Functional Properties of Modified Black Gram (Phaseolus mungo L.) Starch

Black gram (Phaseolus mungo L.) starch was modified by heat and moisture treatments, acetylation, oxidation, cross-linking, and adding free fatty acids (palmitic, stearic, and linoleic). Heat and low moisture treatment, acetylation, oxidation, and cross-linking lowered the starch gelatinization temperature by 1–6°C, while adding fatty acids and the high moisture-heat treatment raised it by 1–4°C. All modifications caused an increase in least gelation concentration of starch. High moisture-heat treatment increased both water and oil absorption of starch. At 95°C, heat-moisture treated, acetylated, and oxidized starches were more soluble, while fatty acid treated and cross-linked starches were less soluble compared to raw starch. The modified starches had greater swelling capacity and solubility at pH 2.0 and 10.0. Heat-moisture treated and chemically modified starches had lower swelling capacity (at 95°C) than that of isolated starch, whereas addition of fatty acids increased it.     

Scanning Electron Microscopy of Chemically and Enzymatically Treated Black Gram (Phaseolus mungo) and Ragi (Eleusine coracana) Starch Granules

Amylolysis of chemically - treated starch granules of black gram and ragi was followed colorimetrically and by scanning electron microscopy. From the percent hydrolysis values it was evident that oxidation with periodate resulted in considerable resistance, whereas urea treatment resulted in granule susceptibility towards in vitro amylolysis. The action of α-amylase and/or glucoamylase on periodate oxidised black gram starch showed on SEM sufficient enlargement of the granules and hollow craters as well; whereas similar treatment on oxidised ragi starch resulted in folded, distorted and deformed granules. Treatment with 8M urea resulted in the total loss of characteristic granular shape and formation of the socalled amylopectin “sacs”. Like waxy starches the latter showed an increase in enzymic activity. Particularly, the synergistic action of α-amylase and glucoamylase on ureatreated starches virtually collapsed the granules, forming innumerable “flat” ribbon like fragments.     

Isolation, Partial Characterization and Modification of the Great Northern Bean (Phaseolus vulgaris L.) Starch

The yield of the Great Northern bean starch was 18.23% (bean flour basis). The starch granule size ranged from 12 × 12 μm to 58 × 40 μm (length × width). The shape of starch granules was round to oval to elliptical, and in some cases, concave as well. Lamellae were present on all the starch granules observed. Amylose content of the starch was 10.2% (starch basis). Hog pancreatic α-amylase hydrolyzed more starch than did malt α-amylase under similar conditions. The Great Northern bean starch had good water and oil absorption capacities at room temperature (21°C). The bean starch formed a stable gel at concentrations of 7% and above (w/v). The viscoamylographic studies of the isolated starch indicated the restricted-swelling character of the bean starch.     

Physicochemical,Thermal, Morphological and Pasting Properties of Starches from some Indian Black Gram (Phaseolus mungo L.) Cultivars

The starches separated from thirteen different black gram cultivars were investigated for physicochemical, thermal, morphological and pasting properties. Amylose content, swelling power, solubility and water binding capacity of starches ranged between 30.2–34.6%, 16.0–22.3 g/g, 14.8–17.3% and 73.5–84.5%, respectively. The diameter of starch granules, measured using a laser‐light scattering particle‐size analyzer, varied from 12.8 to 14.3 μm in all black gram starches. The shape of starch granules varied from oval to elliptical. The transition temperatures (T_o, T_p and T_c) and enthalpy of gelatinization (ΔH_gel) determined using differential scanning calorimetry, ranged between 66.1–71.3, 71.0–76.2, 75.9–80.4°C and 6.7–9.4 J/g, respectively. Pasting properties of starches measured using the Rapid Visco Analyser (RVA) also differed significantly. Pasting temperature, peak viscosity, trough, breakdown, final viscosity and setback were between 75.8–80.3°C, 422–514, 180–311, 134–212, 400–439 and 102–151 Rapid Visco Units (RVU), respectively. Turbidity values of gelatinized starch pastes increased during refrigerated storage. The relationships between different properties were also determined using Pearson correlation coefficients. Amylose content showed a positive correlation with swelling power, turbidity and granule diameter. Swelling power showed a negative correlation with solubility and setback. T_o, T_p and T_c showed positive correlation with turbidity, pasting temperature and were negatively correlated to peak and breakdown viscosity.     

