Osman Gul

Recovery potential of cold press byproducts obtained from the edible oil industry: physicochemical, bioactive, and antimicrobial properties.

Physicochemical, bioactive, and antimicrobial properties of different cold press edible oil byproducts (almond (AOB), walnut (WOB), pomegranate (POB), and grape (GOB)) were investigated. Oil, protein, and crude fiber content of the byproducts were found between 4.82 and 12.57%, between 9.38 and 49.05%, and between 5.87 and 45.83%, respectively. GOB had very high crude fiber content; therefore, it may have potential for use as a new dietary fiber source in the food industry. As GOB, POB, and WOB oils were rich in polyunsaturated fatty acids, AOB was rich in monounsaturated fatty acids. Oil byproducts were also found to be rich in dietary mineral contents, especially potassium, calcium, phosphorus, and magnesium. WOB had highest total phenolic (802 ppm), flavonoid (216 ppm), and total hydrolyzed tannin (2185 ppm) contents among the other byproducts. Volatile compounds of all the byproducts are mainly composed of terpenes in concentration of approximately 95%. Limonene was the dominant volatile compound in all of the byproducts. Almond and pomegranate byproduct extracts showed antibacterial activity depending on their concentration, whereas those of walnut and grape byproducts showed no antibacterial activity against any pathogenic bacteria tested. According to the results of the present study, walnut, almond, pomegranate, and grape seed oil byproducts possess valuable properties that can be taken into consideration for improvement of nutritional and functional properties of many food products.

Manufacture and characterization of kefir made from cow and buffalo milk, using kefir grain and starter culture.

The microbiological and chemical characteristics as well as organic and amino acid profiles of kefir samples made from cow and buffalo milks fermented by kefir grains and starter culture were investigated during storage for 21 d at 4°C. After incubation, lactic, acetic, and citric acid concentrations showed a difference among the samples due to milk type and production methods. Storage time had little effect on the organic acid values of kefir samples. As compared with cow milk kefir, buffalo milk kefir had higher numbers of microorganisms, except lactobacilli, at the end of storage. Whereas pH and titratable acidity exhibited similar changes during storage in all kefir samples, ethanol levels were significantly increased in buffalo milk kefir samples. Glutamic acid was the major amino acid at all sampling times for all samples. Tyrosine, serine, histidine, alanine, methionine, and lysine concentrations were determined to be different in all samples depending on milk type. In general, due to the higher microbial population (especially yeast), kefir made from buffalo milk may be preferred.

Natamycin content and quality evaluation of yoghurt from small- and large-scale brands in Turkey.

In this study, the presence of natamycin and quality parameters of yoghurt samples manufactured by small- and large-scale dairy firms in Turkey were investigated. Physicochemical and microbiological results revealed that, except Lactobacillus bulgaricus and Streptococcus thermophilus counts, the majority of the yoghurts manufactured by small-scale dairy firms were found to be out of the limits. Natamycin was detected in 31 and 2 yoghurt samples from small- and large-scale brands, respectively. The levels of natamycin in small-scale brand yoghurts were higher than those in large-scale brand yoghurts. Of the analysed samples, 42.3% did not comply with the Turkish Food Codex.

Occurrence of Aflatoxin M1 in Vacuum Packed Kashar Cheeses in Turkey

In this study, aflatoxin M1 (AFM1) levels of vacuum packed Kashar cheese marketed in the Black Sea Region of Turkey were determined during October 2008 and June 2009. The occurrence of AFM1 contamination in vacuum packed cheese samples was investigated using immunoaffinity column extraction and high-performance liquid chromatography. AFM1 was detected in 144 (97.96%) of cheese samples ranging from 0.015 to 3.774 μg/kg cheese, and mean value of AFM1 was found to be 0.273 μg/kg cheese. AFM1 level in 16 (11.11%) of positive samples was higher than the maximum tolerance limit (0.5 μg/kg) accepted by Turkish Food Codex.

Phenolic Compounds and Chemical Characteristics of Pears (Pyrus Communis L.)

