Pasting Properties of Potato Starch and Waxy Maize Starch Mixtures

The pasting viscosity, morphological properties, and swelling properties of potato starch and waxy maize starch mixtures at different ratios were investigated. Pasting analysis of the starch mixtures (7% solids in water, w/w) using a Rapid Visco Analyser showed linear changes in peak viscosity and pasting temperature according to the mixing ratios of both starches, but not in breakdown and setback. The pasting profile revealed that the starches rendered mutual effects during pasting, more significantly when the amounts of potato and waxy maize starches were similar. The volume fraction of swollen granules and the presence of amylose appeared to be important parameters in the mutual effects of both starched during pasting. Under a light microscope, the swelling of potato starch granules was delayed by the presence of waxy maize starch. Overall results indicate that new pasting properties can be generated by mixing starches of different botanical sources.     

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.     

The effect of electrostatic interactions on pasting properties of potato starch/xanthan gum combinations

The effects of electrostatic interactions on pasting properties of potato starch (PS)/xanthan gum (XG) combinations were investigated. The RVA peak viscosity of combinations was decreased firstly and then increased with the adding of XG. The analysis and regression model performance of RVA measurement showed that there was the relationship between pasting properties of combinations and XG concentrations. Electrostatic repulsions between native potato starch or anionic modified potato starches (AP) and XG could be present by decreasing peak viscosity, but the pasting temperatures showed increasing trend. However, electrostatic attractions between cationic modified potato starch (CP) and XG showed the opposite effect. Negative zeta potential determination for combinations (− 54.6 mv) was higher than PS (− 35.2 mv) illustrated that combinations had more electronegativity and stability, in addition a phase-separated microstructure was exhibited in the combinations determined by Zeta potential results. SEM micrographs presented that XG film attached to the surface of PS granules, which inhibited the starch granules destruction and leaching of amylase. The electrostatic repulsion leaded to more stability of the three dimensional network structures of combinations. The strong electrostatic interactions between PS and XG were found to play an important role on the pasting properties of the combinations.     

Substituent distribution within cross-linked and hydroxypropylated sweet potato starch and potato starch

Revealing the substituents distribution within starch can help to understand the changes of starch properties after modification. The distribution of substituents over cross-linked and hydroxypropylated sweet potato starch was investigated and compared with modified potato starch. The starches were cross-linked with sodium trimetaphosphate and/or hydroxypropylated with propylene oxide. The native and modified starches were gelatinized and hydrolysed by pullulanase, β-amylase, α-amylase and a combination of pullulanase, α-amylase and amyloglucosidase. The hydrolysates were analysed by HPSEC, HPAEC and MALDI-TOF mass spectrometry. Cross-linking had only a slight effect on the enzymatic hydrolysis, where hydroxypropylation evidently limited the enzymatic hydrolysis. The results obtained suggest that the hydroxypropyl substituents are not distributed regularly over the starch chains. Although the average substitution was around 2 hydroxypropyl groups per 10 glucose units, in the enzyme digests of hydroxypropylated starches, oligomer fragments of 10–15 glucose units, carrying 5–8 hydroxypropyl groups, were identified. It is hypothesised that higher levels of substituents are present in the amorphous regions and periphery of clusters of starch granules. This is the first time that the location of hydroxypropyl groups within sweet potato starch has been examined in this detail. Despite significant differences in granule architecture between starches from potato and sweet potato, similar patterns of hydroxypropylation have been found.     

Development of oxidised and heat-moisture treated potato starch film

This study investigated the effects of sodium hypochlorite oxidation and a heat-moisture treatment of potato starch on the physicochemical, pasting and textural properties of potato starches in addition to the water vapour permeability (WVP) and mechanical properties of potato starch films produced from these starches. The carbonyl contents, carboxyl contents, swelling power, solubility, pasting properties and gel texture of the native, oxidised and heat-moisture treated (HMT) starches were evaluated. The films made of native, oxidised and HMT starches were characterised by thickness, water solubility, colour, opacity, mechanical properties and WVP. The oxidised and HMT starches had lower viscosity and swelling power compared to the native starch. The films produced from oxidised potato starch had decreased solubility, elongation and WVP values in addition to increased tensile strength compared to the native starch films. The HMT starch increased the tensile strength and WVP of the starch films compared to the native starch.     

