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1.
Genetic variation in the physical properties of sweet potato starch.   总被引：10，自引：0，他引：10  
Sweet potato starch, prepared from 44 genotypes adapted to Philippine conditions, showed wide variation and distinctly different pasting profiles in Rapid Visco-Analyzer (RVA) analysis at 11% and 7% starch concentration. At 11% starch concentration, the pasting profiles were type A, characterized by high to moderate peak with a major breakdown and low cold paste viscosity. At 7%, the pasting profile was generally type C, characterized by the absence of a distinct peak with none to very slight breakdown and high cold paste viscosity. However, differentiation among genotypes was better achieved from RVA pasting profiles at 11% starch concentration. Peak viscosity (PV) and hot paste viscosity (HPV) at 11% starch paste concentration had significant negative correlation with amylose content. PV, HPV, and setback ratio were significantly correlated to adhesiveness of the starch gel. Sweet potato starch generally had high swelling volume but low solubilities at 92.5 degrees C.  相似文献   

2.
Changes in pH and pasting properties of instant‐noodle formula dry‐mix suspensions containing each of 12 phosphate salts were investigated. The pH values of solutions alone and then solution and flour suspensions decreased as the level of phosphate salts increased, except that of trisodium phosphate, which increased the pH value. The changes in the Rapid Visco Analyser (RVA) pasting parameters of instant‐noodle formula suspensions were not consistent with the respective changes in pH, but the change trends of the RVA parameters for the two different wheat flours (hard red winter and soft white wheat) were similar. Five of the phosphate salts gradually increased the RVA peak viscosity (PV) as phosphate concentration increased. Seven other phosphate salts increased the PV at 0.05% and then decreased PV as the phosphate concentration increased. The change in trough viscosity owing to phosphate salt and concentration was similar to that of PV. The final viscosity (FV) gradually declined, to varying degrees, as the phosphate concentration increased for some of the phosphate salts. However, seven of the phosphate salts caused slight increases in FV as their concentrations increased. The response of starch gelatinization and pasting behavior, as measured by RVA, indicated that phosphate salts exert an influence on starch during heating in water. Because RVA parameters have been linked to instant‐noodle processing and textural properties, phosphate salt identity and concentration can likely be manipulated to affect end‐product quality.  相似文献   

3.
Starch pasting properties and amylose content from 17 waxy barley lines (waxy gene originating from indigenous lines and an artificial mutant) were analyzed using rapid viscosity analysis (Rapid Visco Analyser [RVA]). Amylose contents varied from 0% (Shikoku‐hadaka 97) to 9.5% (Shikoku‐hadaka 96) compared with 30% for normal barley. Eight parameters were obtained from RVA profiles of these lines and correlation between each of these parameters and amylose content were evaluated. These parameters include pasting temperature (PT), peak viscosity (PV), temperature at PV, minimum viscosity (MV), final viscosity (FV), breakdown (BD), setback (SB), and time maintained at >80% PV (hot paste stability [HPS]). Significant correlations (0.64 and 0.61) were found between amylose content and FV and SB, respectively. High correlation (0.72) was found between amylose content and temperature at PV. HPS calculated from RVA profiles showed the highest correlation (0.79) to amylose content. Outer part of barley grains contained higher amounts of amylose than the inner part. There was a tendency that both PT and FV positively correlated to the amylose content of these parts.  相似文献   

4.
The Rapid Visco‐Analyzer (RVA) was used to characterize the pasting properties of 68 sorghum grains with a standard 23‐min temperature profile. The results showed a strong linear relationship between ethanol yield and final viscosity as well as setback. Ethanol yield increased as final viscosity decreased. A modified RVA procedure (10 min) with an application of α‐amylase was developed to simulate the liquefaction step in dry‐grind ethanol production. There was a remarkable difference in mashing properties among the sorghum samples with the normal dosage of α‐amylase. The sorghum samples which were difficult to liquefy in the mashing step had much higher peak viscosities than the samples that were easily liquefied. The results also showed that the relationship between conversion efficiency and mashing property was significant. Tannins cause high mash viscosities. There was a strong linear relationship between tannin content and final viscosity as well as peak viscosity. The modified RVA procedure is applicable not only for characterization of mashing properties but also for optimization of α‐amylase doses for starch liquefaction.  相似文献   

