The genetic diversity in agronomic, grain (physical), and whole wheat meal (WWM) (physicochemical and pasting) properties from 61 old and new wheat lines were evaluated. Furthermore, the rheological and functional properties of chapatti and deep fried puffs prepared from 61 old and new wheat lines were also evaluated. Statistical analysis exhibited significant difference in grain characteristics. Among old and new wheat lines, new lines showed higher grain hardness index, thousand grain weight (TGW), and gain diameter (GD) value. TGW range from 33 to 37 g for maximum old varieties, while it ranged from 36 to 40 g for new varieties. Redness in new wheat lines (a* value ranged from 6.5 to 7.1) was higher compared to old varieties (6.3 to 6.9). Moreover, WWM obtained from different wheat lines exhibit statistically significant difference in physico-chemical and pasting properties. Peak viscosity, breakdown viscosity, final viscosity, set back value, and pasting temperature ranged from 1,530 to 2,665 cP, 558 to 1,106 cP, 2,349 to 3,685 cP, 1,284 to 2,322 cP, and 85.5 to 89.75 degrees C, respectively, in different wheat lines. The G ' value for chapati and deep fried puffs dough ranged from 5,673,300 to 13,393,600 Pa and 4,884,800 to 9,230,800 Pa, respectively. Furthermore, the water holding capacity, water holding time, and breaking strength of deep fried puffs ranged from 23 to 55 ml, 40 to 135 s, and 2.3 to 17.38 N, respectively. The frequency distribution and principal component analysis discovered notable difference in quality traits amongst 61 old and new wheat lines.
Polyphenol oxidases (PPOs) are enzymes found in several plant species, including wheat (Triticum aestivum L.), that contribute to the undesirable brown discoloration of many food products. Wheat serves as a fascinating system for studying PPO function due to its complex genome and economic significance. Over the past two decades, wheat PPOs have received considerable attention due to their well-established role in causing brown discoloration and their suspected involvement in various adverse reactions to wheat-based end products such as bread, chapati, pasta and noodles. Wheat PPOs have been extensively studied over two centuries, with a focus on the PPO activity assay and their role in causing brown discoloration of wheat-based products like pasta, chapati, bread and noodles. This scientific review provides a quick overview of wheat PPOs, emphasising the mechanism, activity assay and characteristics that are pertinent to its function in brown discolouration of wheat-based end products. It covers descriptions of PPOs’ biological roles, the structures and interactions of PPO gene families and the presence of similar forms of PPOs that may alter nutritional characteristics and the end-product quality of wheat. Thus, it provides a basic overview of the PPOs system and impact on wheat end products.
Polyphenol oxidase (PPO) activity is a primary cause of the development of unattractive dark brown discoloration of wheat-based end products. The present study aims to evaluate a set of 41 diverse wheat genotypes grown at three different locations in India for grain phenol color reaction, PPO activity and molecular marker-based characterization of alleles of PPO genes. Relationships among these parameters were analyzed along with the effects of grain PPO activity on dough and chapati color at different time intervals. The mean PPO activity ranged from 7.42 to 27.57 min−1 g−1 10−3 among the genotypes and it showed a significant negative correlation with color brightness (L*) of dough rested for 0 min (r = -0.406), 15 min (r = -0.406), 2 h (r = -0.502) and 4 h (r = -0.551) and whole wheat flour-derived chapati rested for 2 h (r = -0.267) and 4 h (r = -0.424). The overall quality color score was negatively correlated with PPO activity (r = -0.863) and showed a positive correlation with both dough and chapati visual color measured at different time intervals. PPO activity in the genotypes carrying different alleles was found to be Ppo-A1a>Ppo-A1b; Ppo-B2d>Ppo-B2a; and Ppo-D1b>Ppo-D1a. The allelic constitution Ppo-A1bPpo-B2aPpo-D1a and Ppo-A1bPpo-B2dPpo-D1 was found to produce the lowest PPO activity, and thus these alleles are recommended to be used in marker assisted breeding for low PPO activity genotypes to minimize the discoloration of wheat-based end-products.