Morphological,thermal, rheological and noodle‐making properties of potato and corn starch

A comparison between the morphological, thermal, rheological and noodle‐making properties of corn starch and potato starches separated from five different potato cultivars was made. The granule size and shape of all starches differed significantly. Potato starch granules were comparatively larger than corn starch granules, while the transition temperatures were found to be higher for corn starch. Consistency coefficients and flow behaviour indices measured by back extrusion were higher for potato starches than for corn starch. Stickiness of cooked starch pastes was observed to depend upon their consistency coefficient. The gels made from all potato starches showed higher gel strength than those from corn starch. The gel strength of starches from both corn and potato increased during refrigerated storage. The amylose content, swelling power, solubility and light transmittance values of potato starches were significantly higher than those of corn starch. Noodles made from potato starches had higher cooked weight and cooking loss than corn starch noodles. Texture profile analysis revealed that potato starch noodles also had higher hardness and cohesiveness than corn starch noodles. Hardness of cooked noodles from all starches increased and cohesiveness decreased during storage. Noodles made from starches of higher viscosity exhibited higher hardness and cohesiveness. Textural differences among cooked starch noodles appeared to be associated with morphological, thermal and rheological properties of corn starch and potato starches. © 2002 Society of Chemical Industry     

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.     

Altering pasting characteristics of sweet potato starches through amino acid additives

ABSTRACT:  This study assessed the effects of amino acid additives, aspartic acid, leucine, lysine, and methionine, on the pasting and thermal characteristics of white- and orange-fleshed Beauregard sweet potato starches. A rapid visco analyzer 3D was used to determine pasting properties. In comparing pasting characteristics, starch from orange-fleshed sweet potato was found to be easier to cook, had a lower potential for retrogradation, and was less stable during heating than the white-fleshed sweet potato starch. The RVA analysis showed that the charged amino acids, aspartic acid and lysine, altered pasting characteristics of the 2 starches more than the neutral amino acids, leucine and methionine. Aspartic acid had similar effects on both starches, making them less stable during cooking and lowering the potential for retrogradation. Lysine, when added to the orange-fleshed sweet potato starch, decreased the breakdown, allowing for more stability during cooking. This study showed that pasting properties of sweet potato starches can be altered by the addition of amino acids.     

Properties of starch from root tuber of Stephania epigaea in comparison with potato and maize starches

The dry root tuber of Stephania epigaea contained 36.5% starch, indicating a good starch source. In this study, starch was isolated from S. epigaea. Its morphology, physicochemical, and functional properties were investigated and compared with potato and maize starches. S. epigaea starch had small spherical granules with centric hila and large ellipsoidal granules with eccentric hila, and granule sizes varied from 7 to 40 μm. The starch had 33.9% amylose content and B-type crystallinity. The gelatinization onset, peak, and final temperatures were 59.4, 62.3, and 66.2°C, respectively, and were lower than those of potato and maize starches, but the enthalpy (16.3 J/g) was higher than that of potato and maize starches. The peak, hot, final, and breakdown viscosities were 2227, 1623, 2149, and 594 dPa s, respectively, and were significantly higher than those of maize starch and lower than those of potato starch. S. epigaea starch was more susceptible to amylase hydrolysis and in vitro digestion than potato starch and less than maize starch. This study would be useful for the applications of starch from S. epigaea in the food and non-food industries.     

