Pigeon Pea Starch Research Articles

Physicochemical Properties Of Native And Acetylated Pigeon Pea Starches

Starch was extracted from pigeon pea, an underutilized legume, and acetylated (2.43%) using acetic anhydride. The starch yield increased from 28.24% (native) to 83.63% (acetylated). The pH was 6.8 and 6.9, respectively. Apparent amylose content decreased after acetylation (25.95% to 19.67%). Moisture, ash, fat, crude protein, and carbohydrate contents showed minimal variation between native and acetylated starches. Bulk density, water absorption, and oil absorption capacities increased with acetylation. Acetylated starch had higher dispersibility (98.50%) than native starch (87.50%), but a higher least gelation concentration (16% vs. 6%). Viscosity decreased with acetylation, while solubility index and swelling power increased. Acetylation improved pasting properties, particularly setback and breakdown. These findings suggest acetylation enhances the functional properties of pigeon pea starch for potential industrial applications.

Effect of chemical treatments on the functional, morphological and rheological properties of starch isolated from pigeon pea (Cajanus cajan)

Different chemical treatments (cross-linking, oxidation, and hydroxypropylation) were used to modify pigeon pea starch, and its effect on physiochemical, pasting and rheological properties were studied. Cross-linking and oxidation decreased while hydroxypropylation increased the swelling power of pigeon pea starch. All starch samples showed a decrease in their paste clarities. FTIR spectra of all starch samples displayed characteristic absorption bands of starch at wave numbers 1076, 1148, 1376, and 1632 cm−1. A significant reduction occurred in peak, cold paste, hot paste, and setback viscosity after chemical modification. Rheological determinations showed that starch pastes had viscoelastic behaviour. G′ and G″ of all starch paste increased after chemical modification. Native and chemically treated starches revealed oval to elliptical-shaped granules and no change was observed after modification when examined in SEM. These results confirmed that the undesirable properties of native pigeon starch can be suitably altered via chemical treatments to make them suitable for several food applications.

Enzymatic hydrolysis as a tool to improve total digestibility and techno-functional properties of pigeon pea (Cajanus cajan) starch

Recent studies have indicated that starch from legumes can potentially be used as an alternative to commercial flour with applications in food and biomaterials; however, some modifications may be required first to improve their functionality, as they show relatively lower solubility and functional properties compared to commonly marketed flours (e.g. good water retention capacity). This work used multiple enzymes in flour extracts of pigeon pea (Cajanus cajan), a legume, to optimize the enzyme hydrolysis process of such extracts by the Response Surface Method (RSM), to increase the digestibility and obtain desirable functional attributes at the nutritional level. The pH, temperature, time and enzyme/substrate (E/S) ratio were evaluated, and the degree of hydrolysis (DH) was calculated as well as the reducing sugar content (%RS), used as response variable. According to the experimental design, the best pH, temperature, time and E/S ratio were 6.8, 43 °C, 1.84% m/m and 270 min, respectively. The %RS for the samples under optimal conditions was 3.49 ± 0.02%, and the in vitro digestibility yielded values of 39.2 ± 0.4, 58.6 ± 0.3 and 2.2 ± 0.2 for slowly digestible starch (SDS), rapidly digestible starch (RDS) and resistant starch (RS), respectively. Total digestibility (TD) was 97.8 ± 0.5. The statistical analysis revealed a strong positive relationship for E/S ratio followed by pH: (E/S) ratio, temperature and pH. Enzymatic hydrolysis carried out on pigeon pea showed an increase in TD. Viscosity, water retention capacity (WRC) and solubility were evaluated showing good response for future applications at the industrial level.

