Effect of egg yolk lipids on structure and properties of wheat starch in steamed bread

Effects of acidification by traditional Jiaozi starter and neutralization with alkali (Na2CO3) on whole wheat dough properties

BACKGROUND

Whole wheat steamed bread has been recommended for its potential nutritional benefits to human health. Given the positive role of both organic acid and alkali in improving dough development and product quality, the present study investigated the effects of neutralization by addition of alkali (Na2CO3) after dough acidification with traditional Jiaozi starter on the properties of whole wheat dough.

RESULTS

The population of yeast and lactic acid bacteria and the acidification level of the dough increased significantly after fermentation with Jiaozi. Incorporation of alkali greatly improved the leavening capacity of the remixed dough and the quality of steamed bread. Jiaozi fermentation and alkali addition changed the water distribution patterns (T2) and affected the secondary structures of gluten protein, starch crystallinity and pasting properties. The storage modulus (G') of the dough increased significantly with the alkali addition, which could be attributed to the promoted cross-linking of the gluten structure and the altered hydration state of the macromolecules.

CONCLUSION

The results of the present study indicate that a combination of Jiaozi fermentation and alkali addition could improve the technological properties of whole wheat dough and the quality of steamed bread. The results will help us to further explore the potential application of moderate acidification and alkali addition in the production of leavened whole wheat products. © 2024 Society of Chemical Industry.

New insights into starch, lipid, and protein interactions - Colon microbiota fermentation

Starch, lipids, and proteins are essential biological macromolecules that play a crucial role in providing energy and nutrition to our bodies. Interactions between these macromolecules have been shown to impact starch digestibility. Understanding and controlling starch digestibility is a key area of research. Investigating the mechanisms behind the interactions of these three components and their influence on starch digestibility is of significant practical importance. Moreover, these interactions can result in the formation of resistant starch, which can be fermented by gut microbiota in the colon, leading to various health benefits. While current research has predominantly focused on the digestive properties of starch in the small intestine, there is a notable gap in understanding the colonic microbial fermentation phase of resistant starch. The benefits of fermentation of resistant starch in the colon may outweigh its glucose-lowering effect in the small intestine. Thus, it is crucial to study the fermentation behavior of resistant starch in the colon. This paper investigates the impact of interactions among starch, lipids, and proteins on starch digestion, with a specific focus on the fermentation phase of indigestible carbohydrates in the colon. Furthermore, valuable insights are offered for guiding future research endeavors.

Characterizing the Internal Structure of Chinese Steamed Bread during Storage for Quality Evaluation Using X-ray Computer Tomography

Chinese steamed bread (CSB) is a traditional food of the Chinese nation, and the preservation of its quality and freshness during storage is very important for its industrial production. Therefore, it is necessary to study the storage characteristics of CSB. Non-destructive CT technology was utilized to characterize and visualize the microstructure of CSB during storage, and also to further study of quality changes. Two-dimensional and three-dimensional images of CSBs were obtained through X-ray scanning and 3D reconstruction. Morphological parameters of the microstructure of CSBs were acquired based on CT image using image processing methods. Additionally, commonly used physicochemical indexes (hardness, flexibility, moisture content) for the quality evaluation of CSBs were analyzed. Moreover, a correlation analysis was conducted based on the three-dimensional morphological parameters and physicochemical indexes of CSBs. The results showed that three-dimensional morphological parameters of CSBs were negatively correlated with moisture content (Pearson correlation coefficient range-0.86~-0.97) and positively correlated with hardness (Pearson correlation coefficient range-0.87~0.99). The results indicate the inspiring capability of CT in the storage quality evaluation of CSB, providing a potential analytical method for the detection of quality and freshness in the industrial production of CSB.

Effects of egg powder on the structure of highland barley dough and the quality of highland barley bread

The influences of egg white (EW), egg yolk (EY) and whole egg (WE) on the structure of highland barley dough and the quality of highland barley bread were explored. The results showed that egg powder reduced G' and G" of highland barley dough, which led to the softer texture of dough and endowed bread with a larger specific volume. EW increased the percentage of β-sheet of highland barley dough, EY and WE promoted the transformation from random coil to β-sheet and α-helix. Meanwhile, more disulfide bonds were formed from free sulfhydryl groups in the doughs with EY and WE. These properties of highland barley dough could help highland barley bread develop a preferable appearance and textural feature. It is worth noting that highland barley bread containing EY has more flavorful substances and a better crumb structure, which were similar to that of whole wheat bread. The highland barley bread with EY received a high score according to the sensory evaluation in consumer acceptance.

