Physicochemical and structural properties of wheat gluten/rice starch dough-like model

Quality improvements of reconstituted noodles by pre-hydrating gluten: Insights at different levels

Reconstituted noodles containing multi-grain are superior to plain noodles in terms of health benefits, but their lower gluten levels cause deterioration in cooking performance and textural quality. To this end, this study investigated the efficacy of gluten pre-hydration in a model dough. The results indicated that, with the increase in the ratio of pre-hydrated gluten, the final hydration level of gluten in reconstituted noodles, the proportion of ordered secondary structures of gluten, and the intensities of molecular interactions continuously increased, resulting in a more compact gluten network. This made the dough more deformable, granting noodles higher cooking resistance (optimal cooking time: 230 s to 265 s) and hardness (1837 g to 2538 g). Gluten pre-hydration was more effective, convenient, and cost-efficient than existing methods in improving the quality of reconstituted noodles. However, it lowered the yield and transparency of cooked noodles and made them yellowish.

Effect of rice storage proteins on the physicochemical properties of indica rice during after-ripening

The processing quality of indica rice stabilizes after a period of post-harvest storage known as after-ripening, during which proteins play an important role according to our previous research. The present study investigated the effects of rice storage proteins (RSPs) on the physicochemical properties of after-ripening rice, employing protein analysis, rapid viscosity analyzer, hydration properties assessment, morphological analysis and fourier transform infrared spectroscopy (FTIR). The results indicated that the crude protein content remained relatively unchanged during after-ripening, while the band intensities of 13 kDa and 20 kDa protein subunits increased with increasing storage time. Removing RSPs decreased the setback viscosity, final viscosity and pasting temperature of after-ripening indica rice flour but led to an increase in its breakdown viscosity, especially by 93.45 % after storage at 36 °C for 90 d. Protein-removal also contributed to increasing the water solubility and swelling power of after-ripening indica rice flour by 31.66 % and 37.31 % for 90 d respectively. Morphological analysis revealed that RSPs had wrapped the starch granules, thus delaying the migration of water into the starch during heating. FTIR spectra indicated that the presence of RSPs enhanced the short-range ordered structure of starch. These findings will contribute to further elucidating the mechanisms underlying indica rice quality changes during storage.

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.

Comparative study on nutritional and technological properties of two varieties of black wheat flour and their noodle-making potential

Comparative studies were conducted on physicochemical and technological properties of two black wheat (BW) varieties (cultivated in Shanxi Agricultural University) and their noodle-making potential. Whole-grain BW noodles showed acceptable cooking loss (≤10%) and strong antioxidant capacity. However, their textural quality remains to be enhanced. Regarding refined flour (RF) of the two BW varieties, Yunhei 14207 showed more anthocyanins, brighter color, and greater thermal stability (as reflected by the higher pasting temperature). 16W16 resulted in greater gluten content and better gluten quality of flour and higher dough stability, which contributed to the lower cooking loss and stronger tensile property of noodles. RF noodles of Yunhei 14207 displayed brighter appearance, although they had weaker tensile property. The stronger gluten network in noodles of 16W16 protected phenolics from release and degradation during drying, cooking, and steaming. Despite phenolics loss, RF noodles of Yunhei 14207 showed antioxidant capacity up to 14.97 mg TE/100 g. This research would promote understanding of characteristics of BW varieties. Considering the stronger gluten network of 16W16, its fortification in common wheat noodles at high proportion (>50%) may be promising to develop antioxidant noodles with further improved sensory quality.