Summary Flours from four wheat varieties grown at high (~3180 m) and low altitude (~247 m) were compared for particle size distribution, protein composition (monomeric and polymeric), amino acids, pasting and dough rheological properties. High altitude wheat (HAW) flours showed greater proportion of large size particles and higher protein content, gluten, ash content and each category of gliadins and high molecular weight glutenins but revealed lower gluten index than low altitude wheat (LAW) flours. HAW showed higher extractable polymeric, unextractable monomeric proteins, pasting temperature, damaged starch and arabinoxylans while lower unextractable polymeric, extractable monomeric protein, paste viscosity, dough stability and development time than LAW flours. HAW flours from PBW725 and HD3086 showed higher concentration of total aromatic and lower of total sulphur amino acids than their counterpart LAW flour. Differences in flours characteristics of LAW and HAW were clearly due to differences in accumulation of protein, starch and arabinoxylans.
Malnutrition due to micronutrients and protein deficiency is recognized among the major global health issues. Genetic biofortification of wheat is a cost-effective and sustainable strategy to mitigate the global micronutrient and protein malnutrition. Genomic regions governing grain zinc concentration (GZnC), grain iron concentration (GFeC), grain protein content (GPC), test weight (TW), and thousand kernel weight (TKW) were investigated in a set of 184 diverse bread wheat genotypes through genome-wide association study (GWAS). The GWAS panel was genotyped using Breeders' 35 K Axiom Array and phenotyped in three different environments during 2019–2020. A total of 55 marker-trait associations (MTAs) were identified representing all three sub-genomes of wheat. The highest number of MTAs were identified for GPC (23), followed by TKW (15), TW (11), GFeC (4), and GZnC (2). Further, a stable SNP was identified for TKW, and also pleiotropic regions were identified for GPC and TKW. In silico analysis revealed important putative candidate genes underlying the identified genomic regions such as F-box-like domain superfamily, Zinc finger CCCH-type proteins, Serine-threonine/tyrosine-protein kinase, Histone deacetylase domain superfamily, and SANT/Myb domain superfamily proteins, etc. The identified novel MTAs will be validated to estimate their effects in different genetic backgrounds for subsequent use in marker-assisted selection.
Malnutrition due to micronutrients and protein deficiency is recognized among the major global health issues. Genetic biofortification of wheat varieties is both cost-effective and sustainable strategy to contain global micronutrient and protein malnutrition. Genomic regions governing grain zinc concentration (GZnC), grain iron concentration (GFeC), grain protein content (GPC), test weight (TW), and thousand kernel weight (TKW) were investigated in a set of 183 diverse bread wheat genotypes through genome wide association study (GWAS). The RIL population was genotyped using Breeders' 35K Axiom Array and phenotyped in three environments during 2019-2020. A total of 55 marker-trait associations (MTAs) were identified, of which four significant MTAs for GFeC on chromosome 2B, 3A, 3B, 6A and two for GZnC on chromosomes 1A and 7B. Further, a stable SNP was detected for TKW and also identified pleiotropic regions controlling GPC and TKW. In silico analysis revealed a few important putative candidate genes viz., F-box-like domain superfamily, Zinc finger CCCH-type proteins, Serine-threonine/tyrosine-protein kinase, Histone deacetylase domain superfamily and SANT/Myb domain superfamily proteins , etc. The identified novel MTAs will be validated to estimate their effects on different genetic backgrounds for subsequent use in marker-assisted selection (MAS).
