Physical and chemical characteristic of stem starch and sheath flour from oil palm tree (Elaeis guineensis) (original) (raw)
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Journal of Thermal Analysis and Calorimetry, 2017
The aim of this work was to evaluate the morphological characteristics and physicochemical properties of coproducts obtained in wet milling of waxy maize starch (WMS). Coproduct A was obtained from the sieving process and was characterized by its high content of dietary fiber and starch (44 and 37 g 100 g-1 , respectively), and the coproduct B was obtained from the flotation and decantation of the aqueous part and showed high contents of proteins and lipids (16 and 32 g 100 g-1 , respectively). Micrographs showed higher content of WMS and dietary fiber in coproduct A. Both the coproducts showed a diffraction pattern of X-ray type A with higher definition of peaks in coproduct A. There was not significant difference between the gelatinization temperatures of coproducts A and B (73.47 and 73.90°C, respectively), since the WMS granules did not degrade during extraction steps of WMS. Coproduct A showed higher waxy maize starch content retained during the wet processing, with T p 73.47°C, DH 47.34 J g-1 and relative crystallinity 67.10%. Principal component analysis showed both the morphological and physicochemical behaviors were important in the discrimination of coproducts from wet milling of waxy maize. Coproduct A can be used as raw material in the preparation of bakery products due to the high fiber content and higher WMS content. On the other hand, coproduct B did not show viscosity but showed higher content of lipid and protein; then, it is indicated to be used as a supplement of lipids and proteins in preparations of food products.
Physicochemical and pasting properties of starch extracted from four yam varieties
Yams are not among the most common sources of industrial starch, which are mostly imported at a cost. Exploiting alternative sources of starch would lessen the burden of its importation. Starches from four local varieties of Dioscorea rotundata namely Pona, Labreko, Asobayere and Muchumudu were analyzed for their physicochemical and functional properties. Results obtained showed significant differences (p<0.05) in some physicochemical properties (moisture, ash, starch yield and pH). Moisture, ash, starch yield, pH, amylose, amylopectin, swelling power, solubility and water binding capacities ranged from 7.22 to 7.82%, 024 to 0.86%, 12.61 to 20.89%, 5.57 to 6.25, 27.48 to 31.55%, 68.45 to 72.52%, 10.57 to 12.48%, 8.52 to 9.32% and 175.25 to 182.69% respectively. Asobayere had the highest starch yield (20.89%) and may be exploited for starch production. There were significant differences (p<0.05) in the pasting properties. The pasting temperature ranged from 75.10 (Asobayere) to 77.30°C (Muchumudu). Peak temperature ranged from 81.7 (Asobayere) to 94.8°C (Muchumudu). Peak viscosity for Asobayere, Pona, Labreko and Muchumudu were 726, 614, 685 and 639 BU respectively. Final viscosity ranged from 385 (Pona) to 817 BU (Muchumudu). Values of 385 (Asobayere), 142 (Labreko), 293 (Pona) and 25 BU (Muchumudu) were observed for breakdown viscosity. Labreko had the highest value of 337 BU and Pona the lowest value of 79 BU for setback viscosity. Muchumudu may be used industrially in products that require high unit yield, low viscosity and paste stability at low temperatures. Asobayere and Labreko may be used for foods that require thick and cohesive paste such as fufu and pounded yam due to its high pasting viscosities. Yam starches can be exploited for diverse uses.
Distribution of Oil Palm Starch for Different Levels and Portions of Oil Palm Trunk
It is widely known that starch can be heated to have adhesive characteristic. The proper ties of starch rich, low density oil palm wood from the inner part of oil palm trunk (OPT) have been seen to be possible improved through steam-densification process by using in situ starch as binding agent. For that, the distribution and characteristic of the ex tracted starch at different height and por tions of OPT are first need to be investigated. Star ch ex traction of OPT was made by traditional grating-dissolving method in water. Starch distributions were found more concentrated in core por tion and it increased as the heights increasing. At the first 2m height above the ground, mean ex tracted starch content was 2.9% , 4.3% and 5.6% for the outer, middle and core respectively. Regardless of por tion, mean extracted starch content was 4.3% , 7.4% , 7.7% and 8.5% for the first, second, third, and four th 2m trunk height respectively. Regardless of level, mean ex tracted starch content was 4.9% , 7.2% and 8.8% for the outer, middle and core por tion respectively. Other study using Na2S2O5 as solvent gave 7.15% mean star ch content for the oil palm slabs (the outer por tion). Further study on the ex tracted starch characterization, it was found that the starch from cor e portion turned into darker blue color than the outer, and the starch from upper level turned into darker blue color than the lower level when they were subjected to iodine test. The blue color is usually used to indicate the pur ity of starch, the darker th e color, the purer the starch. The results suggest that both the extracted starch content and the star ch purity were showing the same trend, increased from outer inside and from bottom upside, in the OPT.
Properties of Some Starch Blends 1
Cereal Chemistry, 1997
Cereal Chem. 74(4):431-436 Normal corn, high-amylose corn, waxy corn (waxy maize), wheat, rice, potato, cassava (tapioca), and a modified waxy corn starch were blended in various combinations and ratios. Pasting behavior, paste and thermal properties, and retrogradation tendency were determined. Differential scanning calorimetry (DSC) traces of the mixtures did not resemble those of either of the two components, nor did any DSC trace have two peaks suggestive of a mixture of two distinct starches. Amylograph data suggested that some mixtures behaved like a chemically modified starch. Observations from light microscopy suggested that intermolecular, molecular-supermolecular, and intersupermolecular interactions may be responsible for this behavior.
