Preparation of Anionic Starch Containing Carboxyl Groups and its Utilization as Chelating Agent

Poly(methyl acrylate)‐starch graft copolymer was treated with sodium hydroxide. The influence of sodium hydroxide concentration, reaction temperature and duration of treatment were studied. The extent of hydrolysis was assessed by estimating acrylic acid, methyl acrylate and total polymer content before and after treatment. It was found that the increase in acrylic acid content is equal to the decrease in the methyl acrylate content on using sodium hydroxide concentration up to 1 N, while using higher concentration leads to a difference in amount of acrylic groups formed and decrease in methyl acrylate content. This difference depended on sodium hydroxide concentration, on treatment temperature and duration. The optimum condition gave a release of 455 mmol acrylic group/100 g sample using 1 N sodium hydroxide at 100 °C for 150 min, showing 94.8% conversion of the poly(methyl acrylate) content of the treated copolymer. The alkali treated samples were evaluated for use as chelating agent. The sorption values for different heavy metals depended on the metal ion and follow the order Hg²⁺ > Cu²⁺ > Zn²⁺ > Pb²⁺ . Sorption efficiency of the alkali treated samples increased with increasing the acrylic content. The sorption values of alkali treated copolymer was compared with that of carboxymethylated starch (having the same carboxy group content) to clarify the effect of the chemical structure of both starch derivatives on heavy metal sorption. It was found that the sorption value of Cu ²⁺ on carboxymethylated starch was twice the value on alkali treated copolymer.     

Rheological characterization of corn starch isolated by alkali method

The pasting properties of alkali-isolated corn starches obtained from corn grits, as well as the rheological behaviour of their 8% gels were investigated. The alkali isolation was performed using different conditions concerning alkali concentration (0.15% and 0.30%), steeping time (30 min and 90 min) and temperature (25 °C and 50 °C).Alkali-isolated starches exhibited lower pasting temperatures and higher peak viscosities than the wet-milled starch. With respect to the steady shear measurements, alkali starch gels showed higher viscosities and greater extent of thixotropy.Changes in alkali isolation conditions did not influence the changes in gelatinization and peak temperature values. On contrary, peak viscosity was significantly influenced by these factors. Steady shear, as well as dynamic shear tests, showed that gels formed from starch isolated using higher alkali concentration were stronger than those obtained from starch isolated at lower alkali concentration. However, isolation at higher steeping temperature and longer steeping time resulted in starch with weak gel-like behaviour.     

乙醇碱法处理对荞麦颗粒状冷水可溶淀粉溶解度的影响

以荞麦淀粉为原料,采用乙醇碱法对荞麦淀粉进行改性修饰,系统分析了乙醇体积分数、碱浓度、反应温度、反应时间等因素对改性后淀粉溶解度的影响。结果表明：反应温度对改性后荞麦颗粒状冷水可溶淀粉溶解度的影响最大,碱用量和乙醇体积分数的影响次之,反应时间的影响较小,各因素对产物溶解度影响均达到显著水平;在反应条件为反应温度70℃、反应时间25 min、乙醇体积分数55%、碱用量为45 mL时对荞麦颗粒状冷水可溶淀粉溶解度的影响最大,此时其溶解度达到22.52%。     

Production of a high concentration of ethanol from potato tuber by high gravity fermentation

To produce a high concentration of ethanol from viscous potato tuber mash, potato tuber mash containing high contents of solids (28%) was prepared by grinding the potato tuber without the addition of water. The viscosity of the potato mash was reduced by using Viscozyme (0.1%) at 50°C for 30 min. The potato mash was then liquefied using Liquozyme (0.1%) at 90°C for 30 min and optimal conditions for the simultaneous saccharification and fermentation (SSF) of the potato mash for ethanol production were investigated using statistical methods. Using 2⁴ factorial design, saccharifying-enzyme and incubation temperature were found to be important factors. Using response surface methodology, the optimal saccharifying-enzyme dosage and incubation temperature were determined to be 1.45 AGU/g dry matter and 31.3°C, respectively. Under these optimal conditions for SSF, 14.92%(v/v) ethanol with 91.0% of theoretical yield was produced after 60 h, and all the starch was completely used up.     

