Effect of Heat‐Moisture Treatment on Structural and Thermal Properties of Rice Starches Differing in Amylose Content

Starches from glutinous rice (1.4% amylose), Jasmine rice (15.0% amylose) and Chiang rice (20.2% amylose) were exposed to heat‐moisture treatment (HMT) at 100 °C for 16 h and at different moisture levels (18, 21, 24 and 27%). The effect of heat‐moisture treatment on structural and thermal properties of these three rice starches was investigated. The HMT did not change the size, shape and surface characteristics of rice starch granules. The A‐type crystalline pattern of rice starches remained unchanged after HMT. The relative crystallinity (RC) and the ratio of short‐range molecular order to amorphous (RSA) of heat‐moisture treated glutinous and Jasmine rice starches decreased with increasing moisture level of the treatments. In contrast, the RC of the treated Chiang rice starch remained practically unchanged. A peak of crystalline V‐amylose‐lipid complexes was clearly presented in all treated Chiang rice starches. The peak became progressively stronger with increasing moisture level of the treatment. Differential scanning calorimetry (DSC) of all treated rice starches showed a shift of the gelatinization temperature to higher values. Increasing moisture level of the treatments increased the onset gelatinization temperature (T_o) but decreased the gelatinization enthalpy (ΔH) of rice starches. A broad gelatinization temperature range (T_c‐T_o) with a biphasic endotherm was found for all treated Chiang rice starches and Jasmine rice starch after HMT₂₇ (HMT at 27% moisture level). Additionally the (T_c‐T_o) of treated Chiang rice starches increased linearly with increasing moisture level of the treatments.     

Influence of Heat‐Moisture Treatment and Acid Modifications on Physicochemical,Rheological, Thermal and Morphological Characteristics of Indian Water Chestnut (Trapa natans) Starch and its Application in Biodegradable Films

Water chestnut starch was subjected to acid modification and heat‐moisture treatment. Hydrochloric acid was used for acid modification at three different concentrations (0.25 M, 0.5 M and 1 M) for 2 h. Modifications did not alter the granule morphology. Heat‐moisture treatment (HMT) resulted in slight reduction in the granular size of the starch granules. Acid modification lowered the amylose content, swelling power, water‐ and oil‐binding capacity but improved the solubility of starch to a considerable level. Light transmittance of acid‐modified (AM) starches improved significantly. A significant reduction in peak, trough, final and setback viscosity was observed by acid‐thinning. In case of heat‐moisture treated starch the final viscosity (F_v) was found to be even higher than the peak viscosity (P_v). Native water chestnut starch exhibited a lower onset temperature (T_o) and peak temperature (T_p) of gelatinization than the corresponding acid‐treated starches. Starch films prepared from native starch exhibited excellent pliability, whereas those prepared from AM and HMT starches showed good tensile strength. Starch films prepared from acid‐treated starches provided better puncture and tensile strength.     

Microstructural and physicochemical properties of heat-moisture treated waxy and normal starches

Starches from normal rice (21.72% amylose), waxy rice (1.64% amylose), normal corn (25.19% amylose), waxy corn (2.06% amylose), normal potato (28.97% amylose) and waxy potato (3.92% amylose) were heat-treated at 100 °C for 16 h at a moisture content of 25%. The effect of heat-moisture treatment (HMT) on morphology, structure, and physicochemical properties of those starches was investigated. The HMT did not change the size, shape, and surface characteristics of corn and potato starch granules, while surface change/partial gelatinization was found on the granules of rice starches. The X-ray diffraction pattern of normal and waxy potato starches was shifted from B- to C-type by HMT. The crystallinity of the starch samples, except waxy potato starch decreased on HMT. The viscosity profiles changed significantly with HMT. The treated starches, except the waxy potato starch, had higher pasting temperature and lower viscosity. The differences in viscosity values before and after HMT were more pronounced in normal starches than in waxy starches, whereas changes in the pasting temperature showed the reverse (waxy > normal). Shifts of the gelatinization temperature to higher values and gelatinization enthalpy to lower values as well as biphasic endotherms were found in treated starches. HMT increased enzyme digestibility of treated starches (except waxy corn starch); i.e., rapidly and slowly digestible starches increased, but resistant starch decreased. Although there was no absolute consistency on the data obtained from the three pairs of waxy and normal starches, in most cases the effects of HMT on normal starches were more pronounced than the corresponding waxy starches.     

