Granular Structure and Physicochemical Properties of Starches from Amaranth Grain

The granular structure and physicochemical properties of starches isolated from grain amaranth cultivar K112 (Amaranthus cruentus L.) were studied in this study. Detailed physical and chemical analyses were performed by determining the granular morphology, crystallinity, particle size, thermal characteristics, blue value, enzyme susceptibility, and pasting properties. Results showed polygon-shaped A. cruentus L. K112 starch granules. The average diameter was 1.38 μm, in which half of the diameter was <2.91 μm. An A-type X-ray diffraction pattern was revealed with intense peaks of 15.2°, 17.5°, and 23.2°. The peak viscosity was 181 BU and the breakdown value was 2 BU. Amaranth starch obtained the highest pasting temperature (70.7°C) and enzymatic digestibility (absorbance value = 0.41 ± 0.013) compared with corn, cassava, and sweet potato starches.     

Physicochemical,Pasting, Thermal and Morphological Characteristics of Indian Water Chestnut (Trapa natans) Starch

Starch extracted from Indian water chestnut was investigated for its physicochemical characteristics. The results were compared with those obtained from two commercial starches (corn and potato). The pasting properties were tested in the Rapid Visco Analyser and thermal properties with a differential scanning calorimeter. Water chestnut starch possessed higher breakdown viscosity (BV) and setback viscosity (SV) than corn and potato starches. However, the pasting temperature of water chestnut starch was not significantly different from that of corn starch. Lower ΔH_gel values were obtained for water chestnut starch than for the other two starches whereas the onset, peak and conclusion temperatures of gelatinization (T_o, T_p and T_c) for water chestnut starch were quite comparable with corn starch. Scanning electron micrographs showed similarity in starch granule shape between water chestnut and potato starch with corn starch showing surface wrinkles on starch granule surfaces.     

Physicochemical and Gelatinization Properties of Starches Separated from Various Rice Cultivars

Morphological, viscoelastic, hydration, pasting, and thermal properties of starches separated from 10 different rice cultivars were investigated. Upon gelatinization, the G′ values of the rice starch pastes ranged from 37.4 to 2057 Pa at 25 °C, and remarkably, the magnitude depended on the starch varieties. The rheological behavior during gelatinization upon heating brought out differences in onset in G′ and degree of steepness. The cultivar with high amylose content (Goami) showed the lowest critical strain (γ_c), whereas the cultivars with low amylose content (Boseokchal and Shinseonchal) possessed the highest γ_c. The amylose content in rice starches affected their pasting properties; the sample possessing the highest amylose content showed the highest final viscosity and setback value, whereas waxy starch samples displayed low final viscosity and setback value. The onset gelatinization temperatures of the starches from 10 rice cultivars ranged between 57.9 and 64.4 °C. The amylose content was fairly correlated to hydration and pasting properties of rice starches but did not correlate well with viscoelastic and thermal characteristics. The combined analysis of hydration, pasting, viscoelastic, and thermal data of the rice starches is useful in fully understanding their behavior and in addressing the processability for food applications.     

Cross-linking of corn starch with phosphorus oxychloride under ultra high pressure

To investigate the effect of UHP treatment on the cross-linking reaction, normal corn starch was subjected to UHP-assisted reaction with a single addition level of POCl₃, at varied pressure levels ranging from 0.1 to 400 MPa. Swelling power, gelatinization, and pasting properties were assessed for all native and cross-linked starches. UHP-assisted reaction achieved a 12.5% level of conventional reaction time. UHP-assisted POCl₃ starch derivatives, reacted at 100–400 MPa, exhibited reduced swelling powers and gelatinization properties relative to that at 0.1 MPa, though both attributes did not possess any tendency depending on pressure levels. UHP-assisted POCl₃ reaction generated pasting viscosity profiles similar to those observed for conventional cross-linked starches. Pasting viscosity profiles were significantly different among various UHP treatments, though no trends were present. At 400 MPa, the UHP-assisted POCl₃ starch derivative revealed pasting viscosity profiles most similar to those of the conventional POCl₃ starch derivative.     

Characterization of amorphous granular starches prepared by high hydrostatic pressure (HHP)

Amorphous granular starches (AGS) and non-granular amorphous starches (non-AGS) of corn, tapioca and rice were prepared using high hydrostatic pressure (HHP) treatment with ethanol and water washing, respectively and their physicochemical properties were investigated. Water holding capacity and apparent viscosity of AGS and non-AGS were higher than those of native one in all starches. In RVA pasting properties, AGS and non-AGS showed higher pasting temperature and lower peak viscosity than those of native one. Furthermore, non-AGS showed distinctively lower peak viscosity compared to that of AGS possibly due to its non-granular structure. Apparent viscosity of non-AGS revealed relatively lower than commercial pre-gelatinized starch because of heat and pressure-induced gelatinization. Maintaining granular structure in HHP treated pre-gelatinized starch provide a distinctive physicochemical characteristics compared to native starch and preparation of gelatinized starch with different gelatinization and washing methods could cause big differences in their physicochemical properties.     