Composition, structure, and physicochemical characteristics of pigeon pea (Cajanus cajan) starches from Indonesia

Abstract. A’yuni NRL, Marsono Y, Marseno DW, Triwitoyo P. 2021. Composition, structure, and physicochemical characteristics of pigeon pea (Cajanus cajan) starches from Indonesia. Biodiversitas 22: 3430-3439. Information on the characteristics of pigeon pea (Cajanus cajan (L.) Millsp.) starch would provide a scientific basis for developing its application. However, data about characteristics of pigeon pea starch, especially from the Southeast Asia region, has been limited. This study determined the composition, structure, and physicochemical characteristics of pigeon pea starches from three different Indonesian regions, i.e., Bali, Yogyakarta, and West Nusa Tenggara (NTB). We also investigated the potential application of Indonesian pigeon pea starches. Pigeon pea starch was extracted using a wet method, and then pigeon pea starch was characterized. The yield of pigeon pea starches ranged from 29.83-31.68%. Pigeon pea starches showed a significant difference (P<0.05) in amylose content (54.74-58.51%), relative crystallinity (24.20-28.97%), water-binding capacity (0.70-0.76 g/g), oil binding capacity (0.55-0.58 g/g), swelling power (13.19-14.52 g/g), and solubility (9.48-11.15%). The pasting properties (except for final viscosity) and thermal properties (except for onset temperature and gelatinization enthalpy) differed significantly. Granules of pigeon pea starch were oval to elliptical, with a mean granule diameter of 18.41-19.98 µm. According to X-ray diffraction patterns, pigeon pea starches showed CA type, contained orthorhombic and hexagonal crystals. Pigeon pea starches also showed the same FTIR spectra. The results revealed that the differences in pigeon pea growing locations affect pigeon pea starch's composition and physicochemical properties. The highest amylose content and lowest relative crystallinity were found in Yogyakarta pigeon pea starch. In the future, our findings could be used to develop pigeon pea starch for various food applications.

Morphological, Structural and Functional Properties of Starches from Different Legume Resources

Background: Legume is well known for its high nutrition and health care values. Considering that starch is the main carbohydrate in legume, its properties directly affect the development and utilization of legume resources. Methods: Starches were extracted from the seeds and root tubers of five legumes. The morphological, structural and functional properties of the starches were investigated and compared using scanning electron microscopy, X-ray diffraction and attenuated total reflectance-Fourier transform infrared spectroscopy.Result: The granules of kudzu, broad bean and pigeon pea starches were kidney-shaped with a large size, while groundnut and white pea starches were small granules with a mixture of irregularly polyhedral and spherical shape. The five legume starches had different apparent amylose contents and exhibited remarkably different crystalline properties. Among the samples, the relative crystallinity of kudzu starch was the highest, while pigeon pea starch had the highest short-range ordered degree. The swelling power and water solubility of the five legume starches were also varied. Furthermore, white pea starch is more susceptible to acid and enzymatic hydrolysis than the four other starches. The results are important for the processing and utilization of legume starches and can provide reference for the development of legume-based functional food.

Technological Properties of Acetylated Pigeon Pea Starch and Its Stabilized Set-Type Yoghurt.

The behaviour of graded acetylated pigeon pea starch during heat processing was evaluated in addition to the corresponding effect of their incorporation at 1.5% (w/v) as a stabilizer in set-type yoghurt. Acetylated starch possessed higher solubility and swelling power than native starch under the temperature regimes considered. Addition of acetylated pigeon pea starch as a stabilizer in yoghurt had positive influence on the water holding capacity (7.7% to 10.4% compared to 13.3% in yoghurt stabilized with native pigeon pea starch) and whey syneresis (approximately 15%, 12%, and 8% increase observed in yoghurt with acetylated pea starch compared to 47% in yoghurt with native pea starch stabilizer) at the end of a 28-day cold storage period. In addition, pea starch-stabilized yoghurt possessed an enhanced sensory attribute (firmness), and compared favourably with gelatin-stabilized yoghurt in terms of overall acceptability. Thus, acetylated pigeon pea starch exhibited improved physicochemical properties and showed usefulness as a stabilizer in yoghurt because it enhanced the physicochemical, storability, and sensorial quality, while improving the body and texture of the product.

