Pisum sativum and Vicia faba Carbohydrates: Structural Studies of Starches

The fine structure of laboratory purified broadbean and smooth pea starches, with an amylose content of 32-34%, has been studied by pullulanase debranching, before or after beta-amylolysis, and by the properties of the chemically fractionated amylose and amylopectin. The enzymatic study has shown the presence of the three chain populations (DP > 60, 45 and 15) observed with other starches. The linear DP 15 and 45 chains occur in a ratio of 8.5 for broadbean and 9.75 for pea, which indicates an amylopectin similar to cereal starches. The λ_max, beta-amylolysis limit and intrinsic viscosity of the two amylopectins confirm the cereal-like nature. The two amylose components are not completely linear according to their beta-amylolysis limit of 81.5% which corroborates the in complete debranching of the total starch. The physical structure, studied by X-ray diffractometry, is of C-type. By submitting legume starch granules to mild acid hydrolysis (lintnerization), a residue has been obtained from both starches, which has an increase in the crystalline fraction, with a tendency towards the A-type pattern for broadbean and the B-type for pea. The crystallites are mainly formed of linear chains (CL 15) with some singly branched material (DP 25). Gelatinization of starch granules occurs at 44-65-86°C for broadbean with a heat of gelatinization of 3.8 cal g^?1 and at 48-61-80°C for pea with a heat of gelatinization of 3.2 cal g^?1.     

Chemical compositions,fine structure and physicochemical properties of kudzu (Pueraria lobata) starches from different regions

Three commercial kudzu starches from Vietnam, Japan and Korea were used to determine chemical compositions, isoflavone compounds, fine structure and physicochemical properties. The kudzu starch from Vietnam had polygonal granules, whereas the kudzu starches from Japan and Korea contained both polygonal and spherical granules. Total protein, lipid, ash and phosphorus contents present in these kudzu starches were less than 1% (starch basis). The kudzu starch from Vietnam and Korea contained both daidzein and daidzin, whereas the kudzu starch from Japan had only daidzein. These starches had similar actual amylose contents (22.2–22.9%). However, λ_max, blue value and apparent amylose contents of the kudzu starch from Vietnam were lower than those from Japan and Korea. Amylose molecules of the kudzu starch from Vietnam had the largest average degree of polymerization (DP_n) and number of chains (NC), followed by the kudzu starches from Japan and Korea. Amylopectin molecules of the kudzu starch from Vietnam also had the largest DP_n and NC, followed by the kudzu starches from Korea and Japan. X-ray diffraction patterns of the kudzu starches from Vietnam, Japan and Korea were A-type, C-type and B-type, respectively. The kudzu starch from Vietnam was found to have the specific characteristics such as significantly high gelatinization temperature, transition enthalpy and degree of crystallinity as compared to the kudzu starch from Korea and Japan.     

体内外消化高直链抗性水稻淀粉的波谱特性

以基因工程培育出来的高直链抗性淀粉水稻(TRS)为材料,利用粉末X射线衍射、傅里叶变换红外光谱分析技术,研究体内外消化TRS淀粉的波谱特性。结果表明：不被消化的抗性淀粉直链淀粉含量显著升高;TRS淀粉为C型晶体淀粉,由A型和B型晶体淀粉组成,其中A型晶体比B型晶体消化降解快,B型晶体具有抗消化降解的作用;TRS淀粉的无定形区域易被消化降解。     

Properties of Residual Starches of Sugary-2 and Sugary-2 Opaque-2 Maize Following Amylase Hydrolysis

Properties of residual starches of sugary-2 opaque-2 and sugary-2 maize starch granules hydrolyzed with glucoamylases were investigated. A crude and two crystalline glucoamylases were used. The amylopectin fractions of both starches hydrolyzed easier than that of amylose with all enzymes. Residual starches hydrolyzed by the crude glucoamylase accumulated low-molecular weight materials, which was not observed in residual starches attacked by crystalline glucoamylase. It was suggested that in the crude enzyme the contaminating α-amylase caused the accumulation of the minified fraction. It is also suggested that the crystalline region of sugary-2 opaque-2 starch may consist of a mixture of A-type and B-type patterns. Evidence for this was from observation of the changes in X-ray diffraction patterns of residual starch following amylase and acid hydrolysis.     

Structure and Viscoelastic Properties of Starches Separated from Different Legumes

A 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 (T_o T_p and T_c, respectively) were determined by differential scanning calorimetry. T_o and T_c 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 (ΔH_gel) 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> kidney bean> chickpea> blackgram> 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.     