Isolation and Partial Characterization of Okenia (Okenia hypogaea) Starch

Okenia hypogaea (Schlech. & Cham.) belongs to the family of the Nyctaginacea, which produces a seed that is composed mainly of starch, the probable origin of Okenia hypogaea is Mexico. The aim of this work was to isolate the starch from Okenia hypogaea and to evaluate its chemical composition, along with some physicochemical and functional properties. Okenia gave a starch yield of 36 %; this starch had an amylose content of 26.1 %, with a fat content similar to corn starch, but with a higher ash fraction. Okenia starch possessed a small granule size (1—3 μm), the same as amaranth starch, with similar characteristics of stability and clarity of pastes as corn starch. At 60 °C the water retention capacity of okenia starch was higher than that of corn starch, but at higher temperatures an inverse pattern was found. When the temperature in the experiments increased, solubility and swelling values increased; okenia starch had higher swelling values than corn starch over the range of temperatures assayed. Okenia starch also presented a lower freeze‐thaw stability than corn starch on the first two cycles. Overall, it was concluded that due to its physicochemical and functional properties, it is worthwhile to test the use of okenia starch in the cosmetic and food industry.     

Functional Characteristics of the Mucilaginous Polysaccharides Derived from Cowpea (Vigna sinensis), Black Gram (Phaseolus mungo) and Linseed (Linum usitatissimum)

The cowpea polysaccharides had the maximum viscosity at around pH 6 and it decreased with increase in temperature but increased with increase in concentration. Both black gram and cowpea polysaccharides stabilized against thermal disruption the foam formed by the surface active proteins. Black gram starch and the mucilage together showed greater foam stability, probably due to enhanced viscosity caused by synergistic interactions between these polysaccharides. Gelatinization temperature as well as the peak and set back viscosities of wheat starch were considerably decreased by adding either the black gram or the linseed polysaccharide. In farinograph experiments the black gram polysaccharide exhibited a strengthening effect on wheat flour dough, whereas the linseed polysaccharide resulted only in an increased water absorption. Extensographic data indicated increased resistance and decreased extensibility of wheat flour dough by the addition of black gram and linseed polysaccharides.     

Amaranth Starch - Isolation and Partial Characterization

Starch was isolated from a new amaranth variety (Amaranthus hypochondriacus Mercado type) with outstanding agronomic traits. Some of its physicochemical and functional properties were comparable to a maize starch sample. After annealing, both starches exhibited little change in gelatinization peak temperature as assessed by differential scanning calorimetry. It is suggested that this behaviour might be due to the high amylopectin content of the amaranth starch and to a previous annealing effect undergone by the commercial sample during the isolation procedure. Amaranth starch granules showed by scanning electron microscopy a polygonal shape.     

Physicochemical and functional properties of flours from three Black gram (Phaseolus mungo L.) cultivars

Flours processed from three black gram cultivars (Mash1‐1, PU‐19 and T‐9) were studied for proximate composition, physicochemical and functional properties. Protein, fat, ash and crude fibre content varied significantly (P ≤ 0.05) from 24.5 – 28.4%, 1.1–1.4%, 2.7–3.3% and 2.7–3.4%, respectively, among the cultivars. Significant differences were also observed in other physicochemical properties. Pasting properties like peak viscosity, breakdown viscosity and setback viscosity were in the range of 2078.7–2473.0 cP, 644.0–863.7 cP and 588.3–804.0 cP, respectively. Textural profile analysis of flour gels displayed significant differences in hardness (13.0–18.9 g), gumminess (2.8–5.9 g), chewiness (2.0–5.7 g) and adhesiveness (21.0–40.9 g). Differential scanning calorimetry revealed starch gelatinisation from 63.5 to 75.6 °C and amylose lipid complex melting from 105.0 to 136.1 °C. Protein solubility profile in the pH range of 2–9 varied from 6.3 to 97.3%. Emulsifying activity index and Emulsifying stability index at pH 3, 5 and 7 varied correspondingly from 6.0 to 14.5 m² g^?1 and 18.8 to 64.9 min. Foaming capacity of 2% flour suspensions at pH 2, 4, 6, 8 and 10 varied significantly from 67.3 to 130% among the cultivars. Foam stability varied at different pH and was observed between 0 and 70.8% among the cultivars.     

Isolation and Partial Characterization of an Arabinogalactan from the Great Northern Bean (Phaseolus vulgaris L.)

A trichloroacetic acid-soluble polysaccharide of the Great Northern bean (Phaseolus vulgaris L.) was isolated. Arabinose and galactose were the major constituents of this polysaccharide (92.5% of the total mass). The arabinose to galactose ratio was 2.0:1.7. Viscosity of the aqueous polysaccharide dispersion was concentration, temperature, and pH dependent. Highest viscosity for a 0.5% (w/v) aqueous dispersion was observed at a pH of about 6.0.     

Isolation and Partial Characterization of Phytic Acid-Rich Particles from Great Northern Beans (Phaseolus vulgaris L.)

