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《Starch - St?rke》2017,69(9-10)
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修饰预糊化木薯淀粉性能研究   总被引:4,自引:1,他引:3       下载免费PDF全文
盛建国 《食品科学》2002,23(5):29-31
介绍了经化学修饰后再进行预糊化制备得到的修饰预糊化木薯淀粉的性能,并与国产预糊化木薯淀粉和泰国泰花牌预糊化木薯淀粉的性能进行了比较。结果表明:修饰预糊化木薯淀粉的性能达到且超过泰国泰花牌预糊化木薯淀粉的性能,远远优于国产预糊化木薯淀粉。  相似文献   

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  总被引:1,自引:0,他引:1  
The effect of rice variety and starch isolation method on the pasting and rheological properties of rice starches was evaluated. One waxy and three non-waxy rice varieties from California with a range of amylose contents of 1.6–26.5% and four methods of isolation were evaluated. A rotational rheometer (RR) was used to measure the pasting and rheological properties of starch dispersions (8% w/w). The RR pasting curves had similar shapes to those from a rapid visco-analyzer (RVA). The four treatments used for isolating starch were a protease, NaOH (0.1% and 0.4%), or sodium dodecyl sulfate (SDS) (1.0%). The NaOH (0.4%) and SDS treatments were found to reduce the peak pasting temperatures of the non-waxy starches as compared with the protease and NaOH (0.1%) treatments. The same trend of the treatments was found with the elastic moduli, low shear viscosities, and yield stresses of the non-waxy starch pastes measured at 65 °C, immediately after pasting. The elastic moduli of the waxy starch pastes appeared to be least affected by method of starch isolation, but the low shear viscosity and yield stress of the protease starch paste was significantly higher than the paste from the other three treatments. Overall, the method of rice starch isolation was found to affect the gelatinization and rheological characteristics of hot rice starch paste.  相似文献   

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The pasting viscosities of starches from Angelica dahurica (three cultivars named Chuan Baizhi, Yu Baizhi and Qi Baizhi in Chinese, respectively), in the presence of NaCl, Na2CO3, NaOH, glucose, fructose and sucrose were determined with a rapid visco analyser. The pasting peak, trough or final viscosities and the pasting temperatures (Pt) of Baizhi starches increased with NaCl concentration increased from 0 to 3.0%. The peak viscosities of Baizhi starches increased at 0.2% Na2CO3 concentration and then decreased with Na2CO3 concentration up to 0.8%. The trough and final viscosities and the Pt decreased with Na2CO3 concentration up to 0.8%. The peak viscosities increased in 0.1%, but decreased in 0.2% NaOH concentration. The trough and final viscosities and the Pt decreased in the presence of NaOH. With the concentration of sugar (glucose, fructose and sucrose) increased from 0 to 20%, the pasting peak, trough and final viscosities of these starches increased significantly. For the same Baizhi starch, the elevation of peak viscosity was the most significant when fructose was added, and the elevation of final viscosity was the greatest when sucrose was added.  相似文献   

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Addition of chemicals during the extraction of cassava starch for enhancing the settling rate, whiteness and compactness of the settled starch is an accepted commercial practice. The effect of addition of selected chemicals such as acids (sulphuric and hydrochloric acids), bleaching and oxidising agents (sodium metabisulphite and sodium hypochlorite) and alum during settling on the thermal and pasting properties of the cassava starch was examined. Treatment with sulphuric acid produced a noticeable increase in all DSC gelatinisation parameters, viz. onset gelatinisation temperature (To), temperature at peak minimum (Tp) and end temperature (Te), with increasing concentration of acid, while only a marginal shift could be obtained even at higher concentration of hydrochloric acid. However, no major effect resulted from treatment with sodium metabisulphite, sodium hypochlorite and alum. The gelatinisation enthalpy was hardly affected by the treatments. An exception was hydrochloric acid, which brought about a perceptible decrease in enthalpy at higher concentrations indicating that starch crystallinity is influenced to a small extent by hydrochloric acid. Pasting characteristics studied using a Rapid Visco Analyser showed that sulphuric acid, even at the lowest concentration (5 mM), considerably affected the structural characteristics of cassava starch, while hydrochloric acid induced similar effect only at higher concentrations. Alum reduced the paste viscosity while the bleaching agents (sodium metabisulphite and sodium hypochlorite) were not so effective in modifying the starch viscosity characteristics.  相似文献   

