Flash extraction optimization of low-temperature soluble pectin from passion fruit peel (Passiflora edulis f. flavicarpa) and its soft gelation properties

Low-temperature soluble and soft gelation (LT-SG) pectin belonging to special gum is an important food additive. Flash extraction optimization of pectin from passion fruit ( Passiflora edulis f. flavicarpa ) peel at low temperature (50   °C) by response surface methodology and LT-SG properties was investigated in the present study. Under the optimized conditions of a rotation speed of 5000   r/min, extraction time of 9   min, and the liquid–solid ratio of 42:1   mL/g, the pectin yield was 7.52%. The DE value of 57.02% indicated it was high methoxyl pectin, which easily dissolved at a low temperature (70   °C). Gel texture analysis revealed that the soft gelation properties were depended on the sucrose concentration and pH in the pectin solution. Both adding sucrose and decreasing pH refined gel network structure, as results, the gel texture was strengthened.