The Influences of Chain Length of Amylopectin on Resistant Starch in Rice (Oryza sativa L.)

Amylopectin is the principle component of starch. To elucidate the relationships between amylopectin and resistant starch content, six rice mutants with altered fine structure of amylopectin were selected for comparative studies with the primary wild type and two types of amylose‐extender (ae) mutants. Significant differences in resistant starch content were observed among mutants with similarity or differences in amylose levels. Mutants high in resistant starch had significantly increased proportions of short amylopectin chains with DP≤12, decreased levels of intermediate chains with size of 13≤DP≤36, and decreased fractions of long chains with DP≥37. Additionally, there was a mutant different to ae, which was characterized by an increased level of short chains with 8≤DP≤12 and 13≤DP≤24, and a decreased proportion of long chains with DP≥37. The increased contents of short chains with 8≤DP≤12 and decreased of intermediate and long chains with 24≤DP were clearly associated with the increase of resistant starch in rice.     

湿热处理对不同晶型淀粉理化性质及消化性的影响

采用三种不同晶型淀粉即玉米淀粉(A型)、马铃薯淀粉(B型)、豌豆淀粉(C型)为原料,在水分含量为25%、温度120℃条件下湿热处理13 h,研究湿热处理对不同晶型淀粉的理化性质及消化性的影响。研究表明,与原淀粉相比,经湿热处理的三种淀粉的结晶结构均发生了改变,玉米淀粉由A型变为了A+V型,马铃薯淀粉和豌豆淀粉分别由B型和C型变为了A型;三种淀粉颗粒表面均出现了不同程度的破损;三种淀粉的部分颗粒的偏光十字的中心强度有所减弱;三种淀粉样品的糊化温度均升高,但A型和B型淀粉的焓值降低,而C型淀粉的焓值升高;三种淀粉的抗性组分含量均有所升高,抗消化性显著增强,其中C型淀粉变化最明显。     

Modification of granular corn starch with 4-alpha-glucanotransferase from Thermotoga maritima: effects on structural and physical properties

ABSTRACT:  Corn starch was converted using α-1,4-glucanotransferase from Thermotoga maritima (TmαGT), a hyperthermophilic bacterium, without inducing gelatinization, and the structural changes and physical properties of the modified starches were investigated. Enzyme modification was induced at 65 °C for 8, 16, or 24 h, and the morphology of the modified starches was observed with light and scanning electron microscopy. Granule integrity was mostly maintained after enzyme treatment, although some granules were partially fragmented as evidenced by enlarged surface pores and some cracks. The modified starches had lower apparent amylose levels than raw starch. The molecular weights of amylose and amylopectin molecules in the treated starches were lower than those of raw starch, and the amount of branched molecules, which had much lower molecular weights, also increased in the treated starches. The chain-length distribution of amylopectin showed an increased number of shorter branched chains. The modified starches showed a wider melting temperature range and a lower melting enthalpy than that of raw starch. The X-ray diffraction pattern of the modified starches showed typical A-type starch peaks, but the relative crystallinities were lower than that of raw starch. The solubility and paste clarity of the modified starches were much higher than those of raw starch. The modified starch gels maintained their rigidity over the whole frequency range tested and showed thermoreversibility between 4 and 75 °C. These results suggest that TmαGT can be used to produce granular corn starch, which contains amylose and amylopectin having lower molecular weights and a thermoreversible gelation property.     

Comparative studies on morphological and crystalline properties of B-type and C-type starches by acid hydrolysis

Comparative studies on acid hydrolysis of B-type Fritillaria starch and C-type Rhizoma Dioscorea and Radix Puerariae starches were carried out using a scanning electron microscope (SEM) and X-ray diffraction (XRD). Fritillaria, Rhizoma Dioscorea and Radix Puerariae starches were hydrolyzed with 2.2 mol/L at 35 °C for 2, 4, 8, 16 and 32 days, respectively. The SEM and XRD results revealed that B-type starch and C-type starch displayed different hydrolysis mechanisms. The acid corrosion started from the exterior surface of B-type starch granules followed by the interior core of starch granules. However, the hydrogen ion primarily attacked the interior of the C-type starch granules and then the exterior of starch granules. B-type starch granule started to crack at the hydrolysis period of 4 days while C-type starch granule was not cracked until the hydrolysis progressed up to 16 days. The crystalline type of B-type starch was not changed with increasing hydrolysis time. However, the crystalline type was gradually changed from C-type to A-type for the Rhizoma Dioscorea and Radix Puerariae starches with increase in the hydrolysis time. This result showed that the B-type polymorphs present in the C-type starch granule was preferentially hydrolyzed during the first stage of hydrolysis.     

