Cavit Bircan

Incidence of ochratoxin A in dried fruits and co-occurrence with aflatoxins in dried figs

Ninety eight dried figs, 53 sultanas and 20 dried apricots destined for export from Turkey to the European Union were tested for ochratoxin A (OTA) contamination utilizing immunoaffinity column clean-up and high-performance liquid chromatography (HPLC). While only 2 (4%) of the sultanas exceeded the 10 ng g(-1) maximum limit set by the EU, 28 (53%) of 53 sultana samples contained detectable levels of OTA, in the range of 0.51-58.04 ng g(-1). Eighteen of 98 (18%) dried figs contained detectable levels of OTA, in the range of 0.87-24.37 ng g(-1). Only one of the 20 dried apricots was contaminated, with 0.97 ng g(-1) OTA. Dried figs analyzed for OTA were also tested for aflatoxin contamination to determine the co-occurrence of both toxins. Seven samples were confirmed aflatoxin positive, in the range of 0.23-4.28 ng g(-1), and only 2 samples contained both toxins, with a maximum concentration of 24.37 ng g(-1)for OTA and 1.02 ng g(-1) for aflatoxin B(1). The average recovery and relative standard deviation (RSD) obtained from dried fruits spiked with OTA ranged from 80.5% to 91.5% and 0.99-5%, respectively. The average recovery and relative standard deviation (RSD) obtained from dried figs spiked with aflatoxin ranged from 88.78% to 93.53% and 2.54-7.25%, respectively.

Use of Dielectric Properties to Detect Whey Protein Denaturation

Denaturation of whey proteins can be detected by the dielectric properties. The dielectric properties of 20% whey protein with 0, 5 or 15% sugar, 2% salt, at pH 4 and isolated whey proteins were measured from room temperature to 100°C at 300–2450 MHz. The temperature at which a decrease in the dielectric loss factor, or increase in the dielectric constant, occurred was compared to the temperature of denaturation as determined by DSC and found to match. The change in the dielectric properties is likely caused by binding of water and/or ions that occurs during protein denaturation. For most of the samples, the dielectric loss factor showed the protein denaturation, but when ions were present due to salt or low pH, the dielectric constant showed the denaturation.

The Dielectric Properties of Meats as a Function of Temperature and Composition

The dielectric properties of cod, perch, salmon, chicken breast, chicken thigh and beef were measured at 15 to 65°C at 2450 MHz. The samples covered a moisture range of 68.9–81.2% and ash range of 0.96–1.20%. Equations were developed as a function of temperature, moisture, and ash, and compared to literature equations. The dielectric constant decreased with temperature and increased with moisture content. It was not affected by ash content. The dielectric loss factor increased with moisture content for moisture contents lower than 74.9%, then decreased for higher moisture contents. The dielectric loss factor was quadratically related to temperature, decreasing to 30.2° C then increasing. The dielectric loss factor increased with ash content. The effect of moisture content and temperature on the dielectric loss factor in the literature is reviewed to explain these results.

Increased aflatoxin contamination of dried figs in a drought year

Dried figs (4917 samples) destined for export from Turkey to the European Union were collected between September and December during the very dry crop year of 2007 and tested for aflatoxins B1, B2, G1 and G2 by immunoaffinity column clean-up and reverse-phase high-performance liquid chromatography (RP-HPLC). While 32% of the samples contained detectable levels of total aflatoxins, 9.8% of them exceeded the European Union limits. Aflatoxin levels were in the range of 0.2–259.46 µg kg−1 and 2.04–259.46 µg kg−1 for all samples and samples that exceeded the limits, respectively. A substantial increase in the incidence of aflatoxins was observed in 2007 compared with previous years, most likely due to the drought stress, high temperatures and low relative humidity encountered during the period from January to September of that year. In 2007, the mean temperature was 1–2°C higher, there was 300 mm less total rain, and the mean relative humidity was 10–15% lower than in 2002–06. The average concentration of individual aflatoxins present in the samples was quantified to determine whether the drought conditions promoted certain types of aflatoxins. Among the contaminated samples, aflatoxin B1 occurred in 97% of the contaminated samples, followed by G1 in 47%, B2 in 24%, and G2 in 6% of samples. Concentrations of individual aflatoxins exhibited great variability among the samples but were not significantly different from those reported in previous studies, which were conducted under conditions without drought and high temperatures.

