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.     

荞麦淀粉糊化特性研究

本实验采用快速黏度分析仪及流变仪对荞麦(甜荞、苦荞)淀粉糊化过程中的黏度和流变特性进行系统分析,并测定荞麦淀粉膨胀度、凝沉性、冻融稳定性、透光率等糊化特性。结果表明,荞麦淀粉(甜荞、苦荞)的糊化温度高于绿豆淀粉,低于大米淀粉和小麦淀粉。苦荞麦淀粉膨胀过程与绿豆淀粉相似,而甜荞淀粉与小麦淀粉相似;荞麦淀粉(甜荞、苦荞)糊透明性好;荞麦淀粉(甜荞、苦荞)冻融稳定性高于大米淀粉,低于小麦淀粉和绿豆淀粉;荞麦淀粉(甜荞、苦荞)糊具有较好的凝沉稳定性;荞麦淀粉糊属于非牛顿流体中的假塑性流体,其流变曲线符合Sisko 方程。     

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

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

Functional Properties and Retrogradation of Heat‐Moisture Treated Wheat and Potato Starches in the Presence of Hydroxypropyl β‐cyclodextrin

Some functional and retrogradation properties of native and heat‐moisture treated potato and wheat starches were examined in the presence of hydroxypropyl β‐cyclodextrin (HPβ‐CD). HPβ‐CD increased swelling factor, amylose leaching, and solubility of both native and heat‐moisture treated wheat starches but it had less impact on corresponding potato starches. Gelatinization enthalpy of native wheat starch was decreased in the presence of HPβ‐CD but was increased in potato starch with increasing concentration. Reduction of amylose‐lipid complex endotherm in both native and heat‐moisture treated wheat starch was observed in the presence of HPβ‐CD. Heat‐moisture treatment did not change the transition parameters of amylose‐lipid complex showing its resistance to hydrothermal treatment. HPβ‐CD greatly decreased the pasting temperature of wheat starch. Cold paste viscosity of both native and heat‐moisture treated wheat starch was increased by HPβ‐CD to a greater extent than corresponding potato starch. Amylopectin retrogradation of all the starches was unaffected in the presence of HPβ‐CD but heat‐moisture treatment slightly decreased retrogradation of potato starch. These results suggest that HPβ‐CD can disrupt the amylose‐lipid complex within the starch granule in both native and heat‐moisture treated wheat starch but has no influence on amylopectin retrogradation. However, greatly increased wheat starch setback with HPβ‐CD indicates its greater effect on wheat starch amylose retrogradation.     

蔗糖对不同品种赤小豆淀粉性能的影响

以三种不同赤小豆淀粉为原料,通过分析添加蔗糖前后淀粉的糊化性能、热力学性能、消化性能等特性,探究蔗糖对淀粉性能的影响。结果表明：直链淀粉含量较高的珍珠红赤小豆淀粉,具有较大的粒径、较高的峰值黏度和回生值,但其糊化温度和最终黏度较低;当添加10%的蔗糖后,三种淀粉的平均粒径、峰值黏度、凝沉性和快速消化淀粉（Rapidly digestible starch,RDS）显著降低（P<0.05）,而三种淀粉的糊化温度、热焓值、回生值和衰减值却显著增加（P<0.05）;慢速消化淀粉（Slowly digestible starch,SDS）含量除珍珠红赤小豆淀粉外均显著增加（P<0.05）,淀粉凝胶性以及抗性淀粉（Resistant starch,RS）虽有下降,但不显著。蔗糖的添加促进了赤小豆淀粉的回生;抑制了淀粉的糊化、降低了抗老化性和消化性。     

Starch of diverse Mexican rice cultivars: physicochemical,structural, and nutritional features