Influence of acetylation on physicochemical and morphological characteristics of pigeon pea starch

Native starches exhibit some technological drawbacks in industrial food applications associated with poor physico-chemical properties; however, modification of starch can remedy the lack of functionality. Starch was extracted from pigeon pea seeds, modified by esterification with acetic anhydride to obtain 0.05, 0.09 and 0.14 degree of substitution (DS). Acetylation decreased the heat transition temperatures and enthalpy of gelatinization. DS (0.05) starch showed the least retrogradation tendency (30.54%). FTIR spectra showed characteristic absorption peaks at 1245, 1370 and 1732 cm−1 (C–C, C–O and CO stretch vibrations, respectively). Integrated band intensities of all three characteristic FTIR peaks increased linearly with increasing DS. SEM imaging showed that acetylation did not lead to any observable change in starch granule shape and size; however, there was a significant rupture of starch granules at 0.14 DS. The physicochemical properties of the acetylated starches were significantly improved, demonstrating its potential usefulness as food additive.

Gaseous Ozonation of Pigeon Pea, Lima Bean, and Jack Bean Starches: Functional, Thermal, and Molecular Properties

Pigeon pea, lima bean and jack bean starches are oxidized with gaseous ozone (O3) and their functional, thermal, and molecular properties are determined. Carbonyl content, carboxyl content and the amount of the reacted ozone are positively correlated (p < 0.01). Swelling and solubility profiles of the native starch samples increases upon oxidation. Higher values of peak viscosity, cold paste viscosity, and hot paste lower setback viscosity values and, significantly, similar peak times and pasting temperatures are observed upon ozonation (p < 0.05). Texturally, the oxidized gels are softer and more elastic than the native gels. The range values of gel strengths, among the oxidized starches, are 2.83–5.42 N (pigeon pea), 4.38–4.84 N (lima bean), and 2.98–4.20 N (jack bean). Absorption band peaks at 2925.11 and 2927.14 cm−1 of CH2 asymmetric stretching, 3200–3400 cm−1 of OH groups are obtained for the native starches, which were unaltered upon oxidation. Gelatinization temperatures (To, Tp, and Tc) of the starches remains unchanged after oxidation, except for To, Tp for lima bean and jack bean starches. The gelatinization and retrogradation studies of the oxidized pigeon pea starches exhibits higher endothermic enthalpies than their native starches. The crystals of the starch samples are CB‐type X‐ray patterns and the oxidized starches possessed higher crystallite sizes than the native starches. Amylose contents, weight averages, and polydispersity ratios improve upon oxidation whereas an opposite trend is observed in terms of amylopectin content and number averages.

Seed Protein and Starch Qualities of Drought Tolerant Pigeonpea and Native Tepary Beans

Tepary bean and pigeonpea were highly drought tolerant food legumes and were profitable in arid regions with sustainable productivity. Protein and starch, major constituents of legume grain, were used in various forms for human and animal consumption. Therefore, present investigation was carried out with an objective to evaluate protein content and various factors influencing qualities of starch in pigeonpea and tepary bean. Significant differences (p < 0.05) were observed for protein and starch qualities among the two crops and between the drought responsive cultivars of these crops. The protein content of pigeon pea (22.5-26.2 mg/100 mg) was high compared to tepary bean (17 to 26 mg/100 mg) seed. The resistant starch content of pure starch extracted from drought responsive cultivars varied from 1.09 (TB #7) to 8.75 (TB #31) in teparybean and 14.68% (G2) - 21.35% (W1) in pigeonpea. Amylose content of pigeonpea varied from 7.76 to 12.31% and the degree of crystallinity were 13.42 - 19.30% with X-ray diffraction pattern of the C-type. The pigeonpea starch granules were large, oval to ellipsoidal shape with a smooth surface and mean granule size of 47.6 µm in length X 36.4 µm in width. The transition temperatures and enthalpy of gelatinization ranged from 67.25-68.29 oC (To); 71.4-72.49 oC (Tp) and 77.04-78.51 oC (Tc) and 4.80-6.43 J/g respectively. Amylose content of tepary starch varied from 8.08 to 12.38% and the degree of crystallinity were 13.52-18.29% with X-ray diffraction pattern of the C-type. The tepary bean starch granules were round to oval shape with a smooth surface and mean granule size of 39.26 µm in length X30.36 µm in width. The transition temperatures and enthalpy of gelatinization ranged from 73.12-74.65 oC (To); 77.71-78.85 oC (Tp); 82.65-84.29 oC (Tc) and 2.21-5.27 J/g respectively. Pigeon pea starches were with low molecular weights of amylopectin (5.26 x 108 Da) and high molecular weights of amylose (4.63 × 105 Da) compared to those in tepary bean (13.6 × 108; 1.35 × 105) on an average. In both crops, the gelatinization showed significant correlation with amylose content, crystallinity and granule size. Pigeonpea grain was superior with quality starch and protein with adequate amounts of digestible fiber without any reduction in quality during extraction of starch compared to tepary bean. Black seed coated tepary had lowest gelatinization energy compared to brown and white. The drought tolerant cultivars identified in teparybean (TB #24) and Pigeonpea (W1) with high resistant starch and protein content will be useful in selection for crop production, developing homozygous line for industrial use in southern USA.