5.
The possibility to identify or develop new rice cultivars with low glycemic response was investigated. Twelve rice cultivars with a narrow range of amylose contents were selected based on their wide variation in rapid viscoanalyzer (RVA) pasting breakdown to study the relationship between starch digestibility and amylopectin fine structure and pasting properties. Rice flour samples were cooked for in vitro digestibility analysis using the standard Englyst assay. RVA was performed for pasting properties of starches. Results showed that rapidly digestible starch (RDS) was highly and negatively correlated (r = -0.86, p < 0.01; r = -0.81, p < 0.01) with FrI long and FrII intermediate/short debranched amylopectin linear chains, respectively, and positively correlated (r = 0.79; p < 0.01) with FrIII very short linear chains. Slowly digestible (SDS) starch was positively correlated (r = 0.80, p < 0.01; 0.76, p < 0.01) with FrI and FrII, respectively, and negatively correlated (r = -0.76, p < 0.01) with FrIII. RVA breakdown viscosity was positively correlated (r = 0.88, p < 0.01) with RDS and negatively correlated (r = -0.89, p < 0.01) with SDS. Thus, the RVA method potentially could be used as a screening tool for starch digestion properties. This study reveals a molecular basis in amylopectin fine structure variability for starch digestion properties in rice cultivars and could have value in identifying slowly digesting cultivars as well as developing a breeding strategy to produce low glycemic rice cultivars. Keywords: Rice; starch; RVA; amylopectin; digestibility.  相似文献   

6.
Waxy wheat (Triticum aestivum L.) contains endosperm starch lacking in amylose. To realize the full potential of waxy wheat, the pasting properties of hard waxy wheat flours as well as factors governing the pasting properties were investigated and compared with normal and partial waxy wheat flours. Starches isolated from six hard waxy wheat flours had similar pasting properties, yet their corresponding flours had very different pasting properties. The differences in pasting properties were narrowed after endogenous α‐amylase activity in waxy wheat flours was inhibited by silver nitrate. Upon treatment with protease, the extent of protein digestibility influenced the viscosity profile in waxy wheat flours. Waxy wheat starch granules swelled extensively when heated in water and exhibited a high peak viscosity, but they fragmented at high temperatures, resulting in more rapid breakdown in viscosity. The extensively swelled and fragmented waxy wheat starch granules were more susceptible to α‐amylase degradation than normal wheat starch. A combination of endogenous α‐amylase activity and protein matrix contributed to a large variation in pasting properties of waxy wheat flours.  相似文献   

7.
The breadmaking potential of six oat varieties was compared with and related to their physicochemical properties. The most significant differences in the bread characteristics were found in the crumb structure. The varieties Buggy, Energie, and Zorro resulted in good bread quality with an even gas‐cell distribution characterized by a high number of relatively small pores. In contrast, Typhon, Ivory, and Nord 08/311 each had a large hole in the center of the crumb and accordingly poor quality. Breads differed little in specific volume, bake loss, and density. Rheological analysis revealed positive effects of low batter resistance to deformation on oat bread quality. On the basis of the physicochemical characterization, protein and fat contents were identified as key factors responsible for differences observed in bread quality, provided that starch damage and water‐hydration capacity were low. Additionally, high setback and final viscosity, as determined by Rapid Visco Analyser (RVA) analysis, positively affected oat bread quality. High α‐amylase activity was found to influence negatively the breadmaking performance of oats. Overall, protein, fat, dietary fiber content, starch pasting properties, and α‐amylase activity were responsible for the breadmaking properties of oat varieties.  相似文献   

