Quality characteristics of northern-style Chinese steamed bread prepared from soft red winter wheat flours with waxy wheat flour substitution

Rheological, textural, and pasting properties of A- and B-type wheat starches in relation to their molecular structures

A- and B-type wheat starches have significant differences in rheological, textural, and pasting properties; however, the structure-property relationship is not fully revealed. Herein, the physicochemical characteristics and molecular structures of A- and B-type starches isolated from three wheat varieties with different apparent amylose contents (2.41%-27.93%) were investigated. A-type starches exhibited higher pasting viscosities, relative crystallinity, onset gelatinization temperatures, and enthalpies, while B-type starches had wide gelatinization temperature ranges. B-type starches had lower resistant starch contents than their A-type counterparts, but B-type starches formed more stable gels and had a lower tendency to retrograde, resulting in lower hardness, storage (G') and loss (G'') moduli but higher tan δ values. A-type starches had lower contents of short amylose (100 ≤ X < 1000) and amylopectin chains (DP 6-12) than B-type. These findings elucidated the differences in molecular structures between A- and B-type starches, which can contribute to their effective application.

Empirical and Theoretical Bases of Good Steamed Bread Production

Chinese steamed bread (CSB) is a main staple food in China, accounting for 40% of wheat flour usage in China. Due to its health benefits, CSB is gaining popularity across the world. In this review, the effects of gluten proteins (particularly glutenins and gliadins) on the quality of CSB are summarized from the literature. Requirements of appropriate rheological parameters in different studies are compared and discussed. Along with the increasing demand for frozen storage food, there are obvious increases in the research on the dynamics of gluten proteins in frozen dough. This review also summarizes the factors influencing the deterioration of CSB dough quality during frozen storage as well as effective measures to mitigate the negative effects.

Study of Noodle Quality Based on Protein Properties of Three Wheat Varieties

Waxy wheat offers unique benefits in food processing, including improving the smoothness and performance of the product. However, waxy wheat is not yet commercially available. The protein characteristics, including the protein content, subunit distribution, secondary structure, chemical interactions, and microstructure of the gluten, were explored to realize the full potential of waxy wheat. The results showed that the noodles prepared from waxy wheat had a gentle and glutinous texture compared with GY2018 and YM13. Partial-waxy and waxy wheat had a lower gluten index and glutenin macropolymer (GMP) content than GY2018, indicating a reduced gluten strength. Confocal laser scanning microscopy (CLSM) images showed that the starch granules were not securely attached to the partial-waxy and waxy wheat protein matrix. In addition, the waxy protein chains appeared more elongated and they weakened the protein network. In particular, HMW-GS subunit 2 + 12 may be the essential cause of the weak dough from SKN1. Compared with GY2018 and YM13, SKN1 had the highest number of free sulfhydryl groups. Rather than ionic bonds, hydrophobic interactions increased the gluten network in GY2018, YM13, and SKN1. The weak molecular forces in the gluten will result in a soft noodle texture.

Influence of Waxy (High Amylopectin) and High Protein Digestibility Traits in Sorghum on Injera Sourdough-Type Flatbread Sensory Characteristics

Injera, an East African leavened sourdough fermented pancake has remarkable textural properties despite being made from non-wheat flours. However, teff flour, which produces the best quality injera, is expensive and limited in availability. The effects of waxy (high amylopectin) and high protein digestibility (HD) traits in sorghum on injera quality were studied. Eight white tan-plant sorghum lines expressing these traits in various combinations and three normal sorghum types were studied, with teff flour as reference. Descriptive sensory profiling of fresh and stored injera revealed that injera from waxy sorghums were softer, spongier, more flexible and rollable compared to injera from normal sorghum and much closer in these important textural attributes to teff injera. Instrumental texture analysis of injera similarly showed that waxy sorghum injera had lower stress and higher strain than injera from normal sorghum. The improved injera textural quality was probably due to the slower retrogradation and better water-holding of amylopectin starch. The HD trait, however, did not clearly affect injera quality, probably because the lines had only moderately higher protein digestibility. In conclusion, waxy sorghum flour has considerable potential for the production of gluten-free sourdough fermented flatbread-type products with good textural functionality.

Effect of β-endoxylanase and α-arabinofuranosidase enzymatic hydrolysis on nutritional and technological properties of wheat brans

Wheat bran (WB) was treated using xylanase and arabinofuranosidase from Thermotoga maritima and added to steamed breads on 15% flour weight basis. The antioxidant capacity and water and oil retention capacity of brans were increased while their soluble xylooligosaccharides and phenolic acids content were increased. Two enzymes treatment was found to be more effective in decreasing the resistance to extension, softening degree, water absorption and development time, and in increasing the extensibility, stability time, porosity and sensorial characteristics of the steamed breads. Two enzymes treatment had significantly (P < 0.05) greater specific volume, springiness and cohesiveness and lower crumb firmness, gumminess, chewiness than single enzyme treatment. All results highlighted that combination of xylanase and arabinofuranosidase can improve the degrees hydrolysis of WB and its soluble AX xylooligosaccharides produced, having a synergetic effect on the dough rheology and nutritional and quality characteristics of steamed bread.