Gliadin and glutenin genomes and their effects on the technological aspect of wheat-based products.

Wheat is the most important crops worldwide, providing about one-fifth of the daily protein and calories for human consumption. The quality of cereal-based products is principally governed by the genetic basis of gluten (glutenin and gliadin proteins), which exists in a wide range of variable alleles and is controlled by clusters of genes. There are certain limitations associated with gluten characteristics, which can be genetically manipulated. The present review aimed to investigate the correlation between the genetic characteristics of gluten protein components and wheat-based product's quality. According to various references, Glu-B1d (6 + 8), Glu-B1h (14 + 15) and Glu-B1b (7 + 8) are related to higher gluten strength and pasta quality, while, subunits Dx2 + Dy12 and Dx5 + Dy10, are usually present at the Glu-D1 locus in bread wheat, resulted in lower cooked firmness in pasta. Moreover, introducing Gli-D1/Glu-D3 and Glu-D1 loci into durum wheat genomes, causing to provide the maximum values of gluten index in pasta products. 1Dx5 + 1Dy10 alleles determine the level of increase in dough's consistency, elasticity, viscosity, and extensibility quality of baking and appropriate bread loaf volume, while 1Dx2 + 1Dy12 as the alleles associated with poor baking quality, being more suitable for soft wheat/pastry end uses. Bx7, Bx7OE, 1Bx17 + 1By18, 1Bx13 + 1By16, Bx7 + By9 and 1Bx7 + 1By8 at Glu-B1alleles and 1Ax2* found on Glu-A1, augmented dough strength and has positive effects on consistency, extensibility, viscosity, and elasticity of bread dough. Breeding programs by genome editing have made gluten a promoting component for improving cereal-based products.

A kinetic analysis of the aflatoxin detoxification potential of lactic acid bacteria in Terxine (a cereal-based food).

Aflatoxin B1 (AFB1) is a hazardous component that can seriously threaten the public health. Terxine is a component used in traditional soup and found in the western mountainous regions of Iran. Several microorganisms have been reported to bind or degrade aflatoxins (AFs) in foods and feeds. This research aimed to investigate the effect of Terxine fermentation by Lactobacillus plantarum strains AF1 and LU5 on AFB1. Fermentation was carried out, and pH, lactic acid and AFB1 amount and microbial count were further determined. In addition, the kinetic experimental data of AFB1 by L. plantarum AF1 and LU5 (obtained at 37°C) were fitted to the zero-order, first-order and parabolic diffusion models. According to the coefficient of determination (R2) and root mean square of errors (RMSE), the zero-order model best described AF degradation. The growth of Lactobacillus strains was increased by the rise in the fermentation time; in this regard, the number of L. plantarum AF1 increased from 4.2 to 5.1 log cfu/g and that of L. plantarum LU5 increased from 4.1 to 5.2 log cfu/g in the first 8 h, reaching 7.2 and 7.4 log cfu/g in the next 8 h, respectively. The results also showed that the amount of lactic acid increased whereas the pH value decreased during the 24 h fermentation. Both microorganisms reduced the amount of AFB1 while L. plantarum AF1 was more effective. Therefore, L. plantarum strains AF1 and LU5 can be effectively used to reduce AFB1 in fermented foods.

Hydrolytic enzymes and their directly and indirectly effects on gluten and dough properties: An extensive review.

Poor water solubility, emulsifying, and foaming properties of gluten protein have limited its applications. Gluten is structured by covalent (disulfide bonds) and noncovalent bonds (hydrogen bonds, ionic bonds, hydrophobic bonds) which prone to alteration by various treatments. Enzyme modification has the ability to alter certain properties of gluten and compensate the deficiencies in gluten network. By hydrolyzing mechanisms and softening effects, hydrolytic enzymes affect gluten directly and indirectly and improve dough quality. The present review investigates the effects of some hydrolytic enzymes (protease and peptidase, alcalase, xylanase, pentosanase, and cellulase) on the rheological, functional, conformational, and nutritional features of gluten and dough. Overall, protease, peptidase, and alcalase directly affect peptide bonds in gluten. In contrast, arabinoxylan, pentosan, and cellulose are affected, respectively, by xylanase, pentosanase, and cellulase which indirectly affect gluten proteins. The changes in gluten structure by enzyme treatment allow gluten for being used in variety of purposes in the food and nonfood industry.