This study was carried out to determine the phenolic compounds and some chemical characteristics at flesh and peel in some pear cultivars. The fruit weight was varied from 45.9 to 479.9 g and flesh firmness was varied from 29.4 to 89.7 N. Soluble solids content was higher in the flesh than in the peel, while pH, titratable acidity and all phenolic compounds were generally higher in the peel than in the flesh. Quantitative differences were found in the phenolic compounds among the pear cultivars. Arbutin and chlorogenic acid were detected as major phenolic compounds in the peel and flesh, while rutin hydrate and rutin-tri-hydrate were detected as a minor in the peel and flesh. Catechin ranged from 40.0 to 543.8 mg kg−1 in the flesh and 42.4 to 695.2 mg kg−1 in the peel. Epicatechin content varied from 11.47 to 243.1 mg kg−1 in the flesh and 12.6 to 315.4 mg kg−1 in the peel. The ranges of vitamin C content were from 9.1 to 29.7 mg 100 g−1 in the flesh and 9.5 to 35.9 mg 100 g−1 in the peel. Pear peel indicated higher contents of phenolics than pear flesh, confirming the health benefit of the consumption of pears together with peel.

Effect of ultrasound treatment on the properties of nano-emulsion films obtained from hazelnut meal protein and clove essential oil

Hazelnut meal protein (4% (w/v)) and clove essential oil (CEO) (3% (v/v)) were homogenized with ultrasound (US) at different times (2, 4 and 6 min) and amplitudes (50, 75 and 100%) to obtain nano-emulsion films. Film forming nano-emulsions (FFNs) were analyzed for average particle size (Dz) and zeta potential, and edible film characterization were evaluated depending on US treatment, as well as antibacterial and antioxidant activities. Dz values and zeta potential of FFNs decreased with increasing acoustic energy delivered to nano-emulsion system. Thickness and water solubility of films significantly decreased with increasing US treatment. Films became more transparent depending on US treatment probably due to particle size reduction. Tensile strength (TS) of films significantly increased with US treatment, while elongation at break (EAB) slightly increased. Microstructure of films became more homogeneous after US treatment and caused to lower water vapor permeability. Enrichment with CEO has given the films antibacterial activity against L. monocytogenes, B. subtilis, S. aureus, P. aeruginosa and E. coli, and antioxidant activity, and US application has improved these activities. US technology can be used to improve mechanical, barrier and antimicrobial properties of hazelnut meal protein based edible films enriched with CEO.

Inhibition kinetics of Penicillium verrucosum using different essential oils and application of predictive inactivation models

ABSTRACT This study deals with the efficacy of Origanum onites, Salvia officinalis, and Mentha piperita essential oils (EOs) and their mixture (1:1:1, v/v/v) against ochratoxigenic P. verrucosum D-99756 and modelling the effects of EOs on fungal growth using modified Gomperz and logistic models. O. onites, S. officinalis, and M. piperita EOs were used at their minimal lethal concentration levels at 65, 125, and 250 µL/mL, respectively, which were determined in our preliminary studies. Inactivation of fungi sporulation by EO treatments was higher than 50–60% within 48 h, while 78.50–81.41% lethality was observed at the end of the 168 h for all of the tested EOs. The most effectiveness time for lethal effect was found at 84 h for O. onites and S. officinalis, while it was 168 h for mix EOs (p < 0.05). The modified Gompertz model successfully produced better fits than the logistic model as evidenced by the root mean square error, the modelling efficiency, and accuracy efficiency. In conclusion, data confirmed the potential use of plant and spice EOs for their fungistatic and fungicidal effects in food systems.

Effect of brewing process and sugar content on 5-hydroxymethylfurfural and related substances from Turkish coffee

ABSTRACT The effect of brewing process on 5-hydroxymethylfurfural, 2-furylmethylketone, and 2-furoic acid levels of traditionally prepared and instant Turkish coffee samples containing different amounts of table sugar (0, 2, 4, or 8 g in 20 mL of coffee) were analyzed by high pressure liquid chromatography with diode array detector. The highest change at the levels of furfurals was observed in sample of traditional and instant Turkish coffee named T4 and S4 both of containing 8 g of sugar, respectively. The results showed that 5-hydroxymethylfurfural, 2-furylmethylketone, and 2-furoic acid concentrations in both traditionally prepared and instant Turkish coffee samples increased with increasing sugar concentration. The brewing method and sugar concentration had a significant effect on furfural contents of Turkish coffee (p < 0.05). Daily intakes of furfurals for Turkish population were calculated as 8.14–13.54 and 9.36–10.25 µg kg−1 body weight for traditionally prepared and instant Turkish coffee samples, respectively, and daily intakes of furfurals were lower than the acceptable daily intake value of 0.5 mg kg−1 body weight.

