As an additive, it improves water holding capacity, texture, elasticity, consistency and stability of foods (Zhou and Regenstein, 2005). The proteinaceous nature of gelatin makes it an ideal food ingredient with high digestibility in certain types of diets (Johnston-Banks, 1990). Gelatin is one of the most commonly used food additive and is an ingredient of many recipes. Generally, compared to mammalian gelatin, fish gelatins hold lower gelling and melting temperatures, and lower gel strength as well (Norland, 1990). According to one report (Farris et al., 2009) fish gelatin holds around 20% of proline and hydroxyproline than the bovine or porcine gelatins, which lower the gelling and melting by 5-10☌. The higher the level of proline and hydroxyproline, the higher will be the melting point and gel strength (Karim and Bhat, 2009). Moreover, the specific amino acids and their respective amounts determine physical and functional behavior of gelatin. The quality of resultant gelatin is determined by its physicochemical behavior that is further based on the species as well as the process of manufacture. The gelatin is water soluble and forms thermo-reversible gels with the melting temperature near to the body temperature (Norziah et al., 2009). In the conversion process of collagen to gelatin, acid or alkali pretreatment hydrolyze the cross-linking bonds between polypeptides and irreversibly results in gelatin (Yang et al., 2008). Technically, the term gelatin, applies for a series of proteins obtained from collagen after partial hydrolysis, obtained from bones, skin, hides, ligaments and cartilages, etc. A number of studies have addressed the properties of fish skin gelatins, indicating that their properties differ from those of mammalian gelatins and vary among fish species. Nevertheless, fish, being in bulk and abundant, accounts more significantly than the insects. Thus, fish (skin and bone) and other marine sources, along with insects (melon and sorghum bugs) are being exploited simultaneously. Moreover, in the case of bovine gelatin, the prevalence of spongiform encephalopathy necessitates a look up for possible alternatives (Karim and Bhat, 2009). Due to the fact that half of the production is harvested from porcine source, concerns about Halal or Kosher market strongly dominate. In 2009, the global production of gelatin reached 326 thousand tons majorly derived from pig skin, bovine hides, bones and others sources contributing 46%, 29.4%, 23.1% and 1.5%, respectively. Introduction: As the global demand for gelatin is continuously on the rise, many potential sources are being sought for combating this growing need. Fish gelatin applications should be expanded with the growing technological advances in industrial processes. Furthermore, a minor description of legislation regarding toxicity issues of the frequently used active additives (plant extract and nanoparticles) in gelatin films is also presented. Additionally, studies related to possible improvement in film barrier and mechanical properties are also enlisted. This review focusses on extraction, physicochemical properties and film forming ability of fish gelatin. Nonetheless, it has a good film forming ability and has been suggested as an alternative to the petroleum-based polymers. However, fish gelatin presents some less desirable properties due to the lesser amount of proline and hydroxyproline residues compared to the mammalian gelatins. The extraction method, fish type and intensity of the treatment determines the fate of produced gelatin. Mammalian gelatin is the main contributor to total gelatin production, but fish gelatin is also a potential alternative. Especially, its rheological and thermal properties diversify its applications. Based on physico-functional properties, gelatin is a biopolymer of great interest in food industry.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |