Khetan Shevkani

Bioactive constituents in pulses and their health benefits

Abstract Pulses are good sources of bioactive compounds such as polyphenols, phytosterols and non-digestible carbohydrates that play important physiological as well as metabolic roles. These compounds vary in concentration amongst different pulse species and varieties. Pulse seed coats are rich in water-insoluble fibres and polyphenols (having high antioxidant activities), while cotyledons contain higher soluble fibres, oligosaccharides, slowly digestible and resistant starch content. Ferulic acid is the most abundant phenolic acid present in pulses, while flavonol glycosides, anthocyanins and tannins are responsible for the seed coat colour. Sitosterol (most abundant), stigmasterol, and campesterol are the major phytosterols present in pulses. Pulse fibres, resistant starch and oligosaccharides function as probiotics and possess several other health benefits such as anti-inflammatory, anti-tumour, and reduce glucose as well as lipid levels. Beans and peas contain higher amounts of oligosaccharides than other pulses. Processing methods affect resistant starch, polyphenol composition and generally increase antioxidant activities of different pulses. In this review, the current information on pulse polyphenols, phytosterols, resistant starch, dietary fibre, oligosaccharides, antioxidant and associated health benefits are discussed.

Physicochemical and rheological properties of starch and flour from different durum wheat varieties and their relationships with noodle quality.

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.

Physicochemical, Pasting, and Functional Properties of Amaranth Seed Flours: Effects of Lipids Removal

UNLABELLED The present work was carried out to evaluate physicochemical (composition, hunter color, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis [SDS-PAGE]), pasting, and functional properties (foaming, emulsification, water, and fat absorption capacity) of amaranth full-fat flours from 6 lines/cultivars (AFs), and to see the effects of lipid removal/defatting on these properties. Protein, ash, and lipid content of AFs ranged between 12.5% to 15.2%, 3.0% to 3.5%, and 7.1% to 8.0%, respectively. The flours showed a number of bands between 97 and 7 kDa, with main subunits of approximately 58, 37, 33, 31, 23, and 16 kDa in the SDS-PAGE profiles. The protein content and L* value increased, while b* values decreased following defatting for most of the lines/cultivars. The defatted flours (DAFs) had higher final viscosity and stability (lower breakdown viscosity) as compared to counterpart AFs. The protein profiling of the flours was not affected with the lipid removal/defatting. However, water absorption capacity and foam stability of the flours improved upon defatting. Principal component analysis revealed that pasting temperature was positively related to lipid content, while breakdown viscosity was negatively related to protein content. Foaming properties (capacity and stability) showed negative relationship with lipid content, and positive with protein content, ash content, water, and fat absorption capacity. PRACTICAL APPLICATION Amaranth grains are known to have higher amount of proteins and lipids than cereals. Amaranth lipids are rich in unsaturated fatty acids, which are prone to oxidative rancidity. Removal of lipids or defatting of flours may be carried out to enhance product shelf life by preventing undesirable oxidative chain reactions. Therefore, this research was undertaken to see the effects of defatting on the functional properties of amaranth flours. The defatting was a value addition process as it improved the functional properties of the flours.

Effect of banana flour, screw speed and temperature on extrusion behaviour of corn extrudates.

Effect of extrusion parameters (banana flour, screw speed, extrusion temperature) on extrusion behaviour of corn grit extrudates were studied. Second order quadratic equations for extrusion properties as function of banana flour (BF), screwspeed (SS) and extrusion temperature (ET) were computed. BF had predominant effect on the Hunter color (L*, a*, b*) parameters of the extrudates. Addition of BF resulted in corn extrudates with higher L* and lower a* and b* values. Higher ET resulted in dark colored extrudates with lower L* and a* value. Higher SS enhanced the lightness of the extrudates. Expansion of the extrudates increased with increase in the level of BF and ET. WAI of the extrudates decreased with BF whereas increased with SS. However, reversed effect of BF and SS on WSI was observed. Flextural strength of the extrudates increased with increase in SS followed by BF and ET. The addition of BF and higher ET resulted in extrudates with higher oil uptake.

Maize: composition, bioactive constituents, and unleavened bread.

Publisher Summary This chapter discusses maize, also known as corn, which is grown throughout the world. The United States, China, Brazil, Argentina, India, France, and Indonesia are the main corn-producing countries. Corn of different types (flour corn, flint corn, dent corn, sweet corn, popcorn, waxy corn, and amylomaize) and color (ranging from white to yellow, red, and purple) is grown. Corn grain is composed of endosperm (82–83%), germ (10–11%), pericarp (5–6%), and tip cap (0.8–1.0%). The pericarp is the outermost layer that is characterized by high crude fiber content, mainly consisting of hemicellulose, cellulose, and lignin. High-amylose corn is a good source of resistant starch (RS), which can be used in various food products for its health benefits. RS has been associated with improved cholesterol metabolism and reduced risk of type II diabetes and colon cancer. Various bioactive compounds with the health-promotion and disease-prevention properties present in fruits and vegetables have also been reported in corn. The purple-, blue-, and red-pigmented corn inhibits colorectal carcinogenesis in male rats and possesses antimutagenic and radical scavenging activities. These bioactivities have been associated with the presence of anthocyanins.

Wheat starch production, structure, functionality and applications—a review

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).

Maize: Grain Structure, Composition, Milling, and Starch Characteristics

Maize is the third important food grain after wheat and rice, and its demand is increasing because of its increased use for biofuel production. Starch is the main component of maize, which is produced by wet milling process. Maize starch functionality varies with the starch structure and composition, which vary with genotypes and cultural practices. The average size of maize starch granules ranges between 1 and 7 μm and 15 and 20 μm, respectively, for small- and large-sized granules. Maize starches exhibit a typical A-type pattern, in which double helices comprising the crystallites are densely packed. Sugary maize starch has lower crystallinity, while waxy maize starch has greater crystallinity as compared to normal maize starches. The sugary maize starch has lower gelatinization temperature and enthalpy. The maize starch with long-branch chain length amylopectin and higher crystallinity has higher gelatinization temperature and enthalpy. The maize products (canned, frozen, and boiled sweet maize) have lower glycemic index (GI) than white rice and wheat flour bread. Waxy maize starch is more rapidly digested and have high GI than high-amylose starches. Thermal treatments such as autoclaving, baking, steam cooking, and parboiling processes affect starch digestibility and consequently the GI of maize-based products. Maize also contains various bioactive constituents, such as carotenoids, anthocyanins, and phenolic compounds, which vary with maize type. Maize has a higher antioxidant capacity compared to wheat, oat, and rice.