Effects of ultrasound-assisted multienzymolysis combined with gallic acid grafting or acetylation on the structural and lipid adsorption-relative properties of Ziziphus jujuba residue dietary fibre

Although Ziziphus jujuba juice residue is rich in fibre and polyphenols, it has relatively poor functionalities and limited application in food industry. This study investigates the effects of ultrasound-assisted multienzymatic treatment combined with acetylation or gallic acid grafting on the structural characteristics and lipid adsorption-relative properties of Ziziphus jujuba juice residue dietary fibre (ZJJRDF). More porous or fragmented microstructure, lower crystallinity and lightness were observed in ZJJRDF upon performing ultrasound-assisted multienzymatic treatment combined with acetylation or gallic acid grafting. The combination of ultrasound-assisted multienzymatic treatment and gallic acid grafting is the most effective at increasing the soluble fibre and polyphenol contents, oil-holding capacity (2.23 g∙g ‒1 ), hydrophobicity (2,553), emulsifying activity (103 m 2 ∙g ‒1 ), emulsion stability (89.7%) and cholesterol-sorption ability (43.5 mg∙g ‒1 ) of ZJJRDF. Alternatively, the largest surface area (148 m 2 ∙kg ‒1 ) as well as the highest sodium cholate sorption ability (79.2 mg∙g ‒1 ) and pancrelipase-inhibitory activity (28.5%) were observed in ZJJRDF modified via ultrasound-assisted multienzymatic treatment combined with acetylation. Therefore, ultrasound-assisted enzymolysis combined with gallic acid grafting or acetylation are both effective in improving the lipid adsorption-relative properties of ZJJRDF. However, the special mechanisms of these composite methods warrant further investigation. • Ultrasound, enzymolysis and acetylation increased hydrophobicity of ZJJRDF • Ultrasound, enzymolysis, gallic acid grafting increased total phenols of ZJJRDF • Ultrasound, enzymolysis, gallic acid grafting enhanced ZJJRDF’s emulsion properties • Ultrasound, enzymolysis and acetylation improved ZJJRDF’s bile sorption ability • Ultrasound, enzymolysis, acetylation enhanced the pancrelipase-inhibitory ability