Enzymatic modifications of gluten protein: Oxidative enzymes.

Oxidative enzymes treat weak flours in order to restore the gluten network of damaged wheat flour and reduce the economic and technological losses. The present review concentrates on oxidative exogenous enzymes (transglutaminase, laccase, glucose oxidase, hexose oxidase) and oxidative endogenous enzymes (tyrosinase, peroxidase, catalase, sulfhydryl oxidase, lipoxygenase, lipase, protein disulfide isomerase, NAD(P)H-dependent dehydrogenase, thioredoxin reductase and glutathione reductase) and their effects on the rheological, functional, and conformational features of gluten and its subunits. Overall, transglutaminase is used in wheat-based foods through introducing isopeptide bonds (ε-γ glutamyl-lysine). Glucose oxidase, hexose oxidase, peroxidase, sulfhydryl oxidase, lipase, and lipoxygenase form disulfide and nondisulfide bonds through producing hydrogen peroxide. Laccase, tyrosinase, and protein disulfide isomerase form cross-links between tyrosine and cysteine residues by generating radicals. Thioredoxin reductase and glutathione reductase create new inter disulfide bonds. The effect of oxidative enzymes on the formation of covalent cross-linkages were substantially more than non-covalent bonds in gluten structure.

The effect of redox agents on conformation and structure characterization of gluten protein: An extensive review.

Gluten protein as one of the plant resources is affected by redox agent. Chemical modifications by redox agent have myriad advantages mainly short reaction times, no requirement for specialized equipment, low cost, and highly clear modification impacts. The gluten network properties could be influenced through redox agents (oxidative and reducing agents) which are able to alter the strength of dough via different mechanisms for various purposes. The present review examined the impact of different redox compounds on gluten and its subunits based on their effects on their bonds and conformations and thus with their impacts on the physico-chemical, morphological, and rheological properties of gluten and their subunits. This allows for the use of gluten for different of purposes in the food and nonfood industry.

The effect of pre and post-ultrasonication on the aggregation structure and physicochemical characteristics of tapioca starch containing sucrose, isomalt and maltodextrin.

The present research investigated the aggregation behaviors of different levels (4, 8 and 12%) of incorporation of sucrose, isomalt and maltodextrin to pre or post- ultrasonication (400 W, 10 min at 60 °C) by fourier transform infrared spectroscopy (FTIR), microstructure by scanning electron microscopy (SEM), water absorption, pasting by rapid visco analysis (RVA), and thermal by differential scanning calorimetry (DSC). FTIR results showed that the aggregation process between polyol and starch after ultrasonication is more effective than before ultrasonication owning to more hydroxyl groups of polyols are engaged with the hydrogen bonds of starch which is more pronounced peaks at 1500-1750 cm-1, 1700-2700 cm-1 and 3000-3700 cm-1. These findings are in line with the results from SEM analysis. The spots, deformations and cross-linking created by the polyols were more significant after ultrasound assisted pregelatinizion. Impact intensity of polyol on starch granule was reduced in the following order: isomalt > sucrose > maltodextrin. RVA profiles showed that through the incorporation of polyols after sonication, were higher in samples pregelatinized in comparison with those before sonication.

Dual-frequency ultrasound for ultrasonic-assisted esterification.

The optimization of wheat starch esterification (acetylation) with a high degree of substitution was performed through response surface methodology (RSM) via various concentrations of reagents (acetic anhydride), pHs, and temperatures under various ultrasonication frequencies (25, 40, and 25 + 40 kHz). According to RSM methodology, optimized samples were selected by achieving high degrees of substitution at various frequencies, temperatures, and pHs. Solubility, swelling, X-ray, RVA, DSC, freeze-thaw stability, texture, and SEM analysis of the optimized samples were performed at three frequencies. X-ray pattern exhibited a more significant reduction in the crystallinity percentage of esterified starch at frequency 25 + 40 kHz compared with 25 kHz, 40 kHz, and native starch. According to DSC analysis, To, Tp, Tc, and enthalpy of gelatinization (ΔH gel) were lower in AC at frequency 25 + 40 kHz compared with AC at frequency 25 and 40 kHz and N starches. According to morphology analysis, in acetylated starches at 25 and 40 kHz, the surfaces and small granules underwent more damage, whereas in 25 + 40 kHz, large granules were more affected than small granules. Upon acetylation, freeze-thaw stability and textural properties of the starch significantly increased and decreased, respectively. The peak and final viscosity of acetylated starch increased (25 + 40 kHz Ëƒ 25 kHz Ëƒ 40 kHz Ëƒ N starch).

