Structuring Diluted Wheat Matrices: Impact of Heat-Moisture Treatment on Protein Aggregation and Viscoelasticity of Hydrated Composite Flours

Impact of pre-meal immersion on multi-scale structural changes and starch digestibility of cooked dried noodles

Pre-meal immersion is a common process for both the consumption of dried noodles and development of takeaway noodles, but its impact on the structure and digestibility of dried noodles is still unclear. In this study, dried noodles cooked for the optimal time were immersed at 80 °C for different time durations. Multi-scale structural changes, including texture, molecular structure, microstructure, and in vitro starch digestibility were studied using a combination of kinetic (first-order exponential decay function, the Peleg model, and LOS plots), physicochemical, and microscopic analysis. The relationship between multi-scale structural changes and starch digestibility was derived. As the immersion progressed, the hardness first rapidly decayed and then reached equilibrium. The decay rate in the initial stage depended on the gluten content. In most cases, the immersion process caused depolymerization of gluten proteins and further gelatinization of starch granules, which was observed from an increase in the free -SH content and decrease in the short-range ordered structure, although there were fluctuations over immersion time. Structural changes resulted in the corresponding changes in substance migration. However, a high gluten content (∼15% w/w) imparted a denser microstructure to the noodles, weakening the deterioration effects compared with a low gluten content (∼10% w/w). In vitro digestion experiments proved that samples with higher gluten content had higher starch digestion rates and lower starch digestion extent during immersion. Correlation analysis revealed that there was a negative correlation between k1 and the tightness of the gel. This study helps to reveal the structural mechanisms of starch digestibility in cooked noodles during immersion.

Inherent molecular characteristics and effect of garlic polysaccharides on dough micro- and mesoscopic properties

Directional control of the process of doughs with nutrition fortification is challenging. Thus, this study aimed to develop non-starch polysaccharides that can modify the quality of flour products. Polysaccharides were extracted from three different garlic cultivars, evaluated for physicochemical properties and used to enrich doughs for microstructure and mesoscopic characteristics analysis. We assessed the moisture distribution, texture characteristics, thermodynamic properties, dynamic viscoelastic properties, protein structure, microstructure and molecular interaction of the doughs and demonstrated a relatively high molecular weight, lower steric hindrance of molecular chains and higher cross-linking ability with the dough network in the supernatant polysaccharide from Yunnan single-clove-garlic (SGSOS) fraction. These features of SGSOS fraction improved the rheological, thermodynamic, texture characteristics, and water distribution of doughs. These findings provide information on the use of garlic polysaccharides during the processing and manufacturing of foods to enhance their processing adaptability and qualities.

The effect of microwave stabilization on the properties of whole wheat flour and its further interpretation by molecular docking

In order to stabilize the whole wheat flour and extend its shelf life, microwave was employed to heat the wheat bran to inactivate the lipase in this paper. The effects of microwave heating of wheat bran on the lipase activities, gluten properties, dough properties and storage stability of the stabilized whole wheat flour, and the quality of steamed bread made of stabilized whole wheat flour were investigated. Furthermore, molecular docking was applied to interpret the mechanism. The results showed that microwave can reduce lipase activity, maintain the quality of whole wheat flour dough and steamed bread, and retard rancidity. The molecular docking results displayed that the conformation of the amino acids chains near the lipase catalytic center changed, which made the substrate difficult to enter the catalytic center and prevented the hydrolysis of the fat substrate.

Recent advances in heat-moisture modified cereal starch: Structure, functionality and its applications in starchy food systems

Cereals, one of the starch sources, have a tremendous and steady production worldwide. Starchy foods constitute the major part of daily calorie intake for humans. As a simple and green modification approach, heat-moisture treatment (HMT) could change the granular surface characteristics and size, crystalline and helical structure, as well as molecular organization of cereal starch. The changing degree is contingent on HMT parameters and botanical origin. Based on the hierarchical structure, this paper reviews functionalities of heat-moisture modified cereal starch (HMCS) reported in latest years. The functionality of HMCS could be affected by co-existing non-starch ingredients through non-covalent/covalent interactions, depolymerization or simply attachment/encapsulation. Besides, it summarizes the modulation of HMCS in dough rheology and final food products' quality. Selecting proper HMT conditions is crucial for achieving nutritious products with desirable sensory and storage quality. This review gives a systematic understanding about HMCS for the better utilization in food industry.