بررسی اثر عوامل مختلف بر هدایت حرارتی و گرمای ویژه پوره کدوتنبل
محورهای موضوعی : میکروبیولوژی مواد غذایی
1 - استادیار گروه علوم و صنایع غذایی، واحد نیشابور، دانشگاه آزاد اسلامی، نیشابور، ایران
کلید واژه: پوره کدوتنبل, گرمای ویژه, هدایت حرارتی,
چکیده مقاله :
مقدمه: تعیین خصوصیات حرارتی مواد غذایی به منظور طراحی فرآیندهای حرارتی صورت میگیرد. از جمله مهمترین خواص حرارتی موادغذایی، گرمای ویژه و هدایت حرارتی میباشد.مواد و روشها: در این تحقیق، گرمای ویژه و هدایت حرارتی پوره کدوتنبل در پنج سطح رطوبتی ) 25 ، 30 ، 35 ، 40 و 45 درصد(، پنجسطح دمایی ) 25 ، 35 ، 45 ، 50 و 55 درجه سانتیگراد(، درصدهای وزنی مختلف نمک ) 0 ، 5 / 0 ، 1 ، 5 / 1 و 2 درصد( و درصدهای وزنیمختلف شکر ) 0 ، 10 ، 15 ، 20 و 25 درصد( بررسی گردید.یافتهها: نتایج نشان داد که درجه حرارت و درصد رطوبت سبب افزایش مقدار گرمای ویژه و هدایت حرارتی محصول میشود در حالیکهافزودن نمک و شکر سبب کاهش مقدار گرمای ویژه و هدایت حرارتی در پوره کدو تنبل میشود. برای پیشبینی تغییرات گرمای ویژه وهدایت حرارتی برحسب متغیرهای دما، درصد وزنی رطوبت، درصد وزنی نمک و درصد وزنی شکر از مدلهای رگرسیونی استفاده شد.ضریب تعیین مدلهای خطی در مورد گرمای ویژه پوره کدوتنبل و متغیرهای دما، درصد وزنی رطوبت، درصد وزنی نمک و درصد وزنیشکر به ترتیب برابر با 920 / 0 ، 941 / 0 ، 949 / 0 و 961 / 0 تعیین شد. ضریب تعیین مدل خطی در مورد هدایت حرارتی پوره کدوتنبل ومتغیرهای دما، درصد رطوبت، درصد نمک، درصد شکر به ترتیب برابر با 851 / 0 ، 962 / 0 ، 956 / 0 و 979 / 0 میباشد.نتیجهگیری: درجه حرارت و درصد رطوبت اثر مستقیم بر خواص حرارتی پوره کدو تنبل و میزان نمک و شکر اثر معکوس بر خصوصیاتحرارتی پوره کدو تنبل دارند.
Introduction: For the precise designing of thermal processes, determination of thermal properties of foods is necessary. The specific heat and thermal conductivity are the two main thermal properties of food products. Materials and Methods: In this research, the thermal properties of pumpkin purée in five levels of moisture (25, 30, 35, 40 and 45 percent), five temperature levels (25, 35, 45, 50 and 55ºC), different percentages of salt (0, 0.5, 1, 1.5 and 2%) and different percentages of sugar (0, 10, 15, 20 and 25%) were investigated. Results: The experiments showed that temperature and moisture caused increases in specific heat and thermal conductivity in pumpkin puree whereas the addition of salt and sugar caused reductions in both specific heat and thermal conductivity of pumpkin puree. In order to predict the effect of moisture, temperature, salt and sugar content on thermal properties of pumpkin puree, regression modes are used. Coefficient of Determination (R2) of specific heat capacity for temperature, moisture content, salt content and sugar content were 0.920, 0.941, 0.949 and 0.961, respectively. Coefficient of Determination (R2) of thermal conductivity for temperature, moisture content, salt content and sugar content were 0.851, 0.962, 0.956 and 0.979, respectively. Conclusion: Temperature and moisture content have direct effect on thermal properties while salt and sugar contents have reverse effect on thermal properties of pumpkin puree.
