Dietary Fiber-Induced Changes in the Structure and Thermal Properties of Gluten Proteins Studied by Fourier Transform-Raman Spectroscopy and Thermogravimetry

Abstract

Interactions between gluten proteins and dietary fiber supplements at the stage of bread dough formation are crucial in the baking industry. The dietary fiber additives are regarded as a source of polysaccharides and antioxidants, which have positive effects on human health. The fiber enrichment of bread causes a significant reduction in its quality, which is connected with changes in the structure of gluten proteins. Changes in the structure of gluten proteins and their thermal properties induced by seven commercial dietary fibers (fruit, vegetable, and cereal) were studied by FT-Raman spectroscopy and thermogravimetry (TGA), respectively. For this aim the bread dough at 500 FU consistency was made of a blend of wheat starch and wheat gluten as well as the fiber, the content of which ranged from 3 to 18% w/w. The obtained results revealed that all dietary fibers apart from oat caused similar changes in the secondary structure of gluten proteins. The most noticeable changes were observed in the regions connected with hydrogen-bonded β-sheets (1614 and 1684 cm(-1)) and β-turns (1640 and 1657 cm(-1)). Other changes observed in the gluten structure, concerning other β-structures, conformation of disulfide bridges, and aromatic amino acid microenvironment, depend on the fibers' chemical composition. The results concerning structural changes suggested that the observed formation of hydrogen bonds in the β-structures can be connected with aggregation or abnormal folding. This hypothesis was confirmed by thermogravimetric results. Changes in weight loss indicated the formation of a more complex and strong gluten network.

Effect of barley β‐glucan on water redistribution and thermal properties of dough

“…The dough was hermetically sealed with two layers of the plastic membrane to prevent the evaporation of water and equilibrated for 30 min to make the water evenly distributed. Dough samples of approximately 15 mg were weighted into 70 μL ceramic pans, heated from 30 to 170 °C at a heating rate of 10 °C min −1 and with a nitrogen flow of 50 mL min −1 (TGA/SDTA 851e, Mettler Toledo Corp., Zurich, Switzerland) (Nawrocka et al ., ). The first derivative of TGA (DTGA) was used to integrate the different mass loss steps.…”

“…These properties can be affected by the water state and mobility (Raun et al ., ). In the complex network of dough systems, the water distribution is significantly affected by changes in the dough components (Nawrocka et al ., ). The addition of guar gum (Linlaud et al ., ), trehalose (Peng et al ., ), soy (Simmons & Vodovotz, ), and whole grain flour (Li et al ., ) cause the redistribution of water in the dough.…”

Impact of ground Ajwa (Phoenixdactylifera L.) seeds fortification on physical and nutritional properties of functional cookies and chocolate sauce

“…The interactions between gluten and dietary fiber during the dough formation are crucial. The dietary fiber fortification as a source of polysaccharides exerts positive effects on human health, despite the significant reduction in quality due to changes in the structure of gluten proteins (Nawrocka et al, 2016). Time to breakdown is shown by the drop of the farinograph curve from the 500 BU line.…”

Interactions between dietary fiber and ferulic acid change the aggregation of glutenin, gliadin and glutenin macropolymer in wheat flour system

“…Thermogravimetric analysis (TGA; TGA 8000, PerkinElmer, Shelton, CT, USA) was applied to analyze the thermal properties of proteins according to the method of Nawrocka et al 22 . The weight loss at 600 °C and degradation temperature ( T d ) were calculated using Pyris Version 11 software.…”