Thermodynamics of the Process of Adsorption of Phosphate Starch on Cellulose

Subject of this study is the adsorption of phosphate starch (PHS) on cotton cellulose and unbleached pulp from coniferous wood at temperature of 0.20, 40 and 60°C. resp., and concentration of the PHS solutions ranging from 0,030 to 2,00 g/l. It was found that with an increase of temperature the quantity of adsorbed PHS decreases. Adsorption equilibrium is described by the adsorption isotherm of Langmuir. The equilibrium constants, isosteric heats, standard affinity and entropy of the process are defined. It was established that the desorption of PHS of sulphate unbleached pulp of coniferous wood was 46.5%.     

Adsorption of Amylose Triacetate on Porous Adsorbents

Adsorption studies of amylose triacetate from its chloroform solutions on porous adsorbents viz. calcium silicate, aluminium silicate, and cellulose powder have been carried out at 35° ± 0.05°C. The adsorption follows first order kinetics. The adsorption data have been analysed according to the Langmuir and Simha-Frisch-Eirich isotherms. Viscosity measurements of supernatant polymer solutions as a function of adsorption time indicate the preferential adsorption of low molecular weight material.     

Production of short‐chain fatty acids following in vitro fermentation of saccharides,saccharide esters,fructo‐oligosaccharides,starches, modified starches and non‐starch polysaccharides

A range of carbohydrates including modified starches and short‐chain fatty acid esters of di‐, tri‐, tetra‐ and polysaccharides were subjected to an in vitro fermentation using human‐derived faecal bacteria. The production of the short‐chain fatty acids (SCFAs) acetate, propionate and butyrate was monitored at 6, 12, 24 and 36 h for all substrates; however, it was found that the proportions of acids produced were reasonably constant after 6 h. Between substrates there was variation in both the proportions and quantities of acids produced. Relative substrate fermentability as measured by total acid production at 24 h was: sucrose octa‐acetate > sucrose > stachyose > pregelatinised starch > Raftilose^® > verbascose > raffinose > starch acetate > bleached starch > phosphated distarch phosphate > locust bean gum > corn starch > oxidised starch = starch sodium octenyl succinate > di‐starch phosphate > acetylated di‐starch adipate = gum arabic > acid‐treated starch > gum tragacanth > gum guar > acetylated di‐starch phosphate = hydroxypropyl di‐starch phosphate > hydroxypropyl starch > pectin > raffinose undeca‐acetate > stachyose acetate > gum karaya = cellulose propionate > cellulose acetate > cellulose > cellulose butyrate > hydroxypropyl methyl cellulose > carrageenan > methyl cellulose. Chemically modified starches were similar to corn starch in the amounts of total SCFAs produced at 24 h. Synthetic sugar esters could have potential application as vehicles to deliver supraphysiological amounts of SCFAs during in vivo studies of colonic fermentation. © 2000 Society of Chemical Industry     

PURIFICATION AND PHYSICOCHEMICAL PROPERTIES OF AN EXTRA CELLULAR AMYLASE FROM A STRAIN OF BACILLUS AMYLOLIQUEFACIENS ISOLATED FROM DRY ONION POWDER

An extracellular α-amylase from Bacillus amyloliquefaciens, isolated from dry onion powder, has been purified to homogeneity by ammonium sulfate fractionation, adsorption on starch, column chromatography on DEAE-cellulose, and gel filtration on Sephadex G-100 column. The enzyme consisted of one polypeptide chain with a molecular weight of 60,000. The isoelectric point was pH 5.2, the pH optimum 5.5 and the temperature optimum ranging from 50°-70°C. Prolonged digestion by trypsin did not affect the catalytic properties of the enzyme. The K_m for starch was 6.9 mg/ml. The enzyme was quite stable at 50°C, but lost about 85% of its activity at 60° after 30 min (pH 6.0).     

Starch Characterisation of Araucaria angustifolia and Araucaria araucana Seeds

Araucaria angustifolia and Araucaria araucana are conifers that cover different areas of South America. Their seeds have been consumed from prehistoric times until today in Brazil, Argentina and Chile. In this work, the starch of Araucaria angustifolia and Araucaria araucana seeds were analysed by light and environmental scanning electron microscopy, X‐ray diffraction, and differential scanning calorimetry. The starch granules of A. angustifolia and A. araucana were round or slightly oval, with a central hilum. Both starches gave X‐ray diffraction patterns compatible with the A‐type, with strong peaks at 15°, 17°, and 23°. The gelatinisation temperature of A. angustifolia starch (68.5°C) was higher than that of A. araucana (66.6°C), probably due to the higher amylose content of the former (22.4 % and 17.3 %, respectively). The thermograms of A. araucana starch presented a minor peak at about 71°C, which was attributed to the fact that the starch granules population of A. araucana was heterogeneous, with large and small granules, whereas A. angustifolia starch contained mainly large granules.     

