Fig. 4
Effects of types and concentrations of acid on a the resulting sugar composition after the hydrolysis of pineapple peel with 1, 1.5, 2, 2.5, and 3% (v/v) H2SO4; b the resulting sugar composition after the hydrolysis of pineapple peel with 1, 1.5, 2, 2.5, and 3% (v/v) H3PO4; c the resulting inhibitor composition after the hydrolysis of pineapple peel with 1, 1.5, 2, 2.5, and 3% (v/v) H2SO4; and d the resulting inhibitor composition after the hydrolysis of pineapple peel with 1, 1.5, 2, 2.5, and 3% (v/v) H3PO4. The error bars represent the standard deviations (n = 3). An asterisk indicates a significant difference (P < 0.05)