RVA study of mixtures of wheat flour and potato starches with different phosphorus contents

A rapid visco analysis (RVA) system was used to study the pasting properties of mixtures of wheat flour and potato starches with high phosphorus (HPS), medium phosphorus (MPS) and low phosphorus (LPS) contents, different granule sizes and different amylose contents. The peak viscosities, trough and breakdown, final viscosities, setback viscosities and peak times of control potato starches were found to be higher than those of wheat flour. The peak viscosities were increased significantly with increase of potato starches in the mixtures. Thus, the peak times decreased with increase of potato starch in the mixtures. The breakdown viscosities increased significantly with increase of potato starches in the mixtures and the values were found to be higher in HPS-wheat, followed by MPS-wheat and LPS-wheat mixtures. The final viscosities of HPS-wheat mixtures were highest, followed by MPS-wheat and LPS-wheat mixtures. The setback viscosities of LPS-wheat were significantly higher than those of MPS-wheat and HPS-wheat mixtures at 30 to 50% potato.     

Physicochemical Characterization and Application of Yam (Dioscorea cayenensis‐rotundata) Starch as a Pharmaceutical Excipient

Yam starch from Dioscorea cayenensis‐rotundata complex was isolated and characterized by scanning electron microscopy (SEM), particle size analysis, X‐ray diffraction, differential scanning calorimetry (DSC), compaction and rheology, and compared to maize (Zea mays) and potato (Solanum tuberosum) starches. Yam starch exhibited a log‐normal distribution of flattened ovoid shaped granules with a mean particle size of 25 µm. X‐ray diffraction showed a C‐type crystalline pattern with the degree of relative crystallinity estimated to be 34%. DSC analysis suggests that the crystalline regions in yam starch are thermally and structurally more stable as in maize and potato. Irrespective of the relative humidity (39, 67, 78% R.H.) yam starch exhibited higher moisture uptakes than maize starch and lower than potato. Intermediate values of swelling power and amylose leaching were obtained for yam as compared to maize and potato. Compaction properties of yam and potato starches were similar. However, compacts from yam presented a relatively lower tensile strength. Aqueous starch systems (4%) of yam and maize starches showed analogous shear‐thinning (pseudo‐plastic) behavior suitably described by the power‐law model. These results support the potential use of yam starch as excipient comparable to potato starch in pharmaceutical solid forms and as thickening agent similar to maize in pharmaceutical applications.     

Physicochemical Characteristics of Starches from Unripe Fruits of Mango and Banana

Mango and banana starches were isolated from unripe fruits and their morphology; thermal and pasting properties; molar mass and chain length distribution were determined. Mango starch granules were spherical or dome‐shaped and split, while banana starch had elongated granules with a lenticular shape. Amylopectin of both fruit starches had a lower molar mass than maize starch amylopectin; however, mango amylopectin had the highest gyration radius. Banana amylopectin showed the lowest percentage of short chains [degree of polymerization (DP) 6–12] and the highest level of long chains (DP ≥ 37); mango amylopectin presented the highest fraction of short chains, but the level of longest chains was intermediate between those of banana and maize amylopectins. Banana starch presented the highest average gelatinization temperature followed by mango starch and maize starch had the lowest value; a similar pattern was found for the gelatinization enthalpy. The two fruit starches had a lower pasting temperature than maize starch, but the former samples showed higher peak and final viscosities than maize starch. Structural differences identified in the fruit starches explain their physicochemical characteristics such as thermal and pasting behavior.     

马铃薯抗性淀粉理化性质的研究

以马铃薯原淀粉为对照,研究了纤维素酶-压热法制备的马铃薯抗性淀粉的理化性质。结果表明,马铃薯原淀粉颗粒呈椭球形,表面光滑;而抗性淀粉的颗粒状结构消失,形成了连续的致密结构,表面不再光滑。红外光谱分析表明,抗性淀粉分子中未出现新的基团,只较原淀粉形成了更多的氢键。马铃薯原淀粉的分子晶型为A型,整体结晶度为22.82%;抗性淀粉的分子晶型为B型,整体结晶度为29.64%。马铃薯抗性淀粉的溶解度、透明度远远低于原淀粉;膨润度、持水性优于原淀粉。抗性淀粉的沉降速度较快,沉降性比原淀粉强。原淀粉糊化温度为65.8 ℃,峰值黏度可达到10 770 mPa·s;而抗性淀粉其糊化温度高于95 ℃。     