Effect of heating rate at different moisture contents on starch retrogradation and starch–water interactions during gelatinization

The objective of this research was to investigate the effect of heating rate at different moisture contents on starch retrogradation and gelatinization process. Starch retrogradation was not influenced by either moisture content (water/starch ratio of 0.7 or 2.0) or heating rate (5°C/min, 20°C/min, or 40°C/min). In order to further understand the effects of heating rate on starch–water interactions, starch suspensions at a water/starch ratio ranging from 0.7 to 3.0 were heated at 5, 15, or 25°C/min by using a DSC to different final temperatures and rescanned. The deconvoluted G and M1 endotherms and the corresponding additional unfrozen water (AUW) were determined. The results showed that the G and M1 endotherms merged at higher heating rates and at higher moisture contents as expected. A significant interaction was observed between moisture content and heating rate. The results suggest that the gelatinization process is governed by moisture content at the lower heating rate (5°C/min) and by heating rate at the higher heating rates (15 or 25°C/min). Results from the AUW data suggest that the M1 component of gelatinization dominated at moisture content below water/starch ratio of 1.5 and at 5°C/min heating rate. However, at moisture contents above water/starch ratio 1.0, an interaction was observed between moisture content and heating rate. The data suggest that at higher moisture content (>1.5 water/starch ratio) and at higher heating rate (≥15°C/min), there is still a kinetic limitation to the complete melting of the M1 endotherm.     

Synthesis of Diethylaminoethyl-Starch (DEAE-Starch). Part I

This work dealt with the synthesis of soluble aminated starch having a tertiary amino group. Factors affecting the degree of substitution of the tertiary amino group mainly: reaction temperature, time, amine and sodium hydroxide concentration besides the liquor ratios were studied and discussed briefly. It was concluded that higher nitrogen content of aminated starch is obtained at 80°C and in 30 min while the concentration of 2-chloro-ethy-diethyl amine hydrochloride (amine) and sodium hydroxide were 30% and 40%, respectively. Increasing the liquor ratio was accompanied by an increase in nitrogen content.     

Effect of Hydrothermal Treatment on Formation and Structural Characteristics of Slowly Digestible Non‐pasted Granular Sweet Potato Starch

The formation and structural characteristics of slowly digestible non‐pasted granular starch in sweet potato starch were investigated under various hydrothermal treatment conditions. The moisture content of the sweet potato starch was adjusted to 20, 50 or 90%, and the starch was heated at 40, 55 or 100°C for 12 h in a dry oven. The relative crystallinity of the hydrothermally treated samples was decreased with increasing temperature, and the X‐ray diffraction patterns of the samples were altered from C_b‐type to A‐type. Microscopic observations did not reveal any changes in the starch granules of any samples except those with moisture contents of 50 and 90% that were heated at 100°C. When gelatinization parameters were examined, samples with moisture contents of 50 and 90% that were heated at 55°C and samples of all moisture contents that were heated at 100°C had peak temperatures higher than that of raw starch but gelatinization enthalpies lower than that of raw starch. The swelling factor of the samples heated at 40°C did not change significantly, whereas that of samples heated at 55 and 100°C was decreased at increased moisture levels. The sweet potato starch with 50% moisture content that was heated at 55°C had the highest content of granular slowly digestible starch, about 200% that of raw starch, although our study did not involve further hydrothermal treatment conditions. Further study is required to complete a process for more efficient production of heat stable and slowly digestible starch.     