Edible coatings and films for shelf-life extension of fruit and vegetables

The execution of the edible coatings and films for food preservation; vegetables, fruits, meat, and dry fruits has been ladened in history. The study of literature portrays enough pieces of evidence dating back from centuries of coatings or films being utilized for the conservation of numerous fruits and vegetables to stretch their average shelf-life. The mechanism that remains operative in extending the shelf-life of fruits and vegetables beyond the normal shelf-life is the controlled entry and exit of moisture and gases. The non- biodegradable packaging which is also non-sustainable can be substituted with compostable and edible coatings and films made up of natural biopolymers. Therefore, keeping in mind the environment and consumer safety, a score of research has been going on from former decades for the development of edible coatings and films with efficient shelf life-extending qualities. The films composed of proteins exhibit a good mechanical strength while the polysaccharide composed films and coatings show efficient gas blocking qualities, however, both lack moisture shielding attributes. These shortcomings can be fixed by combining them with lipids and or some appropriate hydrocolloids. The edible coatings and films have been integrated with various food products; however, they haven't been completely successful in substitution of the total fraction of their non-edible counterparts. The implementation of edible coatings and films have shown to serve an immense value in extending the shelf-life of fruits and vegetables along with being a sustainable and eco-friendly approach for food packaging.

Ultrasonic Treatment of Corn Starch to Improve the Freeze-Thaw Resistance of Frozen Model Dough and Its Application in Steamed Buns

Modification of corn starch using ultrasonic waves to improve its freeze-thaw resistance in frozen model doughs and buns. Analysis was performed by rheometry, low-field-intensity nuclear magnetic resonance imaging, Fourier infrared spectroscopy, and scanning electron microscopy. The results showed that the addition of ultrasonically modified corn starch reduced the migration of water molecules inside the model dough, weakened the decrease of elastic modulus, and enhanced the creep recovery effect; the decrease in α-helical and β-fold content in the model dough was reduced, the destruction of internal network structure was decreased, the exposed starch granules were reduced, and the internal interaction of the dough was enhanced; the texture of the buns became softer and the moisture content increased. In conclusion, ultrasound as a physical modification means can significantly improve the freeze-thaw properties of corn starch, providing new ideas for the development and quality improvement of corn-starch-based instant frozen pasta products.

Optimization of freezing methods and composition of frozen rice dough reconstituted by glutinous rice starch and gluten

This study investigated the effects of four different freezing methods on the texture of rice dough reconstituted by glutinous rice starch and gluten, and the changes of properties of rice dough with different gluten ratios after liquid nitrogen (LF) treatment. The profiles of frozen rice dough were studied by texture analyzer, low-field NMR, SEM, FT-IR, DSC, CLSM, X-RD and RVA. Results revealed that with the slowing down of freezing rate, the damage of freezing process to starch granules and protein structure in frozen rice dough increases, resulting in the increase of damaged starch, the decrease of protein ordered structure, the change of bound water in frozen rice dough to free water, the decrease of frozen rice dough hardness and elasticity, the decrease of storage modulus (G') and the deterioration of frozen rice dough texture. The addition of gluten in frozen rice dough will increase the short-range ordered structure and crystal structure of starch, reduce the digestibility of starch, and change the viscosity characteristics of frozen rice dough. Based on the experimental results, adding 10 % gluten is more suitable for making frozen rice dough, while LF has the least effect on frozen rice dough texture.

Study of Physico-Chemical Properties of Dough and Wood Oven-Baked Pizza Base: The Effect of Leavening Time

The research objective was to investigate the morpho-rheological, chemical, and structural changes of dough and Neapolitan pizza TSG as the leavening time varies and to evaluate their effects on the digestibility of starch and on the formation of acrylamide during baking. Pizza dough leavening was monitored for 48 h at 22 °C/80% RH, and the analyses were conducted at selected leavening times (0, 4, 8, 16, 24, and 48 h). It was observed that in 30 h the volume tripled and the viscoelastic dough relaxed in the first 4 h, as evidenced by the lower value of the relaxation percentage “a” and the higher rate of decay “b”, associated with a high value of the compression work, indicating the presence of a very strong gluten mesh. In the following hours, the dough lost elasticity, and in fact, the G’ modulus decreased due to the weakening of the weak interactions between the gluten proteins and the starch. This suggests that a long leavening improved the extensibility of the pizza disc, facilitating the action of the pizza maker. Thermal (TGA and DSC) and morphological (SEM) analyses evidenced the highest water removal rate from the dough, a wider starch gelatinization temperature range, a ∆H of 0.975 ± 0.013 J/g, and a more open and weak gluten structure in dough balls leavened for 16 h. As the leavening time increased, both dough and pizza base samples showed an increase in reducing sugars and free amino groups, while the rapidly digestible starch decreased in the dough following the metabolism of the yeasts and increased in the pizza base due to the starch gelatinization that occurs during baking, which makes it much more susceptible to α-amylase. Finally, the levels of acrylamide remained at the same values despite the higher availability of reducing sugars and its precursors during leavening.

