Summary Starch is the main component of wheat having a number of food and industrial applications. Thousands of cultivars/varieties of different wheat types and species differing in starch functionality (thermal, retrogradation, pasting and nutritional properties) are grown throughout the world. These properties are related to starch composition, morphology and structure, which vary with genetics, agronomic and environmental conditions. Starches from soft wheat contain high amounts of surface lipids and proteins and exhibit lower paste viscosity, whereas that from hard cultivars contain high proportion of small granules and amylose content but lower gelatinization temperature and enthalpy. Waxy starches exhibit higher‐percentage crystallinity, gelatinization temperatures, swelling power, paste viscosities and digestibility, but lower‐setback viscosity, rate of retrogradation and levels of starch lipids and proteins than normal and high‐amylose starches. Starches with high levels of lipids are less susceptible towards gelatinization, swelling and retrogradation and are good source of resistant starch, while that with high proportion of long amylopectin chains are more crystalline, gelatinize at high temperatures, increase paste viscosity, retrograde to a greater extent and decrease starch digestibility (high resistant and slowly digestible starch and low rapidly digestible starch).

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A comparison between structural, morphological, functional and digestibility studies of starches from cereals i.e. wheat (WS), corn (CS), low amylose corn (LACS) and rice (RS), tubers i.e. potato (PS) and sweet potato (SP), and legumes i.e. kidney bean (KB) were investigated. The shape of granules varied from oval to elliptical or spherical according to the source. Distribution of iso- amylase debranched materials revealed that long and short side chains fractions of amylopectin ranged from 12.6 to 33.1% and 40.5 to 52.5% respectively. KB starch showed the highest amylose content (49.50%) while RS showed the lowest (8.51%). Starches with greater granule size (PS, SP and KB) showed higher proportion of long side chains of amylopectin (AP) (Fr.II) than short side chains of AP (Fr.III). Peak viscosity (PV), breakdown viscosity (BV) and final viscosity (FV) showed significant positive relationship with Fr. II and negative with apparent amylose content (AAC) and Fr.III. Tuber starches showed greater paste viscosities followed by legume starches. Tuber and legume starches with higher apparent amylose content and Fr. II showed greater crystallinity. Gel hardness and gelatinization temperatures showed inverse relationship with RS starch having higher proportion of smaller granules (0-10 µm). KB with higher amylose content showed maximum rapidly digestible starch (RDS) content while SP showed the highest resistant starch. Above observations would be utilized in modifying properties of native starches and help in improving texture, moisture retention capacity and gel firmness of starch and its products.

Starch from different sources (wheat, rice, corn, waxy corn, potato, sweet potato, and kidney bean) are subjected to high pressure treatment (HPT) at 300 and 600 MPa and are evaluated for changes in digestibility, structural, thermal, and pasting properties. HPT alters the surface of starch granules and significantly disrupts morphology of granules. Increase in average granule size and decrease in relative crystallinity is observed in high pressure treated starches. However, a significant decrease average granule size is observed at 600 MPa. High pressure treated starches show progressive reduction in both swelling power and solubility with increase in pressure. HPT results in reduction in gelatinization temperatures and enthalpy of gelatinization (𝚫H gel ) while starches except potato starch treated at 600 MPa do not show any endothermic peak indicating complete destruction of crystalline structure. Peak and final viscosity of native starches is higher than those of their counterpart high pressure treated starches except waxy corn starch. Increase in gel firmness and destruction of internal structure of starches especially that of tuber starches treated at high pressures is observed. HPT lowered rapidly digestible starch fraction and increased slowly digestible starch and resistant starch fraction.

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Effect of addition of native and gelatinized starches from various sources (CS, corn; WCS, waxy corn starch; WS, wheat; PS, potato starch; KB, kidney bean SP, sweet potato; and RS, rice starch) on viscoelasticity and sponge-making properties of wheat flour (WF) was investigated. Sponge cakes prepared using native and gelatinized starches were compared to those prepared with 100% WF. The addition of gelatinized starches from various botanical sources led to increase in batter viscosity (increased storage and loss modulus and decreased tan d) of batter. Sponge cakes made with addition of native and gelatinized starches from different botanical sources showed higher springiness, specific volume and cohesiveness. Firmness of sponge cakes showed variation among botanical sources and type (native or gelatinized) of starch. Sponge cakes prepared from gelatinized RS showed firmer texture. The crust color became more reddish brown on addition of gelatinized starch from all sources, however, crumb color varied with the source. Overall, it was observed that addition of gelatinized starches resulted in sponge cakes with softer texture and better organoleptic properties as compared to those made from WF.

Brown rice after germinating for 24 and 48 h was milled into flour and incorporated in whole wheat flour at a level of 10% to prepare chapattis. The objective was to use chapatti as a delivery vehicle for germinated brown rice. The flour blends and chapattis made from the flour blends were evaluated for their antioxidant properties. Incorporating germinated brown rice flour increased the total phenolic content of the flour blend from 1897 to 2144 µg FAE/g. The total flavonoids content increased significantly from 632.3 to1770.9 µg CAE/g and metal chelating activity significantly increased by 71.62%. Antioxidant activity increased significantly by the addition of brown rice flour and addition of 24- and 48-h germinated brown rice flour further increased the antioxidant activity significantly. The total phenolic content and total flavonoids content decrease significantly in all the blends after baking the flour into chapatti. A decrease of 3% to 29% was observed in the total phenolic content and a decrease of 25% to 42% was observed in the total flavonoids content. However, baking of the flour blends into chapatti increased the reducing power, metal chelating activity by three folds and antioxidant activity from 64% to 104%.

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 ApplicationHigher 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.