Effect of Osmotic Pressure on Starch: New Method of Physical Modification of Starch

A new method of physical modification of starch in the presence of high concentrated salt solution is presented, called “Osmotic Pressure Treatment” (OPT). OPT was introduced in order to produce the same physically modified products as obtained by conventional heat‐moisture treatment (HMT) of starch. Potato starch was selected for the comparative study of the two methods. For the OPT method, potato starch was suspended in a saturated solution of sodium sulfate and heated in an autoclave at 105°C and 120°C ,which corresponded to the calculated osmotic pressures of 328 and 341 atm (332 and 345 bar, respectively) (assuming sodium sulfate dissociates completely) for 15, 30 and 60 min, respectively. For the HMT method, starch with 20% moisture content was placed in a Duran bottle, then the same heat treatment method in the autoclave was applied. Light and scanning electron microscopy (SEM) showed that OPT of starch changed the shape of the starch granules to a folded structure, while the starches remained unchanged after HMT. The RVA viscogram for the OPT starch exhibited a decrease in the peak viscosity without a breakdown and an increase of the pasting temperature when increasing the temperature and time, which was in an agreement with the viscosity patterns for the HMT starches. X‐ray diffraction patterns were altered from B to A+B for the HMT and from B to A type for the OPT starch when treated at 120°C. After OPT, the gelatinization temperatures (T_o, T_p, and T_c) of the starch increased significantly with increasing temperature and time, whereas only the T_c of starch increases after HMT. The biphasic broadening of the peaks (high T_c‐T_o) can be explained by an inhomogeneous heat transfer during HMT. Narrow peaks in the DSC curve can be an indication for a better homogeneity of the OPT samples. However, both methods provide a similar decrease in the gelatinization enthalpy (ΔH). The amylose‐amylopectin ratio calculated from the HPSEC patterns was strongly increased for HMT starches at 105°C for 60 min and 120°C for 30 min and decreased after treatment at 120°C for 60 min. For OPT starches the ratio was strongly increased at 120°C for 15 min and decreased after prolong heating. The OPT provides a uniform heat distribution in the starch suspension. This allows the modified starch to be produced on a larger scale.     

Effect of heat-moisture treatment on the formation and physicochemical properties of resistant starch from mung bean (Phaseolus radiatus) starch

Mung bean starch was subjected to a range of heat-moisture treatments (HMT) based on different moisture contents (15%, 20%, 25%, 30%, and 35%) all heated at 120 °C for 12 h. The impact on the yields of resistant starch (RS), and the microstructure, physicochemical and functional properties of RS was investigated. Compared to raw starch, the RS content of HMT starch increased significantly, with the starch treated at 20% moisture having the highest RS content. After HMT, birefringence remained at the periphery of the granules and was absent at the center of some granules. The shape and integrity of HMT starch granules did not change but concavity was observed under scanning electronic microscopy. Apparent amylose contents of HMT starch increased and the HMT starch was dominated by high molecular weight fraction. Both the native and HMT starches showed A-type X-ray diffraction pattern. Relative crystallinity increased after HMT. The gelatinization temperatures (To, Tp, and Tc), gelatinization temperature range (Tc–To) and enthalpies of gelatinization (ΔH) increased significantly in HMT starch compared to native starch. The solubility increased but swelling power decreased in HMT starches. This study clearly shows that the HMT exhibited thermal stability and resistance to enzymatic hydrolysis owing to stronger interactions of starch chains in granule.     

Effect of raw and heat–moisture‐treated high‐amylose corn starches on the process of digestion in the rat digestive tract

High‐amylose corn starch (HAS) is widely known as a resistant starch foodstuff. We developed heat–moisture‐treated high‐amylose corn starch (HMT‐HAS) that was more resistant to enzymatic hydrolysis. Resistant starch contents of HAS and HMT‐HAS using the enzymatic–gravimetric method were found to be 30% and 65% respectively. Rats were given 10% ordinary corn starch (CS), HAS or HMT‐HAS by meal feeding for 10 days. The caecum contents increased and the caecal pH was lower after their diets were supplemented with HAS and HMT‐HAS. Starch contents increased in the upper and the lower small intestine with HAS and HMT‐HAS. Caecal starch with HAS and HMT‐HAS was more than that with CS. Particularly, caecal starch with HMT‐HAS was seven times more than that with HAS. There were no differences in starch content in the large bowel between CS and HAS, but the content increased with HMT‐HAS. These results suggested that HAS and HMT‐HAS were resistant to digestion and absorption in the small intestine, and any indigestible starches reached the caecum. In the caecum, HAS was hydrolysed almost completely by intestinal bacteria; however, some HMT‐HAS escaped bacterial hydrolysis. This escaped HMT‐HAS reached the large bowel and was excreted in the faeces. © 1999 Society of Chemical Industry     

