Gluten Gel and Film Properties in the Presence of Cysteine and Sodium Alginate

Abstract

Wheat flour has an ability of forming dough by mixing with water, which exhibits a rheological property required for making bread. The major protein is gluten, which is a valuable protein material for food industry. In this study, gluten protein gels and films were formed with cysteine and sodium alginate. Adding cysteine improved gel and film properties (stress relaxation behavior, bending strength). The gel containing 0.01 M cysteine had a longer relaxation time and was more rigid than the gel without cysteine. Although adding sodium alginate to the gluten suspension containing cysteine improved the water-holding ability and homogeneity of the gel network, the film from this gel was more brittle than the gluten film with cysteine alone. Microstructural observations of the gels and films with scanning electron microscopy suggested that water evaporation was more heterogeneous from the gel containing sodium alginate than from the gel with cysteine alone. Fourier transform-infrared (FT-IR) analysis during film formation suggested that the presence of cysteine encourages interaction between gluten molecules and results in intermolecular beta-sheet formation in earlier stages than in the no additive condition. FT-IR results also suggested that the combined effect of sodium alginate and cysteine on the protein secondary structure was remarkably different from that of cysteine alone. Our results suggest that addition of a suitable amount of cysteine (0.01 M) and heat treatment to 80 degrees C during gluten gel and film formation induces a homogenous network in the gel and film by regulating disulfide-sulfide interactions.

Impact of Sodium Alginate and Xanthan Gum on the Quality of Steamed Bread Made from Frozen Dough

“…Incorporating NaCl shielded the proteins by neutralizing the positive charge. These results were most probably caused by the interactions of sodium alginate with gluten proteins (Yuno-Ohta et al 2009), as well as the increased viscosity of the dough (Upadhyay et al 2012). The decreasing of specific volume by the addition of sodium alginate was consistent with another study reporting reduced specific volumes of baked bread made from frozen dough at a concentration of 0.05-0.075% sodium alginate (Selomulyo 2007).…”

Effect of cysteine on structural, rheological properties and solubility of wheat gluten by enzymatic hydrolysis

“…Hence, the analogous hydrophilic groups are capable of binding water through hydrogen bond formation. Cysteine acts as a reducing agent promoting intra‐ and/or intermolecular sulfydryl/disulphide interchange reactions (Yuno‐Ohta et al. , 2009).…”

“…Hence, the analogous hydrophilic groups are capable of binding water through hydrogen bond formation. Cysteine acts as a reducing agent promoting intra-and ⁄ or intermolecular sulfydryl ⁄ disulphide interchange reactions (Yuno-Ohta et al, 2009). Consequently, the hidden polar groups in polypeptide chains were exposed to the gluten protein network surface, which makes it more attractive to the hydrogen bond in water.…”

“…, 2007). Yuno‐Ohta et al. (2009) reported that adding cysteine improves the gluten gel properties in the aspects of stress relaxation behaviour, bending strength and water‐holding ability through regulating disulphide–sulphide interactions.…”

“…These reducing agents enhanced the solubilisation of wheat proteins (Kim & Bushuk, 1995) and inhibited glutenin polymer formation (Schurer et al, 2007). Yuno-Ohta et al (2009) reported that adding cysteine improves the gluten gel properties in the aspects of stress relaxation behaviour, bending strength and water-holding ability through regulating disulphide-sulphide interactions. The cysteine supplementation resulted in gluten dough weakening, with increase in adhesiveness, extensibility and machinability; decrease in the elastic and viscous properties (Frater et al, 1960;Koh et al, 2005;Angioloni & Rosa, 2007) because of the destruction ⁄ reduction in intermolecular disulphide bonds (Tilley et al, 2001).…”