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研究NaCl对氧化淀粉浆料糊化性能的影响。采用快速黏度仪(RVA)测试了不同NaCl浓度下氧化淀粉的糊化温度、糊化时间、峰值黏度、终值黏度和回生值。结果表明:随着NaCl对淀粉质量浓度的增大,氧化淀粉的糊化温度、糊化时间和峰值黏度逐渐增大;终值黏度和回生值随着NaCl对淀粉质量浓度的增大,先减小后增大;NaCl对淀粉质量浓度在2%~6%的范围内时,淀粉浆液的低温稳定性和抗老化性能有所提高。  相似文献   

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Cassava root spoils rapidly after harvest but can be well preserved by storing under freezing. This study investigated the functional, chemical and physicochemical properties of flour produced from frozen cassava roots. Freezing period did not significantly (p < 0.05) alter the moisture, ash, fat and fibre, but had slight effect on the carbohydrate and protein contents of the flour. Lightness, yellowness index and bulk densities of the flour samples reduced with freezing period. While freezing did not significantly (p < 0.05) change the ability of the flour samples to absorb oil, a slight but significant increase in the water absorption capacity was observed. Potassium (1.29–3.46 mg/kg), sodium (1.24–1.28 mg/kg), and calcium (0.94–1.34 mg/kg) were the major minerals in the cassava flour samples. The cyanide content (10.80–22.95 mg/kg) reduced as freezing days increased but peak, setback, breakdown and final viscosities did not follow a particular pattern. The information from this study is important to further determine the industrial potentials of flour from stored cassava roots.  相似文献   

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This article reports our investigation on the effect of cassava varieties on the physicochemical and functional properties of sour starches. There were significant differences (P < 0.05) in the ash, pH, amylose, amylopectin, starch damage, total titratable acidity (TTA), sugar, and starch content but not moisture contents of various cassava sour starches. There were no significant differences (P > 0.05) in Water Absorption Capacity (WAC), swelling power, and solubility index, while significant differences were recorded in Least Gelation Concentration (LGC) and color at 5% level and granule size at P < 0.0001 for cassava sour starches. Peak viscosity values ranged from 333.17RVU (clone 4(2) 1425) to 380.75RVU (clone TME 1). There were significant differences (P < 0.05) in pasting properties except for pasting temperature and breakdown.  相似文献   

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Starch isolated from five grain tef (Eragrostis tef) varieties was characterized and compared with commercial maize starch. Grain tef starch is formed of compound granules, comprising many polygonal shape (2—6 μm in diameter) simple granules. The crude composition is similar to that of normal native cereal starches. The amylose content ranges from 24.9—31.7%. Gelatinisation temperature range was 68.0—74.0—80.0 °C, typical of tropical cereal starches, and resembling the temperature range of rice starch. The mean intrinsic peak viscosity (269 RVU), breakdown viscosity (79 RVU), cold paste viscosity (292 RVU) and setback viscosity (101 RVU) determined were considerably lower than that of maize starch. Tef starch has higher water absorption index (WAI) (mean 108%) and lower water solubility index (WSI) (mean 0.34%) than maize starch.  相似文献   

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Cassava (Manihot esculenta Crantz) is one of the most important sources of starch in the tropics. There is limited and contradictory information regarding cassava starch characteristics. The International Center for Tropical Agriculture (CIAT) holds in trust FAO's cassava germplasm collection. Starches from 3272 landraces (including 12 wild relatives) and 772 improved clones were extracted and analyzed over a period of several years. In most cases only one starch sample per genotype was analyzed. Average cyanogenic potential was 327 ppm but considerably higher in the landraces (340 ppm) than in improved clones (267 ppm). Average total and reducing sugars were slightly higher in improved clones (4.06 and 1.56%, respectively) than in landraces (3.68 and 1.25%, respectively). Amylose content was similar in both types of germplasm with an average of 20.7%. Average pasting temperature was 65.3°C. Maximum viscosity was 777.5 mPa s, breakdown was 298.1 mPa s, consistency was 155.8 mPa s and setback was ‐144.5 mPa s. The large sample of starches analyzed provides very robust information regarding the actual characteristics of cassava starch.  相似文献   