Structure‐function relationship of rice starch is scarce in the literature. Starch was isolated from diverse Mexican rice varieties and their swelling power (SP), soluble solids (ss), thermal and pasting properties, XRD pattern, in vitro starch digestibility, and AP chain‐length distribution were evaluated. Rice starches with low SP at 60°C had higher temperature and enthalpy of gelatinization. The peak viscosity of rice starches ranged between 2426 and 3519 cP, and the samples presented high values for setback due to the AM content. Rice starches presented the typical A‐type XRD pattern with crystallinity values between 32.7 and 36.3%. Rice starches presented high amounts of short chains (A and B1), and differences were found among the cultivars. AM content for rice starches ranged between 18.4 and 22.9%, and the main fraction recorded by HPSEC was the Fraction III (short chains) with values around 60%. The uncooked rice starch samples presented high values of slowly digestible starch (SDS) and rapidly digestible starch (RDS), and differences were found among the cultivars. In cooked samples decreased SDS and increased RDS and RS. Onset temperature and enthalpy of gelatinization were correlated with the percentage of A‐chains and an opposite pattern was found with the percentage of B1 chains. AP structural characteristics affect the functional, physicochemical, and digestibility properties of rice starches.     

Morphological,thermal and rheological properties of starches separated from rice cultivars grown in India

Morphological, thermal and rheological properties of starches separated from five rice cultivars (PR-106, PR-114, IR-8, PR-103 and PR-113), varying in amylose content, were studied. Amylose contents of starches separated from PR-103, IR-8, PR-106, PR-114 and PR-113 were 7.83, 15.62, 16.05, 16.13 and 18.86%, respectively. The granular size, measured using a Scanning Electron Microscope, varied from 2.4 to 5.4 μm in all rice starches. PR-103 starch, with lowest average granular size, amylose content and solubility, had the highest swelling power, while PR-113 starch, with the highest average granular size and amylose content had the lowest swelling power. PR-103 starch showed highest transition temperatures, enthalpies of gelatinization, peak height index, range and enthalpies of retrogradation. The retrogradation (%) was observed to be highest in PR-113 starch and lowest in PR-103 starch. The changes in rheological parameters of rice starches during heating were measured using a Dynamic rheometer. PR-113 rice starch showed the highest G′, G″ and breakdown in G′ values, whereas PR-103 starch showed the lowest values for these parameters. Turbidity value of gelatinized pastes from all rice starches progressively increased up to the 3rd day during refrigerated storage, PR-103 starch paste showed the lowest turbidity value and PR-113 starch showed the highest value. The syneresis (%) of starch pastes, from different rice cultivars during storage at 4 °C, was also measured. The syneresis of starch pastes from all rice cultivars, except PR-103, increased with storage. PR-103 starch paste showed negligible syneresis during storage.     

干热处理对藜麦淀粉结构和理化性质的影响

以高筋小麦粉为原料添加酵母制作面团,在温度28℃、湿度80%条件下发酵1～6 h,提取小麦淀粉。研究发酵时间对小麦直链淀粉含量、损伤淀粉含量、粒径、颗粒表面结构、糊化及消化特性的影响。结果表明：面团发酵1 h后直链淀粉含量和损伤淀粉含量均显著低于原淀粉(P<0.05)。快速黏度分析结果表明,发酵1 h的小麦淀粉峰值黏度、热浆黏度和冷浆黏度最低。发酵处理后淀粉的粒径均小于原淀粉,其中发酵5 h的平均粒径最小。扫描电镜结果表明,发酵6 h的小麦淀粉颗粒表面出现破裂现象。体外消化实验表明,发酵5 h和6 h小麦淀粉的消化速率最高,发酵后抗性淀粉含量低于原淀粉,而慢消化淀粉含量高于原淀粉(P<0.05)。     

Effect of hydroxypropyl β-cyclodextrin on physical properties and transition parameters of amylose–lipid complexes of native and acetylated starches