8.
Amylase and calcium chelators, such as disodium ethylene diaminotetraacetate (EDTA), are used in analysis of neutral detergent fiber (NDF) to dissolve starch and pectin, respectively. However, these reagents may interfere with each other's activity. Six combinations of alpha-amylase and EDTA were examined for determining NDF values of beet pulp (Beta vulgaris), ground corn (Zea mays L.), timothy hay (Phleum pratense), and soybean meal (Glycine max L). For treatment A, 2.5 mL of alpha-amylase was added 5 min after boiling. Other treatments differed as follows: (B) 4.5 mL of alpha-amylase, (C) 4.5 mL of alpha-amylase added 30 min after boiling, (D) delayed addition of EDTA to 30 min after boiling, (E) no EDTA, and (F) no alpha-amylase. Inclusion of EDTA interfered with amylase activity in corn grain samples, and addition of amylase to beet pulp and soybean meal samples reduced the effectiveness of EDTA and increased ash in the NDF residue. Amylase should not be used for samples that do not contain starch. Calculating NDF on an ash-free basis minimized the negative effects of amylase on EDTA activity.  相似文献   

9.
Wheat landraces possess a wide diversity in starch physical properties that could be useful in breeding for improved quality of specific products, such as various types of Asian noodles. The pasting properties (using a Rapid Visco-Analyser [RVA]) and flour swelling volume (FSV, using silver nitrate to inactivate α-amylase activity) of wholemeal, were measured for 242 hexaploid accessions of Iranian landrace wheat. FSV values and the peak viscosities were positively correlated (r = 0.73***). FSV values in the landraces ranged from 8.3 to 15.9 mL/g and peak viscosities ranged from 139 to 305 RVA units (RVU). In comparison, FSV of cvs. Eradu and Klasic were 18.6 and 15.0 mL/g, and peak viscosities were 355 and 303 RVU, respectively. Of the landraces, Iranian Wheat Accession (IWA) 8602488 had the highest peak viscosity (305 RVU) and exceptionally high hot- and cool-paste viscosities. Two accessions, IWA 8602430 and 8600544, displayed pasting characteristics considered desirable for high-quality Japanese white-salted noodles. Four landraces were identified that had starch with unusually high resistance to shearthinning. Texture profile analysis was done on the wholemeal gels formed in the RVA canister. The variation in parameters such as hardness, chewiness, and adhesiveness in the landraces greatly exceeded that in the cultivars. The hot-paste viscosity, breakdown, setback, and final viscosity values, but not the peak viscosity or FSV, were highly significantly correlated with the hardness, chewiness, and adhesiveness of the gel. The Iranian landraces appear to present useful genetic variation for developing wheats for special uses.  相似文献   

10.
Pasting profiles of selected starches were compared by using a Micro Visco‐Amylo‐Graph (MVA) and a Rapid Visco Analyser (RVA). Effects of cooking (heating/cooling) rate and stirring speed on starch pasting properties were examined. The pasting viscosity of a starch suspension (8%, w/w, dsb) was measured at a fast (6°C/min) and slow (1.5°C/min) cooking rate while being stirred at either 75 rpm or 160 rpm. The pasting temperatures (PT) of all starches were higher when measured at the fast cooking rate than those at the slow cooking rate, except for wheat measured by using the RVA. PT was also higher when measured at the slow stirring speed (75 rpm) than at the fast stirring speed (160 rpm) in both RVA and MVA. When stirring speed increased from 75 rpm to 160 rpm, peak viscosity of all starch pastes except potato decreased measured by using the RVA, but increased by using the MVA. In general, amylograms of these starches obtained by using the MVA showed less breakdown, but greater setback viscosity than did that obtained by using the RVA. Differences in starch pasting properties between MVA and RVA, measured at the same cooking and stirring rates, were attributed mainly to the difference in spindle structure.  相似文献   

