关键词: 菠萝果渣, 膳食纤维, 酸法, 碱法

Abstract: The soluble and insoluble dietary fibers were prepared with acid hydrolysis and alkali hydrolysis from pineapple pomace and their properties were also compared. The extraction process was optimized by orthogonal tests. The results showed that the optimal extraction conditions for insoluble dietary fiber required reaction temperature of 60 ℃, reaction time of 60 min and hydrolysis pH of 2.0 during acid hydrolysis; NaOH concentration of 1%, material-liquid ratio of 1:15, reaction temperature of 50 ℃ and reaction time of 40 min during alkali hydrolysis. The optimal extraction condition for soluble dietary fiber required reaction temperature of 90 ℃, hydrolysis pH of 1.0, hydrolysis duration of 90 min and material-liquid ratio of 1:10 during acid hydrolysis. The maximum yield of soluble and insoluble dietary fiber by acid hydrolysis could reach 8.1% and 24.4%, respectively, and the maximum yield of insoluble dietary fiber by alkali hydrolysis was 62.80%. The waterholding capacity, swelling capacity, oil-holding capacity and cation exchange capacity (CEC) of water insoluble dietary fiber from both hydrolysis methods were 5.85 g/g and 3.82 g/g, 9.25 mL/g and 10.66 mL/g, 1.35 g/g and 1.75 g/g, and 0.21 mmol/g and 0.27 mmol/g, respectively. Therefore, higher maximum yield and better properties of dietary fibers were achieved during alkali hydrolysis.

Key words: pineapple pomace, dietary fiber, acid hydrolysis, alkali hydrolysis