Comparisons of physicochemical properties and antioxidant activities among pumpkin (Cucurbita moschata L.) flour and isolated starches from fresh pumpkin or flour

Physicochemical properties (pasting and thermal properties, swelling power, water solubility and antioxidant activities) and chemical composition of pumpkin flour (PF) and starches, isolated from fresh pumpkin (SFF) or flour (SFP) were compared. SFP and SFF had similar proximate composition and amylose content. Drying process during PF preparation modified starch properties. PF exhibited greater antioxidant activities (DPPH, ABTS and FRAP), but had lower β‐carotene than fresh pumpkin. SFF and SFP had higher amylose content than PF, and exhibited a B‐type X‐ray diffraction pattern with spherical and dome‐like starch granules. Peak viscosity of SFP was relatively higher than that of SFF, probably due to lower swelling power and water solubility, which indicated increased granular rigidity in the SFP starch structure. Compared with SFF and SFP, PF had significantly higher onset (T_o), peak (T_p) and conclusion (T_c) temperatures due to a lower starch content and relatively higher fibre content, which resulted in lower gelatinisation enthalpy (ΔH).     

Morphological,thermal, rheological and retrogradation properties of potato starch fractions varying in granule size

The physicochemical properties of small, medium and large starch granules separated from four potato cultivars were investigated to reveal whether functional properties differed among the various size classes of the starches. Large‐size fractions showed higher amylose content and light transmittance and lower swelling power than small‐size fractions. The granules from the three fractions had diameters of 5–20, 25–40 and 40–85 µm respectively. The large and medium granules were ellipsoidal to irregular or cuboidal while the small granules were spherical or ellipsoidal in shape. The transition temperatures and gelatinisation temperature range of the fractionated starches increased while the enthalpy of gelatinisation decreased with decreasing granule size. Rheological parameters such as peak storage (G′) and loss (G″) moduli increased in the order small‐, medium‐ and large‐granule starches when subjected to temperature sweep testing. The breakdown in peak G′ during the heating cycle and retrogradation during storage were found to be highest for large‐ and lowest for small‐size fractions. The differences in functional properties among the different size fractions suggested that the granule size distribution is an important parameter that can influence the behaviour of potato starch during processing. Copyright © 2004 Society of Chemical Industry     

Effects of oligosaccharides on phase transition temperatures and rheological characteristics of waxy rice starch dispersion

BACKGROUND: The creation of starch‐based foods incorporated with functional ingredients such as probiotics is of great current interest in the food industry. This study aimed to investigate the effects of prebiotic oligosaccharides on the phase transition temperatures and rheological characteristics of waxy rice starch dispersions. Four oligosaccharides were applied to the rice starch dispersions: chitooligosaccharides, fructooligosaccharides, isomaltooligosaccharides and xylooligosaccharides. RESULTS: The addition of 125 g kg^?1 oligosaccharides elevated the onset and peak temperatures for gelatinisation of 200–400 g kg^?1 waxy rice starch dispersions. The temperature of the storage modulus (G′) for gelatinisation increased markedly on adding fructooligosaccharides to 200–300 g kg^?1 waxy rice starch. For gelatinisation of 300 g kg^?1 rice starch dispersion the effectiveness of the oligosaccharides in changing the above parameters was as follows: chitooligosaccharides > fructooligosaccharides > isomaltooligosaccharides > xylooligosaccharides. Moreover, their effectiveness was dependent on the amylose content, as illustrated by comparing waxy and non‐waxy rice starches (amylose contents 9–256 g kg^?1). Importantly, the logarithmic G′₉₅ change was linearly and negatively correlated with amylose content. CONCLUSION: The results suggest that oligosaccharide‐containing rice starch dispersions may potentially be used for the formulation of oligosaccharide‐containing starchy functional foods owing to the rheological changes of these starch dispersions. Copyright © 2011 Society of Chemical Industry     

