Effects of acid and base hydrolysis on the yield and purity of squid ink melanin

• Main Authors: Lin, Shih-Chuen, 林士淳
• Other Authors: Chang, Ke-Liang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/2h9vda

碩士 === 國立臺灣海洋大學 === 食品科學系 === 102 === The squid ink sac in squid processing waste may pollute the environment, and become a waste of potential resource if it were not treated properly. The objective of this study was to recover and purify squid ink to do recover melanin, for potential use as a natural food colorant or dye. First, the squid ink melanin was separated from soluble substances by high-speed centrifugation to obtain crude melanin, with an average yield of 29.49% (wet wt %). The yield had no significant correlation with ink sac wet weight used in the centrifugation step. The crude melanin was purified by acid and base hydrolysis. The highest yield, 72.75% (dry wt %), was achieved by acid hydrolysis of the crude melanin at an average weight of 3.1 g powder with 1M HCl solution nunder a solid-liquid ratio of 1:10 (w/w). The weightr of crude melanin powder used in the acid hydrolysis had a positive correlation with the yield. In order to determine melanin purity, high performance liquid chromatography (HPLC) was used to detect the content of pyrrole-2, 3-dicarboxylic acid and pyrrole-2, 3, 5-tricarboxylic acid. Base hydrolysis of the crude melanin at an average weight of 5.5 g powder with 1M NaOH solution at a solid-liquid ratio of 1:10 (w/w) effectively increased the purity of melanin from 0.58% to 2.37%. Sensory evaluation of odor and flavor revealed that there were significant differences between commercial squid ink samples and those obtained in this study. Most sensory panelists said that purified squid ink colorant in this study did not smell like the odor of commercial squid ink samples, suggesting that we can effectively remove the squid ink odor by hydrolysis. Black coloring power of the L*a*b*values indicated of base hydrolysis of the crude melanin with 1M NaOH solution at a solid-liquid ratio of 1:10 (w/w) of the strongest staining, noodles darkest color rendering. Hydrolysis purification methods can effectively improve the dyeing force. The heavy metal content measurements of lead (Pb), cadmium (Cd), mercury (Hg) indicated that there were no detectable levels according to the atomic absorption spectrometry. Consequently, the heavy metal levels of the squid ink melanin prepared in this study were in compliance with the food regulations and standards of cephalopod aquatic animal established by Executive Yuan of the Ministry of Health and Welfare, Taiwan.