Mahmut Dogan

Bioactive and Physicochemical Properties of Persimmon as Affected by Drying Methods

In this study, the effects of three different drying methods (freeze drying, oven drying, and vacuum oven drying) on bioactive (total phenolics, total flavonoids, condensed tannin and total hydrolyzable tannin contents, antiradical activity, and antidiabetic activity) and some physicochemical (dry matter, ash, water activity (a w ), color, protein, hydroxymethylfurfural, glucose and fructose content) properties of persimmon fruit were investigated. Simplex lattice mixture design methodology was applied to determine the best solvent mixture for the extraction of phenolics from the samples. It was found that the mixture of acetone:water at the ratio of 50:50 % (v/v) was the best solvent mixture for the extraction. The persimmon powder sample obtained from freeze drying showed significantly (p <0.05) higher bioactivity values than oven- and vacuum-oven-dried samples. Antiradical activity changed significantly depending on the drying method employed and it was superior in freeze-dried samples than that of the other drying methods.

Physicochemical, bioactive, and sensory properties of persimmon-based ice cream: Technique for order preference by similarity to ideal solution to determine optimum concentration

In the present study, persimmon puree was incorporated into the ice cream mix at different concentrations (8, 16, 24, 32, and 40%) and some physicochemical (dry matter, ash, protein, pH, sugar, fat, mineral, color, and viscosity), textural (hardness, stickiness, and work of penetration), bioactive (antiradical activity and total phenolic content), and sensory properties of samples were investigated. The technique for order preference by similarity to ideal solution approach was used for the determination of optimum persimmon puree concentration based on the sensory and bioactive characteristics of final products. Increase in persimmon puree resulted in a decrease in the dry matter, ash, fat, protein contents, and viscosity of ice cream mix. Glucose, fructose, sucrose, and lactose were determined to be major sugars in the ice cream samples including persimmon and increase in persimmon puree concentration increased the fructose and glucose content. Better melting properties and textural characteristics were observed for the samples with the addition of persimmon. Magnesium, K, and Ca were determined to be major minerals in the samples and only K concentration increased with the increase in persimmon content. Bioactive properties of ice cream samples improved and, in general, acetone-water extracts showed higher bioactivity compared with ones obtained using methanol-water extracts. The technique for order preference by similarity to ideal solution approach showed that the most preferred sample was the ice cream containing 24% persimmon puree.

Effects of certain polyphenols and extracts on furans and acrylamide formation in model system, and total furans during storage.

Using a glucose-glycine and asparagine-fructose system as a Maillard reaction model, the effects of seven polyphenols and solid phase extracts of three plants on the formation of furans and acrylamide were investigated. The polyphenols and extracts were used in biscuit formulation and acrylamide formation was observed. They were used for the storage of the glycine-glucose model system at three different temperatures. The addition of some of the extracts and polyphenols significantly decreased furan formation to different extents. All phenolic compounds and plant extracts decreased in the range of 30.8-85% in the model system except for oleuropein, and all of them decreased in the range of 10.3-19.2% in biscuit. Total furan formation was inhibited by caffeic acid, punicalagin, epicatechin, ECE and PPE during storage. This study evaluated and found the inhibitory effect on the formation of furans and acrylamide in Maillard reactions by the use of some plant extracts and polyphenols.

Sensitivity of three pathogenic bacteria to Turkish cemen paste and its ingredients.

Pastirma is a dry cured meat product which is pasted with cemen. This paste is prepared from ground fenugreek, garlic and red hot pepper (RHPP). In this study, the cemen mix/paste and all its ingredients were tested for their inhibitory effects on Escherichia coli, Staphylococcus aureus and Yersinia enterocolitica. All samples had a varying inhibitory effect against all the bacteria tested during 4 days of storage. Complete cemen paste showed the strongest inhibitory effect on the three pathogens compared to ingredients alone. Fenugreek and RHPP had a bacteriostatic effect while the cemen paste and garlic had a bactericidal effect. S. aureus was the most sensitive bacterium while Y. enterocolitica was the most resistant. The results of this study confirmed the protective effect of cemen paste and garlic in food preservation especially against E. coli, S. aureus and Y. enterocolitica proving safety for public health. Hence it might be concluded that cemen paste is the first hurdle to prevent bacterial contamination, and a low pH (∼4.83) value would also add an additional barrier to secure safety of the product. Finally, it can be suggested that similar studies should be conducted on actual meat systems to confirm these findings.

Rheological Properties of Reconstituted Hot Salep Beverage

Abstract In this study, some physicochemical (solubility index, apparent density and dry matter content) and rheological properties of the hot salep, an indigenous Turkish beverage, were determined. The samples were prepared by adding water or milk to the commerical instant salep powder. The apparent viscosity of samples was measured in the temperature range of 10–50 °C, with the rotational speed of 20–200 rpm. The empirical power law model was used for the determination of the flow behavior and consistency indices of the samples. Dry matter content and apparent density of salp-milk beverage were significantly (p < 0.05) higher than those of salep-water counterpart. Apparent viscosity, consistency and flow behavior indices were also higher in the salep-milk samples. Salep-water sample was more pseudoplastic with lower flow behavior index. Since there is a close relationship between the rehological properties of beverages and consumer preference, the results might be useful in the formulation of instant hot salep beverages.