Physicochemical,crystallinity, pasting and thermal properties of heat‐moisture‐treated pinhão starch

The effect of heat‐moisture treatment (HMT) on the properties of pinhão starches under different moisture and heat conditions was investigated. The starches were adjusted to 15, 20 and 25% moisture levels and heated to 100, 110 and 120°C for 1 h. The X‐ray diffractograms, swelling power, solubility, gel hardness, pasting properties and thermal properties of the native and HMT pinhão starches were evaluated. Compared to native starch, there was an increase in the X‐ray intensity and gel hardness of HMT starches, with the exception of the 25% moisture‐treated and 120°C heat‐treated starch. HMT reduced the swelling power and solubility of the pinhão starches when compared to native starch. There was an increase in the pasting temperature, final viscosity and setback and a decrease in the peak viscosity and breakdown of HMT pinhão starches compared to native starch. HMT increases the gelatinisation temperature of native pinhão starch and reduces gelatinisation enthalpy.     

Characterisation of starches separated from sorghum cultivars grown in India

Starches from 15 Indian sorghum cultivars were separated and evaluated for physicochemical, morphological, thermal, retrogradation, pasting and textural properties. The morphological characterisation revealed the presence of irregular-polyhedral as well as spherical shaped granules. A wide variation in amylose content ranging from 11.2% to 28.5% was observed. Thermal, retrogradation, pasting and textural characteristics also showed significant differences amongst all the starch cultivars. Principal component analysis was carried out to extract five principal components that could explain 75% of the total variance. The first two principal components PC1 (T_o, T_p, T_c and ΔH_gel) and PC2 (amylose content, range of gelatinisation, PHI and pasting and textural properties) could explain a cumulative variance of 44%, indicating the importance of amylose, thermal and textural properties on the sorghum starch functionality.     

Amylopectin structure of heat–moisture treated starches

The effects of heat–moisture treatment (HMT; moisture content of 25%, at 100°C for 24 h) on starch chain distribution and unit chain distribution of amylopectin in normal rice, waxy rice, normal corn, waxy corn, normal potato, and waxy potato starches were investigated. After HMT, starch chain distribution (amylose and amylopectin responses) of waxy corn and potato starches were identical to those of untreated starches, whereas the chromatographic response of waxy rice starch showed a slight decrease, but with a slight increase in peak tailing. This result indicated that HMT had no (or very limited) effect on the degradation of amylopectins. Analysis of unit chain distribution of amylopectins revealed that waxy characteristics affected the molecular structure of amylopectin in untreated starches, i.e., the CL of normal‐type starches was greater than that of waxy‐type starches. After HMT, the CL and unit chain distribution of all starches were no different than those of untreated starches. The results implied that changes in the physico‐chemical properties of HMT starches would be due to other phenomena rather than the degradation of amylopectin molecular structure. However, the thermal degradation of amylopectin molecules of waxy starches could occur by HMT at higher treatment temperatures (120 and 140°C).     

Structural Transformation of Sago Starch by Heat‐Moisture and Osmotic‐Pressure Treatment

Sago starch was modified by osmotic‐pressure treatment (OPT) and heat‐moisture treatment (HMT) and physicochemical characteristics were compared. In OPT, sago starch was suspended in saturated sodium sulfate solution and heated for 1 h at 100, 110 and 120°C, corresponding to a calculated osmotic pressure of 32,728, 33,640 and 34,552 kPa (assuming sodium sulfate dissociates completely), respectively, and in HMT, sago starch with 20% moisture content was used. Change of X‐ray diffraction pattern from C‐type to A‐type was obtained for OPT and HMT starch at 110°C and 120 °C, respectively. RVA viscograms of both OPT and HMT starch exhibited a decrease of peak and breakdown viscosity but increase of final viscosity and pasting temperature. Onset (T_o), peak (T_p), and conclusion temperature (T_c) of gelatinization of both OPT and HMT starch increased significantly with increase of treatment temperature. Biphasic broadening of T_p was observed for HMT starch indicating an inhomogeneous heat transfer during HMT. The observed narrow peaks of DSC curves indicated better homogeneity of OPT. These properties suggest that OPT starch is more suitable for large‐scale production.     

