Main content area

Role of Gluten in Surface Chemistry: Nanometallic Bioconjugation of Hard, Medium, and Soft Wheat Protein

Mandial, Divya, Khullar, Poonam, Gupta, Vikas, Kumar, Harsh, Singh, Narpinder, Ahluwalia, Gurinder Kaur, Bakshi, Mandeep Singh
Journal of agricultural and food chemistry 2019 v.67 no.28 pp. 7886-7897
Gram-positive bacteria, X-ray photoelectron spectroscopy, adsorption, antimicrobial properties, cetyltrimethylammonium bromide, chemical bonding, food industry, gluten, molecular weight, nanogold, polyacrylamide gel electrophoresis, solubilization, wheat protein
Hard, medium, and soft wheat proteins, based on gluten content, were studied for their important roles in nanometallic surface chemistry. In situ synthesis of Au nanoparticles (NPs) was followed to determine the surface adsorption behavior of wheat protein based on the gluten contents. A greater amount of gluten contents facilitated the nucleation to produce Au NPs. X-ray photoelectron spectroscopy (XPS) surface analysis clearly showed the surface adsorption of protein on nanometallic surfaces which was almost equally prevalent for the hard, medium, and soft wheat proteins. Wheat protein conjugated NPs were highly susceptible to phase transfer from aqueous to organic phase that was entirely related to the amount of gluten contents. The presence of higher gluten content in hard wheat protein readily enabled the hard wheat protein conjugated NPs to move across the aqueous–organic interface followed by medium and soft wheat protein conjugated NPs. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS page) analysis allowed us to determine molar masses of nanometallic surface adsorbed protein fractions. Only two protein fractions of high molar masses (74 and 85 kDa) from SDS solubilized hard, medium, and soft wheat proteins preferred to adsorb on nanometallic surfaces out of more than 15 protein fractions of pure wheat protein. This made the surface adsorption of wheat protein highly selective and closely related to gluten content. Cetyltrimethylammonium bromide (CTAB) solubilized wheat protein conjugated NPs demonstrated their strong antimicrobial activities against both Gram negative and Gram positive bacteria making them suitable for their applications in food industry.