Physicochemical Properties of Field Pea, Pinto and Navy Bean Starches

Legume starches were compared for physicochemical properties that may explain differences in functional properties. Field pea starch had higher amylose, greater swelling power and solubility, and lower pasting temperatures than pinto and navy bean starches. Scanning electron microscopy (SEM) showed that field pea starch had larger, more irregularly shaped granules and more broken large granules than pinto or navy starches. The most starch damage was observed for field pea. Pinto and navy bean starches had greater resistance to swelling at 60°C than field pea indicating a more strongly bonded micellar network. Higher cold paste viscosity was observed for navy bean and field pea.     

甘肃主要杂豆淀粉理化特性分析

以甘肃产三角豌豆、白豌豆、小白芸豆、麻豌豆为材料,采用湿磨法提取淀粉,以玉米、马铃薯及绿豆淀粉为对照,对杂豆淀粉的理化特性进行分析。结果表明：参试杂豆淀粉颗粒多呈卵圆形,偏光十字较明显,多呈“X”形和斜十字形,部分淀粉颗粒呈现明显多脐点现象,平均粒径为21～29μm,其中三角豌豆淀粉的粒径最大而麻豌豆淀粉颗粒最小;淀粉颗粒的结晶类型与绿豆淀粉相同,为C型。其直链淀粉含量远高于玉米淀粉和马铃薯淀粉,且麻豌豆＞小白芸豆＞白豌豆＞三角豌豆淀粉。杂豆淀粉属限制型膨胀淀粉,起糊温度为72.6～78.8℃,且具有较好的热糊和冷糊稳定性,淀粉糊的透明度较高,但凝沉速度均极快,冻融稳定性也都较差。4种杂豆淀粉的理化特性与绿豆淀粉相近,可耐受高温处理,但不宜用于冷冻类食品的生产。     

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。     

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.     

Characterization of Different Starches Oxidized by Hypochlorite

The effects of starch origin (potato, corn, and rice starches) and hypochlorite level (NaOCl, 0.8% and 2% w/w) on the structures and physicochemical properties of oxidized starches were investigated. Carboxyl and carbonyl group contents of oxidized starches increased with increasing NaOCl level, with potato starch having the highest and corn starch having the lowest carboxyl groups content at both NaOCl levels. Oxidation generally reduced the pasting temperature and viscosity of native starches as demonstrated by using a Rapid Visco Analyser. The peak viscosities of oxidized rice and corn starches were higher than those of their native counterparts at 0.8% NaOCl. The morphology of starches was not altered and X‐ray diffraction patterns of all the starches remained unchanged after oxidation. Oxidized starch batters exhibited greater adhesions than did native starch batters, with rice starch batter exhibiting the greatest adhesion. Carbohydrate profiles by high‐performance size‐exclusion chromatography indicated that both amylopectin and amylose were degraded during oxidation. The level of oxidation was largely dependent on the degree of crystallinity of starch and the degree of polymerization of amylose, whereas the adhesion property of oxidized starch was mainly attributed to its granular size and shape.     

热处理对不同直链淀粉含量的玉米淀粉理化性质的影响

采用快速黏度分析法、离心法、差示扫描量热分析法、动态流变仪分析法等,研究了干热与湿热处理对3种不同直链淀粉含量的玉米淀粉糊化性质、膨润性质、热力学性质、流变性质的影响,为淀粉的物理改性研究和加工应用提供理论依据。结果表明,干热处理使淀粉更易糊化,表现为3种玉米淀粉糊化温度降低,溶解度、膨胀度增加。湿热处理加大糊化难度,使3种玉米淀粉的糊化温度升高,膨胀度降低。热处理使玉米淀粉糊稠度、糊化焓值降低。蜡质玉米淀粉经热处理后,溶解度和老化率增加。流变性质测定结果表明,湿热处理不利于高直链玉米淀粉黏弹性凝胶的形成。     

Development and Physicochemical Characterization of New Resistant Citrate Starch from Different Corn Starches