Laboratory Wet‐Milling of Grain Sorghum With Abbreviated Steeping to Give Two Products

Short‐time and no‐time steeping were used in the wet‐milling of grain sorghum to give two products, starch in over 78% recovery (starch basis) plus the remaining grain solids. In the wet‐milling process 1.5 parts of fresh water were used per part of grain to compensate for drying and transfer losses. Starting with 100 g (dry solids) of commercial No.2 grain sorghum, steep time (1—3 h), steep temperature (25—60 °C), and coarse‐grinding speed (7, 500—12, 500 rpm with tip speed of 90.4—150.7 km/h) were varied in a model study; starch recovery, starch lightness (L*), and damaged starch were the responses. Grain sorghum was steeped with twice its weight of process water containing 0.2% sulfur dioxide and the steeped kernels were added to an equal volume of process water and the mixture was ground for 6 min in a Waring blender with blunt blades (d = 3.2 cm). The course‐ground material was sieved (opening 1190 μm) to collect the bran/germ, and the throughs were allowed to stand. The sedimented phase was finely ground by one pass through a plate mill, and the fine fiber removed by sieving (opening 73 μm). The slurry was adjusted to a specific gravity of 1.04, and the starch was separated from the protein fraction on a starch table. The protein fraction was combined with the steep‐liquor concentrate (54% solids) plus the bran/fiber and the fine‐fiber fractions to give the co‐product, which contained 70% moisture (wet basis, wb) and 27% protein (dry basis, db). In the surface response study, recovery of starch ranged from 57 to 89%, starch protein content from 0.4 to 0.5%, and lightness (L*) from 90 to 93. Damaged starch content was constant at around 0.4%. Commercial grain sorghum gave the highest starch recovery (90%) after steeping 2 h at 55 °C and coarse‐grinding at 10, 500 rpm; whereas a food‐grade, a white and a red sorghum gave 85, 84, and 80% recoveries, respectively. The four starches had lightness (L*) values of 93—94 and damaged starch contents of 0.4—0.6%. When the commercial grain sorghum was wet‐ground without steeping in 2 parts of water containing 0.2% sulfur dioxide, a 78% recovery of starch was obtained with L* 93.7 and starch damage 0.5%.     

Effect of separate pod and root zone temperatures on yield and seed composition of three Spanish cultivars of groundnut (Arachis hypogaea L)

The effect of separate pod and root temperature regimes (all four combinations of 28/22 and 40/34 °C day/night temperature), imposed from the time of peg penetration until harvest, on yield and seed composition of three Spanish genotypes of groundnut (Arachis hypogaea L) was investigated. A decrease in pod temperature from 40/34 to 28/22 °C increased yield and oil, starch and protein mass per plant irrespective of root temperature. Additionally, a reduction in pod temperature decreased protein concentration and increased the sum of oil and starch concentration at a root temperature of 28/22 °C, whereas at a root temperature of 40/34 °C a decrease in pod temperature increased protein concentration. Root temperature reduction diminished oil concentration of genotypes AH 6179 and TMV 2 at a pod temperature of 40/34 °C. A decline in pod temperature affected fatty acid composition through a decrease in palmitic acid irrespective of root temperature and an increase in linoleic acid at a root temperature of 28/22 °C. A root temperature effect on fatty acid composition was not detected. It is concluded that field management practices and choice of genotype can influence groundnut yield and seed composition through effects on pod and root temperature. © 2001 Society of Chemical Industry     

纤维素酶-压热法制备马铃薯抗性淀粉工艺参数优化

为了提高抗性淀粉的得率,并获得抗性淀粉制备方法的最佳工艺参数,该试验以马铃薯淀粉为原料,抗性淀粉得率为评价指标,采用纤维素酶-压热法制备马铃薯抗性淀粉。研究淀粉乳浓度、酶添加量、酶解时间、压热温度、压热时间5个因素对马铃薯抗性淀粉得率的影响,在单因素试验的基础上,通过正交试验优化得出马铃薯抗性淀粉的最佳制备工艺条件,即淀粉乳含量25%、淀粉乳pH 5.0、酶用量30 U/mL、酶解时间50 min、压热温度125 ℃、压热时间30 min、老化温度4 ℃、老化时间18 h,在此条件下抗性淀粉的得率为30.33%。     

