Mustafa Erbaş

The effect of fermentation and storage on free amino acids of tarhana.

A study on the evaluation of free amino acids (FAAs) in tarhana during fermentation and storage was performed. The FAAs in tarhana were determined by RP-HPLC with a fluorescence detector following extraction from the sample and derivatization with dansyl chloride. The amount of FAAs increased significantly (p<0.01) during fermentation and storage. The increase in the content of total free amino acids (TFAAs) and total free essential amino acids (TFEAAs) of fermented tarhana, which was used with yogurt bacteria and bakers yeast, was 57% and 93%, respectively. The amino acids primarily responsible for the increase were valine and tryptophan followed by methionine, alanine, isoleucine + leucine, phenylalanine, arginine, proline, and lysine. The TFAA content of tarhana at the end of fermentation was found to be 8% of total protein (16.8%). The ratio of TFEAAs/TFAAs was initially 0.46 and increased to 0.57 at the end of fermentation. The TFAA content of wet tarhanas was higher than that of the dry counterpart. It was found that the TFAA content of dry tarhana was 25% lower than the fresh wet tarhana (FWT), at the end of fermentation. It was concluded that the decrease in FAAs in dry tarhana was due to the Maillard reaction and partial degradation of FAAs during dehydration.

Adsorption behaviour of bulgur

The aim of this research was to determine the adsorption behaviour of bulgur. Three different particle sizes (2<coarse<3.5, 1.6<medium<3.0, 0.5<fine<2.0 mm) of bulgur, purchased from market, were kept in nine different equilibrium levels of relative humidity (8.2-97.3%) at 20, 30 and 40 °C. The data obtained were evaluated using BET (Brunauer-Emmett-Teller) and GAB (Guggenheim, Anderson and deBoer) sorption equations. The equilibrium moisture content of bulgur increased both with decreasing temperature and bulgur size. The constants m0 and C of BET and GAB equations were determined to be between 2.54 and 5.03 g water per 100 g of dry matter and 4.96-16.57, respectively. Constant k was between 0.85 and 0.93, and GAB equation was determined to fit very well for bulgur adsorption, because of %E values lower than 10%. Bulgur must be stored below 70% relative humidity and with less than 10 g water per 100 g of dry mater.

Determination of Microbiological and Chemical Properties of Probiotic Boza and Its Consumer Acceptability

Objective: The aim of research was producing boza as a probiotic product with certificated probiotic starter cultures (Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum BB-12 and Saccharomyces boulardii). Methods: Analysis were done in boza samples taken in fermentation and storage. Probiotic and non-probiotic bacteria were enumerated with pour plate technique and yeast enumerated spread plate technique. Sugar, organic acid and Water soluble vitamin content were determined by using of HPLC. Sensory analyses were done by two different types of panels, once comprised of trained panelists and the other of consumers. Shelf life was determined according the results of sensory analysis. Results: It was determinated that S. boulardii and L acidophilius counts increased nearly 0.5 log unit during of boza fermentation. Lactic, acetic, citric, butyric and succinic acid as organic acids and thiamin, niacin, B6 and pantothenic acid as water soluble vitamin evaluated in boza samples. Shelf life of the probiotic boza determined as 12 days at +4°C fridge storage temperature. Conclusion: The boza samples had a probiotic effect because it had viable microorganisms more than 106 cfu/ml which was defined enough for functional foods. All boza samples had lower pH value than 4.5, so it is evaluated that boza is a safety food as its low pH preventing pathogen growth.

Quality properties and adsorption behavior of freeze-dried beef meat from the Biceps femoris and Semimembranosus muscles

The aim of this research was to determine the quality properties and adsorption behavior of freeze-dried beef meat from the Biceps femoris and Semimembranosus muscles. Most quality properties of both muscles were similar apart from total fat content. Freeze-dried meat pieces were kept in ten different equilibrium levels of relative humidity (2.0-97.3%) at 5, 15, 25 and 30°C. The experimental data were evaluated using BET (Brunauer-Emmett-Teller) and GAB (Guggenheim, Anderson and deBoer) models. The equilibrium moisture contents of freeze-dried Biceps femoris were lower than those of Semimembranosus at all water activities and temperature. The constants m0 and C of BET and GAB equations were determined to be between 6.27 and 8.07g/100g dry matter and 9.32-13.73, respectively. Constant k was about 0.90 at all temperatures, and the GAB equation exhibited a better fit to the experimental data of both muscles as a result of all %E values being approximately equal to 10%.

Physicochemical, Thermal, and Sensory Properties of Blue Corn (Zea Mays L.): Sensory properties of blue corn…

The aim of this study was to investigate some physicochemical and sensory properties of blue corn cultivated in Turkey. The length and width of the cob with kernels, hectoliter, and 1000-kernel weight of blue corn were measured as 7.66, 2.02 mm, 84.40 kg/100 L, and 44.27 g, respectively. The gelatinization onset, peak, and end temperatures were measured as 61.12 °C, 64.35 °C, and 75.65 °C, respectively. The water activity, moisture content, total protein, lipid, and crude fiber contents of the blue corn sample were detected as 0.44, 9.39%, 13.13%, 4.30%, and 2.68%, respectively. Total starch and resistant starch contents of blue corn were determined as 63.94% and 8.89%, respectively. Also, total monomeric anthocyanin content and antioxidant capacity of blue corn were detected as 915.43 mg CGE/kg and 7.99 μmol TE/g, respectively. Additionally, the major fatty acids detected in blue corn samples were palmitic, stearic, oleic, and linoleic acids. PRACTICAL APPLICATION Blue corn can be utilized in the production of enjoyable and healthier snacks, such as popcorn and chips, because of its color and high phenolic, anthocyanin, and fiber contents.