Aghbashlo, M., Kianmehr, M. H. & Hassan-Beygi, S. R. (2008). Specific Heat and Thermal Conductivity of Berberis Fruit (Berberis vulgaris). American Journal of Agricultural and Biological Sciences, 3 (1), 330-336.
Azadbakht, M., Khoshtaghaza, M.H., Ghobadian, B. & Minaei, S. (2013). Thermal Properties of Soybean Pod as a Function of Moisture Content and Temperature. American Journal of Food Science and Technology, 1(2), 9-13.
Carvalho, G. R., Chenlo, F., Moreira, R. & Telis-Romero, J. (2015). Physicothermal properties of aqueous sodium chloride solutions. Journal of Food Process Engineering, 38, 234–242.
Fasina, O. O., Farkas, B. E. & Fleming, H. P. (2003). Thermal and Dielectric Properties of Sweet potato Puree. International Journal of Food Properties, 6(3), 461–472.
Kian Mehr, M. H., Hasan Beygi, R. & Hashemi Fard Dehkordi, H. (2012). Determination of specific heat and thermal conductivity of pomegranate. Iranian Journal of Biosystem Engineering, 42(2), 175-181 [In Persian].
Kocabiyik, H., Kayisoglu, B. & Tezer, D. (2009). Effect of Moisture Content on Thermal Properties of Pumpkin Seed. International Journal of Food Properties, 12(2), 277-285.
Kurozawa, L. E., El-Aouar, A. A., Simões, M. R., Azoubel, P. M. & Murr, F. E. X. (2005). Determination of thermal conductivity and thermal diffusivity of papaya (carica papaya l.) as a function of temperature. 2nd Mercosur Congress on Chemical Engineering.
Mahapatra, A. K., Lan, Y. & Harris, D. L. (2011). Influence of Moisture Content and Temperature on Thermal Conductivity and Thermal Diffusivity of Rice Flours. International Journal of Food Properties, 14, 675–683.
Oniţa, N. & Ivan, E. (2005). Estimation of the specific heat and thermal conductivity of foods only by their classes of substances contents (water, proteins, fats, carbohydrates, fibers and ash). Scientifical Researches. Agroalimentary Processes and Technologies, 1, 217-222.
Razavi, S. M. & Taghizadeh, M. (2007). The specific heat of pistachio nuts as affected by moisture content, temperature, & variety. Journal of Food Engineering, 79,158-167.
Roosta Poor, O. R., Ghobadian, B., Khosh Taghaza, M. H. & Fakhr Poor, Q. (2005). Determination of thermal-physical properties of lemon juice. Iranian Journal of Agriculture Science, 36(4), 833-848 [In Persian].
Saenmuang, S., Sirijariyawat, A. & Aunsri, N. (2017). The effect of moisture content, temperature and variety on specific heat of edible- wild mushrooms: model construction and analysis. Engineering Letters, 25, 4-12.
Santos Jr, L. C. O., Simão, V., Opuski de Almeida, J. S., Moura de Sena Aquino, A. C., Carasek, E. & Regina Amante, E. (2017). Study of Heat Treatment in Processing of Pumpkin Puree (Cucurbita moschata). Journal of Agricultural Science, 9(10), 234-243.
Shrivastava, M. & Datta, A. K. (1999). Determination of specific heat and thermal conductivity of mushrooms (Pleurotus -florida). Journal of Food Engineering, 39, 255-260.
Tansakul, A. & Lumyong, R. (2007). Thermal properties of straw mushroom. Journal of Food Engineering, 87, 91-98.
Villa-Vélez, H. A., Telis-Romero, J., Cano Higuita, D. M. & Nicolletti Telis, V. R. (2012). Effect of maltodextrin on the freezing point and thermal conductivity of uvaia pulp (Eugenia piriformis Cambess). Ciência e agrotechnologia., Lavras, 6(1), 78-85.
Yu, D. U., Shrestha, B. L. & Baik, O. D. (2015). Thermal conductivity, specific heat, thermal diffusivity, and emissivity of stored canola seeds with their temperature and moisture content. Journal of Food Engineering, 165, 156–165.