Micronutrient and protein malnutrition is recognized among the major global health issues. Genetic biofortification is a cost-effective and sustainable strategy to tackle malnutrition. Genomic regions governing grain iron concentration (GFeC), grain zinc concentration (GZnC), grain protein content (GPC), and thousand kernel weight (TKW) were investigated in a set of 163 recombinant inbred lines (RILs) derived from a cross between cultivated wheat variety WH542 and a synthetic derivative ( Triticum dicoccon PI94624/ Aegilops tauschii [409]//BCN). The RIL population was genotyped using 100 simple-sequence repeat (SSR) and 736 single nucleotide polymorphism (SNP) markers and phenotyped in six environments. The constructed genetic map had a total genetic length of 7,057 cM. A total of 21 novel quantitative trait loci (QTL) were identified in 13 chromosomes representing all three genomes of wheat. The trait-wise highest number of QTL was identified for GPC (10 QTL), followed by GZnC (six QTL), GFeC (three QTL), and TKW (two QTL). Four novel stable QTL ( QGFe.iari-7D.1, QGFe.iari-7D.2, QGPC.iari-7D.2 , and QTkw.iari-7D ) were identified in two or more environments. Two novel pleiotropic genomic regions falling between Xgwm350–AX-94958668 and Xwmc550–Xgwm350 in chromosome 7D harboring co-localized QTL governing two or more traits were also identified. The identified novel QTL, particularly stable and co-localized QTL, will be validated to estimate their effects on different genetic backgrounds for subsequent use in marker-assisted selection (MAS). Best QTL combinations were identified by the estimation of additive effects of the stable QTL for GFeC, GZnC, and GPC. A total of 11 RILs (eight for GZnC and three for GPC) having favorable QTL combinations identified in this study can be used as potential donors to develop bread wheat varieties with enhanced micronutrients and protein.
Twelve wheat genotypes with variable grain hardness were evaluated for grain, flour, pasting, dough rheological properties, high molecular weight glutenin subunits (HMW-GS) and their relationship with cookie quality characteristics. The degree of hardness played an important role in the expression of characters under study. Genotypes with higher grain hardness index (GHI) showed higher dough development time and dough stability. GHI and solvent retention capacity were positively related to each other and negatively to spread factor. GluD1 locus of majority of hard wheat genotypes showed 5 + 10 subunit while soft wheat (SW) genotypes with 2 + 12 subunit related to gluten quality and dough properties. Overall, variation in subunits at GluD1 locus led to greater variation amongst studied genotypes followed by GluB1 and GluA1. Subunits Null at GluA1, 20, 7 + 8 and 7 + 9 at GluB1, and 2 + 12 and 5 + 10 at GluD1 showed a profound effect on flour, dough and cookie quality. Distribution of different HMW-GS, gluten characteristics and GHI, thus emerged as major parameters for selection of wheat genotypes for development of cookies. SW (QBP 13–11) with the lowest GHI and HMW-GS profile (2*, 7 and 2 + 12 subunit) showed the highest cookie SF and the lowest BS, thereby, turning out to be the best suitable genotype for producing cookies.
Wheatgrass juice powder (WJP) from four wheat varieties grown using soil, coco-peat with nutrient solution (CNS) and water (soaked (8 h), germinated (36 h) and harvested on 10th day) were examined for proximate composition, mineral, amino acid, phenolic (free and bound) composition and antioxidant properties. The yield, ash and protein contents of WJP ranged between 4.88-7.87%, 5.18-15.93% and 38.75-50.17%, respectively. The total phenolic, flavonoid, chlorophyll content (TCC) and antioxidant activity varied from 12.02 to 17.44 mg GAE/g, 4.38-10.10 mg QE/g, 3.01-5.63 mg/g, and 13.54-17.33 mu mol TE/g, respectively. HD-3086 grown using soil exhibited highest antioxidant properties, TCC and Mg content. WJP of C-306 grown using CNS had abundant essential amino acids (AAs). Phenolic acids (ferulic, syringic and sinapic acids) and flavonoids (catechin, rutin, vitexin and isovitexin) and minerals (K, P, Ca, Mg, Na and Fe) were predominant in WJP. The AAs and free phenolics were more in CNS and soil grown WJP, respectively.