Physico–chemical,morphological, and pasting properties of Pine nut (Araucaria angustifolia) starch oxidized with different levels of sodium hypochlorite

The objective of this work was to study the effect of process temperature and active chlorine concentration on the main properties of Pine nut starch (PN). Samples of PN were oxidized with sodium hypochlorite at concentrations varying from 0.5 to 4.0 g active chlorine/100 g starch, at temperatures varying from 20 to 45°C according to a central composite rotational design, analyzing the results using response surface methodology. The concentration of active chlorine had an effect on the WSI, the quantity of carboxyl and carbonyl groups, the AM content and the percentage of light transmittance (650 nm) of the PN. The effect of temperature was observed on the water solubility index, the quantity of carbonyl groups and the percentage of light transmittance (650 nm) of the PN. Oxidation was more intense in the starch treated with 3.5% active chlorine.     

Effect of protein,moisture content and barrel temperature on the physicochemical characteristics of pea flour extrudates

The effects of protein content (6%, 12% or 18%, db), moisture content (15%, 18% or 21%, wb), temperature (set temperature of the final barrel section—100, 120 or 140 °C) and a leavening agent (0.5% sodium bicarbonate) on the direct expansion characteristics of pea flour were determined with a twin-screw, co-rotating extruder. The various levels of protein were obtained by blending air-classified pea starch (6% protein, 85% starch) and pea flour (24% protein, 56% starch). Extrusion of pea flour containing 6% protein and 15% moisture at a set temperature of 120 °C resulted in expansion indices (EIs) of 3.3 and 3.6, respectively, in the absence or presence of the leavening agent. EI decreased, and extrudate bulk, particle densities and hardness increased with increase in protein or moisture content. Lysine losses were proportionally lower at higher protein and moisture contents.     

Thermal and rheological properties of hydrogels prepared with retrograded waxy rice starch powders

Waxy rice starch dispersed in water (50% solids) was gelatinized by heating the dispersion at 121°C for 20 min, and retrograded by storing the paste at 4°C for 2 days. The starch gel was then freeze-dried and ground into powders. The retrograded starch powders were hydrated at 20–30% solid concentration at different temperatures (4 and 23°C), and then thermal and rheological properties were analyzed using the hydrogels. The gel hydrated at 4°C had an onset temperature of melting at 34.9°C, which was approximately 10°C lower than that observed for the gel hydrated at 23°C. The enthalpy value was greater for the gel hydrated at 4°C (14.2 J/g) than the gel hydrated at 23°C (8.8 J/g). The yield stress and consistency of the hydrogels were proportional to the solid concentration. The hydrogel prepared with 30% retrograded starch powders at 4°C displayed a thick creamy texture with retrograded starch crystals that could melt at a temperature range of 35–51°C. The thermal and rheological properties of the hydrogels exhibited the possibility for the retrograded starch powders to be used as fat mimetic in foods.     

Effects of Annealing and Additives on the Gelatinization,Structure, and Textural Characteristics of Corn Starch

The effects of additives (sucrose, glucose, and sodium chloride) on textural properties of native and annealed corn starch gels were measured using differential scanning calorimetry, X-ray diffraction, scanning electron microscopy, and texture analyzer. Annealing temperature, additive concentration, and pH affected the corn starch gels. Firmness, consistency, cohesiveness, and viscosity values ranged from 20.55 to 43.70 g, 213.67 to 412.00 g/sec, –25.81 to –15.22 g, and –104.21 to –6.73 g/sec, respectively. The eigenvalue of the texture characteristics of annealed corn starch decreased without additives, and increased with additives. Annealing at 55°C had more effect than did annealing at 45°C.     

