• Pectin and CIDF were sequentially recovered from carrot pomace. • Carrot pectin solution showed 2.37× the viscosity of commercial pectin (identical conditions). • AHP and ED treatment remarkably improved the CIDF-5′s water and oil holding capacity. • The total product yield of this process is 39-42%, converting waste into valuable resources. Addressing the issue of low resource utilization rates of carrot pomace, this study established a sequential recovery process for pectin from carrot pomace and the preparation of carrot insoluble dietary fiber (CIDF) with high water and oil absorption properties. Carrot pectin was preferentially separated from carrot pomace by acid extraction (yield 15.69%), exhibiting higher viscosity values at low shear rates compared with commercial citrus pectin solution. Especially at shear rate of 0.01 s −1 , its solution viscosity value was 2.37 times that of commercial pectin. The remaining residue after pectin extraction (CIDF-1) was further subjected to three sequential treatments: alkaline hydrogen peroxide (AHP), high-pressure homogenization (HPH), and ethanol dehydration (ED), to prepare CIDF-5 with excellent properties. Compared with CIDF-1, the water holding capacity of CIDF-5 was increased from 15.46 g/g to 22.9 g/g (48.03% increase), the water swelling capacity was increased from 16.67 mL/g to 48.33 mL/g (189.92% increase), the oil holding capacity was increased from 9.43 g/g to 19.93 g/g (111.22% increase), and the static contact angle of water and oil phase decreased by 10.71% and 29.79%, respectively. The AHP and ED treatments play a significant role in improving fiber properties. Altogether, this strategy transformed carrot pomace waste into two high-value-added products: carrot pectin and fibers with high water and oil absorption properties, with an overall yield of 39-42%. This not only significantly increased the resource utilization rate of carrot pomace, but also provided a reference for the comprehensive utilization of fruit and vegetable processing by-products.
Tan et al. (Sun,) studied this question.