Quality evaluation of stiff porridges prepared from Irish potato (Solanum tuberosum) and pigeon pea (Cajanus cajan) starch blends

Quality attributes of stiff porridges prepared from Irish potato and pigeon pea starch blends were studied. Starches were extracted from Irish potato and pigeon pea using a wet extraction method. Various ratios of the starches were mixed and analyzed for chemical, functional and pasting properties. The starch blends were then prepared into stiff porridges for sensory evaluation using a 20-man sensory panel. Substitution of Irish potato starch with pigeon pea starch led to increases in protein (0.15 to 1.2%), fat (0.26 to 0.56%) and ash (0.30 to 0.69%) while the amylose content of the starch blends decreased (from 23.8 to 18.4%) respectively. Functional properties such as bulk density (0.75 to 0.60g/cm(3)), water absorption capacity (3.1 to 2.6g water/ g sample) and dispersibility (58.6 to 42.7%) decreased significantly (P < 0.05) at the highest concentration (50%) of pigeon pea starch respectively. Pasting properties such as peak, breakdown, final and setback viscosities increased with increasing levels of pigeon pea starch while peak time and pasting temperature decreased. The sensory attributes of stiff porridges were not adversely affected by pigeon pea starch inclusion. Therefore it should be possible to incorporate up to 50% of low digestible pigeon pea starch into Irish potato starch from legumes such as pigeon pea as alternatives to cassava starch in the preparation of stiff porridges. Such porridges made from Irish potato and legume starches could provide additional incentive for individuals requiring decreased and or slow starch digestibility such as diabetics.

Suitability of pigeon pea and rice starches and their blends for noodle making

The physicochemical and pasting properties of pigeon pea and rice starches were studied to assess their suitability for noodle making. Amylose content, solubility and freeze thaw stability of pigeon pea starch were significantly higher than those of rice starch ( p < 0.05). The pasting properties of peak viscosity, final viscosity, breakdown and set back showed higher values for pigeon pea starch, whereas hot paste viscosity and pasting temperature were higher for rice starch. Rice starch noodles revealed less cooking time (4 min) and less percent solids loss, whereas pigeon pea starch noodles had higher cooking time (12 min), higher percentage of water absorbed during cooking, more hardness and cohesiveness. Rice starch noodles scored higher for their transparency and slipperiness over pigeon pea starch noodles. Blending of pigeon pea starch with rice starch had significant effects on the cooking and sensory quality of noodles. Among starch blends, 70:30 blend of the pigeon pea and rice starches respectively resulted in good quality of noodles especially in terms of their higher transparency, slipperiness, overall acceptability and cohesiveness values. Blending of pigeon pea starch with 30% rice starch could produce noodles with superior quality as compared to native pigeon pea and rice starch noodles.

Hydroxypropylation of pigeon pea (Cajanus cajan) starch: Preparation, functional characterizations and enzymatic digestibility