Physicochemical properties of pressure moisture treated (PMT) and heat moisture treated (HMT) starches

Physicochemical properties of pressure moisture treated (PMT, 550 MPa, 10 min) and heat moisture treated (HMT, 100 °C, 10 h) starches were investigated. Effects of PMT and HMT were different depending on starch type. PMT starches showed dramatic changes in moisture sorption isotherm, pasting properties, thermal characteristics, solubility and swelling power (at 90 °C), and in vitro digestibility. The most dramatic difference between PMT and HMT starches was amylopectin melting transition, i.e., broadening in PMT and shift to high temperature in HMT starches. Moreover, B- and C-type starches revealed the more increase in amylopectin melting enthalpy than A-type starch. Both PMT and HMT did not increase the crystallinity but reorganized the amorphous area to compact, resulting in lower rapidly digestible starch and higher slowly digestible starch than those of native starches. Consequently, PMT changed the digestibility and physicochemical properties of starches with different modes of action compared with HMT.     

Impact of structural changes due to heat-moisture treatment at different temperatures on the susceptibility of normal and waxy potato starches towards hydrolysis by porcine pancreatic alpha amylase

The objectives of this study were to determine the impact of structural changes within the amorphous and crystalline domains of normal potato (NP) and waxy potato (WP) starches subjected to heat-moisture treatment (HMT) at 80, 100, 120 and 130 °C for 16 h at a moisture content of 27% and to determine the impact of structural changes at each of the above temperatures on the susceptibility on hydrolysis by porcine pancreatic α-amylase (PPA). The results showed that structural changes due to HMT were influenced by differences in starch chain mobility at the different temperatures of HMT. Starch chain mobility in turn was influenced by the interplay between the extent to which B-type crystallites were transformed into A + B-type crystallites, kinetic energy imparted to starch chains and amylose content. The main type of structural changes influencing physicochemical properties at the different temperatures of HMT was starch chain interactions (at 80 and 100 °C), disruption of hydrogen bonds between amylose (AM)–amylopectin (AMP) and AMP–AMP chains (at 120 and 130 °C), disorganization of AMP chains near the vicinity of the hilum (at 100, 120 and 130 °C) and formation of interrupted helices (at 130 °C). The susceptibility of NP and WP starches towards α-amylase decreased at 80 °C, but increased in the range of 100 to 130 °C. This suggested that α-amylase hydrolysis of HMT starches was influenced by the interplay of: 1) amount of A-type crystallites, 2) starch chain interactions and 3) changes to double helical conformation. Differences in granule morphology in PPA hydrolyzed NP and WP starches were largely influenced by the higher granular swelling in the latter. NP and WP starches exhibited heterogeneity in degradation (NP > WP) in both their native and HMT states.     

Xerophytic Gourd Root Starches. Part V: Structural Characteristics,Gelatinization Properties and Rheologic Behavior of Coyote Gourd Starch (Cucurbita digitata Gray)

As part of a continuing study of xerophytic cucurbit starches, coyote gourd (Cucurbita digitata Gray) root starch and starch components have been examined. Coyote gourd amylose and amylopectin fractions were highly susceptible to β-amylolysis; average degree of polymerization and average unit chain lengths of the latter material intimated the large size and multiply-branched asymmetrical structure of the molecules. The isolated granules were small, spherical or irregular in shape and birefringent. Crystalline regions of native granules evinced a B-type diffraction pattern which was altered to that of the C-type by treatment with moist heat. Gelatinization characteristics, restricted swelling and low solubility of the subject material suggested a highly organized granule architecture. Gelatinized suspensions formed stiff opaque gels upon cooling which were resistant to deformation. A strong degree of association among granule components was also evident in the rheologic behavior of the material. In general, the effects of suspension concentration, acidity and sucrose upon the rheologic performance of this material were predictable from known behavior of standard starches; the addition of salt or oil resulted in increased pasting temperatures and had variable influence upon suspension viscosities.     

