Effect of hydrochloric acid extraction on yield and gel properties of gelatine from salted jellyfish by-products

Abstract

Salted jellyfish by-products have collagen protein that is mainly sold for animal feed at a low price. The change of jellyfish by-products into a food ingredient like gelatine could benefit food applications and reduce food waste. Indeed, jellyfish gelatine production is a time-consuming process that includes alkaline pre-treatment, acid pre-treatment, hot water extraction, and drying. Reduced times of acid pre-treatment and water extraction might deliver different gel properties. Therefore, this research aimed to investigate the effect of hydrochloric acid (HCl) pre-treatment on the gel quality of resultant gelatine. Desalted jellyfish by-products were immersed in 0.5 M sodium hydroxide at 4oC for 1 h and then were acidtreated by varying HCl concentrations (0.1, 0.2, and 0.3 M) at 25oC for 2 h. After that, samples were extracted at 60oC for 3 h and dried at 60oC for 3 days. Results showed that gelatine yield significantly increased with increasing HCl concentration. Gelatine yield were 2.97±0.97%, 5.60±1.01%, and 6.34±1.08%, after extraction with 0.1, 0.2, and 0.3 M HCl, respectively. Gel strength generally decreased as HCl concentration increased. Gel strength values were in the range of 118.89-223.60 g. The colour of jellyfish gelatine showed light to dark brown with no differences in Hue values. Thus, the short duration of HCl pre-treatment for 2 h and hot water extraction for 3 h was insufficient for the jellyfish gelatine process.

Keywords

• salted jellyfish by-products
• gelatine
• pre-treatment
• yield
• gel strength