Toxic and essential elements in butter from the Black Sea region, Turkey

In this study, 88 randomly selected samples of butter produced in the Black Sea region of Turkey were purchased from different retail markets during different periods and investigated for toxic and essential elements content. Quantitative analyses of elements in the samples were performed using an inductively coupled plasma-mass spectroscopy (ICP-MS). Mean concentrations of As, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn in the butter samples were 18.93, 100.32, 384.66, 4199.1, 887.47, 168.64, 56.13, 16.34 and 384.66 µg kg−1, respectively. Cd and Co were detected in 19 (mean content 0.29 µg kg−1) and 81 (mean content 3.81 µg kg−1) samples of 88 butter samples, respectively. However, the dietary intake of these elements by the population of the Black Sea region is currently well below the dietary reference intake (DRI) and provisional tolerable weekly intake (PTWI) levels of essential and toxic elements.

Pirinç Üretiminde HACCP Sisteminin Uygulaması / Application of HACCP System in Rice Production

Son yillarda piyasada dusuk kaliteli pirinclerin, daha yuksek fiyatla satabilmek amaciyla yuksek kaliteli pirincler ile karistirilmasi, ithal/yerli ve/veya farkli yerli cesitlerin birlikte ambalajlanarak tuketiciyi yaniltici sekilde etiketlenmesi gibi yontemlerle pazarlandigi ortaya konmustur. Gida uretiminde onemli bir paya sahip olan hububat-bakliyat isleme alaninda faaliyet gosteren isletmelerde, yasal mevzuata uygunluk ve guvenilir gida uretimi icin tehlike ve risk analizleri yaklasimi gosterilmelidir. Bu calismada, celtikten pirinc uretiminde HACCP prensiplerinin olusturulmasi ve sektorel kosullar goz onunde bulundurularak uretim asamalarinda uygulanabilirligi amaclanmistir. Gida guvenligi icin onemli olan tehlikeleri tanimlayan, degerlendiren ve kontrol eden bu sistem, pirinc uretim asamalarinda on gereksinim prosedurleri ve yedi temel prensipleri goz onunde bulundurularak kurulmustur. Tehlikenin risk derecesi, belirlenen her tehlike icin ISO 22000 talimatinda kullanilan karar agaci sorularina gore degerlendirilmis ve risk olcum skalasi olusturulmustur. Buna gore, On Gereksinim Programi (OGP), Operasyonel On Gereksinim Programi (OP OGP) ve Kritik Kontrol Noktalari (KKN) belirlenmistir. Hammadde kabul ve renk ayirici asamalari KKN olarak belirlenmistir. Operasyonel islem gerektiren asamalar icin kontrol planlari, on gereksinim programlari cercevesinde iyi hijyen uygulamalari prosedurleri olusturulmustur. Pirinc uretimi uzerinde HACCP sistemi uygulanarak son urun guvenirligi ve urun tebligine uygun uretim saglanabilecek, idari para cezalari gerektirecek olumsuzluklar onlenebilecektir. Recently, it has been revealed that low-quality rice is mixed with high-quality rice to sell at higher prices, and imported / domestic and / or different domestic varieties packaging together and labeled as misleading for the consumers. Hazard and risk analysis should be approached for compliance in related with legislation and food production as safety in grain-legumes processing plants which have a significant role in food production. In this study, it was aimed to apply HACCP principles in rice production from paddy and its applicability in production stages considering the sectoral conditions. This system, which identifies, evaluates and controls the hazards that are important to food safety, has been established with prerequisite procedures in rice production stages and seven basic principles in mind. The risk level of the hazard was assessed according to the decision tree questions used in the ISO 22000 directive for each identified hazard, and a risk measurement scale was established. According to this, Pre-requisite Programs (PRP), Operational Prerequisite Programs (OPRP) and Critical Control Points (CCP) have been determined. The acceptance of raw material and color separation stages are determined as CCPs. Raw material acceptance and color separation stages have been determined as CCP. Procedures for good hygiene practices have been established within the framework of PRP and also control plans have been formed for the stage of required operational process. F ood legislation suitable production and product safety will be ensured by applying the HACCP system in rice production, and also it will be bend problems required administrative fines.