Aghbashlo, M., Kianmehr, M. H. & Hassan-Beygi, S. R. (2008). Specific Heat and Thermal Conductivity of Berberis Fruit (Berberis vulgaris). American Journal of Agricultural and Biological Sciences, 3 (1), 330-336.
Azadbakht, M., Khoshtaghaza, M.H., Ghobadian, B. & Minaei, S. (2013). Thermal Properties of Soybean Pod as a Function of Moisture Content and Temperature. American Journal of Food Science and Technology, 1(2), 9-13.
Carvalho, G. R., Chenlo, F., Moreira, R. & Telis-Romero, J. (2015). Physicothermal properties of aqueous sodium chloride solutions. Journal of Food Process Engineering, 38, 234–242.
Fasina, O. O., Farkas, B. E. & Fleming, H. P. (2003). Thermal and Dielectric Properties of Sweet potato Puree. International Journal of Food Properties, 6(3), 461–472.
Kian Mehr, M. H., Hasan Beygi, R. & Hashemi Fard Dehkordi, H. (2012). Determination of specific heat and thermal conductivity of pomegranate. Iranian Journal of Biosystem Engineering, 42(2), 175-181 [In Persian].
Kocabiyik, H., Kayisoglu, B. & Tezer, D. (2009). Effect of Moisture Content on Thermal Properties of Pumpkin Seed. International Journal of Food Properties, 12(2), 277-285.
Kurozawa, L. E., El-Aouar, A. A., Simões, M. R., Azoubel, P. M. & Murr, F. E. X. (2005). Determination of thermal conductivity and thermal diffusivity of papaya (carica papaya l.) as a function of temperature. 2nd Mercosur Congress on Chemical Engineering.
Mahapatra, A. K., Lan, Y. & Harris, D. L. (2011). Influence of Moisture Content and Temperature on Thermal Conductivity and Thermal Diffusivity of Rice Flours. International Journal of Food Properties, 14, 675–683.
Oniţa, N. & Ivan, E. (2005). Estimation of the specific heat and thermal conductivity of foods only by their classes of substances contents (water, proteins, fats, carbohydrates, fibers and ash). Scientifical Researches. Agroalimentary Processes and Technologies, 1, 217-222.
Razavi, S. M. & Taghizadeh, M. (2007). The specific heat of pistachio nuts as affected by moisture content, temperature, & variety. Journal of Food Engineering, 79,158-167.
Roosta Poor, O. R., Ghobadian, B., Khosh Taghaza, M. H. & Fakhr Poor, Q. (2005). Determination of thermal-physical properties of lemon juice. Iranian Journal of Agriculture Science, 36(4), 833-848 [In Persian].
Saenmuang, S., Sirijariyawat, A. & Aunsri, N. (2017). The effect of moisture content, temperature and variety on specific heat of edible- wild mushrooms: model construction and analysis. Engineering Letters, 25, 4-12.
Santos Jr, L. C. O., Simão, V., Opuski de Almeida, J. S., Moura de Sena Aquino, A. C., Carasek, E. & Regina Amante, E. (2017). Study of Heat Treatment in Processing of Pumpkin Puree (Cucurbita moschata). Journal of Agricultural Science, 9(10), 234-243.
Shrivastava, M. & Datta, A. K. (1999). Determination of specific heat and thermal conductivity of mushrooms (Pleurotus -florida). Journal of Food Engineering, 39, 255-260.
Tansakul, A. & Lumyong, R. (2007). Thermal properties of straw mushroom. Journal of Food Engineering, 87, 91-98.
Villa-Vélez, H. A., Telis-Romero, J., Cano Higuita, D. M. & Nicolletti Telis, V. R. (2012). Effect of maltodextrin on the freezing point and thermal conductivity of uvaia pulp (Eugenia piriformis Cambess). Ciência e agrotechnologia., Lavras, 6(1), 78-85.
Yu, D. U., Shrestha, B. L. & Baik, O. D. (2015). Thermal conductivity, specific heat, thermal diffusivity, and emissivity of stored canola seeds with their temperature and moisture content. Journal of Food Engineering, 165, 156–165.