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.     

Xerophytic Cucurbit Root Starches. Part VI: Preliminary Investigation of Starches from Apodanthera undulata Gray,Marah gilensis Greene and Maximowiczia lindheimeri Gray

The root starches of Apodanthera undulata Gray, Marah gilensis Greene and Maximowiczia lindheimeri Gray were quantified, isolated and characterized to expand knowledge concerning potentially useful products from xerophytes. Apodanthera roots contained relatively high levels of starch (20.5%) whereas starch levels in the other two species were 8.2 and 9.5%, resp. Starch isolated from Apodanthera manifested physical, physico-chemical and rheologic properties which closely resembled those of the potentially commercial Cucurbita foetidissima and Cucurbita digitata root starches. Granules were composed of approximately 26% amylose, were of medium size, were round, oval, or truncated in shape; and were moderately resistant to gelatinization, swelling and solubilization. Suspensions displayed high initial pasting temperatures. The pastes were resistant to collapse and developed only a modest level of set-back upon cooling. Starch from Maximowiczia also resembled Cucurbita starches for most parameters but exhibited a higher resistance to granule hydration and disintegration than any of its counterparts. Granules of Marah starch were somewhat larger than those of other starches within this group and their equilibrium moistures were high. They offered little resistance to gelatinization, were more free-swelling and soluble than other subject materials, and in suspension they displayed a relatively low initial pasting temperature. Furthermore, Marah pastes were more highly viscous than those of other subject materials during the pasting cycle and suffered regain as they cooled.     

Rapid Visco-Analyzer (RVA) Pasting Profiles of Wheat,Corn, Waxy Corn,Tapioca and Amaranth Starches (A. hypochondriacus and A cruentus) in the Presence of Konjac Flour,Gellan, Guar,Xanthan and Locust Bean Gums

The Rapid Visco-Analyzer (RVA) 20min test was used to study the effects of different levels of konjac flour, guar, gellan, xanthan and locust bean gums on starch cooking properties. Wheat, corn, waxy corn, tapioca and A. hypochondriacus and A. cruentus starches were affected to different degrees by different levels of the gums. Peak viscosity increased at the higher gum concentrations, especially with locust bean gum at the 0.4 g level. The increase in viscosity was more pronounced with wheat and corn starches than with waxy corn and tapioca starches which consist mostly of highly branched amylopectin thus preventing close physical association between molecules. Amaranth starches showed much lower viscosity with all the gums than the other starches. Peak viscosity, time to reach the peak and maximum setback viscosity were affected by the gums. The increase in viscosity of starch/hydrocolloid systems is due to the release of amy-lose and low molecular weight amylopectin which promotes the formation of polymer complexes and significantly adds to the viscosity of the system.     

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。     

Physicochemical Properties of Starches from Lotus Rhizomes Harvested in Different Months

We investigated the physicochemical properties of starches extracted from 8 lotus (Nelumbo nucifera Gaertn.) rhizomes harvested in different months (September 2012 to May 2013). The physicochemical properties of the lotus starches depended on the harvest date. The peak viscosity (PV) in the Rapid Visco-Analyser analysis, and the viscosity at 65 °C (V₆₅) in the rotational viscometer analysis were significantly lower in SEP starch (extracted from the September-harvested sample) than in the other lotus starches. The Spearman’s rank correlation coefficients of potassium ion (K) content vs. V₆₅ and of K content vs. PV were 0.905 and 0.714, respectively, indicating that potassium ions are important for expressing the pasting properties of lotus starch. Principal component analysis suggested that the potassium, magnesium, calcium, and phosphorus contents are important for displaying both the pasting and gelatinization properties of the lotus starches. Meanwhile, the cluster analysis revealed that physicochemical properties of the SEP starch were different from those of the starches harvested in other months.     

Characterization of Pea Starches in the Presence of Alkali and Borax

Refined field pea (Pisum sativum L.) starches were prepared from air‐classified pea starch by washing or from whole pea by wet milling, and analyzed for their physicochemical and pasting characteristics in the presence of alkali and borax. Commercial corn and high amylose corn starches were included in the study for comparative purposes. The two pea starches exhibited similar physicochemical characteristics. Amylose content markedly influenced pasting and other characteristics of the corn starches. Pea starch and high amylose corn starch exhibited little viscosity development during pasting in deionized water. The presence of alkali or borax significantly altered the peak viscosities and cold paste stabilities of all four starches in a concentration dependent manner. Alkali and borax increased peak and cold paste viscosity and reduced syneresis in all cases.     

