Daniel J. van Breda1, Robert Lufu1 and Neill J. Goosen1
1Department of Process Engineering, Stellenbosch University, Banghoek Road, Stellenbosch 7600
Enzyme-assisted-extraction (EAE) could be a useful technology for the extraction of laminarin from brown seaweeds, and has the advantage of mild processing conditions what retain bioactivity of the molecule, compared to conventional chemical extraction. Laminarin is a potential high-value β-glucan that exhibits multiple bioactivities useful in the food and nutraceutical industries. The work aimed to optimise extraction conditions for enzyme-assisted extraction of laminarin from the South African kelp, Ecklonia maxima, using response surface methodology. Celluclast®, a commercial cellulase, was used to hydrolyse Ecklonia maxima over a period of 6 hours, within the range of 0 to 4.0% (v/dw) enzyme–substrate ratio (ES), pH 3.0 to 6.0, and temperatures of 40 to 60 °C. Samples were analysed for solubilised yield (SY), and concentration of reducing sugars (RS) and laminarin (L). Extraction of laminarin was significantly influenced by linear and quadratic effects of pH and temperature, but not by ES over the experimental range. However, RS and SY showed a significant linear effect of the ES term. Compared to conventional dilute-acid thermal hydrolysis (DATH: pH 1.0 and 70 °C), enzymatic extraction was superior in releasing RS and increasing SY at 4.5 h of hydrolysis. However, conventional DATH was more selective toward extraction of laminarin and resulted in higher extraction yields. Future work should determine the chemical structure of the extracted laminarin, and determine whether there are differences in bioactivity for laminarin extracted with EAE vs DATH-extracted laminarin.