Effect of Acetylation on Some Properties of Corn and Potato Starches

Corn starch and starches separated from different potato cultivars were acetylated to evaluate the effect of plant source on the physicochemical, morphological, thermal, rheological, textural and retrogradation properties of the starches. Corn starch showed a lower degree of acetylation than potato starches under similar experimental conditions. The degree of acetylation for different potato starches also differed significantly. Morphological examination revealed that the granules of acetylated Kufri Chandermukhi and Kufri Sindhuri starches tended to appear as fused and less smooth than native starch granules. Acetylation of corn and potato starches decreased the transition temperatures and enthalpy of gelatinization and increased swelling power and light transmittance. However, the change in these was greater in the potato starches with higher percentage of small sized granules. Acetylated starches showed higher peak G', G'' and lower tan δ than their counterpart native starches during heating. Among the starches from different cultivars, the change in the rheological parameters after acetylation differed to a significant extent. The retrogradation was observed to be negligible in the acetylated cooked starch pastes. Results implied that the change in functional properties of starches with acetylation depends on source and granule morphology of native starch.     

Pasting properties of hydroxypropylated starches before or after proteinase treatment

To examine the effect of starch protein on hydroxypropylation, corn (normal and waxy) and potato starches were hydroxypropylated with propylene oxide at two levels (8.3 and 12.3% based on dry basis of starch weight) before or after proteinase (thermolysin) treatment, and then pasting properties of the starches were measured. For normal corn starch, protein appeared to be involved in hydroxypropylation, especially at the higher concentration of reagent (12.3%); the starch hydroxypropylated after proteinase treatment (Enz‐HP) showed less reaction efficiency than that only hydroxypropylated (HP) or proteinase treated starch after hydroxypropylation (HP‐Enz). This suggests a possible reaction between some of the reagent and the starch proteins that exist in the channel and surface of the starch granules. However, not much difference was found with the waxy corn starch, as it contains much lower amounts of amylose and protein than normal corn starch. The potato starch, which has no channels, showed complicated protein effects. For potato starch, a different access of the enzyme and chemical reagents to the granule matrix could be possible.     

Effects of sodium dodecyl sulphate and sonication treatment on physicochemical properties of starch

Effects of sodium dodecyl sulphate (SDS) and sonication treatment on physicochemical properties of starch were studied on four types of starch, namely, corn, potato, mung bean, and sago. The SDS and sonication treatments caused a significant reduction of protein content for all the starches. The SDS treatment did not cause apparent damage on granular structure but sonication appeared to induce changes such as rough surface and fine fissures on starch granules. The combination of SDS and sonication increased amylose content for all starches. This could be attributed to the removal of surface protein by SDS and structural weakening by sonication which facilitated amylose leaching from swollen starch granule. The X-ray pattern for all starches remained unchanged after SDS treatment, suggesting no complexation of amylose–SDS had occurred. Combined SDS-sonication treatment increased swelling and solubility of corn, mung bean, and potato starch. The treated starches showed significant increase in peak viscosity with reduction in pasting temperature, except for potato starch. Results of the present study indicate the possibilities of exploring SDS and sonication treatments for starch modifications.     

Influence of molecular structural characteristics on pasting and thermal properties of acid-methanol-treated rice starches

Rice starches from TKW1, TNG67 and TCS17 varieties, differing widely in amylose contents (0.1, 18.3 and 29.2%) were treated at 45 °C for 1 h in methanol containing various amounts of HCl. The recovery, pasting properties, thermal behaviors, molecular size and chain length distribution of starch were observed. Starches exhibited widely different pasting and thermal behavior upon acid-methanol treated (AMT). Degradation of starches upon AMT affected the leaching extent and chain length of amylose. No obvious changes were found on chain length and content of chain fractions of amylopectin. The pasting viscosity of rice starch decreased with increasing concentration of HCl, and the pasting profiles depended on the variety of rice. The pasting profile of AMT-TNG67 starch showed a two-step increasing pattern during heating, while TKW1 and TCS17 starches showed smoothly increasing pasting curves. The relationship between pasting patterns of AMT-TNG67 starches with amylose leaching and two stages of swelling behavior of starch granules was investigated. Results indicated that the pasting of starch granules depend on the amount, as well as the chain length, of amylose in granules.     