Hydroxypropyl starch derivatives were prepared from pigeon pea starch (NPPS) which is an unconventional starch source. Functional parameters and characterization of both native and modified starches were carried out. The starch granules appeared oval or elliptical in shape with sizes ranging from 7 to 40 μm in width and 10 − 30 μm in length. Hydroxypropylation did not alter the shape of the starch granules in a pronounced way. Generally, the x-ray diffractograms of native pigeon pea starch showed the “A” pattern. However, slight reductions in the diffraction intensity of starches after modification were observed. At all temperatures studied (30–90 °C), swelling and solubility of hydroxypropylated starches were higher than the NPPS. Progressive increases in swelling capacity and solubility were observed as the molar substitution (MS) increased among the hydroxypropylated starches. Hydroxypropylation reduced starch paste turbidity on storage. Also, studies showed that syneresis reduced after hydroxypropylation. In addition, syneresis reduced as the MS of the hydroxypropyl starches increased. The results indicate that pasting temperature and peak temperature reduced after modification but peak viscosity increased in hydroxypropylated starch derivatives compared with the native starch. Setback reduced in hydroxypropylated starches compared with the native starch. Enthalpy of gelatinization and percentage retrogradation reduced after hydroxypropylation and progressive reductions were observed as the MS increased among the starch derivatives. Hydroxypropylation increased enzymatic digestibility.

In vitro digestibility, structural and functional properties of starch from pigeon pea (Cajanus cajan) cultivars grown in India

Abstract Starches isolated from two pigeon pea cultivars (AL-15 and AL-201) were evaluated for their in vitro digestibility, structural and functional properties. Both the cultivars exhibited a characteristic C-type diffraction pattern with relative crystallinity values of 31.9% and 34.2%, for AL-15 and AL-201, respectively. The structural characterization obtained using high performance size exclusion column chromatography revealed that molecular weight of amylopectin and amylose was higher for AL-201 (396 and 3.92 × 106 g/mol, respectively) in comparison to AL-15 starch (354 and 3.31 × 106 g/mol, respectively). AL-201 exhibited higher values for transition temperatures, enthalpy of gelatinization, pasting temperature and percentage retrogradation in comparison to AL-15 starch. Slowly digestible starch, readily digestible starch and resistant starch contents of AL-15 and AL-201 cultivars were observed to be 31.0, 8.1 and 60.9% and 29.6, 5.2 and 65.2%, respectively. The hydrolysis index and RS values indicated that pigeon pea starches were highly resistant to digestion.

Starch noodles: History, classification, materials, processing, structure, nutrition, quality evaluating and improving

Starch noodles, produced from purified starch of various plant sources, are a major category of Asian noodles. This review summarizes the current knowledge on: (1) Definition, naming, history and categories of starch noodles. (2) The morphological, physico-chemical, thermal, rheological characteristics and molecular structure of materials including mung bean starch, pea starch, sweet potato starch, potato starch and corn starch. (3) Processing technology of starch noodles including dropping, extruding and cutting. (4) Structure of starch noodles: it is composed of hydrolysis-resistant crystalline zone, network-like framework and filler mass. (5) Nutrition of starch noodles: it could be evaluated by the digestibility of starch, hydrolysis properties of gelatinized and retrograded starches, hydrolysis property of starch noodles. (6) Quality evaluating of starch noodles: it includes sensory, cooking and texture property. Correlation between the physical properties of starch, processing variables and the sensory, cooking and texture property of starch noodles are summarized. (7) Quality improving for non-mung bean starch noodles: (a) using other materials such as red bean starch, pigeonpea starch, potato starch, sweet potato starch, corn starch, to substitute totally or partly mung bean starch; (b) adding chemically modified starch; (c) adding physically modified starch; (d) biologically treating starch; (e) using additives such as chitosan, polysaccharide gums.

Structure and Viscoelastic Properties of Starches Separated from Different Legumes