Effects of psyllium and cellulose fibres on thermal,structural, and in vitro digestion behaviour of wheat starch

The study investigated the effects of adding different types of fibre (psyllium and cellulose) on in vitro digestion behaviour of wheat starch with its thermal and structural properties. Psyllium and cellulose fibres interfered with the wheat starch differently. Psyllium fibre hindered starch gelatinisation, restricted the loss of starch crystallinity, and decreased the accessibility of enzymes to starch. In contrast, cellulose fibre had no significant effect on gelatinisation and loss of crystallinity but limited the digestive enzyme mobility. The impact of psyllium was more pronounced than cellulose on reducing starch digestibility. Rapidly digestible starch fractions of the cooked starch reduced from between 57.90 ± 0.60–69.72 ± 0.46 (% in starch) to between 28.06 ± 0.36–46.34 ± 1.10 (% in starch) and 53.23 ± 0.36–66.71 ± 0.24 (% in starch) for psyllium and cellulose fibre, respectively. This information could be helpful to design foods containing starch with reduced digestibility for a healthy diet.     

Effect of Temperature and Period of Fermentation on Protein and Starch Digestibility (In vitro) of Rabadi—A Pearl Millet Fermented Food

Rabadi was prepared by allowing pearl millet flour-country buttermilk mixture to ferment for three different periods (3, 6 and 9 hr) at four different temperatures (35°, 40°, 45°, and 50°C). As fermentation time increased, protein as well as starch digestibility (in vitro) of rabadi increased significantly at all the temperatures. Maximum increase in the digestibility of both protein (51%) and starch (58%) occurred after 9 hr fermentation at 45°C.     

Study of the Kinetics of the Adsorption of Dialdehyde Starch on Cellulose

The kinetics of adsorption of dialdehyde starch water solution on sulphite unbleached and bleached coniferous cellulose were studied. The kinetics of adsorption is described by an exponential kinetic equation applied for energetically uniform heterogeneous surfaces. The energy of activation for unbleached cellulose was in the limits from 10.6–27.6, while those of bleached cellulose were from 12.6–20.0 kJ/mol and were not dependent on the initial concentration of the DAS solution but linearly grow with the increase of the adsorbed DAS amount. The studied process was effected by the entropy factors exerting a defining influence on the initial rate, while the energy ones defined the changing of the rate.     

Characterization of the Pasting,Flow and Rheological Properties of Native and Phosphorylated Rice Starches

Phosphorylation of rice starch and its effects on the physiochemical properties of the starch were investigated. Phosphorylation was conducted using the oven heating method by heating mixtures of rice starch and monosodium dihydrogenphosphate at 120‐150°C for 0.5‐2 h, and the pasting, flow and rheological properties of the resulting starch phosphates were analyzed. Phosphorylation with substitution degrees of up to 0.12 was achieved by raising the reaction temperature to 140°C, but further increase in the temperature to 150°C caused a marked reduction in the degree of substitution. Phosphorylation resulted in significant declines in pasting temperature and setback, but increases in peak viscosity and breakdown. Suspensions of rice native starch and starch phosphates were shown to be non‐Newtonian, pseudoplastic fluids, exhibiting typical shear thinning. They also exhibited yield stress, the magnitude of which increased with the degree of phosphate substitution. Dynamic testing showed that phosphorylation resulted in a decrease in the temperature at which storage and loss moduli (G′ and G″) reached a peak during heating and a reduction in G′ during cooling. These results appeared to indicate that phosphorylation improved the shear stability of rice starch pastes and enhanced swelling of starch granules, but impeded starch retrogradation.     