Resistant starch has drawn broad interest for both potential health benefits and functional properties. In this study, a technology was developed to increase resistant starch content of corn starch using esterification with citric acid at elevated temperature. Waxy corn, normal corn and high‐amylose corn starches were used as model starches. Citric acid (40% of starch dry weight) was reacted with corn starch at different temperatures (120–150°C) for different reaction times (3–9 h). The effect of reaction conditions on resistant starch content in the citrate corn starch was investigated. When conducting the reaction at 140°C for 7 h, the highest resistant starch content was found in waxy corn citrate starch (87.5%) with the highest degree of substitution (DS, 0.16) of all starches. High‐amylose corn starch had 86.4% resistant starch content and 0.14 DS, and normal corn starch had 78.8% resistant starch and 0.12 DS. The physicochemical properties of these citrate starches were characterized using various analytical techniques. In the presence of excess water upon heating, citrate starch made from waxy corn starch had no peak in the DSC thermogram, and small peaks were found for normal corn starch (0.4 J/g) and Hylon VII starch (3.0 J/g) in the thermograms. This indicates that citrate substitution changes granule properties. There are no retrogradation peaks in the thermograms when starch was reheated after 2 weeks storage at 5°C. All the citrate starches showed no peaks in RVA pasting curves, indicating citrate substitution changes the pasting properties of corn starch as well. Moreover, citrate starch from waxy corn is more thermally stable than the other citrate starches.     

Effect of Aqueous Ethanol Cationization on Functional Properties of Normal and Waxy Starches

Cationic starch ethers of normal and waxy corn, normal and waxy barley and normal pea starch were prepared by an aqueous alcoholic process for evaluation of their functional properties as compared to the native starch controls. The native starches exhibited a wide range in average granule size (10–21 μm diameter), amylose content (0–34%) and swelling power (13–31). Cationization to degrees of substitution (DS) of 0.030–0.035 with 3-chloro-2-hydroxypropyltrimethylammonium chloride resulted in marked increases in swelling power of all starches, with little corresponding increases in starch solubility. Cationization also decreased the onset of endothermic transitions and pasting temperatures quite substantially, and promoted the development of sharp peak viscosities in the amylographs of all normal and waxy starches, including that of pea starch. Final cold viscosities of the cationic starches exhibited positive setbacks, and the cooked starch gels, after storage for 7 days at 4°C and −15°C, showed no syneresis. All cationic starches except for waxy corn were more susceptible to α-amylase hydrolysis than native control starches. The general improvement in functional properties, especially in the waxy corn, waxy barley and pea starches, due to the aqueous alcoholic-alkaline cationization process would greatly enhance their industrial applications.     

Structures and Physicochemical Properties of Acid‐Thinned Corn,Potato and Rice Starches

The structures and physicochemical properties of acid‐thinned corn, potato, and rice starches were investigated. Corn, potato, and rice starches were hydrolyzed with 0.14 N hydrochloric acid at 50 °C until reaching a target pasting peak of 200—300 Brabender Units (BU) at 10% solids in the Brabender Visco Amylograph. After acid modification the amylose content decreased slightly and all starches retained their native crystallinity pattern. Acid primarily attacked the amorphous regions within the starch granule and both amylose and amylopectin were hydrolyzed simultaneously by acid. Acid modification decreased the longer chain fraction and increased the shorter chain fraction of corn and rice starches but increased the longer chain fraction and decreased the shorter chain fraction of potato starch, as measured by high‐performance size‐exclusion chromatography. Acid‐thinned potato starches produced much firmer gels than did acid‐thinned corn and rice starches, possibly due to potato starch's relatively higher percentage of long branch chains (degree of polymerization 13—24) in amylopectin. The short‐term development of gel structure by acid‐thinned starches was dependent on amylose content, whereas the long‐term gel strength appeared dependend on the long branch chains in amylopectin.     

4种杂豆淀粉结构特征和理化特性比较

以4种我国广泛种植的杂豆为原料，采用湿磨法提取豇豆淀粉、扁豆淀粉、豌豆淀粉、红芸豆淀粉，并对4种杂豆淀粉的结构特征和理化特性进行比较。结果表明：杂豆淀粉的红外光谱均呈现典型的淀粉类多糖结构特征，颗粒完整光滑，主要呈现肾型和椭圆形。样品的平均流体力学半径大小顺序为豇豆淀粉>豌豆淀粉>扁豆淀粉>红芸豆淀粉，扁豆淀粉为CC-型晶体，其余为C_A-型晶体，样品间的相对结晶度差异较大(27.6%～38.5%)。4种杂豆淀粉的糊化特性差异显著，糊化温度均较高(75.3～82.8℃)，不易糊化。豇豆淀粉直链淀粉含量最低(26.3%)，其热糊稳定性优于其他杂豆淀粉，具有不易老化的特性。红芸豆淀粉的直链淀粉含量最高(31.5%)，回生值最高(3 182.3 mPa·s)，最易发生老化行为。综上，4种杂豆淀粉的颗粒形貌相似，均为C-型晶体，分子结构和糊化特性差异较大，凝沉特性相近。     