The effect of hydroxpropyl β-cyclodextrin (HPβ-CD) on physical properties and digestibility of wheat, potato, waxy maize and high-amylose maize starches before and after acetylation was studied. Effect of HPβ-CD on amylose–lipid complexes in native and acetylated potato starches synthesized using α-lysophosphatidylcholine was also studied. Acetylation increased swelling factor, amylose leaching, peak viscosity and susceptibility to α-amylase hydrolysis, but decreased gelatinization temperature and enthalpy and gel hardness in all starches. HPβ-CD markedly increased swelling factor and amylose leaching in native and acetylated wheat starches but had little or no impact on other starches. Wheat starch gelatinization enthalpy decreased in the presence of HPβ-CD but gelatinization temperature of all the starches was slightly increased. HPβ-CD had no influence on enzymatic hydrolysis. Melting enthalpy of amylose–lipid complex in both native and acetylated wheat starches was decreased by HPβ-CD. Acetylation also decreased the melting enthalpy of amylose–lipid complex in wheat starch. Similar trend of thermal transitions was observed in the presence of HPβ-CD for the amylose–lipid complexes synthesized in potato starch. Acetylation reduces the complex formation ability of the amylose polymer. Similar to gelatinization, acetylation widened the melting temperature range of amylose–lipid complexes while shifting it to a lower temperature. Higher swelling and amylose leaching, and decreased gelatinization temperature and enthalpy resulting from acetylation of wheat starch is consistent with its influence on starch hydration. Similar effects resulting from the inclusion of HPβ-CD were consistent with the disruption of amylose–lipid complex by HPβ-CD which promotes granular hydration.     

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.     

Composition,morphology, molecular structure,and physicochemical properties of starches from newly released chickpea (Cicer arietinum L.) cultivars grown in Canada

Starch from four cultivars (CDC Xena, CDC Flip 97-133C, CDC 418-59, CDC ICC 12512-9) of chickpea (cicer arietinum L.) grown in Saskatchewan, Canada was isolated and variability in composition, morphology, molecular structure and physicochemical properties was evaluated. The yield of starch was in the range 32.0–36.8% on a whole seed basis. The starch granules were oval to spherical with smooth surfaces. The granule size distribution ranged from 5 to 35 μm. The free lipid, bound lipid, total amylose and the amount of amylose complexed with native starch lipids ranged from 0.04% to 0.08%, 0.21% to 0.46%, 33.9% to 40.2% and 9.1% to 15.9%, respectively. There was no significant difference in branch chain length distribution of amylopectin among the starches. The X-ray pattern was of the C-type. The relative crystallinity was in the range 31.3–34.4%. Swelling factor and amylose leaching in the temperature range 50–90 °C ranged from 1.6% to 25.9% and 8.61% to 36.1%, respectively. All four starches exhibited nearly identical gelatinization temperatures. However, the enthalpy of gelatinization was in the range 11.2–13.1 J/g, respectively. The starches differed significantly with respect to peak viscosity (3223–4174 cp), breakdown viscosity (394–1308 cp) and set-back (3110–4281 cp). Starches were hydrolyzed by acid to nearly the same extent. The amount of rapidly digestible, slowly digestible and resistant starch contents ranged from 10.9% to 15.7%, 48.5% to 60.2% and 24.1% to 40.6%, respectively.     

Study on the physicochemical properties and in vitro digestibility of starch from yam with different drying methods

Four methods were applied to dry yam slices, and then, starches were isolated from dried yam slices. Starch isolated from fresh yam was as the study control, and physicochemical properties and in vitro digestibility of starches were studied. The results showed that the amylose content ranged from 12.62% to 28.25%, water‐binding capacity (WBC) from 111.67% to 262.88%, paste clarity from 2.1% to 6.23%, resistant starch (RS) from 66.60% to 88.49% and crystallinity from 11.27% to 25.52%. Compared with the control starch, hot air‐drying at 60 °C significantly decreased amylose content, paste clarity, RS and crystallinity, while increasing the WBC. Low levels of rapidly digestible starch and glucose and high RS levels were found in the starch from freeze‐drying yam. Digestibility of the starches was significantly correlated with amylose content, WBC, paste clarity and swelling power. The starch samples were divided into three groups by principal component analysis (PCA).     