Synthesis and Application of Starch 3, 5‐Dinitrobenzoate

A novel starch ester was prepared by the reaction of starch and 3, 5‐dinitrobenzoyl chloride (DNBZ‐Cl). The product (starch 3, 5‐dinitrobenzoate, DNBZ‐ST) was characterized by means of elemental analysis, Fourier Transform Infrared (FTIR) and ¹³C NMR spectroscopy. The influences of molar ratio of DNBZ‐Cl to anhydroglucose (AGU), reaction temperature and time, and amount of pyridine on the degree of substitution (DS) were studied. The esterification reaction is essentially complete after 2 h. Increase in the molar ratio of DNBZ‐Cl to AGU leads to an increase in DS when the former varies from 2:1 to 5:1. DS increases with the reaction temperature when the latter is varied from 70 to 100 °C. DS first increases and then decreases with amount of pyridine, the highest DS was obtained when V(pyridine)/m(starch) was 53 mL/g. The thermal stability of DNBZ‐ST increases when the DS increases, and the degradation starts at 353 °C for the sample of DS 2.14. Creatinine is a toxin accumulated in the blood of chronic renal failure (CRF) patients and a special adsorbent for creatinine is not reported in literature. DNBZ‐ST displayed specific adsorption ability for creatinine, the adsorption equilibrium is reached after 4 h. The adsorption capacity increases with the DS of adsorbent and creatinine concentration. When the creatinine concentration is higher than 300 mg/L, concentration has no apparent effect on the adsorption capacity. As the temperature of the solution is varied from 19 to 49 °C, adsorption capacity first decreases and then increases, being lowest at 37 °C. The adsorption capacity first increases and then decreases as the pH value increases, and is highest at pH 8.The highest adsorption capacity obtained was 25 mg of creatinine per gram of adsorbent at 37 °C, pH 7 and a creatinine concentration of 100 mg/L. The study on the FTIR and UV‐VIS spectra suggested that some chemical reaction took place between the DNBZ‐ST and creatinine in buffer solution.     

Fine Structure,Thermal and Viscoelastic Properties of Starches Separated from Indica Rice Cultivars

Starches were separated from indica rice cultivars (PR‐113, Basmati‐370, Basmati‐386, PR‐115, IR‐64, and PR‐103) and evaluated using gel permeation chromatography (GPC), X‐ray diffraction, differential scanning calorimetry (DSC) and dynamic viscoelasticity . Debranching of starch with isoamylase and subsequent fractionation by GPC revealed 9.7–28.3% apparent amylose content, 3.7–5.0% intermediate fraction (mixture of short amylose and long side‐chains of amylopectin), 20.6–26.6% long side‐chains of amylopectin and 45.8–59.4% short side‐chains of amylopectin). IR‐64 starch with the highest crystallinity had the highest gelatinization temperatures and enthalpy, T_o, T_p, T_c, and ΔH_gel being 71.8, 75.9, 82.4°C and 5.1 J/g, respectively, whereas PR‐113 starch with lower crystallinity showed the lowest gelatinization temperatures (T_o, T_p, T_c, of 60.8, 65.7 and 72.2°C, respectively). Basmati‐386 starch exhibited two endotherms during heating, the first and second endotherm being associated with the melting of crystallites and amylose‐lipid complexes, respectively. T_o, T_p, T_c and ΔH_gel of the second endotherm of Basmati‐386 starch were 99.0, 100.1, 101.1°C and 2.0 J/g, respectively. During cooling, Basmati‐386 also showed an exotherm at a peak temperature of 87°C. PR‐113 starch with the highest amylose content and the lowest content of short side‐chains of amylopectin had the highest peak storage modulus (G′= 1.6×10⁴ Pa). The granules of PR‐113 starch were the least disintegrated after heating. The effects of heating starch suspensions at different temperatures (92°C, 130°C and 170°C) on intrinsic viscosity [η], transmittance and viscoelasticity were also studied to evaluate the extent of breakdown of the molecular structure. The intrinsic viscosity of starch suspensions heated at 92, 130 and 170°C ranged between 103–114, 96–110 and 28–93 mL/g. Transmittance value of starches cooked at 92°C decreased with increase in storage duration. All starches except PR103, cooked at 130°C also showed decrease in transmittance during storage, however, at lower rate. PR103 starch heated at 130°C did not show any change in transmittance up to a storage time of 48 h. The changes in viscoelasticity of starch pastes cooked at different temperatures during cooling and reheating were also evaluated. G′ and G′′ increased with decrease in temperature during cooling cycle. Starches heated at 130°C with apparent amylose content ≤ 21.2% showed an improvement in G′ and G′′ in comparison to the corresponding starches heated at 92°C, this improvement was observed to be higher in starches with lower amylose content. All starches heated at 170°C had a higher proportion of breakdown in molecular structure as indicated by lower G′ and G′′ than the same starches heated at 130 and 92°C.     