Phytic acid-rich particles were isolated from a combined density fraction (CDF) of Great Northern beans. CDF contained more than 80% of the total phytic acid, and 70% of the total crude protein and substantial amounts of certain minerals. CDF had phytic acid in both water soluble and water insoluble forms. An isolate containing phytic acid-rich particles was prepared from CDF using a Tris-base solution. The phytic acid-rich isolate contained 26.6% phytic acid, 34.3% protein, 30.0% total carbohydrates, 0.6% calcium, 2.1% magnesium, and 0.3% potassium. Chemical analysis and fractionation of CDF indicated that the water insoluble form of phytic acid in Great Northern beans was present as a salt of calcium-magnesium-potassium in association with proteins.     

Isolation and Partial Characterization of Mexican Oxalis tuberosa Starch

The chemical, physicochemical and rheological characteristics of Oxalis tuberosa starch were investigated. Oxalis starch presented an apparent amylose content of 33%, similar to maize starch used as control, with a granule size between 25–50 μm with oval and elliptical shapes and A‐type X‐ray diffraction pattern. The gelatinization temperature of oxalis starch was 64.0°C, that was lower than the one determined in maize starch (73.0°C), with an enthalpy value of 12.2 J/g, which was similar to that of maize starch. Both oxalis and maize starch pastes behaved as weak viscoelastic systems with the elastic character (G′) predominating over the viscous character (G′′). An increase in the level of solids in the pastes increased the values of the moduli. The results suggest that heating the systems (gelatinization), causes a more pronounced enhancement in the structure of the maize starch pastes than in that of oxalis starch pastes. Overall, it was concluded that due to its physicochemical, functional and rheological properties, Oxalis starch could be suitable for testing its use in the cosmetic and in the food industry.     

STUDIES ON BLACK GRAM (Phaseolus mungo L.) TRYPSIN INHIBITOR

ABSTRACT A trypsin inhibitor isolated from black gram (Phaseolus mungo L.) had 75 amino acid residues with an estimated molecular weight of 7892. The kinetic constants K_m and V_max as evaluated by the Dixon and Cornish-Bowden plots were 2.7 × 10^?5and 6 × 10^?3M/min, respectively. The dissociation constants of the enzyme-inhibitor complex (Ki) and the enzyme-inhibitor-substrate complex (Ki') were respectively 4 × 10^?7M and 1.9 × 10^?6M. Trypsin inhibition by black gram trypsin inhibitor was of a linear-mixed type. Chemical modification studies suggested the possible involvement of lysine and arginine at the active site of the inhibitor.     

Physicochemical and Functional Characterization of Baby Lima Bean (Phaseolus lunatus) Starch

One potential source of starch is the tropical legume baby lima bean (Phaseolus lunatus) that contains around 56—60% of starch. The objectives of this work were to evaluate this starch's physicochemical and functional properties and compare it with the properties of other starches. The chemical composition of lima bean starch was: 10.16% moisture, 0.20% protein, 0.67% fiber, 0.14% ash, 0.54% fat, 98.43% starch and 0.013% phosphorus. The amylose content was higher (32.7%) than that of other cereal and tuber starches but similar to other legume starches. The average granule size (diameter 17.9 μm) was comparable to that of corn starch and of other legume starches. The granule was heterogeneous, presenting an oval shape. The gelatinization temperature was 80.16 °C (range 75—87 °CC), which is similar to other legume starches but higher than that of corn starch. The molecular size (alkali number 3.22), was smaller than that of potato starch but similar to that of corn starch. Compared to corn starch, the gels were firmer and presented a higher degree of retrogradation even at high concentrations. The water solubility was positively correlated with the temperature: i.e., 1.8, 3.4, 8.5 and 12.3% at 60, 70, 80 and 90 °C, respectively. The swelling power had the same behaviour: 2.6, 3.3,12.8 and 19.9 g of water/per gram of starch at 60, 70, 80 and 90 °C, respectively. The amylogram showed that the viscosity (680 Brabender units) and stability were higher than those of commercial corn starch (252 Brabender units). The use of this starch in the preparation of syrups with high glucose contents, as well as in baked and canned products that require heating, is suggested.     

