Influence of extraction time on collagen yield and proximate composition from yellowfin tuna (<i>Thunnus albacares</i>) bones: Insights from industrial waste valorization

The valorization of tuna bones from industrial waste as a source of halal collagen presents a promising alternative to land-based collagen sources, such as bovine and porcine collagen.This study aims to evaluate the effect of extraction duration on the quality of collagen produced, focusing on yield, proximate composition (moisture, ash, fat, and protein content), functional group analysis, and collagen morphology.Collagen was extracted using the acid-soluble collagen (ASC) method, which involved pretreatment with NaOH to remove non-collagenous proteins, isopropyl alcohol to remove fat, and hydrolysis using acetic acid (CH 3 COOH).The extraction durations tested were 24, 48, 72, and 96 hours, with a solution-to-sample ratio of 1:10 using 0.75 M CH 3 COOH.Results showed that extraction for 96 hours yielded the highest collagen at 4.70%.FTIR analysis confirmed the presence of functional groups Amide I, II, III, A, and B, while SEM analysis revealed collagen morphology as small, rounded particles with fine pores and clearly visible collagen fibers.The moisture content decreased with longer extraction times, from 12.8% at 24 hours to 4.2% at 96 hours, while protein content increased, reaching 85.2% at 96 hours.The fat content was reduced to 0.2%, and ash content minimized to 0.8%.The proximate composition met the Indonesian National Standard (SNI 8076:2014), indicating that tuna bone collagen is a viable and good-quality source of halal collagen derived from industrial waste.