AbstractA comparison between the morphological, structural, thermal and viscoelastic properties of starches separated from pigeon pea, chickpea, field pea, kidney bean and blackgram was made. The shape of the starch granules in the different legumes varied from oval to elliptical or spherical. X‐ray diffraction of the legume starches indicated a typical C‐pattern (mixture of A‐ and B‐type). Granules of blackgram and pigeon pea starch had a higher degree of crystallinity than those of field pea and kidney bean starches. Apparent amylose content of field pea, kidney bean, chickpea, blackgram and pigeon pea starch was 37.9%, 36.0%, 34.4‐35.5%, 32.9‐35.6% and 31.8%, respectively. Distribution of isoamylase‐branched materials among the starches revealed that the proportions of long and short side chains of amylopectin ranged between 13.6‐18.5% and 41.7‐46.5%, respectively. Field pea and kidney bean starch had the highest apparent amylose content and the lowest amount of long side chains of amylopectin, respectively. Blackgram and pigeon pea starch possessed higher proportions of both long and short side chains of amylopectin than field pea and chickpea starches. The onset, peak and conclusion temperatures of gelatinization (To Tp and Tc, respectively) were determined by differential scanning calorimetry. To and Tc ranged from 59.3 to 77.3°C, 66.8 to 79.6°C, 55.4 to 67.6°C and 68.3 to 69.3°C, respectively, for chickpea, blackgram, field pea and kidney bean starch. The enthalpy of gelatinization (ΔHgel) of field pea, kidney bean, chickpea, blackgram and pigeon pea starches was 3.6, 3.0, 2.6‐4.2, 1.6‐1.7 and 2.6 J/g, respectively. Pastes of blackgram and pigeon pea starches showed lower storage and loss shear moduli G′ than field pea, kidney bean and chickpea starches. The changes in moduli during 10 h at 10°C revealed retrogradation in the order of: field pea&gt; kidney bean&gt; chickpea&gt; blackgram&gt; pigeon pea starch. In blackgram and pigeon pea starches, the lower proportion of amylose plus intermediate fraction and higher proportion of short and long side chains of amylopectin are considered responsible for the higher crystallinity, gelatinization temperature and enthalpy of gelatinization.

Digestibility of legume starches as influenced by their physical and structural properties

Digestibility of common legumes in India (black gram, chickpea, mung bean, lentil, field pea and pigeon pea) was studied and related to their physical (thermal and pasting) and structural (amylose content and crystallinity) properties. All legume starches exhibited a characteristic C-type diffraction pattern with relative crystallinity ranging between 27.2% and 33.5%. Pigeon pea starch showed the highest values for molecular weight ( M w) of amylopectin (389 × 10 6 g/mol) and amylose (3.64 × 10 6 g/mol) whereas, field pea starch showed the lowest values for M w of amylopectin (239 × 10 6 g/mol). The enthalpy for melting (Δ H) was the highest for field pea starch whereas, mung bean showed the lowest. Peak viscosity (PV) ranged from 3942 mPa s (chickpea) to 6107 mPa s (mung bean). Slowly digestible starch (SDS) content followed the order: mung bean > chickpea > field pea > lentil > black gram > pigeon pea, whereas, the resistant starch (RS) content followed the following order: pigeon pea > lentil > black gram > field pea > chickpea > mung bean. The hydrolysis indices (HI) of the legume starches ranged from 8.2 to 20.0, and the estimated glycemic indices (GI) based on the HI were between 44.2% and 50.7%. Several significant correlations were observed among different starch properties as revealed both by Pearson correlation (PC) and principal component analysis (PCA). Together, the first two PCs represent 86.6% of total variability. Digestibility of starch was negatively correlated with starch granule diameter ( r = −.791, p < .05) and M w of amylopectin and amylose ( r = −.845 and −.837, respectively, p < .05). A negative correlation between relative crystallinity and amylose content was observed ( r = −.775, p < .5). M w of amylopectin was positively correlated to relative crystallinity ( r = .914, p < .01) and negatively correlated to amylose content ( r = −.874, p < .05).

Effects of Pigeon Pea and Plantain Starches on the Compressional, Mechanical, and Disintegration Properties of Paracetamol Tablets