The physicochemical and functional characteristics of grain, meal and flour of timely sown wheat (TSW) and delayed sown wheat (DSW) were compared to see the effects of heat stress (HS). TSW and DSW of different lines were sown as per the approved timings. DSW experienced higher temperature during flowering and had shorter vegetative and maturation period than TSW. Pasting and dough rheological properties were measured using Rapid Visco-Analyser and Farinograph, respectively, while gliadins and glutenins profiling was done by SDS-PAGE. Delayed sowing decreased grain yield and diameter while increased protein and all categories of gliadins and high molecular weight glutenins. DSW showed higher peak viscosity, breakdown-viscosity and dough stability and lower setback viscosity, damaged starch, arabinoxylans and water absorption than TSW. HS in DSW appeared to lower starch synthesis causing proportionate increase in grain hardness and proteins content leading to changes in milling and rheological characteristics.
The aim of this study was to screen Indian cultivated wheat varieties and list out the parameters/genes required to be improved for an end-product. Therefore, 30 Indian wheat varieties under cultivation by farmers were screened for 14 physico-chemical and rheological parameters, sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) for high molecular weight glutenin subunits (HMW-GS), DNA based molecular markers for low molecular weight glutenin subunits (LMW-GS) and puroindolines (Pin) genes. Based on grain texture, sedimentation value, farinographic, alveographic, HMW-GS and LMW-GS and biscuit making parameters, HS490 was found to be a highly suited for biscuit and soft wheat products. HI1563 and DBW14 were also found to possess characteristics such as low protein, low to medium SDS-sedimentation value and combination of 2*, 7+8 and 2+12 (HMW-GS). DBW14 also had LMW alleles desirable for biscuit quality. DBW14 needs to be improved for grain softness to make it suitable for biscuit quality while both grain softness and LMW alleles need to be improved for HI1563 to improve its biscuit spread factor and alveographic indices for extensible gluten. Rest varieties showed moderate to very strong gluten but the gluten lacked extensibility. Only four varieties K307, DBW39, NI5439 and DBW17 possessed high flour protein and moderately strong gluten. They had more balanced deformation energy (W) and configuration ratio (P/L) combination suggestive of strong and extensible gluten needed for raised bread making. Marker assisted backcross breeding is suggested as solution to produce end-use specific varieties where appropriate alleles at only a few loci need to be incorporated.
A set of 53 wheat genotypes were evaluated for different quality and longevity related traits at NBPGR, New Delhi, India. The selected genotypes included both durum and bread wheat varieties released in India between 1970 and 2014, and bread wheat germplasm lines for comparison. Bread wheat varieties were good repositories for sedimentation value (SV), whereas, durum varieties for kernel hardness (KH) and germplasm lines for grain iron (Fe), zinc (Zn), and thousand kernel weight (TKW). Both vigor index-1 and 2 after controlled deterioration (VIACD-1 and VIACD-2) was highest for durum varieties followed by bread wheat germplasm lines and varieties. Therefore, seed longevity of durum varieties, bread wheat germplasm lines, and bread wheat varieties, respectively, was good, intermediate and poor. Broad-sense heritability was high for all the studied traits except germination percentage before controlled deterioration (GPBCD). Genetic advance as per cent mean (GAM) was high for all the studied traits, with the exception of moisture content (MC) and GPBCD. Six genotypes (IC 542394, IC 542391, IC 542416, IC 542431, IC 542426, and IC 542387) were good storers and also contained high Fe and Zn, which can be used in breeding programs to improve seed storability, and Fe and Zn content. Both intra species and inter species variability were observed for all the studied traits. The close association observed between Fe and Zn may help in improving both the traits simultaneously. Electrical conductivity (EC) of the seed leachates can be used as a surrogate trait for indirect selection for seed longevity of genotypes due to its significant negative association.
