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

Abstract

Sweet potato starch industry produce generous high soluble solid wastewater containing various biochemicals such as proteins. The wastewater could be spray dried into a product called yellow powder (YP). Proteins in the YP were recovered and profiled in this study. The extraction conditions were optimized on dependent variables of YP material-water ratio, pH, and temperature using response surface methodology (RSM). Maximum protein yield (61.2%) using RSM were observed at a material-water ratio of 50 (mg/L), pH 9.5, and extraction temperature of 30°C. Subsequently, a total of 25 proteins were identified by proteomic analysis, which mainly were sporamins, β-amylase, starch phosphorylase, polyphenol oxidase, and superoxide dismutase. The extraction and profiling of proteins from YP would contribute to a comprehensive utilization and added value of the wastewater produced by sweet potato starch processing industry.

Reclaiming Agriceuticals from Sweetpotato (Ipomoea batatas [L.] Lam.) By-Products

“…Similar difficulties as discussed in Section 2.1.3 are met when reprocessing SP wastewater and residue from starch production. Yang et al [79] found that converting spraydrying SP starch industrial wastewater into powder enables efficient extraction of bioactive compounds. The primary techniques utilised for protein extraction and separation from wastewater generated by SP starch manufacturing include isoelectric point precipitation and organic solvent precipitation.…”

“…The proteins extracted from the wastewater were characterised by Yang et al [79]. A total of 25 proteins were identified, with β-amylase, sporamins (sporamins A, sporamins B, and their precursors), and polyphenol oxidase (PPO) being the predominant components.…”

“…Sporamins show antioxidant properties, such as dehydroascorbate reductase and monodehydroascorbate reductase activities [83]. The structure of three sporamin proteins consists of seven common peptides and at least one unique peptide fragment, in which cysteine residue is of great importance in antiradical activities [79,84]. The potential mechanism could involve the reduction of DPPH radical and inhibition of its oxidation by sulfydryl present in SP sporamin [85].…”

“…β-amylase is one of the widely utilised enzymes in the fermentation and food manufacturing industries [79]. It constitutes approximately 5% of the total soluble proteins in SP roots, and its content and activity have been demonstrated to be positively correlated with the maturity of roots and vary between different varieties [88].…”

Physicochemical, structural and metabolic products of yogurt as affected by Coriolus versicolor fermented sweet potato pulp water

“…However, currently, there are still huge problems associated with the processing and utilization of SPPW, and its processing utilization rate is low, which not only brings huge economic losses to the enterprises, but also causes huge environmental pollution in treated unreasonably. ( Cheng et al, 2015a ; Yang et al, 2022 ). At present, the commonly used methods for SPPW treatment include magnetic flocculation ( Mohamed Noor et al, 2022 ), and the modified chitosan method ( Karchiyappan & Pachaiappan, 2022 ).…”