Influence of Amaranthus betacyanin pigments on the physical properties and color of wheat flours

The effect of betacyanin pigments from Amaranthus tricolor and Amaranthus cruentus on chromatic and physicochemical properties of three wheat flours was studied. Addition of Amaranthus betacyanins increased the gelatinization temperatures (T(o), T(p), and T(c)) of all wheat flours without altering their transition ranges (T(c)-T(o)). The melting enthalpies (DeltaH) were either increased or decreased depending on the types of flour and pigment. Amaranthus betacyanins decreased the peak viscosity (PV), hot paste viscosity (HPV), cold paste viscosity (CPV), setback (SB), and pasting time (PT) of all flours and increased the breakdown (BD). Texture profile analysis (TPA) showed that Amaranthus betacyanins decreased hardness, and gumminess, and increased cohesiveness of all gels, without altering adhesiveness. Chromatic investigation exhibited that A. tricolor and A. cruentus pigments imparted gels with red and orange-yellow hues with favorable color stability.     

Effect of salts on the gelatinization and rheological properties of sago starch.

The effects of various salts on the gelatinization and rheological properties of sago starch have been studied using differential scanning calorimetry, small deformation oscillation, and large deformation techniques. The presence of salts affected the gelatinization peak temperature, T(p), gelatinization enthalpy, DeltaH, swelling properties, storage modulus, G', gel strength, GS, and gelation rate constants, k, depending on the type of salt and the concentration. Their influence followed the Hofmeister series, and the effect of anions was more pronounced than that of cations. Sulfate ions increased T(p), G', GS, and k and reduced the swelling properties, whereas iodide and thiocyanate ions reduced T(p), G', GS, and k but increased the swelling properties. For all of the salts studied except for Na(2)SO(4), T(p) increased to a maximum and then decreased again at higher salt concentrations while DeltaH reduced with concentration. In the presence of MgCl(2), CaCl(2), and LiCl complex behavior was observed such that at approximately 3.5 M MgCl(2) and CaCl(2) and 8 M LiCl the starch samples were gelatinized at room temperature, whereas at much higher concentration T(p) increased again and the transition became exothermic.     

拔节期追氮对春播和秋播糯玉米淀粉胶凝和回生特性的影响

以垦粘1号、苏玉糯1号和苏玉糯5号为材料,研究了拔节期追氮量(N 01、50和300 kg/hm2)对春播和秋播糯玉米淀粉胶凝和回生特性的影响,试验于扬州大学实验农牧场进行。结果看出,播期、品种和拔节期追氮量单因素及其互作对淀粉胶凝和回生主要特征值存在显著影响。糯玉米淀粉胶凝和回生特征值在拔节期追氮150 kg/hm2时和秋播条件下较优,即原淀粉具有较低的峰值温度、较高的热焓值,回生淀粉具有较低的回生值,且以垦粘1号表现较好。糯玉米淀粉胶凝和回生特征值之间存在一定的相关性。回生值分别与回生淀粉的热焓值、原淀粉的终值温度显著正相关,相关系数分别为0.82(P0.01)和0.47(P0.05);原淀粉的热焓值与峰值指数显著正相关,相关系数为0.53(P0.05),与原淀粉峰值温度、回生淀粉的终值温度显著负相关,相关系数分别为-0.53(P0.05)和-0.52(P0.05);回生淀粉的热焓值分别与回生淀粉起始温度、终值指数显著正相关,相关系数分别为0.46(P0.05)和0.66(P0.01)。综合考虑淀粉胶凝和回生特性在不同处理下的变化趋势,以秋播糯玉米淀粉在拔节期追N 150 kg/hm2处理下较优。     

Thermal Properties and Paste and Gel Behaviors of Starches Recovered from Accessions Used in the Germplasm Enhancement of Maize Project