The effect of lipids extraction on protein salvation, pasting, and dough rheological behavior of flours dough from hard wheat (HW), extraordinarily soft wheat (Ex-SW), and medium-hard wheat (MHW) flour was analyzed. The varieties selected had wide variation in grain hardness index (17 to 95). Ex-SW revealed lower tryptophan fluorescent emission and water absorption (WA) than MHW and HW varieties. The change in pasting parameters on defatting was the highest for Ex-SW varieties. Native flour (NF) of HW varieties showed high protein content, pasting and dough strength, and fluorescence intensity in comparison to Ex-SW varieties, while on defatting this was reversed. Protein pattern of defatted flour and NF did not differ significantly. Defatting of flours increased WA and decreased dough stability (DS). The decrease in DS on defatting was more for Ex-SW varieties than others. DS for HW and MHW varieties reduced upon defatting. Defatting significantly increased all mixographic and rheological properties except peak time. Overall, results showed that defatting of flour improved paste and dough strength. PRACTICAL APPLICATION: Higher gluten strength of defatted wheat flour of varied grain hardness has wide applications. Most of the Indian bread wheat varieties possess GluD1 high-molecular-weight glutenin subunit (HMW-GS) allelic composition of (2 + 12), which is not suitable for bread making due to weak gluten strength. Defatting of flours improved the gluten strength of strong and weak flour dough of different wheat varieties irrespective of GluD1 allelic composition for HMW-GS. Defatted flour may be used to improve the baking and cooking performance of dough made from weak wheat. These findings are highly suitable for wheat milling and baked product manufacturing industries.
In the present study coarse fraction (CF), medium fine fraction (MFF) and fine fraction (FF) were separated from flours milled from medium-hard and extraordinarily soft wheat varieties and were evaluated for various quality characteristics. Grain hardness of medium-hard and extraordinarily soft wheat varieties varied from 77 to 80 and 17 to 18, respectively. Ash and protein content was the highest for FF and the lowest for CF. Varieties with greater hardness produced higher CF and lower of FF. FF showed higher unextractable polymeric protein (UnEx-PP) and dough stability as compared to MFF and CF. FF showed lower damage starch content as related by lower Sodium SRC (NaSRC) as compared to MFF and FF. CF showed higher paste viscosities than FF and difference were greater amongst fractions from varieties with lower grain hardness. FF with greater proportion of small size particles showed greater accumulation of 98 kDa and 85 kDa PPs than CF. This study demonstrated that fractionation of flours can be employed to produce fractions with varied gluten strength required for production of various products.
Coarse flour fractions (CFFs) and fine flour fractions (FFFs) obtained from flour milled from twelve different wheat cultivars varying in grain hardness index (GHI) were evaluated for particle size distribution, pasting and protein characteristics. Cultivars with greater hardness produce flour with high protein content had more proportion of large size particles. FFF had higher unextractable polymeric protein, solvent retention capacity (SRC), sedimentation value (SV) and dough stability (DS) than their corresponding CFF. Both FFF and CFF from cultivars with lower hardness showed lower sodium SRC. CFF showed higher pasting viscosities than their corresponding FFF, and difference in these properties was greater amongst soft cultivars. DS increased with decrease in grain hardness, but medium hard cultivars showed exceptionally higher value. The concentration of HMW-GS in the CFF was higher than FFF of hard wheat cultivars, whereas the concentration of LMW-GS in the CFF and FFF was not influenced by the fractionation of flour.
Hard wheat (HW), medium-hard wheat (MHW) and extraordinarily soft wheat (Ex-SW) varieties with grain hardness index (GHI) of 83 to 95, 72 to 80, 17 to 29 were evaluated for pasting, protein molecular weight (MW) distribution, dough rheology and baking properties. Flours from varieties with higher GHI had more protein content, ash content and paste viscosities. Ex-SW had more glutenins proportion as compared to HW and MHW. Flours from Ex-SW varieties showed lower NaSRC, WA and mixographic parameters as compared to HW and MHW. Dough from flours milled from Ex-SW had higher Intermolecular-β-sheets (IM-β-sheets) than those from MHW and HW. Muffins volume increased with decrease in GHI, Ex-SW varieties had more muffin volume and less air space. The accumulation of polypeptides (PPs) varied significantly in different varieties. Ex-SW variety (QBP12-10) showed accumulation of 98, 90, 81 and 79kDa PPs, which was unique and was different from other varieties.