Application of Different Multi-criteria Decision Techniques to Determine Optimum Flavour of Prebiotic Pudding Based on Sensory Analyses

The selection of optimum aroma among vanilla, strawberry and cacao for prebiotic pudding was aimed based on sensory analyses by performing multi-criteria decision techniques [analytic hierarchy process (AHP), simple additive weighting (SAW), technique for order preference by similarity to ideal solution (TOPSIS) and elimination et choix traduisant la realite-elimination and choice translating reality (ELECTRE)]. In the first part of the study, the physicochemical (pH, viscosity, dry matter and ash content) and functional properties (bulk density, water-holding capacity and oil-holding capacity) of the dietary fibres (lemon, inulin, apple and wheat) were determined. According to our results, there are significant differences between the fibres (P < 0.05). In the second part of the study, the INU/OLI dietary fibre was added to the different flavoured pudding samples (cacao, strawberry and vanilla). Some of their physicochemical (bulk density, dry matter and viscosity) and sensorial properties (appearance, consistency of appearance, consistency in the mouth, taste and smell, adhesiveness and general acceptability) were identified. In the last part of the study, multi-criteria decision techniques (AHP, SAW, ELECTRE and TOPSIS) were applied to obtain the ranking of the pudding samples based on the sensorial scores. According to the results of this study, strawberry-flavoured pudding (not including fibre) was mostly preferred. By considering the ranking of the puddings, it was seen that strawberry flavour was the most appropriate for prebiotic pudding. As a result of this study, it was found that multi-criteria decision techniques may be performed to sensorial scores in the food industry to reduce many results to one result thus facilitating the comparison of samples and the explication of results obtained from sensory analysis.

The Effect of Ageing at a Low Temperature on the Rheological Properties of Kahramanmaras-Type Ice Cream Mix

The aim of this article was to investigate the effect of ageing on the rheological parameters of ice cream mix. We prepared the model mix in accordance with the traditional Kahramanmaras-type ice-cream manufacturing method. The apparent viscosity (ηa) of the samples was measured as a function of shear rate, and the Power Law model was used to determine flow behavior (n) and consistency indices (K). The ηa of sample was significantly affected from ageing time as it increased up to 24 hours then decreased. The values of n and K of the samples ranged in 0.336 to 0.359 and 3719.72 – 4328.73 mPa.sn, respectively. After 24 hours of ageing, K and ηa of the mix reached the highest, while the n reached the lowest values. These results suggested that 24 hours of waiting would be a proper ageing time for the ice cream mix. It could be recommended that ice cream mix may be aged at 0°C for about 24 hours before proceeding to the freezing step of ice cream manufacturing.

HPLC-DAD Analysis to Identify the Phenolic Profile of Rhododendron Honeys Collected from Different Regions in Turkey

In this study, phenolic compounds of Rhododendron honey (also known as mad honey) samples collected from the Black Sea Region were identified using high performance liquid chromatography-diode array detector system. The major phenolic substances in Rhododendron honeys were found to be chlorogenic and coumaric acids with the amounts of 0.11–191.54 mg/kg and 0–82.83 mg/kg, respectively. Gallic and ferulic acids were detected in the most honey samples. Additionally, significant correlations were determined between the phenolic substances. The present study showed that Rhododendron honeys contained higher quantities of phenolic acids than flavonoids. Chlorogenic and coumaric acids were the dominant phenolic substances detected in honey samples.

New approaches to determination of HMF.

Several techniques have been used for hydroxymethylfurfural (HMF) detection in foods. Most of these involve the protein hydrolysation step process to determine the presence of organic acid with heat treatment. The affinity and separability of HMF to/from some proteins were exhibited in this study. Also, the dependency of HMF level was determined in the presence of some substances such as reductive and non-reductive sugars, gums and polysaccharides due to high temperature and acidity during the hydrolysation stage. Consequently, the HMF levels of the samples were evaluated separately either by no treatment or by the acid-heat treated method. The HMF amount which was measured by the conventional method was found to be dependent on the sample amount. The binding capacity of HMF to casein was about 10% but did not bind to the gluten in the model system. However it was not released from the caseine by acid hydrolysation in the solvent.

5-hydroxymethyl furfural formation and reaction kinetics of different pekmez samples: effect of temperature and storage

Abstract Pekmez (molasses) is a traditional food commonly produced from grape and other kind of fruit juices by evaporation processes. In this study, 5-Hydroxymethylfurfural (HMF) level of various pekmez samples was investigated during storage at different temperatures. HMF content of apricot, mulberry, carob, grape, Juniperus communis pekmez changed from 133.0 ppm to 1060.5 ppm, from 88.2 to 1921.5 ppm, from 11.1 to 1153.6 ppm, from 75.5 to 2077.0 ppm, from 19.9 to 280.1 ppm throughout eight months storage period, respectively. Samples of pekmez from the Juniperus communis had the minimum k values for each temperature that means HMF formation in these samples were slower than other pekmez types. The kinetic data analysis for HMF formation during storage was performed and an Arrhenius equation was used to determine the effect of temperature on reaction kinetics of 5-HMF formation in pekmez samples. Ea values were found between 10.58–37.73 (kcal/mol). Apricot pekmez was found as the least sensitive sample to HMF formation resulted from temperature changes.