The objective of this study was to screen starches recovered from the corn accessions used in the Germplasm Enhancement of Maize (GEM) project for unusual thermal properties and paste and gel behaviors, so that they could be exploited in corn breeding programs to enhance traits important to corn utilization. In general, the values for gelatinization temperatures and peak height indices were greater, but heat of gelatinization values were less for the starches recovered from the GEM accessions (particularly BRA 052051 (SE 32)) than for starches from commercial Dent corn hybrids (11.3 vs. 13.6 J/g). Generally, retrogradation properties were similar among the GEM accessions, although there were specific accessions (particularly Lima 13) that possessed modestly lower percentage retrogradation (34 vs. 42%). Generally, peak viscosities, cold paste viscosities, and viscosity breakdowns were greater for the starches of the GEM accessions (particularly ARZM 01150, Antiqua 3, and URZM 01089, respectively) than for the starches of commercial hybrids. Pasting temperatures were about the same for all starches. Both 1‐day and 7‐day gel strengths were considerably greater for the starches recovered from the GEM accessions (particularly BRA 052051 (SE 32), 21.0 g for 1‐day and FS8A(T), 66.2 g for 7‐day). Although the differences in starch properties were statistically different, only the higher gel strengths of the starches recovered from the GEM accessions were of practical significance to the starch industry.     

Linuron sorption-desorption in field-moist soils

Pesticide sorption or binding to soil is traditionally characterized using batch slurry techniques. The objective of this study was to determine linuron sorption in field-moist or unsaturated soils. Experiments were performed using low-density (i.e., 0.25 g mL(-)(1)) supercritical carbon dioxide to remove linuron from the soil water phase, thus allowing calculation of sorption coefficients (K(d)) at low water contents. Both soil water content and temperature influenced sorption. K(d) values increased with increased water content, if less than saturated. K(d) values decreased with increased temperature. K(d) values for linuron sorption on silty clay and sandy loam soils at 12% water content and 40 degrees C were 3.9 and 7.0 mL g(-)(1), respectively. Isosteric heats of sorption (DeltaH(i)) were -41 and -35 kJ mol(-)(1) for the silty clay and sandy loam soils, respectively. The sorption coefficient obtained using the batch method was comparable (K(f) for sandy loam soil = 7. 9 microg(1)(-)(1/)(n)() mL(1/)(n)() g(-)(1)) to that obtained using the SFE technique. On the basis of these results, pesticide sorption as a function of water content must be known to more accurately predict pesticide transport through soils.     

Effects of Rough Rice Storage Conditions on Gelatinization and Retrogradation Properties of Rice Flours

Changes in gelatinization and retrogradation properties of two rice cultivars, Bengal and Kaybonnet, during rough rice storage were studied using differential scanning calorimetry (DSC). The storage variables included two storage moisture contents (12 and 14%), three storage temperatures (4, 21, and 38°C), and four storage durations (0, 3, 9, and 16 weeks). Rough rice cultivar, storage temperature, moisture content, and duration affected (P < 0.05) the enthalpies and temperatures of gelatinization and retrogradation of rice flour. Bengal had a higher gelatinization enthalpy (P < 0.005) but lower gelatinization temperatures (P < 0.0001) than the long-grain Kaybonnet. Rice stored at 38°C exhibited higher gelatinization enthalpy and temperatures (P < 0.05) than those stored at 4 or 21°C. Storage duration affected the gelatinization and retrogradation properties through a higher order, rather than a linear, relationship.     

Retrogradation of du wx and su2 wx Maize Starches After Different Gelatinization Heat Treatments

Retrogradation of du wx and su2 wx starches after different gelatinization heat treatments was studied by differential scanning calorimetry. Suspensions of 30% (w/w) starch were initially heated to final temperatures of 55–180°C. Gelatinized starch was cooled and stored at 4°C. Starch retrogradation in the storage period was influenced by initial heat treatments. Retrogradation of du wx starch was rapid: when initially heated to 80–105°C, retrogradation enthalpy was ≈10 J/g after one day at 4°C. The retrogradation enthalpy was ≈15 J/g after 22 days of storage, and reached a maximum of 16.2 J/g after 40 days of storage. For du wx starch, application of the Avrami equation to increases in retrogradation enthalpy suggests retrogradation kinetics vary with initial heating temperature. Furthermore, starch retrogradation may not fit simple Avrami theory for initial heating ≤140°C. Retrogradation of su2 wx starch was slow. After 30 days of storage at 4°C, the maximum retrogradation enthalpy for all initial heating temperatures tested was 7.0 J/g, for the initial heating to 80°C. This work indicates that gelatinization heat treatment in these starches is an important factor in amylopectin retrogradation, and that the effect of initial heat treatment varies according to the genotype.     