Physicochemical properties of lotus (Nelumbo nucifera Gaertn.) and kudzu (Pueraria hirsute Matsum.) starches

Lotus and kudzu starches have been used as functional foods in East Asia for thousands of years. The objective of this work is to investigate the starches’ basic physicochemical properties. The amylose content was the highest (30.61%) in lotus starch. The average particle size (diameters) was 50.27, 24.08 and 38.97 μm for lotus, kudzu and corn starches, respectively. Lotus starch exhibited a B‐type X‐ray diffraction pattern and kudzu starch exhibited a C‐type pattern. Kudzu starch was characterised by a maximum viscosity immediately followed by a sharp decrease in viscosity, while the lotus starch was characterised by a plateau when the maximum viscosity was reached.     

Effect of deproteinization on degree of oxidation of ozonated starch

Effects of deproteinization on the degree of oxidation of ozonated starch (corn, sago, and tapioca) were investigated. Starch in dry powder form was exposed to ozone for 10 min at different ozone generation times (OGTs: 1, 3, 5, 10 min), and then native starches (NS) and deproteinized starches (DPS) were analyzed for protein content. Deproteinization caused a significant reduction in protein content for corn (∼21%) and sago (∼16%) starches relative to NS. Carbonyl and carboxyl contents increased significantly in all ozonated deproteinized starches (ODPS) with increasing OGT. Carbonyl and carboxyl contents of ODPS ranged from 0.03 to 0.13% and 0.14 to 0.28%, respectively. The carboxyl content for all ODPS was significantly higher than that of ozonated native starches (ONS). A Rapid Visco Analyser was used to analyze pasting properties of all starches. Deproteinization increased the pasting viscosities of corn and sago starches compared to their native forms. Generally, pasting viscosity of all ODPS decreased drastically as OGT increased. At the highest oxidation level (10 min OGT), all ODPS exhibited the lowest pasting viscosities compared to their ozonated native form, except for peak viscosity, breakdown viscosity, and setback viscosity for ozonated deproteinized corn starch. In conclusion, deproteinization as a pretreatment prior to starch ozonation successfully increased the degree of oxidation in the three types of starch studied. However, the extent of starch oxidation varied among the different starches, possibly due to differences in rates of degradation on amorphous and crystalline lamellae and in rates of oxidation of carbonyl and carboxyl groups.     

羟丙基和磷酸酯化对不同玉米杂交种淀粉糊化特性的影响

采用了实验室方法提取了高直链、糯性和普通玉米杂交种的淀粉，并分别进行了羟丙基化和磷酸酯化反应。采用快速粘度分析仪（RVA）和差示扫描量热仪（DSC）分别分析了淀粉的糊化和热力学性质。结果表明：羟丙基化和磷酸酯化反应都不同程度地降低了所有淀粉的热焓值和糊化温度，缩短了出峰时间，增加了峰值粘度。二者相比，羟丙基化更显著地降低了原淀粉的糊化温度和热焓值，缩短了出峰时间；而磷酸酯化则更明显地提高了原淀粉的峰值粘度和终粘度．     

A current review of structure,functional properties,and industrial applications of pulse starches for value-added utilization

Pulse crops have received growing attention from the agri-food sector because they can provide advantageous health benefits and offer a promising source of starch and protein. Pea, lentil, and faba bean are the three leading pulse crops utilized for extracting protein concentrate/isolate in food industry, which simultaneously generates a rising volume of pulse starch as a co-product. Pulse starch can be fractionated from seeds using dry and wet methods. Compared with most commercial starches, pea, lentil, and faba bean starches have relatively high amylose contents, longer amylopectin branch chains, and characteristic C-type polymorphic arrangement in the granules. The described molecular and granular structures of the pulse starches impart unique functional attributes, including high final viscosity during pasting, strong gelling property, and relatively low digestibility in a granular form. Starch isolated from wrinkled pea—a high-amylose mutant of this pulse crop—possesses an even higher amylose content and longer branch chains of amylopectin than smooth pea, lentil, and faba bean starches, which make the physicochemical properties and digestibility of the former distinctively different from those of common pulse starches. The special functional properties of pulse starches promote their applications in food, feed, bioplastic and other industrial products, which can be further expanded by modifying them through chemical, physical and/or enzymatic approaches. Future research directions to increase the fractionation efficiency, improve the physicochemical properties, and enhance the industrial utilization of pulse starches have also been proposed. The comprehensive information covered in this review will be beneficial for the pulse industry to develop effective strategies to generate value from pulse starch.     

