Sustainable Wheat Protein Biofoams: Dry Upscalable Extrusion at Low Temperature

Abstract

Glycerol-plasticized wheat gluten was explored for producing soft high-density biofoams using dry upscalable extrusion (avoiding purposely added water). The largest pore size was obtained when using the food grade ammonium bicarbonate (ABC) as blowing agent, also resulting in the highest saline liquid uptake. Foams were, however, also obtained without adding a blowing agent, possibly due to a rapid moisture uptake by the dried protein powder when fed to the extruder. ABC's low decomposition temperature enabled extrusion of the material at a temperature as low as 70 °C, well below the protein aggregation temperature. Sodium bicarbonate (SBC), the most common food-grade blowing agent, did not yield the same high foam qualities. SBC's alkalinity, and the need to use a higher processing temperature (120 °C), resulted in high protein cross-linking and aggregation. The results show the potential of an energy-efficient and industrially upscalable low-temperature foam extrusion process for competitive production of sustainable biofoams using inexpensive and readily available protein obtained from industrial biomass (wheat gluten).

Porous Thermoformed Protein Bioblends as Degradable Absorbent Alternatives in Sanitary Materials

“…The results indicate that high glycerol content increases the porosity, pore sizes, and interconnectivity, which are attractive parameters for large absorbent structures relying on capillary actions . Despite glycerol being a large coproduct from the transesterification process for biodiesel manufacturing, it is also water-soluble as it could jeopardize the material’s performance when exposed to liquid during absorption . We estimated that an optimal glycerol content to preserve regular pore size distribution at large and microscale for engineering production of these biomaterials is 50–60 wt %.…”

“…Relatively longer residence time by the formulations within the extrusion barrel can increase the amount of CO 2 generated by the foaming agent, as the temperature used is lower than the maximum degradation peak for the bicarbonate ( ca. 120 °C). , …”

“…The reduction in the swelling in all samples corresponds to extensive mass loss due to the high solubility of glycerol as demonstrated in previous works. 17,20 The porous materials reached up to 4 times more water uptake as compared to the reference nonporous material (see 75Z/25WG/50Gly Figure 4a). The centrifuge retention capacity (CRC) of all porous materials was ca.…”

“…Using industrial biomass as raw material to produce bioplastics with sorbent properties is the current most promising experimental route to avoid exploiting virgin recourses such as cotton (also used in sanitary pads) . Extensive literature is available in superabsorbent hydrogels from biomass such as cellulose and nanocellulose-based composites. − Recent studies include the use of proteins as coproducts from the starch industry to produce biomaterials with conventional polymer processing techniques (extrusion, injection, compression molding) with high degradation rates and bioassimilation. − The potential of using protein-based formulations with high bioassimilation ensures that the product maintains a safe end-of-life scenario even if accidentally disposed of in nature . Nonetheless, an important drawback is that the reported protein formulations resulted in higher CO 2 emissions than conventional absorbents because of the use of chemicals to increase the liquid absorption properties of the proteins .…”

Functionalization Routes for Keratin from Poultry Industry Side-Streams—Towards Bio-Based Absorbent Polymers

“…Absorbent materials are generally derived from non-biodegradable fossil-based acrylic monomers [ 15 ]. Recent studies have shown that biopolymers, such as proteins from industrial by-products, can produce sustainable absorbents with similar swelling behavior to their synthetic counterparts while providing biodegradability and low toxicity [ 16 , 17 , 18 , 19 ]. Additionally, using keratin from side-streams is an advantage from a sustainability perspective over biomacromolecules that need to be extracted from virgin biomass [ 20 ].…”