采用不同方法制备豌豆抗性淀粉及其性质研究

以豌豆淀粉为原料,研究交联、湿热、脱支酶解3种不同方法处理后其抗性淀粉含量及其他性质的变化。实验表明:交联、湿热、脱支酶解处理均能增加豌豆抗性淀粉的含量,且脱支酶解处理>湿热处理>交联处理;交联处理后其溶解度降低,但湿热和酶解均使其溶解度增加,3种处理方式均使豌豆淀粉膨胀度降低;交联和酶解处理使豌豆淀粉的糊化温度和糊化焓增加,糊化变得困难,而湿热处理后其糊化峰变为2个;X射线衍射数据表明,交联处理不会改变豌豆淀粉的晶型,湿热处理和脱支酶解后豌豆淀粉的晶型分别由原来的C型变为A型和B型;体外消化模拟实验表明,经交联处理后豌豆淀粉消化性增加,而经湿热和酶解处理后其消化性能均降低。     

不同热处理方式对大蕉抗性淀粉理化性质的影响

研究了干热、湿热和微波加热在不同条件下处理大蕉抗性淀粉对其保留率、色泽、颗粒形貌、碘吸收曲线、溶解性、膨胀性和持水性等理化性质的影响。结果表明,高温干热、湿热和微波加热均会减少抗性淀粉的含量;湿热和微波加热不利于保护色泽;三种热处理方式均使大蕉抗性淀粉的偏光十字减弱,但没有改变最大碘吸收峰位置;干热和湿热处理使抗性淀粉溶解度减少,微波处理使溶解度增加;干热处理使膨胀度减小,微波加热使膨胀度增大,湿热对膨胀度没有明显的影响。     

海藻酸钠对不同直链淀粉含量的玉米淀粉物化性质的影响

采用快速黏度分析仪、差示扫描量热仪、动态流变仪、物性测试仪等,研究了海藻酸钠对3种不同直链淀粉含量的玉米淀粉糊化、凝胶及老化性质的影响。结果表明:海藻酸钠显著影响高直链玉米淀粉、普通玉米淀粉及蜡质玉米淀粉的物化性质,且对不同直链淀粉含量的玉米淀粉物化性质的影响不同。海藻酸钠使3种玉米淀粉的糊化难度增大,起始糊化温度、峰值糊化温度、终止糊化温度升高,糊化焓增加。海藻酸钠提高3种玉米淀粉的峰值黏度、末值黏度、表观黏度及损耗模量。海藻酸钠提高高直链玉米淀粉的热稳定性和抗老化性,使高直链玉米淀粉的衰减值、老化率降低。海藻酸钠阻碍高直链玉米淀粉形成凝胶,使高直链玉米淀粉的损耗角正切值升高、凝胶硬度降低。     

水分含量对湿热处理玉米淀粉性质的影响

将玉米淀粉中的水分含量分别调节为10%、18%、25%、30%,利用手提式高压灭菌锅在121℃湿热处理5 h,研究湿热处理对玉米淀粉颗粒形貌、糊化温度、膨胀能力和溶解度的影响.试验结果表明:玉米淀粉经湿热处理后,淀粉颗粒仍保持原有外观,部分淀粉颗粒中心出现凹坑;淀粉的糊化温度明显高于原淀粉;糊液黏度低于原淀粉;淀粉颗粒的膨胀能力上升;溶解度较原淀粉降低.湿热处理对玉米淀粉的相关性质产生了明显的影响,并随处理时水分含量的不同表现各异.     

芡实淀粉理化性质的研究

淀粉是芡实中含量最高的组分,其结构和性质对芡实的加工和应用至关重要。研究了芡实淀粉的表面结构,冻融稳定性,溶解度,膨胀度,透明度,直链淀粉和支链淀粉的含量,以及淀粉糊特征曲线等理化性质并与马铃薯和玉米淀粉进行比较。结果表明,与马铃薯和玉米淀粉相比,芡实淀粉的溶解度,膨胀度,透明度以及峰值粘度的值较低,糊化温度的值和直链淀粉的含量较高,冻融稳定性与玉米淀粉相近。     

不同湿热处理方法对玉米淀粉性质的影响

利用烘箱和高压灭菌锅对水分含量为25%(w/w)的玉米淀粉在121℃处理5h,研究淀粉性质发生改变的情况.试验结果表明,玉米淀粉经湿热处理后,淀粉颗粒中心出现凹坑,颗粒结晶程度增加,淀粉的糊化温度上升,糊液黏度降低,膨胀能力升高,溶解度下降.在相同的处理条件下,利用高压灭茵锅湿热处理对淀粉的性质影响更为显著.     

超声处理对玉米淀粉热性质的影响

研究超声处理前后玉米淀粉热性质的变化。采用超声波对70%水分含量的玉米淀粉进行处理。结果表明超声处理提高了糊化转变温度、膨胀度和溶解度,降低了析水率、焓值以及转变温度范围。玉米淀粉经处理后粘度降低,但其粘度曲线不改变。以上数据表明超声处理优先降解无定形区,且直链淀粉比支链淀粉更容易被降解。     

微波辐射对木薯淀粉性质影响

研究微波辐射前后木薯淀粉物化性质变化,采用微波对30%水分含量木薯淀粉进行处理,结果表明,微波处理增强对应X–射线衍射峰强度,降低膨胀度、溶解度和冻融稳定性;木薯淀粉经处理后糊化起始温度升高、粘度降低,但其粘度曲线不改变。以上数据表明,在淀粉颗粒内无定形区和结晶区直链淀粉与直链淀粉、直链淀粉与支链淀粉发生交互作用,微波处理使淀粉分子发生一定程度降解。     