Effects of cross-linking and low molecular amylose on pasting characteristics of waxy corn starch

The action of amylose within the granule of normal corn starch is investigated by changes in pasting characteristics of waxy corn starch in a Rapid Visco Analyzer (RVA), using addition of soluble amylose (DP = 18) and cross-linking with epichlorohydrin. Although waxy corn starch, containing no amylose, did not show an effect of addition of amylose on pasting characteristics, by cross-linking with epichlorohydrin, the pasting peak viscosity and breakdown were greatly enhanced and set-back (viscosity increased in the cooling process after gelatinization) was generated. The cross-linking depressed the disintegration of starch granules in the swelling process, with amylose interaction, resulting in RVA pasting characteristics similar to those seen with normal corn starch containing amylose. Set-back was essentially caused by rearrangement among modified amylopectins. Addition of sodium dodecyl sulfate (SDS) to the RVA more efficiently enhanced the effect. This indicated that amylose in normal corn starch interacts with amylopectin through locally strong linkages.     

Study on physicochemical characteristics of waxy potato starch in comparison with other waxy starches

The physicochemical properties of wx potato, wx corn, and wx rice starches were examined and compared. wx potato starch displayed the B‐type XRD pattern, whereas wx rice and wx corn displayed the A‐type. Shapes of wx potato starch were oval or slightly round, wx corn and wx rice starch granules were polygonal. AM contents of the three starches were between 1.0 and 1.5%. Rapid viscosity analyzer data showed initial pasting temperatures of wx potato, wx corn, and wx rice starches as 69.6, 75.4, and 76.8°C, respectively, peak viscosity, breakdown, and setback of wx potato starch were 2114, 1084, and 4 mPa s. Using DSC, onset temperature of gelatinization of wx potato starch was 5.5–7.2°C higher than those of wx rice and wx corn starches. The thermal enthalpies of the starches studied in our laboratory were in the range of 0.2268–1.9900 J/g with decreasing order of wx potato > wx corn > wx rice starch.     

Influence of enzyme active and inactive soy flours on cassava and corn starch properties

The aim of this work was to study the influence of enzyme active and inactive soy flours on the properties of cassava and corn starches. Four starch/soy flour composites were evaluated: cassava/active soy flour (Cas/AS), cassava/inactive soy flour (Cas/IS), corn/active soy flour (Corn/AS) and corn/inactive soy flour (Corn/IS). Starch gelatinization occurred at 58.67°C for Cas and at 64.19°C for corn; gelatinization occurred at higher temperatures when soy flours were present, while ΔH diminished. The presence of AS reduced 80% the retrogradation enthalpy of Cas and 40% that of corn. Cas presented lower pasting temperature than corn starch (67.8 and 76.8°C, respectively) and higher peak viscosity (427.9 and 232.8 BU, respectively). The pasting properties of both starches were drastically reduced by soy flours, and this effect was more noticeable in Cas; AS had higher effect than IS. X‐ray diffraction pattern of retrograded samples showed that both starches recrystallisation (mainly that of Cas) was reduced when AS was added. Tan δ values decreased with AS addition to corn, but they increased when added to Cas. The images obtained using confocal laser scanning microscopy (CLSM) showed that IS was distributed as large aggregates, whereas AS distribution was more homogeneous, especially when incorporated to Cas. These results show that cassava starch interacts specifically with active soy flour (AS, mainly in native state). The delaying effect of AS on cassava starch retrogradation was clearly shown. This finding could be useful in obtaining gluten‐free breads of high quality and low retrogradation rate.     

常用淀粉对甘薯粉糊化特性的影响

利用Brabender粘度仪考察了几种常用淀粉对甘薯粉糊化特性的影响，认为马铃薯、甘薯淀粉使甘薯粉糊化温度降低，玉米、木薯淀粉则使其升高；甘薯、玉米淀粉使甘薯粉糊化时间延长。添加各种淀粉均可使甘薯粉的峰谷粘度提高；马铃薯、玉米淀粉还可大幅度提高其峰值粘度。但马铃薯淀粉粘度破损值大，玉米淀粉破损值小、峰谷粘度高。     

Effect of Amylose Content on Gelatinization,Retrogradation and Pasting Properties of Flours from Different Cultivars of Thai Rice

Presently, rice cultivars are categorized according to amylose content into three groups: low, medium and high amylose content cultivars. The correlation of amylose content with gelatinization properties, retrogradation, and pasting properties of eleven cultivars of Thai rice were investigated. Rice flour was prepared from milled rice by the wet grinding process. Onset (T_o), peak (T_p) and conclusion (T_c) temperatures of gelatinization, (determined by DSC) were found to be highly positively correlated with amylose levels. This correlation could be used for prediction of amylose content of rice flour. Low amylose starch could also be characterized by low degree of retrogradation (%R). The data obtained from RVA‐viscograms (peak viscosity, breakdown, setback, and pasting temperature) can be used only for characterization of the group of low amylose starches (waxy rice). It was demonstrated that low amylose rice starch provided the highest peak viscosity and breakdown and the lowest setback and pasting temperature among the groups investigated.     