Crystallinity and Pasting Properties of Freeze‐Thawed High Amylose Maize Starch

Native and defatted high amylose (about 70%) maize starch gels were freeze‐dried or repeatedly freeze‐thawed, and the effects of the treatments on the crystallinity, pasting viscosity, and resistance to digestive enzymes of the dried starch were examined. Both native and defatted starches showed a B‐type crystal structure in the X‐ray diffractogram, but the crystallinity was decreased by repeating the freeze‐thawing cycle. In the DSC thermogram, the freeze‐thawed starches exhibited two endothermic transitions in the temperature ranges of 90—110 °C and 130—160 °C, representing amyloselipid complexes and amylose‐amylose double helix crystals, respectively. By defatting, the melting enthalpy for the amylose double helices was increased, indicating that the residual lipids inhibited the amylose crystal formation. Ice crystals in the starch gel matrix became smaller and the ice cell membrane became thinner as freeze‐thawing was repeated. The freeze‐dried or freeze‐thawed starch powders swelled to a paste by heating in water as did typical granular starch, but the setback by cooling was significantly high due to the rapid retrogradation of leached amylose. By the treatments, the resistance of the starch to digestive enzymes was also raised. The defatted starches displayed greater paste viscosity and resistance to digestive enzymes than the native starches. But the overall viscosity was decreased as the number of freeze‐thawing cycles increased.     

Screening Potato Starch for Novel Properties Using Differential Scanning Calorimetry

Thermal and other physicochemical properties of starch from 42 potato genotypes were studied to find those with unique properties for food use, and to analyze relationships between thermal and other physicochemical properties. Onset and peak transition temperatures and gelatinization enthalpy intercorrelated. Transition temperatures intercorrelated with pasting temperature using a Brabender Visco-amylograph. Gelatinization entbalpy correlated with Brabender pasting temperature and peak paste viscosity, and onset temperature correlated with phosphorus content. Genotype E55–3.5 with highest onset and peak transition temperatures also had highest phosphorus and peak Brabender viscosity. DSC might be useful for rapidly screening samples of <1g starch for such. Potato starch DSC characteristics did not correlate with amylose, intrinsic viscosity, or water-binding. For 10 genotypes from successive years, correlations were observed for pasting temperature (r = 0.83), phosphorus content (r = 0.80), and stability ratio (r = 0.66). Direct comparison between samples from consecutive years showed good reproducibility for amylose, but not for phosphorus or pasting.     

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.     

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.     

Effect of genotype and environment on the concentrations of starch and protein in, and the physicochemical properties of starch from, field pea and fababean

BACKGROUND: The effects of genotype and environment and their interaction on the concentrations of starch and protein in, and the amylose content and thermal and pasting properties of starch from, pea and fababean are not well known. RESULTS: Differences due to genotype were observed in the concentrations of starch and protein in pea and fababean, in the onset temperature (To) and peak temperature (Tp) of gelatinization of fababean starch, and in the pasting, trough, cooling and final viscosities of pea starch and fababean starch. Significant two‐way interactions (location × genotype) were observed for the concentration of starch in fababean and the amylose content, To, endothermic enthalpy of gelatinization (ΔH) and trough viscosity of fababean starch. Significant three‐way interactions (location × year × genotype) were observed for the concentration of starch in pea and the pasting, trough, cooling and final viscosities of pea starch. CONCLUSION: Differences observed in the concentrations of starch and protein in pea and fababean were sufficient to be of practical significance to end‐users, but the relatively small differences in amylose content and physicochemical properties of starch from pea and fababean were not. Copyright © 2011 Society of Chemical Industry     

直链淀粉含量对玉米淀粉/瓜尔胶复配体系糊化和流变特性的影响

为考察直链淀粉含量对淀粉/瓜尔胶复配体系性质的影响,以不同直链淀粉含量的玉米淀粉(蜡质玉米淀粉、普通玉米淀粉和高直链玉米淀粉)为原料,加入瓜尔胶,研究复配体系的糊化、流变及凝胶特性。结果表明:瓜尔胶与直链淀粉之间的相互作用是引起淀粉复配体系黏度和稠度系数增加、成糊温度和流体指数降低的主要原因。动态流变实验结果表明淀粉中直链淀粉含量不同对复配体系的动态模量的影响也不同。在糊化过程中,随着直链淀粉含量增加,直链淀粉分子与瓜尔胶间的相互作用增强,阻碍了直链淀粉分子间的聚集重排,使得复配体系硬度值减小,3种玉米淀粉形成了质地更为柔软的凝胶。