Effect of ι-carrageenan and its acidic and enzymatic hydrolysates on ice crystal structure changes in model sucrose solution

Abstract

The aim of the study was to compare the effects of ɩ-carrageenan and its hydrolysates on ice recrystallisation inhibition (IRI) in model solutions. Acid hydrolysis of ɩ-carrageenan was carried out using hydrochloric acid (HCl). Enzymatic hydrolysis was conducted using the enzymes β-galactosidase and commercial lactase. Hydrolysates were used as a stabiliser in model system solutions. The recrystallisation process was analysed on the basis of images of ice crystals in 50% sucrose and 50% sucrose with the addition of sodium caseinate after 24, 48, 72 and 96 h of storage at − 8 °C. The molecular mass after hydrolysis of ɩ-carrageenan was decreased by around 16% after hydrolysis with β-galactosidase use, around 3% after hydrolysis with commercial lactase use and 24% after acid hydrolysis. Furthermore, using the hydrolysates of ɩ-carrageenan had a strong impact on the recrystallisation process. Significant retardation of recrystallisation in the sucrose solution was observed for the addition of both types of hydrolysates (after acid and enzymatic hydrolysis). However, in sucrose with the addition of sodium caseinate, the oligosaccharides obtained after hydrolysis with commercial lactase use were more effective in recrystallisation inhibition – the average diameter of ice crystals was 16.92 µm. The spectra obtained with Fourier Transform Infrared Spectroscopy (FTIR) show changes in the absorption bands, which confirms that functional groups changes could lead to the IRI activity of gained hydrolysates.