Evidence for amylose inclusion complexes with multiple acyl chain lipids using solid-state NMR and theoretical approaches

Amylose is known to form inclusion complexes in the presence of hydrophobic guests. Among lipids, only single-chain fatty acids have been reported as possible guests with the surrounding amylose in a well-defined V-helix conformation. Using experimental ¹³C solid-state NMR, we studied the formation of inclusion complexes between amylose and a variety of multiple-chains lipids of increasing complexity. Molecular dynamics simulations and calculations of ¹³C isotropic chemical shifts using the Density Functional Theory approach were performed to support the interpretation of experimental spectra. We provide unambiguous evidences that amylose forms inclusion complexes with lipids bearing multiple acyl chains. Amylose conformations around these lipids are characterized by {ϕ,ψ} anomeric bond dihedral angles near {115°,105°}. In the ¹³C NMR spectra, this translates into C₁ and C₄ chemical shifts of 102.5 ppm and 81.1 ppm, regardless of the helical conformation of the amylose surrounding the acyl chains.

Complexation of 26-Mer Amylose with Egg Yolk Lipids with Different Numbers of Tails Using a Molecular Dynamics Simulation

A molecular dynamics simulation of mixtures of 26-mer amylose with three different egg yolk lipids, namely, cholesterol, triglyceride and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), demonstrated the formation of a stable complex. The 26-mer amylose fluctuated between a coiled and an extended helical conformation. The complex was a V-type amylose complex, with the hydrophobic tail of the lipids being inside the hydrophobic helical cavity of the amylose. The number of glucose units per turn was six for the two helical regions of the amylose-POPC complex and the palmitoyl tail region of the amylose-triglyceride complex. This value was eight for the cholesterol and the two-tail helical region in the amylose-triglyceride complex. Two tails of the POPC were in two different hydrophobic helical regions of the 26-mer amylose, whereas the palmitoyl tail of the triglyceride lay in one hydrophobic helical region and the linoleoyl and oleoyl tails both lay in another helical region, and the cross-sectional area of the latter was larger than the former to accommodate the two tails. The radii of the gyration of the complex were lower for all three cases compared to that of one single amylose. In addition, the stability of the complexes was ranked in the following order: POPC < cholesterol < triglyceride, with their average binding energy being −97.83, −134.09, and −198.35 kJ/mol, respectively.

Key lipid molecules in hepatopancreas of Eriocheir sinensis: Identification and thermal oxidative degradation characteristics

The hepatopancreas of Eriocheir sinensis are the key parts that form its unique flavor. Lipids are important parts of hepatopancreas; hence, this study used UHPLC-Q E Orbitrap mass spectrometer to investigate the changes in the lipid composition of crabs formed from thermal oxidation system. The results demonstrated that key lipids in the hepatopancreas of female Chinese mitten crabs were phosphatidylethanolamine (PE) and free fatty acid (FFA) during the steaming process. The key fatty acids of PE were C18:1, C18:3, C20:3, C20:4, C20:5, and C22:6. The degradation rate of C24:0 in FFA was greater than the synthesis rate. Principal component analysis, partial least square analysis combined with hierarchical cluster analysis found that PE (16:0/20:5), PE (18:1/20:4), PE (16:0/22:6), PE (16:0/20:4), PE (16:0 /16:1), PE (16:0/18:2), PE (18:0/20:5), PE (18:0/22:6), PE (18:0/20:4), PE (16:0/18:1), PE (18:0/18:2), PE (18:0/22:5), and PE (18:0/18:1) were the key PE molecular species. Simulating thermal oxidation to understand the dynamic change mechanism of lipids is meaningful for processing of Chinese mitten crab products and catering to public sensory orientation. PRACTICAL APPLICATIONS: In this study, the UHPLC-Q E Orbitrap method was used to detect and analyze the molecular species changes of Eriocheir sinensis in the simulated thermal oxidation system, and systematically analyzed the law of changes. Based on these results, we can expand our understanding of the changing characteristics of the hepatopancreas and pancreas of the river crab and provide a direction for the formation mechanism of the aroma substances of E. sinensis during the heat treatment and the improvement of the quality of its products.