ABSTRACTA study has been made of the effects of pigeon pea starch obtained from the plant Cajanus cajan (L) Millisp. (family Fabaceae) and plantain starch obtained from the unripe fruit of Musa paradisiaca L. (family Musaceae) on the compressional, mechanical, and disintegration properties of paracetamol tablets in comparison with official corn starch BP. Analysis of compressional properties was done by using density measurements, and the Heckel and Kawakita equations, whereas the mechanical properties of the tablets were evaluated by using tensile strength (T-a measure of bond strength) and brittle fracture index (BFI-a measure of lamination tendency). The ranking for the mean yield pressure, Py, for the formulations containing the different starches was generally corn < pigeon pea < plantain starch while the ranking for Pk, an inverse measure of the amount of plasticity, was pigeon pea < plantain < corn starch, which indicated that formulations containing corn starch generally exhibited the fastest onset of plastic deformation, whereas those formulations containing pigeon pea starch exhibited the highest amount of plastic deformation during tableting. The tensile strength of the tablets increased with increase in concentration of the starches while the Brittle Fracture Index decreased. The ranking for T was pigeon pea > plantain > corn starch while the ranking for BFI was corn > plantain > pigeon pea starch. The bonding capacity of the formulations was in general agreement with the tensile strength results. The disintegration time (DT) of the formulation increased with concentration of plantain and corn starches but decreased with concentration of pigeon pea starch. The general ranking of DT values was plantain < pigeon pea < corn starch. Notably, formulations containing pigeon pea starch exhibited the highest bond strength and lowest brittleness, suggesting the usefulness of pigeon pea starch in producing strong tablets with minimal lamination tendency. Plantain starch, on the other hand, would be more useful where faster disintegration of tablet is desired. The results show that the starches could be useful in various formulations depending on the intended use of the tablets with the implication that the experimental starches can be developed for commercial purposes.

Effect of Altered Solvent Environment on the Pasting Characteristics of Pigeonpea (&lt;i&gt;Cajanus cajan&lt;/i&gt;) and Cowpea (&lt;i&gt;Vigna unguiculata&lt;/i&gt;) Starches

The (Brabender) pasting characteristics of pigeonpea and cowpea starches as a function of pH, sucrose concentration, added corn oil and legume protein isolates were investigated. Adjusting pH to 2 resulted in complete loss in paste consistency at 97°C for both starches. For pigeonpea starch, incorporation of corn oil and 10% sucrose resulted in significant (p J. agric. Sci. technol. Vol.5(1) 2003:80-90

Effect of Surfactant HLB on Some Gel Properties of Pigeonpea and Cowpea Starches

The pasting profiles, load penetration responses, and freeze-thaw stability of pigeonpea and cowpea starches were investigated as a function of hydrophilic-lipophilic balance (HLB) of surfactants. Incorporation of surfactants varying in HLB values resulted in significant (p < 0.05) increases in the initial pasting temperature of the starch pastes; the magnitude of the increment was concomitant with increases in HLB values. Surfactants of HLB 1.8, 3.8, 6.7, 16.0, and 20.0 significantly decreased the paste consistency of pigeonpea starch pastes at 97 °C. The cowpea starch paste consistencies at the same temperature was reduced by surfactants of HLB 16 and 20. Gel strength, elastic modulus and stickiness of the starch gels were significantly reduced by addition of surfactants. However, no clear-cut trends between surfactant HLB and these gel characteristics were apparent. Cowpea starch gels incorporating surfactants with HLB 1.8—11.0 exhibited significant improvement in freeze-thaw stability relative to the control but the stability of pigeonpea gels decreased. Addition of hydrophilic surfactants (HLB 16 and 20) invariably caused a significant increase in net syneresis of the starch gels. It was concluded that the pasting and rheological properties of cowpea and pigeonpea starches could be manipulated, in the short term, by varying the HLB values of added surfactants.

The physico-functional characteristics of starches from cowpea ( Vigna unguiculata), pigeon pea ( Cajanus cajan) and yambean ( Sphenostylis stenocarpa)

Starches fractionated from cowpea ( Vigna unguiculata, Ife Brown), pigeon pea ( Cajanus cajan, Cita II) and yambean ( Sphenostylis stenocarpa) were comparatively studied for physical and functional properties, including granule morphology, granule sizes, water absorption capacity, water–oil absorption index, swelling capacity, ionic property, bulk density and amylographic viscosities. The three legume starch granules range in diameter size from 5–57.5 μm. The water absorption capacities of all the starches were generally low at room temperature up to 70°C. Pigeon pea starch was the least susceptible to swelling while the cowpea starch was the most susceptible. The starches displayed non-ionic character, low water activity, high bulk density, water and oil absorption capacities and type C Brabender visco-amylograms at 6.2% starch-water slurry (on dry wt basis). ©