Changes in texture and dietary fiber of the brown alga Undaria pinnatifida by various processing methods

To elucidate the effects of simple processing on seaweed as food, several methods were applied to Undaria pinnatifida. In this study, 1) boiling in the NaCl solution or 2) soaking in acetic acid, 3) calcium lactate or 4) sodium gluconate solution were performed for U. pinnatifida. After processing, dietary fiber content, breaking strength and molecular weight of extracted alginate were measured. Breaking strengths and insoluble dietary fiber contents decreased as boiling time increased. Breaking strength of U. pinnatifida after calcium lactate treatment was higher than that for sodium gluconate treatment. Molecular weight of alginate was not affected by processing, excepting heating treatment. Our results indicate that processing methods other than heating primarily affect the texture of seaweed products.