Effect of storage temperature on the ageing of concentrated wheat starch gels

Flour Milling and Baking Research Association, Chorleywood, Rickmansworth, Herts. Using differential thermal analysis (d.t.a.) the progress of ageing of concentrated wheat starch gels stored at temperatures from?1° to 43° has been investigated. A very close relationship has been found between the ageing of starch gels as measured by d.t.a. and the staling of bread as measured by crumb firmness at storage temperatures of?1°, 10° and 21° but some differences have been found at 32° and 43°. The results at ?1°, 10° and 21 ° provide very strong confirmatory evidence that starch crystallisation is the chief factor in the firming of bread. At elevated storage temperatures (32° and 43°) the róle of starch crystallisation in the firming of bread apparently gradually diminishes. Analysis of the results indicates that the mechanism of crystallisation of the starch, instantaneous nucleation followed by rod-like growth of crystals, is the same over the whole range of storage temperatures ?1° to 43°. Evidence is also presented to show that there is a possibility that at higher storage temperatures a more symmetrically perfect crystal structure is being formed.     

HIGH TEMPERATURE DRYING CHARACTERISTICS AND MOISTURE ADSORPTION ISOTHERMS OF BLACK PLUM (VITEX DONIANA) SYRUP AND SYRUP-STARCH

Modified sweeteners were formulated from mixtures of Black plum syrup and phosphorylated corn starch concentrations of 20, 30, and 40% (w/w). Each mixture was coated on an aluminium plate at 1 mm thickness, dehydrated at 60°, 70°, 80° and 90°C, and evaluated for drying and moisture sorption characteristics. Results showed that the mixtures exhibited falling rate drying characteristics. The rate of dehydration increased in the order 20% > 30% > 40% starch at constant temperature. The incremental choice of 10% starch and drying temperature except at 70° and 80°C had significant effect (p < 0.05) on drying rate. The moisture isotherm curves of the pre-dried mixtures were sigmoid in shape. Their monolayer values or upper critical moisture contents necessary for shelf-stability were significantly different from each other for the samples pre-dried at 60°C. The effect of drying temperatures on equilibrium moisture content was only significant at 90°C (p < 0.05).     

Effect of Phytate and Other Myo-inositol Phosphate Esters on α-Amylase Digestion of Starch

The effects of phytate and other myo-inositol phosphate esters (containing one or more phosphate groups) on α-amylase digestion of soluble potato starch were evaluated by an in vitro procedure. Human salivary or Bacillus subtilisα-amylase was treated with either 2 mM or 5 mM phytate, myo-inositol-2-monophosphate (l–2-MP), or phytate hydrolyzed to various degrees, and then incubated at 37°C with the starch at pH 4.15 or 6.90. Starch digestion varied with degree of phosphorylation of inositol, inositol phosphate ester concentration, pH and enzyme source. At pH 4.15, phytate (2 mM) and I-2-MP (2 mM) reduced starch digestion by salivary α-amylase to 8.5 and 78.3%, respectively, of the control.     

Investigation of the Physical and Chemical Properties of Banana Starches

Banana (Musa sp.) starch was isolated after steeping in 0.05N sodium hydroxide. The starch had a granule size of 20–60μ, a gelatinization temperature range of 74–83°C, and a B-type X-ray diffraction pattern. The Brabender viscoamylogram and the swelling pattern indicated a fairly restricted-swelling starch. The starch had low iodine affinity (ca 3.30%) and contained diesterified phosphate. During ripening, the amount of starch converted into reducing sugars and sucrose increased with degree of ripeness. Small granules were converted more rapidly than large granules. Other physical and chemical properties remained similar throughout ripening.     