Physico‐chemical properties of starches from Indian kidney bean (Phaseolus vulgaris) cultivars

Starches isolated from four Kidney bean cultivars (French Yellow, Contender, Master Bean, Local Red) grown in temperate climate were studied for their physico‐chemical, morphological, thermal, pasting, textural and retrogradation properties. Physico‐chemical properties such as composition, amylose content, water absorption capacity, swelling power, syneresis, freeze–thaw stability and light transmittance showed significant differences among starches. Amylose content (36.4–41.7%) showed strong correlations with peak, trough, breakdown, final and setback viscosity, gel hardness, gumminess and chewiness. The starch granule morphology of these starches showed considerable variation when studied by scanning electron microscopy. Starch granules were observed to be round, irregular or elliptical with smooth surfaces. Master Bean starch granules were larger than those of other kidney bean starches. Pasting and textural properties of French Yellow starches were found to be higher than other kidney bean starches. Local Red starches showed the highest gelatinisation transition temperatures, whereas Master Bean starches showed the lowest transition temperatures.     

Structural properties and gelatinisation characteristics of potato and cassava starches and mutants thereof

The molecular size of amylopectin (AP) and amylose (AM), AP chain length distribution, crystallinity and granular structure (morphology and granule size distribution) of five wild type potato starches (wtps), five AM free potato starches (amfps), four high-AM potato starches (haps), one wild type cassava starch (wtcs) and one AM free cassava starch (amfcs) were investigated and related to their gelatinisation characteristics. Starches with higher levels of short chains [degree of polymerisation (DP) 6–9 and DP 10–14)] had lower gelatinisation onset (T_o), peak (T_p) and conclusion (T_c) temperatures, whereas higher contents of longer chains (DP 18–25 and DP 25–80) led to higher gelatinisation temperatures. Gelatinisation enthalpies (ΔH) increased with degree of crystallinity. The granules of wtps were larger than those of amfps and haps, respectively. No differences in morphology were observed between wtps and amfps granules, but the haps granules had more irregular surfaces and showed multi-lobed granules.     

Physicochemical and structural characteristics of starches from Chinese hull‐less barley cultivars

Fourteen hull‐less barley cultivars, collected from four major cultivated areas in China, were employed to investigate the structural and physicochemical properties of their starches in this study. Relatively wide variations in physicochemical properties of the starches were observed. Amylose content ranged from 23.1% to 30.0%, swelling power and water solubility index ranged from 12.8 to 19.9 g g^?1 and 12.7% to 23.7% respectively. Peak viscosity was from 170 to 346 Rapid Visco Unit (RVU), peak temperature (T_p) of starch gelatinisation was from 55.6 to 61.8 °C and enthalpy of starch retrogradation ranged from 0.3 to 3.1 J g^?1. Weight‐based chain‐length proportions of fa, fb₁, fb₂ and fb₃ in amylopectins ranged from 21.65% to 24.95%, 44.48% to 49.44%, 15.56% to 17.19% and 9.83% to 16.66% respectively. Correlation analyses showed that amylose content was inversely related to pasting parameters and enthalpy of gelatinisation. Pasting properties and amylopectin structures were the most important parameters to differentiate starch properties among different hull‐less barley cultivars in this study. This work will be useful for exploring applications of Chinese hull‐less barley starches in food and non‐food industries.     

Modification and properties of African yam bean (Sphenostylis stenocarpa Hochst. Ex A. Rich.) Harms starch I: Heat moisture treatments and annealing