Effects of Gelatinization and Gel Storage Conditions on the Formation of Canna Resistant Starch

The effects of gelatinization and gel storage conditions on the formation of canna resistant starch (RS) were investigated. Starch slurries (10%, dwb) were autoclaved at 121?°C for 30, 60, and 120?min. The gels obtained were subsequently stored at different temperatures (4?°C, 30?°C, and 100?°C) and times (0, 1, 3, 5, and 7?days). Analyses of the RS content in gelatinized starch samples in comparison with that in granular starch showed that the RS fraction in granular starch was very high (97.3% w/w); however, nearly all of the RS was thermally unstable, as indicated by a great reduction in RS content (to 1.9% w/w) after cooking at 100?°C for 20?min. The RS contents in gelatinized starch samples were 12.0?C15.9% w/w, which were reduced to 7.9?C10.8% w/w after cooking. Storage of gels resulted in a significant increase in the amount of the thermally stable RS fraction, e.g., a thermally stable RS content of 16.8% w/w was found in the gel sample gelatinized for 120?min and stored at 4?°C for 3?days. This indicated that the ordered structures of the RS portion were tightened under the storage conditions. The gelatinization temperature of canna starch was 72.2?°C, whereas the RS products exhibited two melting temperature ranges, 51.1?C76.3?°C and 163.1?C165.1?°C, indicating that the newly formed crystals were very strong.     

Application of Differential Scanning Calorimetry to Amaranth Starch Gelatinization – Influence of Water,Solutes and Annealing

Gelatinization phenomena of amaranth starch were investigated using differential scanning calorimetry. Slight variations in onset (To) and peak (Tpl) temperatures were observed at moisture contents over 0.48 g water/g total. However, completion temperature (Tc) increased significantly. The intermediate transition temperature (Tp2) appeared at 0.61 g water/g total and below. The degree of gelatinization decreased by decreasing the moisture content. The three transition temperatures (To. Tpl and Tc) were increased and gelatinization delayed as the concentration of sucrose was enhanced. The three latter transition temperatures tended to increase as the sodium chloride was raised to 0.066 g/g total, but further increases in salt reduced significantly these temperatures. The gelatinization was delayed by increasing the salt concentration. After annealing for 12 h at 25 to 65°C, starch samples exhibited higher To and Tpl values, and narrowed gelatinization ranges. The degree of gelatinization augmented up to the annealing temperature of 55ºC and significantly decreased thereafter.     

Effect of steam-hydrothermal treatment (SHTT) on the physico-chemical properties of cassava (Manihot esculenta crantz)

Effect of steam-hydrothermal treatment (SHTT) on functional properties of cassava was studied using fresh tubers of cultivar Malayan-4 (M-4). Fresh slices were steam-processed for 5, 10 and 20 min at atmospheric pressure. Plain-dried samples were also prepared for comparison. SHTT samples were found to have higher rehydration capacity, equilibrium moisture content by soaking (EMC-S), and sedimentation volume at room temperature (28–30° C). These samples also showed a lower amylose content than plain-dried samples. Electrolytes like sodium chloride, sodium sulphate and sodium phosphate at 1–0 N concentration changed the sedimentation volume, especially of SHTT sample:. Paste stability of steam-processed samples at cooking temperature (95° C) was relatively higher than plain-dried ones. Among the three SHTT samples, that steam-processed for 10 min showed the highest paste consistency and set-back ratio. X-ray diffraction pattern of flour prepared from SHTT samples indicated a clear shift from crystalline to a partially amorphous state. Infra-red spectra of cassava starch and flour samples were generally identical.     

Optimizing Processing Conditions for Chemical Peeling of Potatoes using Response Surface Methodology

Using Response Surface Methodology the effects of NaOH concentration (4–20%), process temperature (55–95°C) and time (1–7 min) was determined on the yield, peeling quality, unpeeled skin and total usage of NaOH. Also evaluated were titratable NaOH in the potato tissue, NaOH penetration and “heat ring” depths during one stage chemical peeling of potatoes (Huincul variety). The best peeling quality, maximum yield and minimum total usage of NaOH was obtained for the following ranges: concentration, 11–13%, time 5–5.70 min and temperature, 90–95°C. The maximum temperature for which the “heat ring” and NaOH penetration depths were equal was 72°C where, at 20% NaOH and 7 min, peeling quality was very good and “heat ring” was absent.     