Effects of Pollination Method and Growing Location on Starch Thermal Properties of Corn Hybrids

Starch gelatinization and retrogradation properties of corn were studied to determine the effect of controlled (self) pollination versus noncontrolled pollination on analytical determinations, and the potential to eliminate the expensive and time-consuming step of self-pollinating before research screening of corn genotypes. Twenty-four hybrids were grown in two Iowa locations, Story City and Ames. At Story City, all hybrids received three pollination treatments: self-pollination; small-plot, openpollination (representing corn from small test plots); and large-plot, openpollination (representing corn from a farmer's field). Self-pollinated and small-plot, open-pollinated corn were grown in replicated two-row plots, whereas large-plot, open-pollinated corn was grown in unreplicated plots of 12.8 m × 8 rows. At Ames, the small-plot, open pollination treatment was not done. Starch was extracted from samples of corn harvested from each plot, and gelatinization and retrogradation properties were determined using differential-scanning calorimetry (DSC). Hybrids exhibited different starch gelatinization and retrogradation properties. Significant differences (P ≤ 0.05) in starch gelatinization and retrogradation properties occurred among pollination methods and between locations. Pollination method did not influence gelatinization enthalpy values, but onset temperature values for gelatinization, and range values for retrogradation differed significantly among pollination methods. At Ames, treatments gave different values for retrogradation enthalpy and percentage of retrogradation. Because of differences in some starch characteristics associated with pollination methods, self-pollination is recommended when growing samples in small plots for research purposes.     

Influence of acyl chain lengths in mono- and diacyl-sn-glycerophosphatidylcholine on gelatinization and retrogradation of starch

The influence of starch with 1- or 2-monoacyl-sn-glycerophosphatidylcholine (GPC) having various chain lengths of fatty acids on gelatinization and retrogradation of starch was studied by the measurement of starch-GPC complex formation, complexing index, and differential scanning calorimetry. The addition of GPC to the starch sample slightly increased the blue value and lambda(max) with increasing chain length of GPC but decreased the phosphorus content and complexing index. The gelatinization onset and peak temperatures of starch complexes increased significantly with increasing chain length, but the enthalpies were statistically lower, except for the treatment with 1,2-distearoyl-sn-GPC when compared with that of the control. Among GPC (di and mono), 1- and 2-monomyristoyl-sn-GPC showed the highest complexing ability, whereas the complexing ability of the GPC decreased with the increasing chain length. According to the Avrami equation, the retrogradation rate (k, day(-1)) of starch was slower than that of the control, whereas the retrogradation rates of 1- and 2-monomyristoyl-sn-GPC were slowest among the GPCs. The positive linear relationship between k and the number of acyl groups of GPC suggests that a GPC with a shorter chain length could retard the retrogradation of starch during storage.     

Thermal Properties of Corn Starch Extraction Intermediates by Differential Scanning Calorimetry

Thermal properties of corn starch extraction intermediates from four types of corn were studied using differential scanning calorimetry. Starch at four different stages of extraction, including a standard single-kernel starch isolation procedure and three starch extraction intermediates, was isolated from mature corn kernels of B73 and Oh43 inbreds and the mutants of waxy (wx) and amylose extender (ae) in an Oh43 background. Differences in thermal properties and moisture and protein contents of starch from the extraction stages were statistically analyzed. Most thermal properties (gelatinization and retrogradation onset temperatures, gelatinization and retrogradation ranges, gelatinization and retrogradation peak temperatures, gelatinization and retrogradation enthalpies, peak height index, and percentage of retrogradation) of starches extracted at stage 3 intermediate (a procedure that did not include a final washing step) were similar to those of starch extracted by the standard single-kernel isolation procedure. Values for gelatinization peak temperature, gelatinization enthalpy, and peak height index were different between the standard and the stage 3 intermediate. The values obtained from starches extracted at stage 3, however, were consistent and predictable, suggesting that this extraction intermediate might be used in screening programs in which many starch samples are evaluated. By using the stage 3 extraction, samples could be evaluated in three rather than four days and the procedure saved ≈0.5 hr of labor time. The other two starch extraction intermediates, which excluded filtering and washing or filtering, washing, and steeping, produced starch with thermal properties generally significantly different from starch extracted by the standard single-kernel isolation procedure.     