Physicochemical Properties of Starch Isolated from Bracken (Pteridium aquilinim) Rhizome

Bracken (Pteridium aquilinum) is an important wild plant starch resource worldwide. In this work, starch was separated from bracken rhizome, and the physicochemical properties of this starch were systematically investigated and compared with 2 other common starches, that is, starches from waxy maize and potato. There were significant differences in shape, birefringence patterns, size distribution, and amylose content between bracken and the 2 other starches. X‐ray diffraction analysis revealed that bracken starch exhibited a typical C‐type crystalline structure. Bracken starch presented, respectively, lower and higher relative degree of crystallinity than waxy maize and potato starches. Ordered structures in particle surface differed among these 3 starches. The swelling power tendency of bracken starch in different temperature intervals was very similar to that of potato starch. The viscosity parameters during gelatinization were the lowest in waxy maize, followed by bracken and potato starches. The contents of 3 nutritional components, that is, rapidly digestible, slowly digestible, and resistant starches in native, gelatinized, and retrograded starch from bracken rhizome presented more similarities with potato starch than waxy maize starch. These finding indicated that physicochemical properties of bracken starch showed more similarities with potato starch than waxy maize starch.     

紫薯淀粉结构与理化性质研究

目的 了解紫薯淀粉的结构和理化性质。方法 利用碱提取法从紫薯中提取淀粉, 与普通玉米淀粉进行对比, 分别对淀粉结构(分子链结构、结晶结构等)和理化性质(透明度、凝沉性、冻融稳定性、热稳定性)进行研究。结果 紫薯淀粉直链含量(24.5%)比玉米淀粉(26.7%)低, 两者均为A型结晶结构, 但紫薯淀粉的结晶度和分子有序程度比玉米淀粉高; 紫薯淀粉糊的透明度高于玉米淀粉糊, 且随时间延长其透明度下降程度比玉米淀粉糊低; 紫薯淀粉糊不易发生凝沉现象, 但其析水率(21.4%)比玉米淀粉糊高, 即冻融稳定性弱于玉米淀粉糊; 此外, 紫薯淀粉部分结构的热稳定性大于玉米淀粉。结论 紫薯淀粉在分子链结构和结晶结构上与玉米淀粉有较小差异, 但在理化性质上与玉米淀粉差别较大, 可为其工业应用提供指导基础。     

三种杂豆淀粉理化特性的比较

以豇豆(Vigna unguiculata (L.) Walp.)、小黑芸豆(Phaseolus vulgaris L.)和小扁豆(Lens culinaris M.)为材料,采用湿磨法提取淀粉,以马铃薯淀粉和玉米淀粉作对照,对淀粉理化性质进行比较研究。结果表明,豇豆、小黑芸豆和小扁豆淀粉颗粒多为肾形,少数圆形,且偏光十字明显,表观直链淀粉含量分别为34.98%、45.35% 和37.24%。3 种淀粉的膨胀度和溶解度均随温度升高而增加,起糊温度在72.9～77.0℃之间,小黑芸豆淀粉起糊温度最高,峰值黏度、破损值、最终黏度和回生值最低。豇豆淀粉糊化特性与小黑芸豆淀粉相反,起糊温度较低,峰值黏度、破损值、最终黏度和回生值最高。3 种豆类淀粉To、Tp 和Tc 具有显著性差异,但焓值差异不显著,焓值大小顺序为小扁豆淀粉＞豇豆淀粉＞小黑芸豆淀粉。