Rheological Properties of Pastes Obtained from Starches Derived from Immature Cereal Kernels
Starch - Stärke, 2004
The results presented in this work concern the starches of three basic varieties of cereal cultivated in Poland-wheat, rye and barley-harvested at different stages of maturity in 1997 and 1998. Starches from these kernels were isolated by a laboratory method. The flow curves and thixotropic properties of 5% starch pastes at 507C and controlled shear rates between 0 and 600 s 21 were obtained. All the investigated starch pastes were non-Newtonian, plastic and thixotropic fluids, that differed in their values of yield stress. The pastes from immature cereal starches were characterised by a higher plasticity because they needed a higher shear stress (t) to achieve the yield stress (t 01) in comparison with the pastes from the mature cereal starches. At applied shear stress the pastes from the "immature" starches had a higher thixotropy in comparison with the "mature" ones. Pastes from immature starch were more susceptible towards shearing forces but at the same time they exhibited a better ability to rebuild their structure. The description of the flow curves by the Ostwald-de Waele equation allows the conclusion that pastes from the immature starches have a higher structural viscosity. In addition, the application of the Casson model allows to describe the flow curves and determine the yield stress and the plasticity properties of the investigated pastes. However, the viscosity values calculated from the Casson model do not reflect differences in viscosity among the samples.
EXTRACTION OF OIL PALM STARCH: A COMPARATIVE STUDY
Potential of oil palm starch from oil palm trunk as a starch based adhesive was evaluated based on collection of starch yields (grams) using two types of steeping methods of starch extraction processes. Sodium metabisulphite (Na2S2O5) was used in both methods and was differentiated by with and without the use of 0.5 % of lactic acid in soaking process. The results showed extraction of starch by steeping method with sodium metabisulphite (Na2S2O5) only, gave higher yield compared to extraction of starch by steeping method with presence of lactic acid. The important characteristics in the starch as a binder such as starch content, solid content and viscosity value were also determined in this study to evaluate the presence of lactic acid from both extraction methods
The effects of low molecular weight additives on the viscosities of cassava starch
Carbohydrate Polymers, 1997
The influence of a range of additives on the change in the viscosity of cassava starch pastes on ageing following gelatinisation has been investigated. The inclusion of sulfite with pasted starch markedly decreases the viscosity of the paste with time and this is prevented by the addition of propyl gallate. Intrinsic viscosity measurements strongly support the view that sulfite addition promotes polysaccharide degradation. Ascorbate has a greater degradative effect than sulfite, whereas only limited degradation is observed with glutathione. Salts such as sodium chloride and sodium sulfate show no effect on viscosity. If the chelating agent EDTA is added as well as sulfite, the reduction in viscosity is smaller, although the effect is not cancelled out completely. Interestingly, the degradative effect of sulfite and ascorbate can be shown at 30, 60 and 80°C. The results presented uphold the previous suggestion that sulfite addition promotes oxidative reductive depolymerisation (ORD) and largely rule out any residual enzyme activity as the cause. It is suggested that the strong degradative action of ascorbate on starch could be one of the explanations for its action in baked products.
Effect of different polyols on wheat and maize starches paste and gel properties
Food Hydrocolloids, 2015
The use of polyols as sugar replacers in bakery products is a common practice. In these products, pasting and gelation properties of starches have a strong influence on the process and on the quality of final products. In this study, the influence of different polyols (maltitol, sorbitol, xylitol and mannitol) on pasting properties of two starches (wheat and maize) was analysed and compared to those made only from native starches and their combinations with sucrose. Rheological properties of gels as well as their texture and colour were also analysed. Even though differences among the different studied polyols and the interactions among them and among starches were observed, in general polyols showed an influence on starch properties similar to those of sucrose. Thereby, in general peak viscosity and setback as well as gel hardness were increased and L* was reduced with the use of polyols. In all cases, the polyol which showed more similar results to those made from sucrose was maltitol. Meanwhile, xylitol was the polyol which modified the native starch properties to a lesser extent, both in RVA curve, especially in the cooling stage, and in gel rheology and hardness.
The effect of some physical and chemical treatments on the functional and pasting characteristics of native tigernut starch (TNNS), native sweet potato starch (SPNS) and blends of tigernut-sweet potato starch were studied. Native tigernut and sweet potato starches were subjected to physical (annealing and heat-moisture) and chemical (acetylation modifications and compared to tigernut (T)-sweet potato (S) starches blends (T75:S25, T50:S50, T25:S75). Only heat-moisture treatment (THMT) significantly (p≤0.05) increased water absorption capacity of the native tigernut starch while only acetylated tigernut starch (TNAS) significantly (p≤0.05) increased the oil absorption capacity of the native tigernut starch. The bulk density was significantly (p≤0.05) reduced by annealed tigernut starch (TANN) and TNAS. In addition, TNAS, mixture of blends and SPNS had higher swelling capacity than TNNS. The final and peak viscosities of TNNS, SPNS and all the starch blends were between (217 -280 RVU) and (214 – 395.3 RVU) respectively with SPNS having the highest values, followed by T75:S25 (75% tigernut starch: 25% sweet potato starch) and TNNS in that order. TNNS also had the highest setback viscosity. Samples THMT, TANN and TNAS significantly (p≤0.05) reduced the breakdown viscosity and the pasting temperature. The scanning electron micrograph showed that the native and modified starches of tigernut were similar to those of other starches. Overall, the results showed that many of the pasting characteristics of TNNS were comparable to SPNS, while SPNS had with better functionalcharacteristics.