Utilization of ultrasound and pulse electric field for the extraction of water-soluble non-starch polysaccharide from taro (Colocasia esculenta) peel

This study investigated the effects of different extraction methods (i.e. conventional (CE), ultrasound-assisted (UAE), and pulse electric field-assisted (PEFAE)) on the yield and physico-chemical properties of the water-soluble non-starch polysaccharide (WS-NSP) from taro peel (Tp). The use of UAE resulted in a significantly (p ≤ 0.05) higher yield (3.65 g/100 g) than PEFAE (2.25 g/100 g) and CE (2.10 g/100 g). Tp-WS-NSP-UAE and Tp-WS-NSP-PEFAE had fewer impurities indicated by the lower amount of ash (UAE: 0.41; PEFAE: 0.20 g/100 g) and protein (UAE: 0.55; PEFAE: 0.42 g/100 g), had lighter color (UAE: L = 39.13; PEFAE: L = 34.72), and higher degradation temperatures (UAE: 252.68; PEFAE: 251.75 °C) than Tp-WS-NSP-CE (ash: 0.47; protein: 1.23 g/100 g; L = 34.18; < 250 °C). All Tp-WS-NSP samples contained the sugars arabinose, galactose, glucose, and mannose, had comparable functional groups in their FTIR spectra, were amorphous, and exhibited shear-thinning behavior (n