Enhancing the release of nutritional components from seaweed biomass through carbohydrase and protease treatments

Seaweeds are sustainable and nutritious food resources, yet their low bioaccessibility and bioavailability hinder broader applications. This study investigated the effects of specific carbohydrases and proteases on four seaweed species, kombu, wakame, hijiki, and nori, to enhance nutrient release. Carbohydrase treatments, particularly Acremo CellulaseKM, significantly increased total reducing sugars, mainly glucose, with up to a 7-fold increase in kombu. Protease treatment, particularly with Flavourzyme_Pangbo, increased the degree of hydrolysis (DH) by up to 7-fold in wakame, raised the essential amino acid ratio from 33.08% to 37.88%, and converted peptides >100 kDa into 1–10 kDa fractions. Protease-treated hydrolysates also showed higher total phenolic content (up to 3-fold compared with control) and antioxidant capacity (up to 4-fold compared with control) than carbohydrase-treated samples. Moreover, sequential protease-carbohydrase treatment led to higher sugar and protein release than single or simultaneous treatments, with reducing sugars and DH increasing by up to 16% and 14%, respectively. Overall, these results demonstrate that enzymatic hydrolysis is an effective approach to improving the nutritional value of seaweeds and promoting their application in sustainable and functional food development.