Ozan Gürbüz

The impact of drying techniques on phenolic compound, total phenolic content and antioxidant capacity of oat flour tarhana

In this study, the changes in phenolic composition, total phenolic content, and antioxidant capacity of tarhanas supplemented with oat flour (OF) at the levels of 20-100% (w/w) after three drying treatments (sun-, oven-, and microwave drying) were investigated. A total of seventeen phenolic standards have been screened in tarhanas, and the most abundant flavonol and phenolic acid compounds were kaempferol (23.62mg/g) and 3-hydroxy-4-metoxy cinnamic acid (9.60mg/g). The total phenolic content amount gradually increased with the addition of OF to tarhana, but decidedly higher total phenolic content was found in samples oven dried at 55°C as compared with other methods. The microwave- and oven dried tarhana samples showed higher TEACDPPH and TEACABTS values than those dried with the other methods, respectively, in higher OF amounts. Consequently, oven- and microwave-drying can be recommended to retain the highest for phenolic compounds as well as maximal antioxidant capacity in OF supplemented tarhana samples.

Phenolics, antioxidant capacity and bioaccessibility of chicory varieties (Cichorium spp.) grown in Turkey

In this study, the changes in phenolics, anthocyanin, antioxidant capacity, and bioaccessibility of chicory varieties (Cichorium spp.) in Turkey were investigated. A total of 19 phenolic standards were screened in the chicory varieties studied and the most abundant compounds in the samples, extracted with methanol, were phenolic acids, syringic (2.54mg/kg) and trans-ferulic acid (1.85mg/kg), whilst (+)-catechin was the major flavanol. The highest flavanol content using either methanol or ethanol was determined in the green chicory samples (0.62mg/kg). The red chicory variety had higher anthocyanin (12.80mg/kg), and contained more phenolics, extractable (8855.50mg GAE/100g) and hydrolysable (7005.51mg GAE/100g), than the other varieties. Also, the antioxidant capacities in this variety, as measured using the CUPRAC assay (570.54 and 425.14μmol Trolox/g dw, respectively), had a wider range of difference than was found in the other assays used. Total phenolics were more bioaccessible from the white chicory variety (61.48%). However, the bioaccessibility of antioxidants was higher in the green chicory variety.

Effect of pretreatments on microbial growth and sensory properties of dry-salted olives.

The effect of various washing solutions (acetic acid, lactic acid, and chlorine dioxide) and NaCl concentrations (2.5, 5.0, and 10.0%) on the stability of dry-salted olives (cultivars Gemlik and Edincik) during storage was studied. Vacuum-packed olives were stored at 4°C for 7 months and monitored for microbiological changes that occurred in the dry-salted olives during the dry-salting process and for their stability during storage. Microbial populations were enumerated using pour plating (for aerobic plate counts) and spread plating (for counts of lactic acid bacteria and yeasts and molds). Aerobic plate counts were <2.5 log CFU/g for olive samples washed in chlorine dioxide at all NaCl concentrations. At 4°C, the population of yeasts and molds increased steadily during the shelf life in Gemlik olive samples washed with all of the solutions, except chlorine dioxide, whereas yeast and mold counts in Edincik olives decreased depending on the increase in salt concentration. Therefore, different combinations of organic acids, NaCl, and vacuum packaging can be successfully used to control the growth of yeasts and molds in these olives. The combination of vacuum sealing (with a 10-ppm chlorine dioxide wash) and storage at 4°C was the most effective approach for controlling the growth of lactic acid bacteria and yeasts and molds. Members of the sensory panel considered saltiness to be appropriate at 2.5 and 5.0% NaCl. Softness and bitterness scores increased with reduced NaCl concentrations, but rancidity and hardness scores increased as NaCl concentration increased.

Influence of hot air drying on phenolic compounds and antioxidant capacity of blueberry ( Vaccinium myrtillus ) fruit and leaf

The present study was undertaken to assess the effects of hot air drying on phenolic compositions, total phenolic (TP) content, total anthocyanin (TA) content, as well as antioxidant capacities of methanol extracts from blueberry ( Vaccinium myrtillus ) fruit and leaf introduced in Kapidag region of Turkey climate conditions. A total of twenty-two phenolic standards were screened by HPLC, total phenols were measured by spectrophotometric methods, antioxidant capacity was determined using DPPH, CUPRAC, ABTS, and FRAP assays in the blueberry fruit and leaf extracts. Analysis by HPLC revealed that fruit extracts have different phenolic profiles due to drying process and contain syringic acid, myricetin, naringin, (-)-epicatechin, and malvidine-3-O-glucoside chloride as the main compounds. Leaf extracts had higher resveratrol concentrations than fruit extracts. The TP and TA contents gradually increased when the blueberry fruits were dried under hot air condition. The fresh and dried blueberry fruit and leaf extracts showed similar antioxidant capacity values. Significant relationships between antioxidant capacity and TP were found.

Effect of polyethylene glycol coating on Salmonella enteritidis in artificially contaminated eggs

This experimental infection study focuses on a specific Salmonella micro-organism commonly found inside hens’ eggs. It outlines the application of polyethylene glycol-based films on hens’ eggs and microbial growth introduced via transovarian contamination. Three molecular weights of polyethylene glycol (PEG) were studied: ranging from 1000 g/mol to 3000 g/mol. PEG coating ratios averaged a PEG film thickness of 0.014 ± 0.006 mm and average eggshell thickness was 0.32 ± 0.022 mm. The effects of molecular weight of PEG coating and storage time on the growth of Salmonella enteritidis of PEG-coated eggs were evaluated during 30 days of incubation in 37°C storage. The initial concentration of 8 log10 CFU/mL was achieved by inoculation. The lowest level of S. enteritidis at the end of 30-day incubation period was 5.07 ± 0.03 log10 CFU/mL, giving an inhibition efficiency of 33.83%. This level was achieved with a PEG coating of 1.0449 ± 0.005 density and 0.02 ± 0.01film thickness.