Determination of industrial pollution effects on citrus honeys with chemometric approach

The aim of this study was to determine the levels of essential, trace and toxic elements, such as K, Ca, Fe, Cu, Al, Ni, Sn, Pb and Cd in citrus honeys from different regions (industrialized and nonindustrialized) of Hatay, Turkey. K, Ca, Na and Mg were the most abundant elements, with mean contents of 363.5, 256.6, 88.1 and 37.7 mg/kg, respectively. The trace element mean contents ranged between 0.032 and 15.58 mg/kg. Significant differences in Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr levels were observed between two different regions. The findings that Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr contents in citrus honeys from industrialized regions were higher than citrus honeys from non-industrialized regions indicate that the honeys were affected by industrial pollution. Chemometric methods were applied to classify honey according to mineral content. Cluster analysis showed three clusters corresponding to the three different regions.     

Characterisation of yoghurt enriched with polyunsaturated fatty acids by using walnut slurry

This study aimed to evaluate the physicochemical, chemical, rheological, sensorial and microbiological properties of yoghurt enriched with polyunsaturated fatty acids (PUFAs). The PUFA‐enriched yoghurt was prepared with walnut slurry (10%?50%) and skimmed milk (50%?90%). Compared with the control yoghurt, it contained a lower content of protein, potassium, sodium and phosphorus, and a higher content of fat, iron, magnesium and zinc. Moreover, it exhibited a lower syneresis value and a higher water‐holding capacity value. Its fat was rich in omega fatty acids, mainly linoleic and linolenic acids. These research findings revealed that walnut slurry could be used in yoghurt manufacture to develop fermented milk products as functional foods, especially when enriched with omega fatty acids.     

The effect of different starter cultures and ripening temperatures on formation of biogenic amine in Turkish fermented sausages

Different starter culture added groups (Group I: Lactobacillus sake, Staphylococcus xylosus; Group II: Lactobacillus plantarum, Staphylococcus carnosus; Group III: Lactobacillus curvatus, Staphylococcus carnosus, and Staphylococcus xylosus) and control group sausage samples were produced experimentally at two different temperatures (22 and 26 °C). In raw materials and all groups, by the 0th, 2nd, 5th and 7th days of the ripening period, the analysis of HPLC and biogenic amine (tyramine, histamine, cadaverine, putrescine, phenylethylamine, tryptamine, spermine, and spermidine) amounts, microbiological (Lactic acid bacteria, Micrococcus/Staphylococcus, Enterobacteriaceae, Enterococcus spp., and moulds–yeasts) and chemical (pH, dry matter, and salt) have been done. During the ripening period, there is no statistical discrepancy (P > 0.05) in terms of biogenic amine amounts, microbiological, and chemical values detected from the sausage samples produced at 26 and 22 °C. However, in both levels of temperature, there is statistical discrepancy (P < 0.001) detected in terms of tyramine, putrescine values and the count of Enterococcus spp. between the starter culture added samples and control group samples. By this study, it has been stated that the ripening temperature does not make any statistical discrepancy (P > 0.05) for all values but the use of starter culture prevents the formation of biogenic amine in Turkish fermented sausages.     

Determination of antioxidant activity of bioactive peptide fractions obtained from yogurt

In this study, physicochemical and microbiological properties of traditional and commercial yogurt samples were determined during 4 wk of storage. Proteolytic activity, which occurs during the storage period of yogurt samples, was also determined. Peptide fractions obtained from yogurts were investigated and the effect of proteolysis on peptide release during storage was determined. The antioxidant activities of peptides released from yogurt water-soluble extracts (WSE) and from HPLC fractions were determined by 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) methods. The antioxidant activity of WSE from traditional yogurt was greater than that of WSE from commercial yogurts. In analysis by the ABTS method, mean values increased from 7.697 to 8.739 mM Trolox/g in commercial yogurts, and from 10.115 to 13.182 mM Trolox/g in traditional yogurts during storage. Antioxidant activities of peptides released from HPLC fractions of selected yogurt samples increased 10 to 200 times. In all yogurt samples, the greatest antioxidant activity was shown in the F2 fraction. After further fractionation of yogurt samples, the fractions coded as F2.2, F2.3, F4.3, and F4.4 had the highest antioxidant activity values. Total antioxidant activity of yogurts was low but after purification of peptides by fractionation in HPLC, peptide fractions with high antioxidant activity were obtained.     

Fatty acid composition in some selected marine fish species living in Turkish waters

The muscle fatty acid (FA) composition of 12 selected marine fish species living in Turkish waters was determined. FA profiles of muscle were compared in terms of total and individual saturated (SFAs) and unsaturated fatty acids. Total SFA, monounsaturated fatty acid (MUFA), n‐3 polyunsaturated fatty acid (n‐3 PUFA) and n‐6 polyunsaturated fatty acid (n‐6 PUFA) contents as well as n‐3/n‐6 FA and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA) ratios differed (P < 0.01) in all fish species. Palmitic acid (16:0) among total SFAs, oleic acid (18:1n‐9) among MUFAs, DHA (22:6n‐3) among n‐3 PUFAs and 18:2n‐6 and 20:4n‐6 among n‐6 PUFAs were the most abundant FAs. The ratio of n‐3/n‐6 PUFA contents, indicating the availability of n‐3 PUFAs that are beneficial for human health, ranged from 2.67 to 12.61. The EPA/DHA ratio was between 0.17 and 0.83 in the marine fish species studied. Copyright © 2005 Society of Chemical Industry     

Compositional,biochemical and textural changes during ripening of Tulum cheese made with different coagulants

In the present study, biochemical, chemical and texture changes in Tulum cheeses made using calf rennet and microbial rennets (Aspergillus niger protease and Rhizomucor miehei protease) were compared during ripening for up to 90 days. A total of 15 free fatty acids (FFAs) were detected in the cheese samples. The peroxide values (PV) of the cheeses increased significantly (P < 0.05) during ripening and the cheese made with calf rennet had the highest PV. Proteolysis in the cheeses increased as the ripening time increased. α_s1‐casein and β‐casein degradation was higher in cheeses manufactured with R. miehei protease. Cheeses made with calf rennet were significantly (P < 0.05) harder, more adhesive, more cohesive and more resilient than those made with microbial rennet.     

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

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.