Ihsan Karabulut

Fatty acid composition of frequently consumed foods in Turkey with special emphasis on trans fatty acids

Fatty acid compositions of frequently consumed foods in Turkey were analyzed by capillary gas chromatography with particular emphasis on trans fatty acids. The survey was carried out on 134 samples that were categorized as meat products, chocolates, bakery products and others. The meat products except chicken-based foods have trans fatty acids, arising as a result of ruminant activity, with an average content of 1.45 g/100 g fatty acids. The conjugated linoleic acid content of meat and chicken doner kebabs were found higher than other meat products. Chocolate samples contained trans fatty acids less than 0.17 g/100 g fatty acids, with the exceptional national product of chocolate bars and hazelnut cocoa cream (2.03 and 3.68 g/100 g fatty acids, respectively). Bakery products have the highest trans fatty acid contents and ranged from 0.99 to 17.77 g/100 g fatty acids. The average trans fatty acid contents of infant formula and ice-cream, which are milk-based products, were 0.79 and 1.50 g/100 g fatty acids, respectively. Among the analyzed foods, it was found that coffee whitener and powdered whipped topping had the highest saturated fatty acid contents, with an average content of 98.71 g/100 g fatty acids.

Fatty acid selectivity of lipases during acidolysis reaction between oleic acid and monoacid triacylglycerols.

With the aim of determining the fatty acid (FA) selectivity of lipases, a mixture of oleic acid and monoacid triacylglycerols (TAGs) including tricaproin (T6), tricaprylin (T8), tricaprin (T10), trilaurin (T12), trimyristin (T14), tripalmitin (T16) and tristearin (T18) was used as the substrate in acidolysis performed in hexane. Three immobilized lipases, namely, Lipozyme TL IM from Thermomyces lanoginosus, Lipozyme RM IM from Rhizomucor miehei and Novozym 435 from Candida antarctica, were used as biocatalyst. The effects of operating variables including the mole ratio of oleic acid to monoacid TAG, temperature, enzyme dosage and reaction time on incorporation were also investigated. Significantly different incorporation rates were obtained for different TAGs used (P < 0.05). Incorporation of oleic acid into TAGs except tricaproin and tricaprylin was higher for all the TAGs with Lipozyme TL IM catalyzed reactions than those of other two enzymes tested. Incorporation of oleic acid decreased as the acyl chain length of FA in the TAG increased with Novozyme 435 catalyzed acidolysis. Compared to the other substrate mixtures, the highest incorporation was observed for oleic acid and tricaproin mixture with three lipases tested. It was shown that the FA selectivity of the lipases is strongly dependent on the acyl chain length of FA in a TAG.

Determination of Chemical Composition, Total Phenolic, Antimicrobial, and Antioxidant Activities of Echinophora tenuifolia Essential Oil

In this study, the antioxidant and antimicrobial activities, total phenolic content, and essential oil composition of Echinophora tenuifolia L. subsp. sibthorpiana were investigated. The antioxidant activity of investigated essential oil was assessed by ABTS and DPPH assays. DPPH radical scavenging activity expressed by IC50 was 2.84 g/L, whereas the TEAC value determined by ABTS assay was 0.032 g TEAC/kg plant. Total phenol content of essential oil determined by Folin-Ciocalteu method was calculated as 1.32 g GAE/kg plant. The essential oil extracted by hydrodistillation (Clevenger apparatus) was investigated by GC-MS technique and 78 compounds were identified. The main components of essential oils were found to be δ-3-carene (17.93%), p-cymene (8.99%), methyleugenol (16.41%), and α-phellandrene (9.33%). The antimicrobial activity of investigated essential oil was tested using a broth dilution method against 13 bacterial and 2 fungal microorganisms. The lowest minimum inhibitory concentration of essential oil against Bacillus cereus was 62.5 μg/mL while the antifungal activity was greater than 1000 μg/mL for both Candida albicans and Saccharomyces cereviciae. Investigated essential oil has a certain level of antioxidant and antimicrobial effects, which may be attributed to their chemical compounds. The antimicrobial efficiency of essential oil, especially against Bacillus cereus and Staphylocoocus spp., offers its effectiveness to treatment of wound or disease caused by Gram positive bacteria.

