Ahmet Faik Koca

Changes in the physicochemical and antioxidant characteristics of watermelon during pekmez production

Watermelon is a health-promoting fruit in terms of being an excellent source of lycopene and gastronomically pleasing. However, its consumption is restricted to a certain season because it is usually consumed as fresh. Therefore, utilisation of watermelon by processing into a more stable product that is available throughout the year would be beneficial. In this research, watermelon was utilised by processing into pekmez (concentrated juice) by concentrating the juice in open boilers until 68°Brix, and changes in some physicochemical properties, colour and antioxidant characteristics that occur during pekmez production were determined. Sensory evaluations for pekmez products were also carried out. It was determined that the redness, yellowness, pH, titratable acidity and formol number values increase, whereas brightness, total sugar and invert sugar values decrease during processing the fruit into pekmez. Hydroxymethyl furfural was produced slightly during processing. Lycopene, total phenolic content and a...

Effect of different production techniques on bioactive compounds and antioxidant capacity of einkorn (Triticum monococcum L.) and durum (Triticum turgidum subsp. durum) bulgur

BACKGROUND The influence of cooking (traditional, microwave, autoclave) and drying techniques (microwave and hot air) on bioactive compounds in the production of einkorn and durum bulgur were investigated. Total phenolic content (TPC), total yellow pigment (TYP), total antioxidant capacity (DPPH• , ABTS•+ , FRAP), soluble free (SF), soluble conjugated (SC) and insoluble bound (IB) phenolic acid contents of the samples were determined. RESULTS For both wheats, a significant amount of antioxidant capacity was preserved after bulgur production. TPC was found to be higher in einkorn but it was exposed to greater loss during bulgur production than durum. The amount of TYP was found to be two-fold higher in einkorn than in durum. Ferulic acid was recorded as the most phenolic acid, and chlorogenic was the least phenolic acid in both wheats. The maximum loss during bulgur production was determined in the SC fraction for einkorn and in the SF fraction for durum. CONCLUSION In respect of the results of the analysis, microwave cooking + hot air drying treatment could be favourable for bulgur production for both wheats.

Physical, rheological and sensory properties of tarhana prepared with two wild edible plants (Trachystemon orientalis (L.) G. Don) and (Portulaca oleracea L.).

Tarhana is a traditional Turkish fermented soup. It is prepared with yoghurt, wheat flour, yeast, some vegetables and spices. In this study, two wild edible plants, kaldirayak (Trachystemon orientalis (L.) G. Don) and purslane (Portulaca oleracea L.) were used to increase the dietary fiber content of tarhana, while keeping the viscosity and sensory properties in acceptable levels. Wheat flour was replaced with plants in 3 proportions (10, 20 and 30%). The fermentation activity, color, rheological and sensory properties of the tarhana products were determined. Soluble, insoluble and total dietary fiber values were determined to be 15.36, 23.04 and 38.40 g/100 g in dry weight for kaldirayak and 7.56, 23.11 and 30.67 g/100 g in dry weight for purslane, respectively. It was determined that addition of these plants in high amounts increase the dietary fiber content but decrease the viscosity. The lightness, redness and yellowness values decreased as the concentration of added plant increased. Also, as the enrichment ratio increased, the sensory evaluation points decreased.