Effect of tea polyphenols on the quality of Chinese steamed bun and the action mechanism

Abstract

Effect of tea polyphenols (TP) on the quality of Chinese steamed bun (CSB) was investigated, while the interaction and action mechanism between TP and vital wheat gluten (VWG, constitutive proteins of flour) were further explored. With a low concentration (1%) of TP, CSB showed positive changes in quality, and the hardness of CSB decreased by 33.95%, while its specific volume, springiness, and resilience separately increased by 1.8%, 11.9%, and 5.5%, whereas the higher concentrations of TP (2% and 4%) caused an adverse impact. By observation of scanning electron microscope, VWG formed a fluffier structure with a low concentration of TP, while the structure deteriorated at high concentration of TP. In addition, the secondary and tertiary structures of VWG were both changed by TP. Along with the results of thermodynamic analysis (thermogravimetric and differential scanning calorimetry measurements), TP could induce the structural rearrangement of VWG. Further, a lower amidogen and sulfhydryl contents of VWG were obtained in TP groups, which illustrated that peptide and disulfide bonds of VWG were not possibly interrupted by TP. Instead, hydrophobic residues of VWG were bonded to form a more hydrophilic structure. Moreover, according to molecular docking results, epigallocatechin‐3‐gallate interacted tightly with VWG by hydrogen bonds and hydrophobic actions, and the action sites were mainly at hydrophobic and hydrophilic residues. All results suggested that the VWG structure was affected greatly by TP, and a low dose of TP might be potential to improve the quality of flour products. Practical Application The physicochemical properties of gluten show the significant effects on the quality of flour products in food industry. In the present study, a low dose of tea polyphenols exhibited a strengthened effect on gluten, so as to ameliorate the texture of Chinese steamed bun (CSB) due to their tight interactions with gluten, while the color of CSB was changed to brown as tea polyphenols. All results suggested that a low dose of tea polyphenols could be potentially utilized to improve flour quality and enhance gluten strength in food industry.

Insight into property, function, and digestion of potato starch modified by phenolic compounds with varying structures

“…So, phenolic hydroxyl groups are more likely to interact with starch molecules to form more hydrogen bonds. In addition, some related studies suggest that the amount and site of hydroxyl groups, molecular weight, esterification degree, and glycoside type of phenolic compounds affect their combining affinity with starch molecules (Chen et al., 2021; Xie & Chen, 2013; Zou et al., 2014). Moreover, the molecular polarity and steric hindrance of phenolic compounds also affect their dispersion in the reaction solvent (Ren et al., 2003), so as to affect their capability to combine water molecules, which contributes to their effects to affect the properties of starch and starchy foods.…”

“…The present results indicated that the high amount of hydroxyl groups, large molecular size, and presence of glycosidic structure could enhance their capability to reduce the digestion of starchy foods. In addition, some related studies also report that phenolic compounds may not only reduce the postprandial GI of starchy foods but also can bring some other benefits to human health (Amoako & Awika, 2016; Chen et al., 2021).…”

“…The different structural characteristics of phenolic compounds have varying influences on their functions and reactivity (Horton et al., 2019; López‐Solís et al., 2020). It has been reported that four catechins show different capabilities to improve bread quality due to their differences about hydroxyl groups’ amount and esterification degree (Chen et al., 2021). Besides these structural parameters, other structural characteristics, such as the site of hydroxyl groups, glycoside structure, molecular size, and steric hindrance, may also affect their interactions with starch molecules (Hotsumi et al., 2019).…”