SPME/GC-MS Characterization and Comparison of Volatiles of Eleven Varieties of Turkish Cheeses

In this study, the volatile aroma profiles of a variety of economically important cheeses for the Turkish dairy sector were characterized. A total of 75 samples belonging to 11 Turkish cheese varieties, including Civil, Canak, Dil, Divle Tulum, Ezine, Hellim, Malatya, Mihalic, Orgu, Urfa, and Van Otlu, were comparatively studied for their volatile profiles. One hundred and twelve volatile compounds were identified in the cheeses by solid-phase microextraction combined with gas chromatography-mass spectrometry and the results are discussed based on their chemical classes (31 esters, 7 acids, 18 ketones, 3 aldehydes, 24 alcohols, 10 terpenes, and 19 miscellaneous compounds). Esters, ketones, and alcohols were the most abundant classes identified and were highly dependent on the variety of cheese. Principal component analysis was applied to aid the interpretation of the gas chromatography-mass spectrometry data and to distinguish the cheeses. Divle Tulum cheese had high levels of aldehydes, ketones, and alcohols and separated from all the other cheeses, and the cheeses including Dil, Hellim, Malatya, Orgu, and Urfa grouped together. The last group of cheeses had low levels of volatiles stemming probably from the restricting effect of scalding or cooking that are employed in the manufacture of these cheeses and on the biochemical and/or microbial activity. Civil, Ezine, and Mihalic cheeses had somewhat different aroma profiles, but they were closely located near the cheeses including Dil, Urfa, Orgu, etc. The results suggest that each variety of cheese had different volatiles profile and that the manufacturing technique as well as ripening conditions of the cheeses played a major role on the individual volatile profiles.

Fatty acid selectivity of lipases during acidolysis reaction between triolein and saturated fatty acids varying from caproic to behenic acids.

The chain length selectivity of three immobilized lipases, namely, Lipozyme TL IM from Thermomyces lanoginosus, Lipozyme RM IM from Rhizomucor miehei, and Novozym 435 from Candida antarctica, was determined in acidolysis performed in hexane using the homologous series of even carbon number, saturated fatty acids (SFAs) of 6-22 carbons. Triolein with individual SFAs or a mixture of equimolar quantities of SFAs was used as the substrate. The effects of operating variables including the mole ratio of fatty acid to triolein, temperature, enzyme dosage, and time on incorporation were also investigated. Incorporation abilities of the enzymes tested were found to be significantly different for most of FAs at the experimental conditions evaluated. Lipases acted weakly on SFAs of which the carbon chain length was shorter than eight carbon atoms and higher than 18 carbon atoms. Lipases showed a bell-shaped distribution in incorporation vs chain length plot with a maximum around C12-C16. Among the experimental parameters tested, the effect of the substrate mole ratio was greater than those of the others, and the highest incorporation was observed for C12 (36.98%), C14 (37.63%), and C16 (38.66%) at a 4:1 substrate mole ratio with Lipozyme TL IM. Lipases caused significantly different levels of acyl migration from sn-1,3 to sn-2 positions.

Characterization and Comparison of Free Fatty Acid Profiles of Eleven Varieties of Turkish Cheeses

Free fatty acids profiles of 11 different cheese varieties sold in Turkey were determined to assess the development of lipolysis. Results obtained showed that the concentrations of short chain fatty acids (C4 and C6 free fatty acids) were close in all cheeses (P > 0.05), except for Canak cheese. However, significant differences were noted among the samples for other free fatty acids including C8 to C18:2 (P < 0.05). Palmitic (C16) and oleic (C18:1) acids were the most abundant free fatty acids in all cheese samples. Principal component analysis was applied to simplify interpretation of the data and distinguish the variety of the cheeses on the plot. Canak cheese gave a dramatically different free fatty acid profile from the other cheeses, probably because of the fact that ripening of this variety is achieved in the earthenware pots for about 1 year. Van Otlu (ripened with special herbs) and Civil (ripened by spontaneously molding on its surface) cheeses differed from the others by ANOVA and principal component analysis techniques. In conclusion, the degree of lipolysis in the cheeses could be classified into extreme (Canak), high (Civil, Divle Tulum, Mihalic, and Van Otlu), mild (Ezine, Orgu, and Urfa), and low (Dil, Hellim, and Malatya) based on their FFA profiles.

