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Journal of food physicsVol. 30. (2017.)

Tartalom

  • S. N. Dirim ,
    G. Çalışkan :

    Abstract: The primary focus of this study is the assessment of the benefits of fortified noodle products by the addition of mint to improve their functional properties. Therefore, the addition of mint in different amounts (2, 4, 6 and 8% weight:weight (w:w)) to the dough of the noodles was tried and the dough formulations were analyzed to maximise the effect of the mint without compromising appearance and consistency of the dough and to achieve a rich green colour for attractiveness of the finished product. Physical properties (moisture content, water activity and colour) and chemical composition (vitamin C, chlorophyll, total carotenoid and protein content analysis) of the plain and enriched dough and the noodles were determined. Cooking tests have also been implemented for a comparison between the samples for water absorption, swelling volume and cooking loss as well as a sensory analysis. The results showed that the addition of fresh mint beyond 4% caused a significant increase in the moisture content of the noodles compared to plain noodle (P 0.05). The water activity of plain dough and noodle were found to be as 0.99±0.03 and 0.59±0.09, respectively. The protein content of dough and “Enriched Turkish Noodle (ETN)” ranged between 15.00 - 16.77 and 16.45 - 19.43% (db), respectively. The water absorption and the total volume increase of all the samples for traditional and microwave cooking test ranged between 36.55 - 42.40g and 265.00 - 307.5%, and 33.23 - 39.06g and 235.00 - 257.50%, respectively. According to results of the sensorial analysis, the noodles containing 4% mint have the highest acceptability compared to both the plain and the other samples.

    Keywords: Turkish Noodles, Mint, Cooking Test, Sensory Analysis

  • A. Mátrai ,
    L. Baranyai :
    Quality Assessment of Bologna Sausages Using Machine Vision15-21en [222.83 kB - PDF]EPA-02408-00010-0020

    Abstract: Non-destructive methods, such as digital image processing, play important role in the quality assessment since all members of the supply chain can check any product delivered. A simple, low cost and portable machine vision system was used in the presented study to estimate quantity of ingredients of Bologna sausages (also known as Lyoner). Five types of tested sliced sausages differ in ingredients: pork sausage with cheese, cucumber, pepper, mushroom and turkey sausage with cheese. Samples were collected from retail store. Ten slices were measured on both sides, therefore 20 images were acquired by sample groups. Pictures were preprocessed using linear or quadratic normalization depending on the contrast. Segmentation was performed using manually selected training samples and cluster analysis. Based on the surface area of segmented clusters and density data, ratio of ingredients were estimated in m/m % and results were compared to the label. The error of estimation was in the range of 0.22 – 5.49 m/m % where the smallest error was observed for ingredient of cheese and the largest for cucumber. Coefficient of variation was similar for all products. The proposed method needs further improvement but already obtained promising results.

    Keywords: digital image processing, cluster analysis, salami, cold cuts, Lyoner

  • M. Talih ,
    G. Çalışkan ,
    S. N. Dirim :

    Abstract: In this study the drying behaviour of black carrot pulp was investigated in a microwave oven. The effect of different sample thicknesses (3, 5, and 7mm) and microwave powers (180, 540, and 900W) on the drying time of the samples were examined. The total drying times of the black carrot pulp samples ranged between 510 to 2430 seconds. Three thin-layer drying models, namely, Logarithmic, Two-Term, and Wang and Singh models were fitted to drying data and Two-Term model was found to satisfactorily describing the drying behaviour of black carrot pulp. The calculated effective moisture diffusivity values ranged between 2.822x10-7 and 8.532x10-6 m2s- 1.The colour values of the samples were measured and it was observed that the best preservation of the reddish colour and L* (the brightness level) were obtained at 7 mm thickness and 180W microwave power. The flow ability and cohesiveness values were found to be in the medium level.

    Keywords: Black Carrot, Microwave, Drying Behavior, Powder Properties

  • P. Hlaváč ,
    M. Božiková ,
    T. Regrut ,
    V. Ardonová :
    Liquid Food Density Affected by Selected Factors33-41en [227.03 kB - PDF]EPA-02408-00010-0040

    Abstract: Density of materials can be used in assessing of material’s quality. Density of food materials depends on temperature. It is caused by thermal expansion during heating. Density of material is defined as a ratio between mass of material and its volume at the same temperature. One of the most exact methods for measurement of liquid density is pycnometric method, which is based on definition. Measurements of materials density could be also performed by hydrometers or densimeters, where exact value of density can be found on the hydrometer´s scale or on the display of measurement device. During our experiments we used two methods of density determination: pycnometric method and determination by densimeter Mettler Toledo DM 40. Our measurements were performed in approximate temperature range (0 – 30) °C. Effect of various parameters (such as temperature, fat content, alcohol content and short storing time) on material’s density is analysed in this article. Linear decreasing character was applied for temperature dependencies of density for all samples in measured temperature range. The highest fat content of milk had caused the lowest density, but lower fat contents (less than 1.5 %) does not proved this proportion due to the different amount of proteins in measured samples of milk. Effect of alcohol content on density had to be investigated together with material composition (wine, whisky, pinacolada). Values of density were a bit higher after short storing due to the loosening of water during the storage.

    Keywords: density, liquid food, measurement, influencing factors, dependence

  • M. Božiková ,
    P. Hlaváč ,
    M. Malínek ,
    P. Kotoulek :
    Thermal Characteristics of Tekov and Lunex Cheeses42-51en [263.40 kB - PDF]EPA-02408-00010-0050

    Abstract: The article presents selected physical parameters of cheeses. Theoretical part contains description of different cheeses, their classifications and properties. Theory of plane source method which was used for the experiments is described. The main part of the article is the presentation of experimental results which were obtained for samples of selected cheeses. Presented results are relations of thermophysical parameters as: thermal conductivity, thermal diffusivity and volume specific heat to the temperature. All measured relations have mainly linear decreasing progress.

    Keywords: cheese, temperature, thermal conductivity, thermal diffusivity, specific heat

  • A. S. Szabo ,
    M. Izsak :

    Abstract: Education of natural sciences is extremely important for understanding the whole world around us. In teaching of physics in the schools the experiments are of primary importance, and the pupils are definitely satisfied if the investigated materials are food samples, wellknown for them. The paper deals with 3 simple experiments of physical type. The following foodstuffs were investigated: beet sugar, apple, tomato, fruit syrups. For teaching the following experiments were prepared and carried out: - determination of sugar content by density measurement in solutions - examination of fruit firmness - application of a microwave oven for determination of water content by temperature measurement

    Keywords: density, fruit firmness, microwave, physical methods, sugar concentration, water content

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