Recovery of Yam Soluble Protein from Yam Starch Processing Wastewater

Abstract

Over the past two decades, many studies have shown that the yam storage protein dioscorin, which is abundant in the wastewater of starch processing, exhibits many biological activities both in vitro and in vivo. In the present study, the acid-precipitation method was optimized using Box-Behnken design (BBD) combined with response surface methodology (RSM) for the recovery of yam soluble protein (YSP) from wastewater. The experimental yield of YSP reached 57.7%. According to relative quantitative proteomics (LC-MS/MS), the crude YSP was mainly composed of 15 dioscorin isoforms, which was further verified by anion-exchange and size-exclusion chromatography. YSP was found to be rich in glutamic acid and aspartic acid, and the eight essential acids made up approximately 33.7% of the YSP. Moreover, the YSP demonstrated antioxidant activity, including scavenging DPPH, hydroxyl and superoxide anion radicals, and the possible structure-activity relationships were discussed. these results indicated that YSp produced by acid precipitation may be used as a protein source with antioxidant properties.

Extraction and Characterization of Proteins from Pachyrhizus ahipa Roots: an Unexploited Protein-Rich Crop

“…Referring to other edible starchy R&T, proteins from a high-protein variety of sweet potato (variety 55-2) presented aspartic and glutamic acid contents of 18.5 and 9.3%, respectively [16], while potato cultivars exhibited up to 7.5 and 13.9% of Asp and Glu, respectively [17]. Yam proteins, which have Asp and Glu as their most abundant amino acids, account for 11.9 and 18.5% of the total amino acids, respectively [18]. Thus, ahipa proteins, with 59% of Asp along with 3% of Glu, become markedly acidic and different from most plant-based food proteins.…”

Extraction and profiling of proteins in yellow powder from sweet potato starch wastewater using response surface methodology and proteomic approach

“…In general, the solubility of proteins is increasing when the pH of solution is far away from pI (Yuliana et al, 2014). However, extreme higher pH disrupted the net of proteins, which may be the reason for lower extraction rate at pH 10.0 (Xue et al, 2020). The effects of temperatures on protein extraction are shown in Figure 2c.…”

“…The most abundant protein was β-amylase, followed by sporamins (sporamins A and B), PPO, ubiquitin extension protein, superoxide dismutase (SOD), and starch phosphorylase. Based on current knowledge, several proteins have been recovered from starch wastewater, including dioscorin from yam starch wastewater, and PPO, β-amylase, sporamin from sweet potato starch wastewater (Cheng et al, 2015;Li et al, 2018;Xue et al, 2020). About ten proteins were firstly identified in sweet potato starch processing wastewater, such as SOD, starch phosphorylase, ubiquitin extension protein, cathepsin B-like cysteine proteinase, protein disulfide isomerase, ribosomal protein L14, etc.…”

“…Although the biological activity of recovered proteins has been demonstrated, such as antioxidant activity (Xue et al, 2020) and enzyme activity (Li et al, 2018), the research on utilization of promising proteins is still limited. The top five proteins in YP appeared to have the potential to be exploited based on their characterization.…”

“…On the other hand, the wastewater contains several useful components, such as high activity enzymes, dietary fiber, storage protein, and small molecular organics. Recovery of these valuable compounds can increase the industrial profits (Hu et al, 2019;Li et al, 2018;Liu et al, 2020).…”