淀粉微球气凝胶的制备及吸附性能与形态研究

以木薯淀粉为原料,利用乳化-凝胶法结合冷冻干燥制备淀粉微球气凝胶,研究加热温度、时间、淀粉乳浓度及油乳比对淀粉微球气凝胶吸附性能的影响。利用响应面法优化工艺,制备淀粉微球气凝胶,以其对亚甲基蓝的吸附力作为评价指标。研究表明：淀粉微球气凝胶吸附性能受温度影响大,温度85℃、加热时间90 min、淀粉乳质量分数为15%,其吸附力为(0.928±0.008)mg/g,较原淀粉的吸附力增69.8%;粒度分布测量及扫描电镜分析结果显示：温度升高,淀粉颗粒膨胀,淀粉微球气凝胶的粒径逐渐增大,当温度升高至100℃时,气凝胶珊瑚状表面形成,表面变粗糙,粒径趋于稳定。     

Studies on the Relationship Between Water-satured State and Crystallinity by the Diffraction Method for Moistened Potato Starch

Crystallinity was measured by X-ray diffraction method and water-saturated state was determined by means of the moisture contents calculated from the crystallinity for moistened cellulose and potato starch. In the X-ray diffractograms the upper areas which were separated by the straight line joined the points of intensity at 37° and 4° (8°) of diffraction angle was the relative reflection area in the crystalline and amorphous portions, and the lower area was the background of the non-relative reflection area. The upper area separated by the smooth curve joined the minimum intensity at 4° to 37° of diffraction angle corresponded to the crystalline portion and the lower area to the amorphous one. The ratio of the crystalline portion to sum of the crystalline and amorphous portions was considered to be crystallinity. Crystallinity of the air-dried and the moisture-saturated (28%) samples of cellulose were 0.68 and 0.71, resp. The crystallinity of the air-dried and water-saturated (49%) samples of potato starch were 0.24 and 0.32, resp.     

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.     

Effect of Osmotic Pressure on Starch: New Method of Physical Modification of Starch

A new method of physical modification of starch in the presence of high concentrated salt solution is presented, called “Osmotic Pressure Treatment” (OPT). OPT was introduced in order to produce the same physically modified products as obtained by conventional heat‐moisture treatment (HMT) of starch. Potato starch was selected for the comparative study of the two methods. For the OPT method, potato starch was suspended in a saturated solution of sodium sulfate and heated in an autoclave at 105°C and 120°C ,which corresponded to the calculated osmotic pressures of 328 and 341 atm (332 and 345 bar, respectively) (assuming sodium sulfate dissociates completely) for 15, 30 and 60 min, respectively. For the HMT method, starch with 20% moisture content was placed in a Duran bottle, then the same heat treatment method in the autoclave was applied. Light and scanning electron microscopy (SEM) showed that OPT of starch changed the shape of the starch granules to a folded structure, while the starches remained unchanged after HMT. The RVA viscogram for the OPT starch exhibited a decrease in the peak viscosity without a breakdown and an increase of the pasting temperature when increasing the temperature and time, which was in an agreement with the viscosity patterns for the HMT starches. X‐ray diffraction patterns were altered from B to A+B for the HMT and from B to A type for the OPT starch when treated at 120°C. After OPT, the gelatinization temperatures (T_o, T_p, and T_c) of the starch increased significantly with increasing temperature and time, whereas only the T_c of starch increases after HMT. The biphasic broadening of the peaks (high T_c‐T_o) can be explained by an inhomogeneous heat transfer during HMT. Narrow peaks in the DSC curve can be an indication for a better homogeneity of the OPT samples. However, both methods provide a similar decrease in the gelatinization enthalpy (ΔH). The amylose‐amylopectin ratio calculated from the HPSEC patterns was strongly increased for HMT starches at 105°C for 60 min and 120°C for 30 min and decreased after treatment at 120°C for 60 min. For OPT starches the ratio was strongly increased at 120°C for 15 min and decreased after prolong heating. The OPT provides a uniform heat distribution in the starch suspension. This allows the modified starch to be produced on a larger scale.     

Moisture Equilibrium in Apples at Several Temperatures: Experimental Data and Theoretical Considerations

Moisture equilibrium data for desorption of water from apples was determined at 20°, 30°, 40°, 50° and 60°C. The rehydration 40°C isotherm was also found. The experimental procedure was a gravimetric dynamic method. Sorptive capacity decreases as temperature increases. Rehydration of the dried material results in hysteresis. The data are interpreted in thermodynamic terms. Specific surface and monolayer concentrations are also found. Pore size distribution studies show that the most frequent pore radius at 20°C and 40°C are, respectively, 26 Å and 22 Å. Hysteresis data are compared with what would be expected from the cellulose wall, indicating that solubility and other effects increase sharply the sorptive capacity of the fruit. A comparison of desorption and adsorption characteristics shows that dehydration results in serious damage of the fruit structure.