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Optimization of antioxidant extraction from edible brown algae Ascophyllum nodosum using response surface methodology

Liu, Xin, Luo, Guanghong, Wang, Lijuan, Yuan, Wenqiao
Food and bioproducts processing 2019 v.114 pp. 205-215
Ascophyllum nodosum, antioxidant activity, antioxidants, ethanol, experimental design, models, polyphenols, polysaccharides, proteins, response surface methodology, solvents, temperature
Brown algae are valuable sources of health-benefiting compounds, such as polyphenols, proteins, and polysaccharides. In the present study, a binary solvent system of ethanol and water was used to obtain crude extracts from edible brown algae Ascophyllum nodosum. The extraction process was optimized using Box–Behnken design and response surface methodology to obtain crude extracts with strong antioxidant activity and high yield. Three variables including solvent-to-solid ratio (30–70ml/g), ethanol concentration in the solvent system (40–80%), and extraction temperature (20–60°C) were investigated to optimize the extraction process. The condition for maximum antioxidant activity of the crude extract was found at 70ml/g solvent-to-solid ratio, 80% ethanol concentration, and 20°C extraction temperature, while the condition for the highest crude extract yield was 40ml/g solvent–solid-ratio, 44.83% ethanol concentration and 60°C extraction temperature. Under the model-predicted optimal conditions, the predicted antioxidant activity and yield of the crude extract were 74.01ml/g (1/IC50) and 55.60mg extract/g-algae, which were in close agreement with the experimental results of 74.05ml/g and 53.80mg extract/g-algae, respectively, suggesting that the models could accurately predict and improve the extraction of antioxidants from A. nodosum.