en Fish processing Fish processing كاربردي Applicable <div style="text-align: justify;">Gelatin is a valuable protein source and a commercial hydrocolloid which is particularly applied for food, pharmaceutical, and photographic industries. Commercial gelatin is basically from pig and cow, which because of religious reasons and risk of transmission of <em>Bovine</em> spongiform encephalopathy (BSE) respectively, not acceptable to use. Therefore gelatin extraction from fish, and especially it^,s waste has considerable importance. In the present study, after the extraction of gelatin from economic fish skin of carp (<em>Cyprinus carpio</em>), various formulations of this gelatin with cow^,s&nbsp; gelatin have been used in ratios of 0, 25, 50, 75 and 100% to pastill production. Then, the physicochemical experiments include of ash, protein, moisture, iron, phosphorus, zinc and lithium content, and color measurement were done on one day after of pastill production. The results showed that the treatment based on 75% fish gelatin had the highest moisture, protein, phosphorus, iron, ash and zinc content (p<0.05) while the highest level of potassium and lithium content was related to treatment based on 100% industrial gelatin (Cow^,s) (p<0.05). Industrial treatment showed the highest L^* value (lightness) and the lowest index a^* (green&ndash;red) and b^* (blue&ndash;yellow) value (p<0.05). It can be concluded that useless waste of fish as halal gelatin can be a good substitute instead of other gelatin for children&#39;s favorite junk foods, which has higher levels of zinc and protein content with economical benefits.</div> pastill, fish skin gelatin, cow's gelatin, color measurement, physicochemical properties 40 54 http://ijaah.ir/browse.php?a_code=A-10-179-2&slc_lang=en&sid=1 N Choobkar nchoobkar20@gmail.com 10031947532846002144 10031947532846002144 Yes Department of Fisheries, College of Agriculture, Kermanshah Branch, Islamic Azad University, Kermanshah, Iran A Aghajani ab.aghajani@yahoo.com 10031947532846002145 10031947532846002145 No Department of food science and engineering, faculty of Industrial and Mechanical engineering, Qazvin branch, Islamic Azad University, Qazvin, Iran A Jokar ajokar1991@gmail.com 10031947532846002146 10031947532846002146 No Department of Food Science and Technology, Mahalat Branch, Islamic Azad University, Mahalat, Iran