Genomic regions responsible for accumulation of grain iron concentration (Fe), grain zinc concentration (Zn), grain protein content (PC) and thousand kernel weight (TKW) were investigated in 286 recombinant inbred lines (RILs) derived from a cross between an old Indian wheat variety WH542 and a synthetic derivative (Triticum dicoccon PI94624/Aegilops squarrosa [409]//BCN). RILs were grown in six environments and evaluated for Fe, Zn, PC, and TKW. The population showed the continuous distribution for all the four traits, that for pooled Fe and PC was near normal, whereas, for pooled Zn, RILs exhibited positively skewed distribution. A genetic map spanning 2155.3cM was constructed using microsatellite markers covering the 21 chromosomes and used for QTL analysis. 16 quantitative trait loci (QTL) were identified in this study. Four QTLs (QGFe.iari-2A, QGFe.iari-5A, QGFe.iari-7A and QGFe.iari-7B) for Fe, five QTLs (QGZn.iari-2A, QGZn.iari-4A, QGZn.iari-5A, QGZn.iari-7A and QGZn.iari-7B) for Zn, two QTLs (QGpc.iari-2A and QGpc.iari-3A) for PC, and five QTLs (QTkw.iari-1A, QTkw.iari-2A, QTkw.iari-2B, QTkw.iari-5B and QTkw.iari-7A) for TKW were identified. The QTLs together explained 20.0%, 32.0%, 24.1% and 32.3% phenotypic variation, respectively, for Fe, Zn, PC and TKW. QGpc.iari-2A was consistently expressed in all the six environments, whereas, QGFe.iari-7B and QGZn.iari-2A were identified in two environments each apart from pooled mean. QTkw.iari-2A and QTkw.iari-7A, respectively, were identified in four and three environments apart from pooled mean. A common region in the interval of Xgwm359-Xwmc407 on chromosome 2A was associated with Fe, Zn, and PC. One more QTL for TKW was identified on chromosome 2A but in a different chromosomal region (Xgwm382-Xgwm359). Two more regions on 5A (Xgwm126-Xgwm595) and 7A (Xbarc49-Xwmc525) were found to be associated with both Fe and Zn. A QTL for TKW was identified (Xwmc525-Xbarc222) in a different chromosomal region on the same chromosome (7A). This reflects at least a partly common genetic basis for the four traits. It is concluded that fine mapping of the regions of the three chromosomes of A genome involved in determining the accumulation of Fe, Zn, PC, and TKW in this mapping population may be rewarding.
Starch and flour properties of different Indian durum wheat varieties were evaluated and related to noodle-making properties. Flours were evaluated for pasting properties, protein characteristics (extractable as well as unextractable monomeric and polymeric proteins) and dough rheology (farinographic properties), while starches were evaluated for granule size, thermal, pasting, and rheological properties. Flour peak and final viscosities related negatively to the proportion of monomeric proteins but positively to that of polymeric proteins whereas opposite relations were observed for dough rheological properties (dough-development time and stability). Starches from varieties with higher proportion of large granules showed the presence of less stable amylose-lipids and had more swelling power, peak viscosity and breakdown viscosity than those with greater proportion of small granules. Noodle-cooking time related positively to the proportion of monomeric proteins and starch gelatinization temperatures but negatively to that of polymeric proteins and amylose content. Varieties with more proteins resulted in firmer noodles. Noodle-cohesiveness related positively to the proportion of polymeric proteins and amylose-lipids complexes whereas springiness correlated negatively to amylose content and retrogradation tendency of starches.