Effect of ionic strength (NaCl and CaCl2) on functional, textural and electrophoretic properties of native and acetylated gluten, gliadin and glutenin.

The main objective of this study was to determine the effects of different ionic strengths (IS) of NaCl and CaCl2 (0.2, 0.4 and 0.6 at pH=7) on the functional (water holding capacity (WHC), water absorption (WA), emulsifying activity (EA), emulsion stability (ES), textural and electrophoretical properties of native (N) and acetylated (AC) gluten, gliadin and glutenin. According to FT-IR and TNBS methods, the modification extent of wheat gliadin and glutenin were somewhat lower and higher than gluten, respectively. The results indicating that functionality AC glutenin was more than AC gluten and gliadin. NaCl and CaCl2 had negative impact on WHC, WA, EA and ES of proteins. Different IS of NaCl and CaCl2 may only alter the molecular conformation of N and AC gluten, gliadin and glutenin without having any significant effect on the molecular weights of these proteins. AC proteins had significantly higher WHC of gels compared to N proteins and also, CaCl2 could enhance the WHC and hardness of N and AC protein compared with NaCl. Hardness of AC glutenin more impressed than gliadin and gluten due to high degree acetylation.

Effects of sucrose, isomalt and maltodextrin on microstructural, thermal, pasting and textural properties of wheat and cassava starch gel.

This study investigated the effect of different levels (4, 8 and 12%) of sucrose, isomalt and maltodextrin on the microstructural, water absorption, physico-chemical, thermal and textural characteristics of wheat and cassava starch gels, by scanning electron microscopy (SEM), rapid visco analysis (RVA), differential scanning calorimetry (DSC) and texture profile analysis. According to SEM analysis, cassava granules were more impressed than wheat starch in the presence of isomalt > sucrose > maltodextrin. Results showed that water absorption decreased when the amount of sucrose, isomalt and maltodextrin increased. In contrast, onset (To), peak (Tp) and conclusion (Tc) temperature, and enthalpy (ΔH) of wheat and cassava starch gels, increased as the level of addition increased. With increasing the sugar concentration, To, Tp, Tc and ΔH gel enhanced significantly relative to the native starch. The polyols had more remarkable effects on the thermal properties of cassava starch than wheat starch. The texture of wheat and cassava starch gels incorporated with polyol sugars had solid-like properties. The gelatinization of starch was delayed more by isomalt than sucrose and maltodextrin. Moreover, the combination of principal component analysis and cluster analysis proved to be a suitable statistical approach to highlight the effect of adding varying levels of polyols to starch.

The effects of beta-glucan rich oat bread on serum nitric oxide and vascular endothelial function in patients with hypercholesterolemia.

INTRODUCTION: Oats are high in soluble fibers and effective in reducing the risk of cardiovascular diseases (CVD). We assessed the effects of beta-glucan from oat bran on serum nitric oxide (NO) endothelial function in patients with hypercholesterolemia. METHOD: Sixty hypercholesterolemic patients were randomly divided to receive an experimental bread rich in beta-glucan from oat bran (intervention) or bread rich in wheat fiber (control) for four weeks. All subjects had the same diet for two-week baseline period and hypocaloric diet for four weeks of intervention. Serum NO concentration and flow-mediated dilation (FMD) were determined before and after the experiment. RESULTS: Mean age of the participants was 51.1 ± 9.3 years and 65% (n = 39) were female. After intervention, serum NO concentration increased by 50.2 ± 19.8 µmol/lit in the intervention group (P = 0.017), but no change was observed in the control group (17.5 ± 27.5 µmol/lit; P = 0.530). No change of FMD was observed in the intervention (0.48 ± 0.78%; P = 0.546) or in the control group (0.59 ± 0.92%; P = 0.533). CONCLUSION: Consumption of oat bread for four weeks increases serum NO concentration but has no effect on FMD. Further studies are warranted in this regard.