Effects of processing on the chemical composition of rice

Changes in the chemical composition of rice from harvest to packaging were searched. The phytic acid content in rice bran and final white rice was 64.25 and 9.66 mg/g (dry basis; db), respectively. Sugars (fructose, glucose, and sucrose), organic acids (citric and malic), and free amino acids (alanine, aspartic, and glutamic acid) decreased according to the progressing stages. The most abundant phenolic compound present in rice kernels was ferulic acid. The antioxidant capacity of rice bran was 428.97 µM Trolox equivalent (TE)/g (db), and it dropped from 126.23 to 60.76 µM TE/g (db) during processing. The L* colour value of rice samples showed a linear increase with decreasing antioxidant capacity. About half the phytic acid content and antioxidant activity was removed as a consequence of the dehulling, whitening, polishing, and grading of rice kernels.

Effect of Bicarbonate Salts and Sequential Using of Frying Oil on Acrylamide and 5-Hydroxymethylfurfural Contents in Coated Fried Chicken Meat

In this research, the effect of different bicarbonate salts (sodium and ammonium) and their doses (0, 1, 2, and 3 g/100 g raw material) in the coating batter formula use and the sequential use of frying oil (1st, 2nd, 3rd, and 4th) on 5-hydroxymethylfurfural and acrylamide contents in coated fried chicken meat. The addition of sodium bicarbonate was efficient for reducing acrylamide content, but it increased browning and 5-hydroxymethylfurfural content compared to the control. When increasing the doses of sodium and ammonium bicarbonate from 1 to 3 g/100 g of raw material, the acrylamide content of samples did not change significantly, although adding sodium bicarbonate significantly reduced the acrylamide content as a control. These research results showed that using about 1 g/100 g raw material sodium bicarbonate rather than ammonium bicarbonate and as little frying oil as possible use during the production of coated and fried meat results in lower contents of 5-hydroxymethylfurfural and acrylamide.

Drying kinetics, adsorption isotherms and quality characteristics of vacuum-dried beef slices with different salt contents

In this study, the effect of salt content (0, 5, 10, 15 and 20 g/100 g dry basis) on the drying kinetics, adsorption isotherms, and quality characteristics of beef slices were investigated. Beef slices were salted and vacuum-dried at 70 °C, until a moisture content of 32% (dry basis). The adsorption isotherms of the dried beef slices were described at 25 °C. The drying time for beef slices at the salt contents of 0, 5, 10, 15 and 20 g NaCl/100 g d.b. were 212, 207, 194, 160 and 137 min respectively. Modified Henderson and Pabis, and Page models exhibited a better fit for the drying kinetics of beef slices than the other drying models tested. The adsorption isotherm of dried beef slices is typical Type-II, but the addition of salt led to this behavior to change to type III. The BET model (R2 > 0.98 and %E ≤ 13.40) for all samples exhibited a good fit to the experimental data.

The Influence of Cooking Methods and Some Marinades on Polycyclic Aromatic Hydrocarbon Formation in Beef Meat

ABSTRACT This study aimed to determine the effect of various marinades and their concentrations, as well as various cooking procedures, on polycyclic aromatic hydrocarbon (PAH) formation in cooked beef. The PAH levels in meat were determined, based on the saponification of lipids by methanolic/potassium hydroxide solution, followed by liquid–liquid extraction and QuEChERS method. Pan frying caused lower levels of BaP (1.39 versus 1.62 µg/kg) and PAH4 (5.58 versus 5.73 µg/kg) in beef meat than barbecuing. For sage and thyme extracts prepared at 0.5 to 2.0 °Brix, a significant decrease in the PAH levels of barbecued meat samples was achieved compared to the controls. The levels of PAHs in the samples containing the commercial marinating material were found to be higher than those in the non-marinated control. The BaP and PAH4 levels found in the meat samples marinated with sage and thyme extracts, were below the EU maximum levels. However, BaP was the highest for Control 2 (2.26 µg/kg), and exceeded the EU maximum limit of 2 mg/kg for BaP in heat-treated meat and meat products. The results show a reducing effect of sage and thyme extracts that are normally used during marinating of meat, on the formation of PAH compounds. Consequently, the extracts of sage and thyme, could be used in the commercial marinating material to reduce the level of PAH compounds formed in meat during cooking.

Effects of Extraction Rates of Wheat Flour on Phyllo (Yufka) Properties at Different Storage Temperatures

ABSTRACT Phyllo sheets were produced with flour obtained at different extraction rates (53, 58, or 67%), and stored at 4 and 25°C. Physical, chemical, and sensory properties of fresh and stored phyllo were researched. Fresh phyllo samples from wheat flour at 53% extraction rate were thinner (0.4 mm) and had whiter color (L* = 87.6). Textural properties and overall sensory acceptability of phyllo samples significantly decreased (P ≤ 0.01) with increased extraction rates and storage times. At the end of four days, toughness and extensibility decreased from 0.88 N and 10.9 mm to 0.65 N and 6.7 mm at 4°C and to 0.45 N and 5.6 mm at 25°C. The 53% extraction rate was more suitable for producing phyllo. The shelf life of phyllo samples for preparing borek was determined four days at 4°C and two days at 25°C according to acid contents and sensory properties.