Optimization of microwave‐assisted extraction of soluble dietary fiber from potato pulp and its properties

Abstract

In this study, the microwave‐assisted sodium hexametaphosphate (SHMP) method was applied for soluble dietary fiber (SDF) extraction from potato pulp; the extraction conditions were optimized by response surface methodology (RSM). The water holding capacity (WHC), swelling capacity (SC), oil binding capacity (OBC), adsorption capacity for cholesterol (ACC), and DPPH and ABTS free radical scavenging capacities of potato pulp SDF were then evaluated. The optimal extraction conditions were 1.0% SHMP, liquid to solid (L:S) ratio; 40:1, and microwave time; 1.26 min. The WHC and SC were 2.66 g/g and 4.47 ml/g, respectively. Adsorption capacities for unsaturated fatty acid (UFA) and saturated fatty acid (SFA) were 1.405 and 1.302 g/g, respectively. At pH 2 and 7, the ACC was 1.87 and 1.33 mg/g, respectively. The free radical scavenging assays show that potato pulp SDF has moderate antioxidative activity. This study serves as a reference for the full processing of potatoes and the comprehensive utilization of potato pulp. Practical applications Potato pulp is often thrown away in starch manufacture, which not only causes waste of resources but also environmental pollution. Extracting functional components such as SDF is one direction for the comprehensive utilization of potato pulp. Compared to traditional methods, microwave‐assisted technology is more efficient and environment‐friendly. In this study, the optimal microwave‐assisted extraction conditions were obtained by single‐factor experiments and RSM, which provides a reference for the application of microwave‐assisted technology in the potato‐processing industry. Moreover, compared with other sources of SDF, the property assays reveal that SDF from potato pulp has good SC, as well as moderate WHC, OBC, and antioxidative activity, which suggest that it has potential for applications in the functional food industry.

Recovery of total, soluble, and insoluble dietary fiber from potato ( Solanum tuberosum ) residues and comparative evaluation of their structural, physicochemical, and functional properties

“…Navarro-González et al (2011) also indicated that low level of OHC might be due to the absence or limited presence of lignin, thus reducing the OHC of SDF; this was also accordance with the results in Table S1. Our OHC values of TDF, and IDF were similar to that of DFs extracted from grapefruits (1.20-1.52 g/g), citrus fruits (1.81 g/g), and apples (0.60-1.45 g/g) (Chen et al, 2019;Ma & Mu, 2016).…”

“…These findings indicated that dietary fibers can absorb cholesterol more effectively in the intestine than the stomach (Xu et al, 2015). However, Chen et al (2019) reported that CBC of SDF (1.33 and 1.87 mg/g) derived from potato residues was lower than this observation, may be due to varietal characteristics or extraction procedure.…”

“…While the WSC of IDF and TDF at each temperature was higher than that of SDF (2.63-4.99 ml/g). Higher WRC and WSC of IDF and TDF might be because a number of hydrophilic groups and porous honeycomb like structures existed in IDF and TDF that provided good hydration properties (Chen et al, 2019 TA B L E 1 Monosaccharides and uronic acids content of total, insoluble, and soluble dietary fiber obtained from potato residues lignin existing in IDF and TDF also exhibited higher water affinity than SDF (Daou & Zhang, 2011).…”

“…In China, most of potatoes are used to produce starch or starch noodles, while a large quantity of residues are produced and discarded, leading to resources waste and environmental pollution. It was reported that 6.5-to 7.5-t potato residue (wet basis) was generated after 1-t potato starch was produced; therefore, how to realize the high value utilization of potato residue is an urgent problem for researchers and related enterprises (Chen et al, 2019;Cheng et al, 2017).…”

Impact of extraction methods on functional properties and extraction kinetic of insoluble dietary fiber from green pea peels: A comparative analysis

“…The water holding capacity (WHC) of the IDF was determined using 1 g of sample () and was taken in a graduated centrifuge tube () followed by the addition of 30 ml of water and stirred for 18 h and the mixture was centrifuged at 3000 g for 20 min. The residue was weighed and oven‐dried at 105°C to constant weight () (Chen et al, 2019). WHC was calculated according to the following Equation (1):where represents weight of centrifuge tube (g), represents dry sample weight (g), represents centrifuge tube with wet sample weight (g).…”