|Rheological and physical properties of gelatin from beluga sturgeon (huso huso) skin
AM Namari 1, SA Mortazavi 2, and A Motamedzadegan 3
1Department of Food Science, Islamic Azad University, Ayatollah Amoli Branch, Amol, Mazandaran, Iran Po Box 678
2Department of Food Science, Ferdowsi University of Mashhad, Mashhad, Khorassan Razavi, Iran Po Box 917751163
3Department of Food Science, Sari Agricultural Sciences and Natural Resources University, Sari, Mazandaran, Iran Po Box 578
Gelatin has a very broad application in the food, pharmaceutical, and photographic industries (1).Although fish collagen does not form particularly strong gels, it is well suited for certain industrial applications, for example micro-encapsulations and light-sensitive coatings.The functional properties of gelatin are related to their chemical characteristics.Quality of gelatin for a particular application depends largely on its rheological properties(2).The objective of this study was survey the rheological and physical properties of gelatins made of beluga sturgeon(huso huso) skins.The gelatin samples were first pretreated with sodium hydroxide(0.2N and 2N), acetic acid(0.2N and 2N) and then extracted with hot water before the measurement and extraction yield, melting point, viscosity and SDS-PAGE electrophoresis pattern of the solution were determined on gelatins obtained with different pretreatment conditions. Physical properties of gelatins are infulenced more by extraction conditions than by imino acid composition(4).The results showed that extraction yield increased by increased in acid concentration or decreasing in NaOH concentration.(p<0.05).The samples treated with 2 N acid- 2 N NaOH solution and 0.2 N Acid -2N NaOH solution had the lowest and the highest melting point respectively.The values were 17°C and 23°C in that order. A decrease in viscosity observerved by reducing in gelatin concentration and increasing in temperature.However, acid concentration was more effective on viscosity than NaOH concentration(p<0.05). The molecular weight distribution of gelatin depends to a large extent on the extraction process(3). chain was observed in SDS-PAGE pattern of all samples. The most density chain was obseverd in sample 0.2N acid- 2 N NaOH.The most density of chain was was observed in sample 2N acid-0.2 N NaOH. However,The results showed a significant correlation between the type of gelatin and its functionatiolaty.
Keywords: Gelatin, Rheological properties, Viscosity, Functionatiolaty
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