Retrogradation of Maize Starch After Thermal Treatment Within and Above the Gelatinization Temperature Range

Studies of starch retrogradation have not considered the initial thermal treatment. In this article, we explore the effect of heating to temperatures within and above the gelatinization range on maize starch retrogradation. In the first experiment, 30% suspensions of waxy (wx) starch were initially heated to final temperatures ranging from 54 to 72°C and held for 20 min. On reheating in the differential scanning calorimeter immediately after cooling, the residual gelatinization endotherm peak temperature increased, the endotherm narrowed, and enthalpy decreased. Samples stored for seven days at 4°C showed additional amylopectin retrogradation endotherms. Retrogradation increased dramatically as initial holding temperature increased from 60 to 72°C. In a second experiment, wx starch was initially heated to final temperatures from 54 to 180°C and rapidly cooled, followed by immediate reheating or storage at 4°C. Maximum amylopectin retrogradation enthalpy after storage was observed for initial heating to 82°C. Above 82°C, retrogradation enthalpy decreased as initial heating temperature increased. A similar effect for ae wx starch was observed, except that retrogradation occurred more rapidly than for wx starch. These experiments show that heating to various temperatures above the range of gelatinization may profoundly affect amylopectin retrogradation, perhaps due to varying extents of residual molecular order in starch materials that are commonly presumed to be fully gelatinized. This article shows that studies of starch retrogradation should take into account the thermal history of the samples even for temperatures above the gelatinization temperature range.     

Pasting properties of gamma-irradiated rice starches as affected by pH.

Changes in the viscosity properties of gamma-irradiated rice starches (from 1 to 25% amylose content) from four genotypes (JY293, Jiayu 293; XS, Xiushui; ZF504, Zhefu 504; and ZXN, Zaoxiannuo) during pasting in water (pH 7) or in different pH solutions were studied using a rapid visco analyzer. Peak viscosity (PV) of all native rice starches was little affected at pH 4 and 10, while hot paste viscosity (HPV) and cool paste (final) viscosity (CPV) were generally lower at pH 4 and higher at pH 10 as compared with that at pH 7. The PV, HPV, and CPV of gamma-irradiated starches were higher at pH 4 and lower at pH 10 than pH 7. All viscosity characteristics of native rice starches were reduced in stronger alkali (pH 11.5) or acidic (pH 2.5) solutions. However, the gamma-irradiated starches were substantially higher at pH 2.5 but lower at pH 11.5, indicating that the effect of irradiation was highly pH dependent. The swelling volume of irradiated ZF504 and JY293 starch at all irradiation levels was higher at pH 4 than pH 7, while the values were lowest at pH 2.5. The irradiated ZXN and XS starches had higher swelling volumes at pH 4 and pH 2.5 than pH 7. Differential scanning calorimetry analysis showed that gamma-irradiation caused progressively lower gelatinization peak temperature (T(p)) and higher gelatinization range (T(r)) at pH 7. T(p) was higher and T(r) was lower at a much stronger acidic condition (pH 1) for both native and irradiated starches. The possibility of using viscosity changes in low pH for the detection of irradiated starch was discussed.     

Role of Phosphorus in Viscosity,Gelatinization, and Retrogradation of Starch

The effect of starch crystallinity and phosphorus on starch gelatinization and retrogradation were studied using wide-angle X-ray powder diffraction, cross polarization/magic angle spinning (CP/MAS) ¹³C nuclear magnetic resonance (NMR) spectroscopy, ³¹P NMR spectroscopy, Rapid Visco Analyzer (RVA) and differential scanning calorimetry (DSC). Two starches differing significantly in peak viscosity (cv. Stephens, 283 BU; cv. Crew, 560 BU) were comparable in amylose content and starch crystallinity, while differing significantly in phospholipids content. Starch of lower peak viscosity had a higher phospholipids content and showed a slower rate of retrogradation. Starch from Stephens (0.098% phosphorus) had an enthalpy value of retrograded starch of 2.2 J/g after 14 days of storage, while starch from Crew (0.062% phosphorus) had an enthalpy value as high as 4.4 J/g. Defatting with a hot n-propanol and water (3:1) mixture caused substantial changes in peak viscosity. Peak viscosity for starch from Crew decreased by 75 RVU due to defatting, while starch from Stephens decreased by as much as 125 RVU. After defatting with the hot n-propanol water mixture, the rate and extent of starch retrogradation were comparable between the prime starches, which differed significantly in peak viscosity.     