Influence of prior acid treatment on physicochemical and structural properties of acetylated sorghum starch

Influence of prior acid treatment on acetylation of starch isolated from an Indian sorghum cultivar was investigated. The starch was acid thinned (AT) using 0.1, 0.5, and 1 M HCl for 1.5 h and then acetylated (Ac) with acetic anhydride (8% w/w). The acid thinning and subsequent acetylation appeared to reduce the percentage acetylation as indicated by degree of substitution. Ac‐AT starches exhibited significantly different physicochemical, thermal, pasting, and gel textural properties from those of AT and Ac starches. Starches after dual modification showed higher solubility, lower AM content, gelatinization temperatures, retrogradation, peak viscosity, and gel hardness than native starch. Enthalpy and range of gelatinization were observed to be higher in dual modified starches than native starch. However, no significant changes in granule morphology or crystalline pattern of Ac‐AT starches were observed compared with native starch.     

Physicochemical,morphological, thermal,pasting, and textural properties of starch acetates

Acetylated starches are a commercially important group of modified starch known for their reduced retrogradation tendency, high clarity, low viscosity, high swelling power, and lower gelatinization temperature and time. Due to these remarkable properties, acetylation is a commonly used chemical modification for preparing stabilized starches. This review summarizes the methods used for preparation of starch acetates and corresponding effects of acetylation on morphological, thermal, pasting, digestibility, textural, and other functional characteristics of starches isolated from various botanical sources. Starch acetates are also useful as packaging material, as wall material for encapsulating active ingredients, and to improve the storage stability of different products.     

酸解和乙酰化改性对木薯淀粉性质的影响

以木薯淀粉为原料,对酸解淀粉、乙酰化淀粉及酸解乙酰化淀粉的糊性质进行了研究,并用扫描电子显微镜、X射线衍射仪和傅里叶变换红外光谱仪对改性淀粉的形貌和结构进行了分析。结果表明:木薯淀粉经酸解改性改善了糊的透明度,膨胀度有所降低,糊化温度升高,峰值黏度显著降低,凝沉性有所改善;乙酰化改性增加了淀粉糊的透明度,膨胀度提高,降低了糊化温度,峰值黏度增加,糊的抗凝沉性增强但热糊稳定性差;酸解乙酰化复合改性显著提高了淀粉糊的透明度,降低淀粉的膨胀度及糊化温度,峰值黏度显著降低,抗凝沉性明显增强,冷、热糊稳定性提高。扫描电镜、X衍射数据及红外图谱表明,3种变性处理均没有改变木薯淀粉的晶型和基本结构,颗粒形貌也没有发生显著变化。     

Studies on tuber and root starches. I. Structure and physicochemical properties of innala (Solenostemon rotundifolius) starches grown in Sri Lanka

Starches from two cultivars (Bola and Dik) of innala tubers (Solenostemon rotundifolius) grown in the same location and under identical environmental conditions in Sri Lanka was isolated and some of the characteristics determined. The yield of starch from both cultivars was 16.0% on initial tuber weight. The shape of the granules in both cultivars was dome shaped and hemispherical with 4–5 slightly concaved facets. Pores were found randomly distributed over the surface of both starch granules. The amylopectin branch chain length distribution was nearly similar for both starches. However, the starches differed with respect to granular swelling, amylose leaching, susceptibility towards acid and enzyme hydrolysis, gelatinization characteristics, pasting properties and retrogradation kinetics. The results showed that differences in amylose content, lipid complexed amylose chains, relative crystallinity and extent of interaction between amylose chains in the amorphous regions of the granule had a substantial impact on the observed differences in physicochemical properties.     