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The dynamic rheological behaviour of skim milk gels containing 2% normal rice starch granules pasted to different temperatures was investigated. The extent of swelling of the starch granules was also measured. It was found that the complex modulus G* was maximal when the starch granules were pasted to the temperature of maximum swelling and not to the temperature of maximum viscosity. It is suggested that, in these systems, the starch granules behave as inactive fillers and that their main effect is to increase the milk protein concentration during swelling by absorbing water from the continuous phase. A simple empirical model that agrees qualitatively well with the experimental results is proposed.  相似文献   

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BackgroundStructure-property relationships of starch components remain a subject of research interest. In recent years, there has been increasing evidence revealing the importance of amylopectin internal structure in determining physicochemical properties of starch. The part between the sole reducing end and out branches of amylopectin forms the internal part of the molecule. It contributes to the formation of the amorphous lamellae of the granules.Scope and approachThis mini-review focuses on the impact of amylopectin internal molecular structure on different physicochemical properties of starch. The properties include gelatinization, swelling power, amylose leaching, pasting, retrogradation, and digestibility of starch. The statistical approach to analyze the structure-property relationships of starch is also discussed. Related nomenclatures are described.Key findings and conclusionsAmylopectin with a longer internal chain length tends to give more ordered packing of double helices in the granules with a higher thermal stability. A longer internal chain length of amylopectin also contributes to the formation of recrystallized amylopectin with a more ordered structure and higher thermal stability. The results summarised in this mini-review clearly show that the molecular structure of amylopectin internal part should be considered in order to better understand the complex structure-property relationships of starch components.  相似文献   

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The balance of total cyanogenic compounds and distribution of each compound including bound cyanide, cyanohydrin and free cyanide were evaluated in a cassava starch factory, having a production capacity around 100 t starch per day. The production of starch began with transferring washed roots to the rasper, followed by a series of extractors, separators, dewatering centrifuge and flash dryer, with an average water consumption of 11.4 t per ton dry starch. The total amount of cyanogenic compounds entering the process varied from 28 to 43 kg HCN equivalent per day, depending on the root quality. In roots, 64% of bound cyanide was primarily found and it significantly decreased to 22% after rasping whereas the cyanohydrin content increased from 34% to 62%. Most of cyanogenic compounds, predominantly present as cyanohydrin (55 to 70%), was discharged in liquid and solid wastes, accounting for 92% and 5% of total cyanide in roots, respectively. Only a negligible amount of cyanogenic compounds remained in the starch products, having less than 2 mg HCN equivalent per kilogram dry starch. Typically, water from the separators with 91% total cyanide content was recycled to the root washer before being discharged as wastewater, whereas the liquid from the coarse extractor (43% of total cyanide) was recycled to the rasper. This could cause the accumulation of cyanogen in the process and, therefore, in the finished products. With knowledge of the balance and transformation of cyanogens in starch processing, it is possible to assure the quality of low‐cyanide starch by modifying starch process features such as water circulation and pH adjustment.  相似文献   

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Cassava starch is an important export commodity of Thailand, about 2 × 106 t are expected annually. Initially, cassava was mainly processed to meal and flour. Due to the high market demand for cassava products, the Thai cassava starch industry was established and has developed from small to large‐scale with improved processing technology. At present, a production capacity of one factory is, on average, 200 t starch per day. Transition from small to large‐scale production was accompanied by varietal development of root having high starch yield and technological improvement of starch production with shorter processing time and better starch quality. Most process technologies are still imported and adopted from those of other starches. The Thai cassava starch industry still encounters impediments, including high production cost, high resource consumption, starch loss, and adverse environmental impact especially sulfur, cyanide, solid and liquid waste. This industry continues to develop, in order to remain internationally competitive.  相似文献   

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