product of the food industry, have an important antioxidant and antimicrobial capacity. Although there are several studies in the literature to determine their antioxidant and antimicrobial activity, a comparison of green extraction technologies including microwave, ultrasound probe and ultrasound bath methods in relation to the maceration technique has not been performed. Also, several parameters such as the extraction temperature, power, extraction mode and extraction time are important parameters for obtaining targeted compounds in the highest amount. For this reason, we aimed to compare various extraction methods including microwave-assisted extraction, ultrasound-assisted extraction with probe, ultrasound-assisted extraction in a water bath and maceration in terms of extraction parameters for obtaining bioactive compounds from artichoke leaves. Experimental approach. M icrowave-assisted extraction at two different power values, ultrasound-assisted extraction with probe in continuous or pulsed mode with two different extraction times each, ultrasound-assisted extraction in a water bath at two different power values with two different extraction times each and maceration with two different times were used for the extraction. The extraction temperature is an important parameter affecting the thermal degradation of bioactive compounds. We used a constant extraction temperature of 50 °C. Total phenolic and total flavonoid content, antioxidant capacity, phenolic compound profile analysis by LC-QTOF-MS and antimicrobial activity by agar diffusion and broth microdilution methods were determined. Results and conclusions. T he bioactive compounds were found to be significantly affected by the parameters used in each extraction method. The microwave-assisted extraction method was more efficient than the other extraction methods at both power values. This method also required the shortest extraction time. The ultrasound-assisted probe extraction method was the second most efficient method. The type of process, continuous or pulsed, did not affect the results, but shortening the extraction time led to lower results. A longer extraction time of the ultrasound-assisted extraction in a water bath method led to better results, similar to the ultrasound-assisted probe extraction, regardless of the used power. The extracts were highly effective against many opportunistic and pathogenic microorganisms. Novelty and scientific contribution. This study provides valuable insights into the extraction parameters of different extraction methods to obtain bioactive compounds from artichoke leaves, which could have potential applications in the food and pharmaceutical industries. © 2024, University of Zagreb. All rights reserved.