Morphological,Thermal, Pasting,and Rheological Properties of Barley Starch and Their Blends

Native barley starch, as well as its blends with corn, wheat, and rice starch at different ratios of 75:25, 50:50, 25:75 were examined in terms of morphology, thermal, pasting, rheological, and retrogradation properties. Amylose content varied between 10.9–41.4% in rice, corn, wheat, and barley while it ranged from 18.02–38.40% in blends of barley starch with rice, corn, and wheat. A rapid visco analyzer showed that barley starch and its blends having low amylose content exhibited higher peak viscosity, breakdown, and setback than the high-amylose-containing starches and their blends. Amylose content was found to be negatively correlated with swelling power while it exhibited nonlinear relationship with solubility index. The transmittance of starch suspension stored at 4°C decreased during storage up to 6 days. Barley starch granules were largest (<110 μm) in size followed by wheat (<30 μm), corn (<25μm) and rice (<20μm) starches. Gelatinization temperatures (To, Tp, Tc) and enthalpies of gelatinization (ΔHgel) of starches from different sources also differed significantly. Corn and rice starches showed higher transition temperatures in general than those from wheat and barley; however, they showed higher ΔHgel values. Barley starch showed a higher tendency towards retrogradation than the cereal starches. Barley starch showed highest peak G′, G″ and lower tan Ð than corn, rice and wheat starches during the heating cycle. This study showed that the magnitude of changes in their properties during blending depends on the amylase content and morphological characteristics.     

Physicochemical Properties of Starches Obtained from Three Varieties of Chinese Sweet Potatoes

ABSTRACT: Starches isolated from 3 typical types of Chinese sweet potato varieties (XuShu18, SuShu2, and SuShu8) were characterized and compared with starches isolated from potato and mung bean. The 3 sweet potato starches differed in granule size; particle size distribution; protein, lipid, and phosphorus contents; pasting behaviors; swelling patterns; and syneresis. The retrogradation tendencies, measured both by setback ratio and by syneresis, differed for the 3 starches, although the amylose contents were quite similar (19.3 to 20.0%). Physicochemical properties of all 3 types of starches are evidently different from each other and from those of potato and mung bean starches. Keywords: sweet potato, starch, gelatinization, retrogradation, swelling, syneresis     

The physicochemical properties and in vitro digestibility of selected cereals,tubers and legumes grown in China

Digestibility, gelatinization, retrogradation and pasting properties of starch in various cereal, tuber and legume flours were determined. Rapidly and slowly digestible starch and resistant starch were present in 11 selected flours. In general, cereal starches were more digestible than legume starches and tuber starches contained a high amount of resistant starch. Thermal and rheological properties of flours were different depending on the crop source.     

Rice Starch Diversity: Effects on Structural,Morphological, Thermal,and Physicochemical Properties—A Review

Abstract: Rice starch is one of the major cereal starches with novel functional properties. Significant progress has been made in recent years on the characterization of rice starches separated from different rice cultivars. Studies have revealed that the molecular structure and functional properties are affected by rice germplasm, isolation procedure, climate, agronomic conditions, and grain development. Morphological studies (microscopy and particle size analysis) have reflected significant differences among rice starch granule shapes (polyhedral, irregular) and in granule size (2 to 7 μm). Nonwaxy and long‐grain rice starches show greater variation in granular size than the waxy starches. Rice starch granules are smaller than other cereal starches with amylose contents varying from virtually amylose‐free in waxy to about 35% in nonwaxy and long‐grain rice starches. Amylose content appears to be the major factor controlling almost all physicochemical properties of rice starch due to its influence on pasting, gelatinization, retrogradation, syneresis, and other functional properties. Waxy rice starches have high swelling and solubility parameters, and larger relative crystallinity values than nonwaxy and long‐grain starches. However, nonwaxy rice starches have a higher gelatinization temperature than the waxy and long‐grain starches. The bland taste, nonallergenicity, and smooth, creamy, and spreadable characteristics of rice starch make it unique and valuable in food and pharmaceutical applications. This review provides recent information on the variation in the molecular structure and functional properties of different rice starches.