Morphological, structural, thermal, and rheological characteristics of starches separated from apples of different cultivars

The starches were separated from unripe apples of five cultivars (Criterion, Ruspippum, Red Spur, Skyline Supreme, and Granny Smith) and evaluated using scanning electron microscopy (SEM), gel permeation chromatography (GPC), X-ray diffraction, differential scanning calorimetry (DSC), and dynamic viscoelasticity. SEM showed the presence of round granules as well as granules that had been partially degraded, probably by amylases. The starch granules in different apple starches ranged between 4.1 and 12.0 mum. Debranching of starch with isoamylase and subsequent fractionation of debranched materials by GPC revealed the presence of an apparent amylose, an intermediate fraction (mixture of amylose and amylopectin), long side chains of amylopectin, and short side chains of amylopectin in the range of 28-35.2, 3.6-4.4, 20-21.3, and 39.9-47.1%, respectively. The swelling power of starches ranged between 14.4 and 21.3 g/g. X-ray diffraction of apple starches showed a mixture of A- and B-type patterns. All apple starches showed peak intensities lower than that observed for normal corn and potato starch, indicating the lower crystallinity. The transition temperatures (onset temperature, T(o); peak temperature, T(p); and conclusion temperature, T(c)) and enthalpy of gelatinization (deltaH(gel)) determined using DSC ranged between 54.7 and 56.2 degrees C, between 57.1 and 59.1 degrees C, between 60.2 and 63.5 degrees C, and between 3.3 and 4.2 J/g, respectively. The viscoelastic properties of starch from different cultivars measured during heating and cooling using a rheometer differed significantly. Red Spur and Criterion starches with larger granule size showed higher G' and G' ' values, whereas those containing smaller size and amylolytically degraded granules showed lower G' and G' '.     

Characteristics of Starch from Eight Quinoa Lines

Starches ranging in amylose content from 3 to 20% from eight quinoa (Chenopodium quinoa Willd.) lines were characterized with respect to thermal, retrogradation, and pasting properties; swelling and solubility behavior; freeze‐thaw stability; water‐binding capacity; shear stability; and granule size and morphology. The starches differed in gelatinization onset temperatures, peak temperatures, and retrogradation tendencies; these characteristics were positively correlated with amylose content. No variation in gelatinization enthalpy was observed. With the exception of pasting temperature, large variations in pasting characteristics were found among starches and were correlated with amylose content. Swelling, solubility, freeze‐thaw stability, and water‐binding capacity also differed among starches and were correlated with amylose content. Granule morphology and size were similar for all starches. The wide variation in amylose content and physicochemical characteristics of quinoa starches suggests applications in a variety of food and nonfood products.     

Gelatinization and Retrogradation Kinetics of High‐Fiber Wheat Flour Blends: A Calorimetric Approach

The impact of dietary fiber (DF) mixtures on dough thermal properties needs to be investigated when designing high‐fiber wheat bread. Effects of flour replacement at different levels (6–34%) by soluble (inuline [FN]), partially soluble (sugar beet [FX], pea cell wall [SW]), and insoluble (pea hull [EX]) DF on wheat dough thermal profiles have been investigated by simulating baking, cooling, and storage in differential scanning calorimetry (DSC) pans. In general, DF incorporation into water‐flour systems delayed endothermic transition temperatures for both gelatinization and retrogradation phenomena except for the peak temperature (T_p) of retrogradation. With some exception, the pattern of the enthalpy of amylopectin retrogradation was lower and slower (lower constant of proportion, k) over 10 days of storage in gelatinized hydrated flour‐fiber blends when compared with control without DF. FX, a partially soluble fiber, provided major effects on gelatinization (T_p decrease and ΔH increase) and retrogradation kinetics (the Avrami exponent, n, increase). Single presence of EX allowed a significant reduction in the Avrami exponent n leading to slower kinetics for amylopectin retrogradation when included in the blends.     