Comparison of homogenization techniques and incidence of aflatoxin contamination in dried figs for export.

To determine differences in mean aflatoxin contamination and subsample variance from dry and slurry homogenizations, 10 kg of six different, naturally contaminated dried fig samples were collected from various exporting companies in accordance with the EU Commission Directive. The samples were first dry-mixed for 5 min using a blender and sub-sampled seven times; the remainder was slurry homogenized (1 : 1, v/v) and sub-sampled seven times. Aflatoxin B1 and total aflatoxin levels were recorded and coefficient of variations (CV) computed for all sub-samples. Only a small reduction in sub-sample variations, indicated by the lower CV values, and slight differences in mean aflatoxin B1 and total aflatoxin levels were observed when slurry homogenization was applied. Therefore, 7326 dried figs, destined for export from Turkey to the EU and collected during the 2008 crop year, were dry-homogenized and tested for aflatoxins (B1, B2, G1 and G2) by immunoaffinity column clean-up using RP-HPLC. While 34% of the samples contained detectable levels of total aflatoxins (0.20–208.75 µg kg−1), only 9% of them exceeded the EU limit of 4 µg kg−1 in the range 2.0–208.75 µg kg−1, respectively. A substantial increase in the incidence of aflatoxins was observed in 2008, most likely due to the drought stress experienced in Aydin province as occurred in 2007.

Sour Cherry By-products: Compositions, Functional Properties and Recovery Potentials – A Review

Abstract Sour (tart) cherry is an industrial fruit where a considerable amount of by-products remain after processing. Sour cherry by-products consist of pomace (skin and flesh) and seeds (pit, stone) which remain after the fruit juice and IQF processes. Sour cherry pomace is characterized with a high content of phenolic compounds and the seed constitutes a high oil yield with beneficial effects on human health because of their antioxidant, antimicrobial, and anti-inflammatory properties. There has been a great interest in sour cherry by-products due to the increasing production rate of sour cherry worldwide and the increasing efforts on seeking bioactive compounds from natural sources as functional food. Thus, there have been a number of studies regarding the sour cherry pomace and sour cherry seed, especially in the last five years. The present review summarizes the chemical, biological, functional, and technological properties of the sour cherry pomace and sour cherry seed with their current and potential applications.

FARKLI ISITMA TEKNİKLERİNİN FINDIK VE KANOLA YAĞININ STEROL BİLEŞİMİNE ETKİSİ

Calismanin amaci farkli isitma tekniklerinin findik ve kanola yaglarinin sterol bilesimine etkisini belirlemektir. Bu amacla, 50 ml rafine findik ve rafine kanola yagi mikrodalga firinda 650 W gucte 1, 3, 5 ve 10 dk bekletilmis; isitma sonunda yag orneklerinin sicakliklari olculerek konveksiyonel ve hibrid firinda da ayni sicakliga (69.5, 129.4, 173.5 ve 238.0 °C ) ulasmayi saglayan isitma islemleri gerceklestirilmistir. Elde edilen yag ornekleri sterol miktar ve kompozisyonu acisindan degerlendirilmistir. Bulgular hibrit firinin isitma hizinin yuksek sicakliklarda diger firinlara kiyasla daha dusuk oldugunu gostermektedir. Findik yaginin temel sterolleri β-sitosterol, kampesterol ve sitostanol olup ve toplam sterol icerigi 683.69-1544.09 mg/kg arasinda degismistir. Tum isitma yontemlerinde sicaklik artisi ile findik yaginin sterol iceriginde genel olarak bir azalma meydana gelmistir. Kanola yagi, β-sitosterol ve kampesterol yaninda yaga ozgu olarak yuksek oranlarda brassikasterol icermektedir. Kanola yagi orneklerinin toplam sterol icerigi 6088.28-9532.72 mg/kg arasinda degismis ve isitma islemleri yagda sterol kaybina yol acmamistir.