Fabrication and Performance of Low-Fouling UF Membranes for the Treatment of Isolated Soy Protein Solutions

Abstract

Consumers are becoming more conscious about the need to include functional and nutritional foods in their diet. This has increased the demand for food extracts rich in proteins and peptides with physiological effects that are used within the food and pharmaceutical industries. Among these protein extracts, soy protein and its derivatives are highlighted. Isolated soy protein (ISP) presents a protein content of at least 90%. Wastewaters generated during the production process contain small proteins (8–50 kDa), and it would be desirable to find a recovery treatment for these compounds. Ultrafiltration membranes (UF) are used for the fractionation and concentration of protein solutions. By the appropriate selection of the membrane pore size, larger soy proteins are retained and concentrated while carbohydrates and minerals are mostly recovered in the permeate. The accumulation and concentration of macromolecules in the proximity of the membrane surface generates one of the most important limitations inherent to the membrane technologies. In this work, three UF membranes based on polyethersulfone (PES) were fabricated. In two of them, polyethylene glycol (PEG) was added in their formulation to be used as a fouling prevention. The membrane fouling was evaluated by the study of flux decline models based on Hermia’s mechanisms.

Advancing Faba Bean Protein Purification Using Membrane Technology: Current State and Future Perspectives

“…Protein isolates should have at least 70% of protein content and protein concentrates at least 90% of protein content, both on a dry basis [82]. Moreover, membrane separation can provide specific benefits for the purification of different plant-based pro teins, including preserved protein properties, low recovery cost, and high recovery yields and purity [31,[82][83][84][85]. According to the reported literature, traditional methods for plant based protein production are unable to efficiently remove phytic acid (an antinutritiona The average ethanol yield was considerably different between filtered mash and whole mash fermentation-75% and 37%, respectively.…”

Clarification of the Cardoon (Cynara cardunculus) Blanching Wastewater by Ultrafiltration—Study of Membrane Fouling and Flux Recovery after Chemical Cleaning

“…However, it has been observed that in certain cases, the pure models described by Hermia (Equations ( 5)-( 8)) are insufficient to explain membrane flux decline [26][27][28]. This is likely due to the involvement of multiple fouling mechanisms.…”

“…This is likely due to the involvement of multiple fouling mechanisms. To address this, some authors have proposed combined mechanisms based on Hermia's pure models to describe the flux fouling (Equations ( 9)-( 13)) [26][27][28]. Table 1 lists both the pure and combined Hermia's mechanisms models, along with the corresponding describing equations and fitted parameters that characterize these models.…”

“…As suggested by some authors [26][27][28], fouling can be explained in some cases as a combination of two pure Hermia's mechanisms, and therefore, combined mechanisms (Equations ( 9)-( 13)) have been assessed to study this possibility as a cause of flux decline. In Figure 8 and Table 4, the results obtained in this evaluation are shown.…”

“…It is evident that none of the combined models fit the experimental data, and this is reinforced when fitting parameters were calculated, which yield error values from 40.11% to 102.20% for the 15 kDa membrane and 30.33% to 91.98% for the 50 kDa membranes (Table 4). As suggested by some authors [26][27][28], fouling can be explained in some cases as a combination of two pure Hermia's mechanisms, and therefore, combined mechanisms (Equations ( 9)-( 13)) have been assessed to study this possibility as a cause of flux decline. In Figure 8 and Table 4, the results obtained in this evaluation are shown.…”