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。     

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。     

酸解对不同链/支比含量玉米淀粉特性的影响

以4种不同链/支比含量的玉米淀粉为原料,酸解处理不同时间,以酸解玉米淀粉的形貌特性、冻融稳定性、膨胀度、溶解度、晶体性质为指标衡量不同酸解时间对玉米淀粉结构性质的影响。结果表明:4种玉米淀粉酸水解程度的顺序为:蜡质玉米普通玉米淀粉G50G80。酸解后,同品种的4种玉米淀粉的析水率随着酸解天数的增加而增加;溶解度增加,膨胀度降低。酸解并未改变淀粉的晶型,随着酸解时间的延长,蜡质玉米淀粉和普通玉米的相对结晶度先增大后保持不变,G50和G80的相对结晶度随着酸解时间的增加而增大。表明酸解对低直链淀粉(蜡质玉米淀粉和普通玉米淀粉)的结构、性能影响最大。     

Physicochemical Properties of Canna edulis Ker Starch on Heat-Moisture Treatment

Canna edulis Ker starch was modified by heat-moisture treatment at moisture levels ranging from 18 to 27 g/100 g starch and its physicochemical properties were investigated. Amylose content, swelling power, solubility as well as water and oil absorption capacity in native starch were higher than in all treated starches. However, alkaline water retention and acid susceptibility of native starch were lower, along with different extent of amylose leaching. The result in the X-ray diffraction measurement revealed that the crystalline type of the starch gradually changed from B-type to A-type, and the degree of crystallinity changed. Investigation on thermal properties showed that the gelatinization enthalpy decreased, whereas the onset temperature, peak temperature, concluding temperature and transition temperature range increased in modified starch than in native starch. In addition, all modified starches exhibited remarkably low values of peak viscosity, hot pasting viscosity and final viscosity, compared to those of native starch.     

Physicochemical properties of thermal alkaline treated pigeonpea (Cajanus cajan L.) flour

Thermal alkaline treatment, normally used for corn, was applied to pigeonpea grains. Starch granules were isolated using wet milling and alkaline treatments. Effects of the calcium hydroxide [Ca(OH)₂] concentration in the range of 0–1% (w/v) on granule structure, crystalline structure, chemical composition, and physicochemical, thermal, and pasting properties of isolated starch granules were determined. Compared to native samples, thermal alkaline treated samples had higher protein, lipid, calcium, and phosphorus contents, but lower starch and amylose contents. Thermal alkaline treatment increased starch granular size and gelatinization temperatures, but decreased relative crystallinity, gelatinization enthalpy, swelling power, solubility, amylose leaching, and the pasting viscosity. Amylose-lipid complexes were not found in thermal alkaline treated flours. As the Ca(OH)₂ concentration increased, the amylose content, relative crystallinity, gelatinization temperature, and enthalpy also increased, but the swelling power, solubility, amylose leaching, and paste viscosity decreased. A higher Ca(OH)₂ concentration produced more stable starch granules that resisted re-gelatinization.     

In situ gelatinization of starch using hot stage microscopy

Starch gelatinization is important in food processing and industrial use. Granule swelling and gelatinization temperature of 11 starches from different plants were investigated in situ using hot stage microscopy during heating. The amylose content, swelling power, pasting temperature and thermal property of these starches were also measured. The results showed that hot stage microscopy was suitable for measuring granule swelling and the gelatinization temperature of starch during heating. The sectional area swelling percentage of starch granules measured using hot stage microscopy was significantly positively correlated with the swelling power. The gelatinization temperature measured using hot stage microscopy was significantly positively correlated with the pasting temperature and with the thermal property for all 11 starches. For rice starches with the same crystallinity and similar size, the gelatinization temperature was negatively correlated with the amylose content and positively correlated with the swelling power and the sectional area swelling percentage at 95°C.     

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.     

Physicochemical Properties of Starch and Flour from Different Rice Cultivars

The starches and flours from four different rice cultivars were evaluated for composition, crystallinity characteristics, blue value, turbidity, swelling power, solubility, pasting properties, and textural and retrogradation properties. The amylose content of starches and flours from different rice cultivars differed significantly. The results showed that the physicochemical properties of rice starch and rice flour were correlated to amylose content. The crystallinity degree of rice starch and flour depended on amylose content. The blue value, turbidity value, and gel hardness were positively correlated to amylose content; however, the swelling power, solubility, and gel adhesiveness were negatively correlated to amylose content. Furthermore, the pasting properties and gel textural and retrogradation properties of rice flours were related to the structure properties of rice starch. And the characteristics of starch, protein, and lipid significantly influenced the turbidity, pasting properties, and gel textural and retrogradation properties of rice flours.     

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

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

Physicochemical,crystallinity, pasting and thermal properties of heat‐moisture‐treated pinhão starch

The effect of heat‐moisture treatment (HMT) on the properties of pinhão starches under different moisture and heat conditions was investigated. The starches were adjusted to 15, 20 and 25% moisture levels and heated to 100, 110 and 120°C for 1 h. The X‐ray diffractograms, swelling power, solubility, gel hardness, pasting properties and thermal properties of the native and HMT pinhão starches were evaluated. Compared to native starch, there was an increase in the X‐ray intensity and gel hardness of HMT starches, with the exception of the 25% moisture‐treated and 120°C heat‐treated starch. HMT reduced the swelling power and solubility of the pinhão starches when compared to native starch. There was an increase in the pasting temperature, final viscosity and setback and a decrease in the peak viscosity and breakdown of HMT pinhão starches compared to native starch. HMT increases the gelatinisation temperature of native pinhão starch and reduces gelatinisation enthalpy.     

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.