Application of inulin in bread: A review of technological properties and factors affecting its stability

Due to its dual function, inulin is an important prebiotic compound in the cereal industry, especially in bread production. In other words, improving technological features and creating health properties (such as reducing the risk of type 2 diabetes, heart disease, metabolic syndrome, and osteoporosis) have led to the widespread use of this compound. Inulin has many important technological functions in bread, including its ability to interact with water, create structure, and influence rheological properties, texture, and overall acceptability of the final product. Nevertheless, bread processing conditions can influence the structural integrity of inulin and thus affect its technological efficiency. Therefore, this review article aims to investigate the technological properties and factors affecting the stability of inulin during bread processing conditions. Generally, the addition of inulin could considerably improve the technical performance of bread. However, the stability of inulin depends on the formulation components, type of fermentation, and baking process.

Wheat Glu-A1a encoded 1Ax1 subunit enhances gluten physicochemical properties and molecular structures that confer superior breadmaking quality

Wheat gluten proteins serve as the largest protein molecules in nature and play key roles in breadmaking quality formation. In this study, we used a pair of Glu-A1 allelic variation lines to perform a comprehensive investigation on the effects of Glu-A1a encoded 1Ax1 subunit on gluten physicochemical properties, molecular structures and breadmaking quality. The results showed that the presence of the 1Ax1 subunit significantly increased gluten content, leading to marked improvement of dough rheological properties. Meanwhile, gluten physicochemical properties such as foaming ability and foaming stability, oil/water-holding capacity, emulsifying activity, disulfide bond content, and gluten degradation temperature were significantly improved. A confocal laser scanning microscope analysis revealed that the 1Ax1 subunit drastically enhanced gluten microstructure. Gluten secondary structure analysis by Fourier transform infrared spectroscopy and laser scanning microscope-Raman spectroscopy indicated that 1Ax1 subunit significantly promoted β-turn and β-sheet content and reduced α-helix content. Three-dimensional structure analysis by AlphaFold2 revealed a similar structural feature of 1Ax1 with the superior quality subunit 1Ax2*. Correlation and principal component analyses demonstrated that α-helix and β-sheet content had a significant correlation with dough rheological properties, gluten physicochemical properties and breadmaking quality. Our results showed that 1Ax1 subunit positively affected gluten molecular structure and quality formation.

Characterization and Preliminary Application of a Novel Lipoxygenase from Enterovibrio norvegicus

Lipoxygenases have proven to be a potential biocatalyst for various industrial applications. However, low catalytic activity, low thermostability, and narrow range of pH stability largely limit its application. Here, a lipoxygenase (LOX) gene from Enterovibrio norvegicus DSM 15893 (EnLOX) was cloned and expressed in Escherichia coli BL21 (DE3). EnLOX showed the catalytic activity of 40.34 U mg-1 at 50 °C, pH 8.0. Notably, the enzyme showed superior thermostability, and wide pH range stability. EnLOX remained above 50% of its initial activity after heat treatment below 50 °C for 6 h, and its melting point temperature reached 78.7 °C. More than 70% of its activity was maintained after incubation at pH 5.0-9.5 and 4 °C for 10 h. In addition, EnLOX exhibited high substrate specificity towards linoleic acid, and its kinetic parameters of Vmax, Km, and Kcat values were 12.42 mmol min-1 mg-1, 3.49 μmol L-1, and 16.86 s-1, respectively. LC-MS/MS analysis indicated that EnLOX can be classified as 13-LOX, due to its ability to catalyze C18 polyunsaturated fatty acid to form 13-hydroxy fatty acid. Additionally, EnLOX could improve the farinograph characteristics and rheological properties of wheat dough. These results reveal the potential applications of EnLOX in the food industry.