Duygu Gocmen

Effects of autoclaving temperature and storing time on resistant starch formation and its functional and physicochemical properties

In this study effects of autoclaving temperature (140-145°C) and storing time (24, 48 and 72 h) on resistant starch (RS) formation from high amylose corn starch were investigated and functional and pasting properties of RS preparations were determined. High autoclaving temperature (145 °C) and long storing time (72 h) showed beneficial impacts on RS formation. Significant decreases were observed in all RVA viscosities of RS preparations as the autoclaving temperature increased. There was significant effect of storage time on all RVA parameters of RS preparations within each autoclaving temperature. The water binding values of RS preparations autoclaved at 145 °C were higher than those of the samples autoclaved at 140 °C. RS preparations had approximately 2-fold higher emulsion capacity values than the native starch. Thermal enthalpy (ΔH) values of RS preparations were lower than those of native starch. Autoclaving temperature and storing time had no effects on TO and TP.

A Traditional Turkish Fermented Cereal Food: Tarhana

Tarhana has a long history. According to historical records, it was first produced by Turkish people in Middle Asia and afterwards it spread out to different parts of the world. It is a fermented cereal-based food and can be simply defined as a mixture of yoghurt, cereal flours, yeast, different vegetables, herbs, and spices. After the mixing process, tarhana dough is fermented for 1 to 5 days and immediately dried. Both lactic acid bacteria (LAB) and yeast fermentations occur simultaneously during tarhana production. Therefore, tarhana has sour and acidic taste with yeast flavour as well. It is sun-dried at the home-made level or oven-dried of the commercial level. Several types of tarhana can be classified depending upon processing method or raw materials used. Low moisture (6–10%), low pH (3.5–5.0), and components (organic acids, bacteriosin, etc.) formed in fermentation have bacteriostatic effect on pathogens and spoilage microorganisms during long term storage (1–2 years) and enhance shelf life. Since tarhana is a good source of B vitamins, minerals, organic acids, and free amino acids, and since it is a product of LAB and yeast fermentation, it may be considered a functional and probiotic food.

Phenolic acid composition, antioxidant activity and phenolic content of tarhana supplemented with oat flour

In this study, oat flour (OF) was used to replace wheat flour in tarhana formulation at the levels of 10, 20, 30 and 40% (w/w). Control sample did not contain OF. The results showed that addition of OF caused increases in levels of phenolic acids within tarhana samples. The most abundant phenolic acids were vanillic and ferulic acids, and they were followed by gallic acid. Tarhana samples with OF also showed higher antioxidant activities than control sample did. Compared with the control sample, the total phenolic content level increased with the increase in the amount of OF. The results of sensory analysis showed that OF addition neither caused any undesirable taste nor an odor and panelists emphasised a sweet taste as the OF amounts were increased. Therefore, tarhana supplemented with OF can be claimed to be a good source of minerals, phenolics and antioxidants as compared to tarhana without OF.

Changes in antioxidant activity and phenolic acid composition of tarhana with steel-cut oats

Steel-cut oats (SCO) was used to replace wheat flour in the tarhana formulation (control) at the levels of 10%, 20%, 30% and 40% (w/w). Control sample included no SCO. Substitution of wheat flour in tarhana formulation with SCO affected the mineral contents positively. SCO additions also increased phenolic acid contents of tarhana samples. The most abundant phenolic acids were ferulic and vanillic acids, followed by syringic acid in the samples with SCO. Tarhana samples with SCO also showed higher antioxidant activities than the control. Compared with the control, the total phenolic content increased when the level of SCO addition was increased. SCO addition did not have a deteriorative effect on sensory properties of tarhana samples and resulted in acceptable soup properties in terms of overall acceptability. SCO addition improved the nutritional and functional properties of tarhana by causing increases in antioxidant activity, phenolic content and phenolic acids.

Chemical and techno-functional properties of flours from peeled and unpeeled oleaster ( Elaeagnus angustifolia L.)

Oleaster flours were produced from two different genotypes (GO1 and GO2) and methods (peeled oleaster flour: POF and unpeeled oleaster flour: UPOF). Oleaster flour samples (OFs) contained high levels of dietary fibers and micro minerals. The contents of Fe, Cu, B, and Cr in flours obtained from oleaster fruits were higher in UPOF than in POF samples. Palmitic acid was the major fatty acid which was followed by oleic acid and lignoceric acid. All samples contained greater amount of saturated fatty acids (SFA) as compared to mono unsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA). Among seven different organic acids detected, the level of citric acid was the highest and it was followed by malic, acetic and oxalic acids. High nutritional contents of oleaster flour indicated that it is a good source of dietary fiber, micro minerals, as well as organic and fatty acids. The water solubilities (WS) and water absorption capacities (WAC) of oleaster flours were adequate for their utilization. They also seem to have an improving effect on emulsion properties of albumin. These results highlighted that it is possible to use the oleaster flour in some processed foods such as bakery goods, dairy products (ice cream and yoghurt), beverages and confectionery. Moreover, the oleaster flour could also be used in the preparation of low-fat, high-fiber dietetic products due to its high dietary fiber content.