Abstract:Effect of prepreg solution with different pH values (3.2, 3.6, 4.0, 4.4, 4.8) on the color changes of peach juice was studied. Several color parameters, including lightness (ΔL), redness (Δa), yellowness (Δb), total color difference (ΔE) and chroma (ΔC), were detected when the peach juice was kept in a sealed container at the ambient temperature for different time. Compared to the control samples, the color of peach juice changed slightly after impregnating in citric acid-sodium citrate buffer with pH 4.4 and 4.8 (especially pH 4.8)for 30 min. After impregnating in pH 4.8 buffer solution,the ΔL value decreased from -3.16 to -1.23, the Δa value decreased from 1.21 to -0.83, the Δb value increased from -1.4 to 0.05, and the ΔE value decreased from 3.67 to 1.49, while the ΔC value almost kept stable. All these results demonstrated that impregnation peach before pulping into the citric acid-sodium citrate buffer with pH 4.8 for 30 min could effectively contain the peach juice browning.