Physicochemical,cooking and textural characteristics of some Indian black gram (Phaseolus mungo L) varieties

Physicochemical, cooking and textural properties of black gram varieties were studied and related to each other using Pearson correlation. Different varieties showed significant variation in their physicochemical, cooking and textural properties. Varieties having higher seed weight and seed volume had higher values of cooking time, swelling capacity, hydration capacity and hardness. The relationships between textural parameters of cooked grains from different black gram varieties showed a significant positive correlation of hardness with cohesiveness (r = 0.472), gumminess (r = 0.938) and chewiness (r = 0.859). Swelling index, cohesiveness and gumminess of black gram varieties were observed to be related to their fibre content. Swelling capacity and swelling index correlated well with cooking time, hardness and gumminess. Cooking time had a positive correlation with hardness (p < 0.05) and gumminess (p < 0.05) and a negative correlation with springiness. Copyright © 2004 Society of Chemical Industry     

Isolation and Molecular Characterization of Makal (Xanthosoma yucatanensis) Starch

Starch was isolated from a non‐conventional source: makal (Xanthosoma yucatanensis) and molecular characteristics were determined using X‐ray diffraction, light scattering and chain length determination. The granules had an oval shape with sizes between 8 and 20 μm, with an average size of 12.4 μm. Amylose content was 22.4% and amylopectin content 77.6%. The granules presented a C‐type X‐ray diffraction pattern, with a degree of polymerization (DP) of 5–19 for branch chain lengths and an average molar mass of 5.4×10⁶ g/mol. The R_H and the R_G was 61.7 and 92.7 nm, respectively. Gelatinization temperature was 72.6 to 84.2°C and transition enthalpy was 15 J/g, which may be related to the X‐ray diffraction pattern and to the small granule size of makal starch. The retrogradation of makal starch increased during storage.     

In vitro digestibility of proteins in black gram (Phaseolus mungo) and green gram (Phaseolus radiatus) papads

‘Papads’, a traditional food of India, were prepared with decorticated black gram and green gram flours and toasted, microwaved or deep fat fried. Toasting was done by holding the papads over direct flame for 1–2 min. Sharp carousal microwave oven was used for microwaving at high temperature for 30 – 40 s. Deep fat frying was done by immersing the product in preheated refined groundnut oil for 5 – 10 s. In vitro digestibility of proteins in prepared papads was investigated by pepsin and pepsin + pancreatin. The percent protein hydrolysed in black gram papads was 80.5, 75.3 and 72.5 for toasted, microwaved and fried papads respectively. They were not significantly different from each other. Green gram papads exhibited significantly higher hydrolysis in microwaved product (79.3%) when compared to toasted (65.2%) or fried products (65.0%). Pepsin digestibilities were not influenced to a significant extent by cooking method and were in the range of 51.4 – 54.6% for black gram papads and 34.4 – 35.6% for green gram papads.     

Studies on Isolation and Physicochemical Properties of Starch from Moth Bean (Phaseolus aconitifolius)

Starch has been isolated and purified from the moth bean. The yield was about 33.5% of starch from the whole legume seeds. The amylose content of the starch was found to be 26.4%. The gelatinization temperature range was 62–72 °C. The starch exhibited single stage swelling and low solubility pattern. The extensive solubility in dimethylsulfoxide may be attributed to heterogeneous bonding forces within the granule. The amylolytic susceptibility of native and gelatinized starch with amylolytic enzymes have been studied. The starch was found to be non-ionic.     

Viscosity Pattern of Native and Fermented Black Gram Flour and Starch Dispersions

The effects of fermentation and added NaCl on aqueous dispersions of black gram flour were studied. After fermentation the apparent viscosities of cold pastes increased significantly over that of native flour dispersions (NFD). Addition of NaCl caused considerable decrease in apparent viscosities of NFD but only marginal decrease in fermented flour dispersions (FFD). Studies on rheological constants showed that changes brought about in these by fermentation were greater than that exerted by adding NaCl. Brabender viscography indicated that peak viscosity (PV) decreased by both NaCl and fermentation. FFD with salt showed 15% increase in PV over that without salt. FFD with or without NaCl showed greater breakdown (BV) and set back (SV) viscosities, but the values were lower in comparison to NFD. Starch was isolated in 33–35% yield from native and fermented batters. Apparent viscosity in 1M KOH showed increase due to fermentation. Brabender viscography indicated a GT of ∽81°C for both starches. The PV of fermented starch increased by 13%, BV by 15% and SV by 30% over that of native. Intrinsic viscosity of starch increased considerably while solubility and swelling power increased only marginally after fermentation.     

Isolation and Characterization of Starch from Bamboo Culm (Guadua flabellata)

Starch was isolated from bamboo culm in 8.5% yield. The starch was characterized by poligonal granules ranging in size from 1 to 12 μm and an amylose content of 24%. The granules were compact, with a density of 1.531 g/cm³. This, probably, reflected in low swelling power and solubility in water and poor solubility in dimethyl sulfoxide (DMSO). Brabender amylogram indicated an initial pasting temperature of 75°C and a high susceptibility to breakdown by thermal and/or mechanical shear.