Modelle für Struktur und Eigenschaften der Stärke

Models for the Structure and Properties of Starch. Regularly-shaped model substances may be helpful to get insight in starch properties. Suitable compounds are prepared by phosphorolytic synthesis with free maltooligomers as primers and maltooligomers coupled to a support leading to linear and different types of branched products carrying amylose chains of uniform length. In the first part of this paper, the influence of chain length, chain length distribution and density of branching on solubility, retrogradation and gel formation is discussed more generally. Interest is focused on conclusions which may be derived for the special role of the natural starch components. The second part reports on studies with pure maltooligomers which extend results from the synthetic models into the short-chain region. X-ray powder patterns of samples precipitated from aqueous solution gave the B-type in the range DP 20 to 13, and the A-type in the range DP 12 to 10. A limit for retrogradation and crystallization is obviously DP 8 to 9. With the pure compounds the C-type is not observed. Results indicate that the x-ray type of different starches may be related to the length of the outer branches of amylopectin emerging from the cluster regions. – In the presence of amylose I₃^- ions are slowly formed from an iodide-free iodine solution. Corresponding studies with the series of maltooligomers show a close correlation between the extent of I₃ formation and the tendency for helix formation as anticipated. Remarkably, maltotriose was found being equally active as α-cyclodextrin indicating that both substances are quite similar in their conformation in aqueous solution.     

Physicochemical properties and amylopectin chain profiles of cowpea,chickpea and yellow pea starches

Starches from cowpea and chickpea seeds were isolated and their properties were compared with those of commercial yellow pea starch. Amylose contents were 25.8%, 27.2%, and 31.2%, and the volume mean diameter of granules, determined in the dry state, were 15.5, 17.9, and 33.8 μm for cowpea, chickpea and yellow pea starches, respectively. All three legume starches showed a C-type X-ray diffraction pattern and two-stage swelling pattern. Amylopectin populations were isolated and the unit chain profiles were analyzed by HPLC after debranching with pullulanase. The degree of polymerization (DP) of short chain populations was about 6–50 and the populations of long chain had a DP of 50–80. Cowpea showed a lower weight ratio of short:long chains than chickpea and yellow pea starches. The larger portion of long side chains in cowpea amylopectin can be correlated with a higher gelatinization temperature, greater pasting peak and a slight difference in crystalline structure found for cowpea starch. Chickpea and yellow pea starches exhibited similarity in unit chain profile of amylopectin as well as in gelatinization temperature and pasting profile, while they differed in amylose content, particle size and syneresis. It is assumed that the chain length distribution of amylopectin has a large influence on starch properties.     

Structural and physicochemical properties of banana resistant starch from four cultivars

Resistant starches were isolated from four banana cultivars: Musa AAA Cavendish, Musa ABB Bluggoe, Musa ABB Pisan Awak, and Musa AA Pisang mas. The structural and physicochemical properties of banana resistant starches were studied. Results showed that the particle size and shape of four banana resistant starches were different. Cavendish and Bluggoe banana resistant starch had a C-type crystalline structure, whereas Pisan Awak and Pisang mas had a B-type. The water-holding capacity of Pisang mas was the maximum. The solubility of Pisan Awak and Pisang mas was higher as compared to Cavendish and Bluggoe. The transparency of Cavendish banana resistant starch was the highest. More amylose was observed in Bluggoe and Pisan Awak banana resistant starch, whereas more amylopectin was observed in Cavendish and Pisang mas banana resistant starch. The initial pasting temperatures of Cavendish and Bluggoe banana resistant starches were higher as compared to Pisan Awak and Pisang mas banana resistant starch. The peak viscosity of Cavendish banana resistant starch was the highest in these four samples. The heat stability of Bluggoe banana resistant starch was the best one in the four banana resistant starches. The retrogradation was hard in the case of Bluggoe and Pisan Awak banana resistant starch. In conclusion, the properties of the four banana resistant starch samples were not the same, indicating that these could be used in different food products.     

Effects of the Barley amo1 and wax Genes on Starch Structure and Physicochemical Properties

Starch structural mutants showing abnormal endosperm characteristics have been used for investigating the effects of the mutation on structure and physicochemical properties of starches. Inbred lines of barley cultivars ‘Shikoku Hadaka 97’ and ‘Glacier AC38’ were used to investigate the impact of amo1 and waxy genes on starch properties. The amo1 type starch had high apparent amylose content and low starch content. The amo1+waxy type starch contained very little amylose. The content of long chains of amylopectin as detected with high‐performance size‐exclusion chromatography (HPSEC) was decreased, and that of amylopectin chains with the degree of polymerization (DP) of 12‐36 was increased in amo1 and amo1+waxy type starches. The amo1 and amo1+waxy type starches exhibited high gelatinization temperatures and low gelatinization enthalpies.     

