Functional and structural properties of gliadin as influenced by pH, extraction protocols, and wheat cultivars.

Gliadin, owing to its low cost, ease to extract, high foaming capacity, easily available and high surface hydrophobicity, has found a wide range of applications both in the food and pharmaceutical sectors. The functional and structural characteristics of gliadin extracted with four extraction protocols from six wheat cultivars were investigated in this study. The surface-active properties of gliadin protein as a function of pH, extraction protocols, and wheat cultivars were compared, including solubility, zeta-potential, foaming properties, emulsion properties, surface hydrophobicity and secondary structure. Overall gliadin extracted using different extraction protocols and from different wheat cultivars was found to be higher in ß-turns (24.88-37.91 %), followed by ß-sheet (12.81-22.37 %), α-helix (15.13-20.70 %) and lower in random coil (6.53-9.08 %). Varied pH ranges, wheat cultivars, and different extraction protocols were found to have a substantial impact on solubility, zeta potential, foaming stability, emulsion capacity and surface hydrophobicity. The foaming capacity was observed to be more influenced by extraction protocols than wheat cultivars. Emulsion stability showed statistically significant (p ≤ 0.05) influence between the wheat cultivars, and a non-significant (p ≥ 0.05) difference among extraction protocols. The functional properties of freeze-dried gliadin extracted using different protocols were found to be pH-dependent. A comprehensive understanding of how the structural, surface active and functional properties of gliadin are influenced by the extraction protocols and wheat cultivars will enable us to understand the gliadin better and broaden its use for both food and non-food applications.

Comparative Quality Evaluation of Physicochemical, Technological, and Protein Profiling of Wheat, Rye, and Barley Cereals.

Agronomically important cereal crops wheat, barley, and rye of the Triticeace tribe under the genus Triticum were studied with special focus on their physical, proximal, and technological characteristics which are linked to their end product utilization. The physiochemical parameters showed variability among the three cereal grains. Lactic acid-solvent retention capacity (SRC) was found to be higher in wheat (95.86-111.92%) as compared to rye (53.78-67.97%) and barley (50.24-67.12%) cultivars, indicating higher gluten strength. Sucrose-SRC and sodium carbonate-SRC were higher in rye as compared to wheat and barley flours. The essential amino acid proportion in barley and rye cultivars was higher as compared to wheat cultivars. Barley and rye flours exhibited higher biological value (BV) owing to their higher lysine content. SDS-PAGE of wheat cultivars showed a high degree of polymorphism in the low molecular range of 27.03-45.24 kDa as compared to barley and rye cultivars. High molecular weight (HMW) proteins varied from 68.38 to 119.66 kDa (4-5 subunits) in wheat, 82.33 to 117.78 kDa (4 subunits) in rye, and 73.08 to 108.57 kDa (2-4 subunits) in barley. The comparative evaluation of barley and rye with wheat cultivars would help in the development of healthy food products.

Comparative evaluation of gliadins from four extraction protocols using advanced analytical techniques.

Gliadin, a major component of gluten, is known to trigger celiac disease; therefore, its extraction is important to study its properties as well as its presence in gluten-free products. Four gliadin extraction procedures Osborne (1924), Weiss (1993), Wallace (1989) and DuPont (2005), were investigated on six wheat cultivars using advanced analytical techniques such as dynamic light scattering (DLS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Higher zeta potential of extracted gliadin was observed in DuPont (23.53-27), followed by Weiss (16.17-20.80), Osborne (16.17-20.13), and Wallace (14.60-19.47). Particle Z-average size (15.74-184.83 nm) was found to have an inverse relationship with the Polydispersity index (0.17-184.83). The surface morphological structure of TEM studies revealed the compact globular particle arrangement of gliadin, besides rod-shaped arrangement, was also found in DuPont and Wallace extracted gliadin. XRD pattern of gliadin exposed the crystalline domain at 44.1°, 37.8°, and 10.4° diffraction peaks. The d-spacing obtained from XRD and TEM-SAED analysis supports the presence of crystalline domains in gliadin apart from the amorphous domain. The insight obtained from this work will provide a better understanding of morphology and other properties of the same protein extracted with different extraction procedures.

Diversity in Grain, Flour, Amino Acid Composition, Protein Profiling, and Proportion of Total Flour Proteins of Different Wheat Cultivars of North India.

Wheat cultivars grown at three different locations in North India were assessed for their variability in kernel and flour characteristics. Protein and the wet and dry gluten contents of the flour varied significantly (p ≤ 0.05) from 9.32 to 12.60%, 23.46 to 43.04%, and from 8.28 to 15.00%, respectively. Wheat varieties exhibited moderate sodium dodecyl sulfate (SDS) sedimentation and solvent retention values. Flour showed a significant (p ≤ 0.05) difference in the amino acid composition. Lysine, having the lowest chemical score, was the first most limiting amino acid in all wheat varieties. The variability of total flour proteins determined by SDS-PAGE showed polymorphism both in the number and intensity of bands, particularly in the molecular weight range of 35.1-42.8 kDa corresponding to the α-, ß-, and γ-gliadin/low-molecular-weight glutenin subunit (LMW-GS) region. Pearson's correlation established between the various grain and flour parameters showed a significant correlation, which can result in better end product use.