Cryoprotective effect of three oligosaccharides on freezing–thawing induced krill mince: with emphasis on physicochemical changes and gelation properties

Summary The physicochemical and gelation properties of krill mince were investigated in relation to the cryoprotective effect of kappa‐carrageenan (KC), carrageenan oligosaccharides (CGO), chitosan oligosaccharides (COS), and alginate oligosaccharides (AOS). The water‐holding capacity of krill mince decreased during freezing–thawing (FT) circles, but KC and three oligosaccharides prevented this decline by increasing hydrogen and ionic bonding. The denaturation and degradation of proteins in krill samples added with oligosaccharides were alleviated with less decrease in protein solubility and Ca 2+ ‐ATPase activity, as well as higher intensity protein bands of myosin heavy chain and paramyosin subject to 9‐FT circles. The notable increase in TBARS value ( P < 0.05) was observed after 3‐FT circles, however, with relatively lower values with the addition of AOS and CGO, demonstrating antioxidative ability against lipid oxidation. Additionally, CGO exhibited higher protein secondary structure maintenance stability, evidenced by a less dramatic decrease in α‐helical fraction than other oligosaccharides. The overall gelation and textural properties of krill mince with CGO could be better maintained with no more than 3‐FT circles.