Gel texture and chain structure of amylomaltase-modified starches compared to gelatin

Amylomaltase (AM) (4-α-d-glucanotransferase; E.C. 2.4.1.25) from Thermus thermophilus was used to modify starches from various botanical sources including potato, high amylose potato (HAP), maize, waxy maize, wheat and pea, as well as a chemical oxidized potato starch (Gelamyl 120). Amylopectin chain length distribution, textural properties of gels and molecular weight of 51 enzyme and 7 non-enzyme-modified starches (parent samples) were analyzed. Textural data were compared with the textural properties of gelatin gels. Modifying starch with AM caused broadening of the amylopectin chain length distribution, creating a unimodal distribution. The increase in longer chains was supposedly a combined effect of amylose to amylopectin chain transfer and transfer of cluster units within the amylopectin molecules.Exploratory principal component analysis (PCA) data analysis revealed that the data were composed of two components explaining 94.2% of the total variation. Parent starches formed a cluster separated from that of the AM-modified starches.Extended AM treatments reduced the apparent molecular weight and the gel texture without changing the amylopectin chain length distribution. However, the gel texture was typically increased as compared to the parent starch. AM-modified HAP gels were about twice as hard as gelatin gels at identical concentration, whereas gels of pea starch were comparable to gelatin gels. Modifying Gelamyl 120 and waxy maize with AM did not change the textural properties. Branching enzyme (BE) (1,4-α-d-glucan branching enzyme; EC 2.4.1.18) from Rhodothermus obamensis was used in just one modification and in combination with AM. The combined AM/BE modification of pea starch resulted in starches with shorter amylopectin chains and pastes unable to form gel network even at concentration as high as 12.0% (w/w). The PCA model of all gel texture data gave suggestive evidence for starch structural features being important for generating a gelatin-like texture.     

The Interaction of the Amylose-Extender and Waxy Mutants of Maize (Zea Mays L.) Fine Structure of Amylose-Extender Waxy Starch

Investigations into the nature of the effect of the amylose-extender (ae) mutant of maize (Zea mays L.) on amylopectin structure were conducted by studying the fine structure of amylose-extender waxy (ae wx) starch. Approximately 59.6% of the starch from ae wx endosperms was converted to maltose by β-amylase. This starch contained 21% apparent amylose and had a λmax of 580 for the iodine-starch complex. Fractionation of ae wx starch on Sepharose 4B-200 gave an elution profile with a single peak characteristic of amylopectin. From these observations we concluded that ae wx starch consisted of an altered amylopectin, with iodine binding properties such that an apparent amylose content of 21% was measured. The fine structures of ae wx and waxy (wx) starches were determined. Pullulanase-debranched chains of whole starches and β-limit dextrins were fractionated by gel permeation. The amylopectin of ae wx was shown to be a loosely branched amylopectin with an average internal chain length of 52 glucose units compared with a length of 30 glucose units for wx. The ae wx outer chains were longer than those of wx and fewer in number per mg of starch. These characterizations demonstrate that ae wx starch has a unique structure which is similar to the anomalous amylopectin reported in ae starch.     

Amylose Content and Chain Profile of Amylopectin from Normal,High Amylose and Waxy Barleys

The amylose content and the chain profile of amylopectin from normal, waxy and high amylose barley starches were determined after enzymatic debranching and gel permeation chromatography and the degree of branching of the amylopectin was analysed by 1H-n.m.r. spectroscopy. The normal barley starch contained around 30%, the high amylose around 40% and the waxy starch 9% amylose. The amylopectin of the high amylose starches had longer chains than those of the normal or waxy starches, especially in the molecular weight interval 5,400-8,000, but less of those below 2,400 in molecular weight. The chain length of amylopectin from high amylose barley was on average 5 units longer than those of normal or waxy barleys.     

Physico-Chemical Characteristics of Starches from Sal (Shorea robusta) and Dhupa (Vateria indica) Seeds

Pure, white starches were isolated in ∼30% yields from defatted sal and dhupa meals. Both starches consisted of granules of varying size and shape characteristics, and contained considerable amounts of protein and lipid constituents. C 18:1, C 16:0 and C 18:0 were the major fatty acids present in both free and bound lipid fractions; whereas the latter in addition contained C 18:2 (∼20%). Both starches exhibited two-stage swelling in water; for sal starch the solubility was markedly lower but its swelling power was considerably higher. In DMSO the sal starch was readily soluble but not dhupa starch (only ∼20% solubility). The hot paste viscosity as well as set back viscosity of dhupa starch was much higher in comparison to those by sal starch. Very highly purified sal starch virtually exhibited no hot paste viscosity, and behaved like amylopectin-rich material. The latter had only 1.5% amylose as against of ∼24% in original sal starch. X-Ray powder patterns revealed sal starch to be of A-type and dhupa starch to be of B-type. Both the starch granules were susceptible for in vitro attack by human salivary α-amylase.