African yam bean (Sphenostylis stenocarpa) starch was subjected to heat moisture treatments at 18% (HMT-18), 21% (HMT-21), 24% (HMT-24), 27% (HMT-27) and excess (Annealing) moisture levels. Proximate chemical composition of the starch samples revealed that the moisture content of the starches ranged between 6.7% and 12.5%. Following modification of the native starch, there was a reduction in the moisture level of the heat moisture treated starches from HMT-18 to HMT-27. However, the annealed starch (HMT-ANN) retained higher moisture content compared to native starch (AYB-Native). The carbohydrate, protein, ash, amylose and fat content reduced with all the forms of heat treatments. At the temperature range studied (60–90 °C), increasing level of heat moisture treatments reduced the solubility and swelling capacity. pH also exert a profound effect both on the solubility and the swelling of the starch. Increasing degree of alkalinity increased both solubility and swelling capacity. In the native and modified starch samples, replacement of the wheat flour by the starch resulted in increased alkaline water retention of the blends. Water absorption capacity of the starch increased with the severity of moisture treatments, while the oil absorption capacity decreased. Apart from HMT-18, there was improved gel forming capacity of all the other heat-modified starches.Pasting temperature increased after hydrothermal modifications, whereas peak viscosity (P_v), Hot Paste Viscosity (H_v), setback and breakdown values all reduced after heat moisture treatments. All the starches were of type-B viscosity.Differential scanning calorimetry studies revealed that heat moisture treatment shifted the onset temperature (T_o), peak temperature(T_p) and conclusion temperature (T_c) to higher values. The gelatinisation temperature of the annealed starch was comparable to native starch. In addition, gelatinisation band of the native starch increased progressively from HMT-18 to HMT-27. Heat moisture treatment reduced the gelatinsation enthalpy (ΔH), while the enthalpy of retrogradation(ΔH_r) increased with the storage time of the gelatinised starch. Retrogradation enthalpy of the heat moisture conditioned starches were lower than the value obtained for the native starch.X-ray diffraction studies of the starch indicated that all the starch samples showed the type-C diffraction pattern. Differences were however observed in their degree of crystallinity. Native starch exhibited the lowest crystallinity (20%) while annealed starch had the highest crystallinity (27%)Microscopy studies revealed surface indentation, formation of groves in the central region, folding of starch granules and formation of doughnut-like appearance in some of the starch samples.     

Chemical and Physical Characterisation of Grain Tef [Eragrostis tef (Zucc.) Trotter] Starch Granule Composition

Chemical and physical properties of starch granules isolated from five grain tef (Eragrostis tef) varieties were characterised and compared with those of maize starch. Endogenous starch lipids extracted with hot water‐saturated n‐butanol and total starch lipids extracted with n‐hexane after HCl hydrolysis were 7.8 mg/g (mean) and 8.9 mg/g (mean), respectively, slightly lower than in the maize starch granules. The starch phosphorus content (0.65 mg/g) was higher than that of maize starch but virtually the same as reported for rice starch. The starch granule‐swelling factor was lower than that of maize starch and extent of amylose leaching was higher. The starch X‐ray diffraction pattern was characteristic of A type starch with a mean crystallinity of 37%, apparently lower than the crystallinity of maize starch and more similar to that reported for rice and sorghum starches. The starch DSC gelatinisation temperature was high, like for other tropical cereals; T_o, T_p, T_c and ΔH were in the range 63.8—65.4, 70.2—71.3, 81.3—81.5 °C and 2.28—7.22 J/g, respectively. The lower swelling, apparently lower percentage crystallinity and lower DSC gelatinisation endotherms than maize starch suggest that the proportion of long amylopectin A chains in tef starch is smaller than in maize starch.     

Physicochemical properties and in vitro digestibility of flours and starches from taro cultivated in different regions of Thailand

This research aimed to study physicochemical properties and in vitro digestibility of flours and starches from taro cultivated in different regions of Thailand, that is, Kanchanaburi (KB), Chiang Mai (CM), Phetchaburi (PB) and Saraburi (SB). Taro starches were extracted from taro flours using either water or alkaline extraction. The taro flours had significantly (P ≤ 0.05) larger particle size, higher pasting and gelatinisation temperatures, and resistant starch content but lower total starch content, whiteness (L* value), paste viscosities and clarity than their corresponding extracted starches. All the taro starches exhibited polygonal and irregular granules and gave A-type X-ray diffraction pattern. The alkaline-extracted taro starches had significantly (P ≤ 0.05) higher extraction yield, total starch content, L* value, pasting and gelatinisation temperatures, and paste clarity but lower granular size, amylose content, resistant starch content, paste viscosities and relative crystallinity than their water-extracted counterparts.     

Extraction,Physicochemical and Compaction Properties of Tacca Starch — a Potential Pharmaceutical Excipient

Some physicochemical properties of tacca starch (Tacca leontopetaloides, Taccaceae) have been examined and the results compared to those of maize and potato starches. Tacca starch was found to have a higher amylose content than maize starch but a lower content than potato starch. The starch granules were small (average particle size 3.5 μm) relative to maize and potato starches and were predominantly polyhedral with edges. The gelatinisation characteristics except from the temperature were similar to those of maize starch but much higher than those of potato starch. Tacca starch had relatively higher swelling power and solubility than the other starches. Its features in the formation of compacts (tablets) were comparable to those of maize starch with tacca starch being more resistant to deformation.