Comparison of the physicochemical properties and pasting characteristics of flour and starch from red and white sweet potato cultivars

This research characterized flour and raw starches isolated from red and white sweet potato cultivars. Their composition, determined by proximate analysis, is typical of sweet potato cultivars. These cultivars have high amylose content (32-34%) and exhibit a Ca-type X-ray diffraction pattern. Similar gelatinization characteristics were detected for both starches with onset temperature of 67 degrees C and enthalpy of 10.5-11.0 J/g. Starches of both red and white cultivars had well-correlated (r (2) = 0.982) and high solubilization and swelling temperatures, starting at 80 degrees C. Pasting properties of the white cultivar exhibit lower tendency for retrogradation. Water and oil absorption capacities were low for both red and white flours. When parboiled, both cultivars showed improved water absorption capacity and decreased least gelation concentration. It is concluded that the white cultivar should be preferred when low retrogradation tendency is required.     

Identification of QTL Controlling Thermal Properties of Maize Starch

Starch has many uses and some of these uses would be facilitated by altering its thermal properties. Genetic manipulation of starch thermal properties will be facilitated by a better understanding of the genetic control of starch gelatinization. We used differential scanning calorimetry to characterize the gelatinization parameters of maize (Zea mays L.) kernel starch prepared from two populations of recombinant inbred lines, an intermated B73xMo17 population (IBM) and an F_6:7 Mo17xH99 population. The traits examined were the onset and peak temperatures of gelatinization and the enthalpy of gelatinization. These traits were measured for both native starch and for gelatinized starch allowed to recrystallize, a process called retrogradation. Substantial variation in these traits was found in spite of the narrow genetic base of the populations. We identified several quantitative trait loci (QTL) controlling traits of interest in each population. In the IBM population, a significant QTL for the peak temperature of gelatinization of retrograded starch co‐localized to a molecular marker in the Wx1 gene, which encodes a granule bound starch synthase. The major QTL identified in this study explain, on average, ≈15% of the variation for a given trait, underscoring the complexity of the genetic control of starch functional properties.     

Adsorption and analysis of the insecticides thiamethoxam and indoxacarb in hawaiian soils

A method was developed for the simultaneous extraction and analysis of the insecticides indoxacarb and thiamethoxam from five Hawaiian soils. Using pressurized fluid extraction followed by liquid chromatography, optimized recoveries from the five soils were obtained ranging from 80% +/- 5 to 101% +/- 10 for thiamethoxam, and 83% +/- 6 to 106% +/- 7 for indoxacarb. Aging studies also showed strong binding of indoxacarb to all soils tested after 30 days, while thiamethoxam remained quite available for extraction during the length of the study (90 days). Freundlich constant (K(f)) and empirical value (n) for thiamethoxam sorption on Lihue soil were 0.007391 mmol((1-1/)(n)).L(1/)(n).g(-1) and 1.1377, respectively; K(f) and n were 0.007844 mmol((1-1/)(n)).L(1/)(n).g(-1) and 0.8473, respectively, on Wahiawa soil. The organic carbon adsorption constant (Koc) of thiamethoxam was 0.53 in Lihue soil and 0.23 in Wahiawa soil.     

Analysis of the retrogradation of low starch concentration gels using differential scanning calorimetry,rheology, and nuclear magnetic resonance spectroscopy

The retrogradation of 5, 10, 15, and 25% corn starch gels was measured using differential scanning calorimetry (DSC), rheology, and an array of NMR spectroscopy techniques. During the initial (<24 h) stage of retrogradation, an increase in G' corresponding to an increase in the number of solid protons participating in cross-relaxation (M(B)(0) was observed for all four concentrations studied. During the latter (>24 h) stage of retrogradation, amylopectin recrystallization becomes the dominant process as measured by an increase in deltaH(r) for the 25% starch gel, which corresponded to a further increase in. A decrease in the molecular mobility of the liquid component was observed by decreases in (17)O T(2), (1)H D(0), and T(2A). The value for T(2B) (the solid transverse relaxation time) did not change with concentration or time indicating that the mobility of the solid component does not change over time despite the conversion of the highly mobile starch fraction to the less mobile solid state during retrogradation.