韧化温度和时间对不同直链淀粉质量分数玉米淀粉物化性质的影响

为进一步探讨韧化处理对淀粉性质的作用机理,通过测定糊化性质、热特性、膨胀力、结晶特性及观察偏光十字现象和微观结构,研究了不同韧化温度和时间对不同直链淀粉质量分数玉米淀粉（普通玉米淀粉（normal corn starch,NCS）和蜡质玉米淀粉（waxy corn starch,WCS））物化性质的影响。结果表明,韧化处理主要作用于NCS和WCS淀粉颗粒的无定形区,对淀粉结晶类型没有影响;但韧化处理能够明显增强NCS和WCS的热稳定性和抗剪切能力,抑制淀粉老化和糊化,显著降低峰值黏度和膨胀力（P＜0.05）。韧化温度升高至60 ℃时韧化效果更加明显,糊化焓和相对结晶度明显降低,颗粒表面被明显破坏。但延长韧化时间对NCS和WCS老化的抑制效果和对糊化焓、膨胀力、颗粒形貌等的影响不明显。     

麦芽糖对糯性谷物淀粉糊化和流变性质的影响

以大黄米、糯米、糯玉米淀粉为原料,通过快速黏度分析仪、流变仪、差示扫描量热仪以及低场强核磁研究不同添加量的（2%、6%和10%）麦芽糖对糯性谷物淀粉糊化和流变性质的影响。结果表明：麦芽糖能够提高3 种糯性谷物淀粉的成糊温度,显著降低3 种淀粉的峰值黏度、终值黏度和回生值;随着麦芽糖添加量的增加,3 种淀粉糊的剪切应力逐渐降低,稠度系数降低,体系仍为假塑性流体,相比于大黄米淀粉和糯米淀粉,10%的麦芽糖对糯玉米淀粉的影响更大,稠度系数由32.546 Pa·sn降至4.801 Pa·sn,剪切变稀现象更为明显;热力学研究显示添加麦芽糖均能增加3 种糯性谷物淀粉的糊化温度和糊化焓值,且随着麦芽糖添加量的增加而升高;通过低场强核磁分析可知,添加麦芽糖使整个体系结合水与不易流动水含量增加,自由水含量减少,进一步解释添加麦芽糖能够降低体系黏度,增加淀粉糊化温度;本研究可为麦芽糖在糯性谷物食品中的应用提供指导。     

Effects of Cationization on Functional Properties of Pea and Corn Starches

Amylography, scanning electron microscopy and storage tests demonstrated that native pea starches were highly resistant to granule disintegration during heating in dilute slurries, resulting in low hot paste viscosity, high retrogradation and syneresis. Cationization at degrees of substitution of 0.02 to 0.05 reduced the pasting and gelatinization temperatures, increased peak viscosities and set-back on cooling but eliminated syneresis after storage at 4°C and − 15°C. The principal effects of cationization were to promote rapid granule dispersion at low pasting temperatures, yielding a molecular dispersion of amylose and amylopectin on heating to 95°C. On cooling, the gel structures were firm and the cationic groups controlled the realignment of starch chains during low temperature storage.     

Effects of mucilage on the thermal and pasting properties of yam, taro, and sweet potato starches

This study investigates the effects of water-soluble mucilages (0, 2.5, and 5 g/100 g; w/w, dry basis) on the thermal and pasting properties of isolated starches from three root and tuber crops. The results show that yam tuber presents the greatest level of mucilage and also possess the largest amylose content of the three isolated starches. The addition of mucilage caused a remarkable increase in the temperature of gelatinization for the three tested starches due to the competition for water during starch gelatinization. Furthermore, adding mucilage increased the phase transition temperature range (Tc-To) of starches but decreased enthalpy (ΔH). However, although the pasting temperature increased with the addition of mucilage into tuber starches, it did not change that of taro starch. The peak viscosity of taro and sweet potato starches decreased significantly as their mucilages were added into each starch suspension system (p < 0.05). However, the addition of mucilage slightly increased the viscosity of yam starch. Furthermore, the addition of mucilage slightly increased the swelling power of yam and taro starches, but did not change that of sweet potato starch.