点浆条件对酸浆豆腐品质的影响

为探究点浆时豆乳温度、点浆后蹲脑温度和蹲脑时间对酸浆豆腐品质的影响,提高酸浆豆腐品质,本研究利用质构分析、SDS-PAGE和低场核磁等技术分析了豆腐品质、豆乳中蛋白凝固过程、大豆蛋白各亚基含量和水分分布的变化规律。结果表明,点浆时豆乳温度对豆乳沉淀中蛋白和大豆蛋白各亚基含量无显著影响,但对豆腐品质和水分分布有较大影响。当点浆时豆乳温度为75℃时,豆腐的硬度最小,而其弹性、得率、含水量、保水性、感官得分和T₂₁弛豫时间最大。蹲脑温度和蹲脑时间对豆腐品质、豆乳沉淀中蛋白含量和大豆蛋白各亚基含量影响显著,当蹲脑温度75℃和蹲脑时间20 min时,豆腐硬度最小为15.80 N,而弹性、得率、含水量、保水性和T₂₁弛豫时间最佳,分别为5.15 mm、241.3%、76.36%、65.68%、43.29 ms,且豆腐品质豆乳沉淀中蛋白含量最佳。当点浆时豆乳温度为75℃、蹲脑温度为75℃和蹲脑时间20 min时,豆腐品质和感官得分最优。     

Short communication: Effects of butyrate supplementation on the productivity of lactating dairy cows fed diets differing in starch content

The objective of this study was to evaluate the effects of butyrate supplementation on the dry matter intake (DMI), milk production, and blood metabolites of lactating dairy cows fed diets differing in starch content. Eight Holstein cows after peak lactation (58.6 ± 9.96 d in milk; mean ± SD) were blocked by parity and assigned to 1 of 2 Latin squares (4 × 4) balanced for carryover effects with a 2 × 2 factorial arrangement of treatments. Treatments differed by dietary starch content (20.6 vs. 27.5%) and butyrate supplementation (butyrate vs. control) with 21-d periods. Experimental diets contained 36 and 30% corn silage, 18 and 15% grass silage, and 46 and 55% concentrates, respectively, for low starch and high starch diets, on a dry matter (DM) basis. Butyrate was provided as Gustor BP70 WS (Norel S.A., Madrid, Spain), containing 70% sodium butyrate and 30% fatty acid mixture, at 2% of dietary DM (providing butyrate at 1.1% of dietary DM), and control premix contained 70% wheat bran and 30% fatty acid mixture. Interaction effects between dietary starch content and butyrate supplementation were not observed for primary response variables, and milk yield was not affected by treatment. Butyrate supplementation increased serum β-hydroxybutyrate concentration compared with control (0.706 vs. 0.930 mM), but did not exceed 1.2 mM, a commonly accepted value for subclinical ketosis, and DMI was not affected. Cows fed butyrate had increased milk fat content (4.58 vs. 4.37%) and milk fat yield (1.51 vs. 1.42 kg/d), tended to have increased 4% fat-corrected milk yield (35.9 vs. 34.3 kg/d) and feed efficiency (1.56 vs. 1.50; 4% fat-corrected milk yield/DMI), and had decreased milk urea nitrogen (MUN) concentration (10.8 vs. 11.7 mg/dL) compared with control. Cows fed high starch diets tended to have increased DMI (23.3 vs. 22.5 kg/d), increased milk protein yield (1.13 vs. 1.05 kg/d), and decreased MUN concentration (10.3 vs. 12.2 mg/dL). Inclusion of butyrate at 1.1% of dietary DM increased milk fat production and decreased MUN concentration without affecting DMI or increasing the risk of subclinical ketosis, regardless of dietary starch content.