Primary and Secondary Proteolysis in Eleven Turkish Cheese Varieties

Levels of proteolysis of 75 samples belonging to 11 Turkish cheese varieties, including Civil, Canak, Dil, Divle Tulum, Ezine, Hellim, Malatya, Mihalic, Orgu, Urfa, and Van Otlu, were comparatively studied. The cheeses were mainly produced using traditional methods; however, some varieties were industrially produced. Chemical composition and the levels of soluble nitrogen fractions of the cheeses varied depending on the cheese variety. Gel electrophoresis of the cheeses showed that the samples presented different gel patterns with αs1-casein being extensively degraded in many cheeses; whereas the hydrolysis of αs1-casein in Malatya and Hellim was observed to be limited. Peptide profiles by RP-HPLC of the water-soluble fractions were largely different for many of the samples, but some similarities were visualized. Multivariate analysis of the RP-HPLC data grouped the cheeses according to their peptide profiles. The results suggested that each variety of cheese had different levels of proteolysis. The manufacturing technique and ripening conditions employed have played a determinative role on the proteolytic patterns of the cheeses analyzed.

Thin Layer Drying Characteristics of Eriste: A Dried Cereal Product of Turkey

Effect of air temperature (50, 60 and 70 °C) and sample thickness (1.0, 1.4 and 1.8 mm) on the thin-layer drying characteristics of eriste was studied by using a tray dryer. The data of sample weight, dry and wet-bulb temperatures were recorded continuously during each experiment and drying curves were obtained. The drying curves were then fitted to five mathematical models available in the literature to estimate a suitable model for drying of eriste. Verma et al. model gave better predictions than other models and satisfactorily described the thin layer characteristics of eriste. The effective diffusivity varied from 1.8 x exp-10 to 1.5 x exp-9 m2 s-1 over the temperature range.

Chemical composition of apricots affected by fruit size and drying methods

ABSTRACT Combined practice of sulfuration and drying is widely applied for extending shelf life of fruits. The differences in fruit size are not taken into consideration during these applications and during fresh fruit consumption. In this study, effect of fruit size and drying methods (hot air-drying and sun drying) on the chemical composition of fresh and sulfurated apricot was investigated. Total drying times for sun drying and hot air-drying were 11 d and 51 h, respectively. A temperature gradient was applied during hot air-drying. The fruit size substantially affects the composition of both fresh and dried apricots. The results were subjected to principal component analysis. The small-sized fresh apricots discriminate themselves from large ones with higher amounts of phenolic compounds, whereas the large-sized fresh apricots contain more sugar and organic acids. Size classification and hot air-drying are advisable for high-quality dried apricot production.

β-carotene rejection mechanism from organic medium by using activated carbon produced from waste biomass apricot

ABSTRACT The present paper deals with the study of adsorption of β-carotene in tetrahydrofuran solution on activated carbon. Activated carbon was prepared from apricot waste, which is a by-product of apricot processing by means of chemical activation with ZnCl2. BET surface area of activated carbon was measured to be 1060 m2 g−1. The effect of adsorption time, percentage of activated carbon in β-carotene solution, and β-carotene concentration on adsorption efficiency was also determined. Results were analyzed by the Langmiur, Freundlich, Dubinin−Redushkevich (D-R), Temkin, Frumkin, Harkins−Jura, Halse, Henderson, and Henry isotherms with linearized correlation coefficient. The characteristic parameters for each isotherm have also been determined. The kinetics of β-carotene adsorption has been discussed by the pseudo-first-order model, the pseudo-second-order model, the Elovich equation, the intraparticle diffusion model, the Bangham equation, and the modified Freundlich equation. Three error analysis methods of residual mean square error (RMSE), chi-square statistic (χ2), and the average percentage error (% APE) have been used.