Modification of vital wheat gluten with phosphoric acid to produce high free swelling capacity

Abstract

Wheat gluten reacts with phosphoric acid in the presence of urea to produce natural superabsorbent gels. Fourier Transform Infra‐red (FT‐IR) spectroscopy and two‐dimensional gel electrophoresis (2DE) reveal chemical changes from the reaction. Temperatures above 120°C and dry conditions create the opportunity for reaction. FT‐IR analyses confirm the formation of esters, carbamates, and phosphoramides on the gluten samples. 2DE protein composition topographies indicate a shift in the isoelectric point (pI) to lower values along with extensive inter‐protein linkages. A free swelling capacity (FSC) in excess of 85× the mass of the converted gluten is obtainable using a conservative vacuum‐assisted method to recover and quantify the properties of the wet gel. Other methods produce FSC values nearly twice as high. FSC for acid‐treated gluten is lower for solutions containing solutes than the FSC for deionized water. Native gluten produces FSC values that are about 2% of those for treated gluten, but these values are less sensitive to the presence of ionic solutes and increase slightly in the presence of aqueous ethanol up to a mole fraction of 0.25.. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39440.

Advances in the Use of Protein-Based Materials: Toward Sustainable Naturally Sourced Absorbent Materials

“…14,20,28,34,40,97,98,107,111,112 ■ FUNCTIONALIZATION OF PROTEINS FOR IMPROVING WATER AFFINITY A range of different experimental routes have been evaluated to modify the water affinity/absorption properties of protein-based materials. 20,35,115,121,122 Chemical functionalization of protein materials is widely described, and both wet and dry chemistry have been applied. 21,28,35,39,40,98,115,121,122 Among these, the radical grafting of synthetic acrylic acid/poly(acrylic acid) units The free swelling is given in g water/g dry polymer, unless otherwise specified.…”

“…20,35,115,121,122 Chemical functionalization of protein materials is widely described, and both wet and dry chemistry have been applied. 21,28,35,39,40,98,115,121,122 Among these, the radical grafting of synthetic acrylic acid/poly(acrylic acid) units The free swelling is given in g water/g dry polymer, unless otherwise specified. onto protein macromolecules has been investigated as one possible route.…”

“…30 min under vacuum. It has been reported that the chemical reactions give rise to a change in the net charged groups of the proteins by the inclusion of −COOH groups and that this increases the free swelling capacity, 121,122 but a comparisons of these results with those of synthetic SAPs is not possible since the free swelling capacity in these studies was not determined by applying the tea-bag method, following the Edana NWSP 240.0 standard. Synthetic acetate groups have been grafted onto proteins to increase their water-swelling properties.…”

“…A range of different experimental routes have been evaluated to modify the water affinity/absorption properties of protein-based materials. ,,,, Chemical functionalization of protein materials is widely described, and both wet and dry chemistry have been applied. ,,,,,,,, Among these, the radical grafting of synthetic acrylic acid/poly­(acrylic acid) units onto protein macromolecules has been investigated as one possible route. ,,,,,, To modify the absorbent capacity kinetics in the materials and to strengthen the gel structures, the cross-linking type and density have been varied with both treated and nontreated protein-based materials. ,− ,,,,, Single or combinations of several of the described routes have resulted in semi-interpenetrated networks (IPN) or the establishment of biobased composites with considerable water-swelling properties. ,− For the chemical functionalization, the hydroxyl (−OH) and amine (−NH 2 ) groups within the proteins are used for the inclusion of acyl groups (−COR) in the protein through acylation with anhydride reagents. ,,− ,,,,,,,− The inclusion of the acyl groups in the protein contribute to the formation of an ester/amide bond and a pendant carboxylic acid moiety, as illustrated in Figure .…”

Protein Characteristics that Affect the Quality of Vital Wheat Gluten to be Used in Baking: A Review

“…According to Ewart (), gliadins have more proline, glutamine (+ glutamic acid), isoleucine, and phenylalanine, although glutenins have more glycine, lysine, and tryptophan than gliadins. Nevertheless, there are major chemical and physical differences between gliadins and glutenins, which have important effects on their functional characteristics (Osborne ; Callejo and others ; Delcour and others ; Robertson and others ; Majzoobi and Adebi ). These protein groups are responsible for the gluten network development that provides the structure of bakery products, due its viscoelastic characteristics (Shewry and Tatham ; Shewry and Halford ; van der Borght and others ; Xu and others ; Wieser ; Koehler and others ; Delcour and others ; Melnyk and others ; McCann and Day ; Khatkar and others ; Singh and Singh ; Majzoobi and Adebi ; Tuhumury and others ).…”