11.
Studies on samples of 20 hard-grained wheat cultivars and a commercial flour that varied in starch and protein quality showed that both characteristics influenced the texture of Japanese alkaline noodles (ramen). Flour swelling volume (FSV) and flour pasting characteristics (peak viscosity and breakdown) determined with a Rapid-Visco Analyser (RVA) assessed independently of α-amylase effects, were negatively correlated with total texture score. Protein quality, as indicated by farinograph stability, was positively correlated with total texture score. RVA pasting characteristics were substantially affected by small levels of α-amylase, and inactivation by means of 1 mM AgNO3 was a critical requirement in characterizing the quality of the starch component of flour.  相似文献   

12.
Experimental (N979-5-2-4 and IA95111) and traditional oat lines (Jim and Paul) with average %β-glucan of 7.5, 7.8, 4.9, and 4.4%, respectively, were grown in 2002, 2003, and 2004. Molecular weight (MW) distributions of the β-glucans were examined for potential variations among growing years and for relationships with pasting properties measured by Rapid ViscoAnalyser under three separate conditions: 1) in silver nitrate (SN) solution to inactivate enzymes; 2) hydrolyzed by α-amylase to eliminate the effect of starch; and 3) treated with lichenase to remove β-glucan. The β-glucan was extracted by a process involving multiple precipitation and dialysis steps, and the MW distributions were determined by HPLC. %β-Glucan in N979-5-2-4 and IA95111 lines were consistently and significantly greater (P < 0.05) than in Jim and Paul lines during three growing years. The contribution of β-glucan to peak viscosity on the RVA was substantially greater than that of the starch for all three years. The molecular number average and peak MW of β-glucan from N979-5-2-4 and IA95111 were greater than these values for Jim and Paul, and values were consistent among years. The MW of extracted β-glucan was associated with pasting properties after amylase hydrolysis, but not after treatment with lichenase or in SN solution.  相似文献   

13.
The use of the Rapid Visco Analyser (RVA) for application in the screening of wheat breeding lines for starch quality and potential noodle quality has been limited by relatively low sample throughput. Current methods generally enable only 20–30 samples to be tested each day. This study sought to develop a more rapid time‐temperature profile that could be applied to whole meal samples. A profile that involved a total analysis time of 7.5 min/sample gave measurements of peak viscosity (PV) and breakdown (BD) on whole meal that were highly correlated with corresponding measurements obtained using a more conventional profile that had been applied to low‐extraction flours. BD and PV were also highly correlated with the total texture score of ramen (Chinese‐style alkaline noodles as manufactured in Japan), but only when 1 mM AgNO3 was used to eliminate the effects of α‐amylase.  相似文献   

14.
Mung bean starch gels (8% solids) were prepared after annealing at 45–60°C for 1–24 hr, and the relationship between the physical properties of gels and the swelling power (SP) and solubility of starch was investigated. The SP and solubility decreased with increasing annealing temperature and time, mostly in the first 6 hr. The solubles were mainly composed of amylose. Gel hardness at a 5 mm depth of annealed starch was larger than that of native starch, and gel hardness increased as SP decreased (r = ‐0.94). Upon continued compression, the yield force of gel showed a different function. Above SP of ≈12.5, the yield force of annealed starch gels decreased, but at <12.5 the yield force increased with increasing SP. Both granular rigidity and extent of packing appeared to determine the yield force. Although annealing increased the gel hardness, α‐amylase digestibility of gel was not affected. Pasting analysis in the Rapid Visco Analyser (RVA) revealed that annealing increased pasting temperature. A pasting peak was found only in 45 and 50°C annealed starches. Overall paste viscosities of the starches annealed at >55°C were lower than that of the control starch. Final viscosities in RVA were correlated with the yield force of gel (r = 0.99).  相似文献   

15.
The starch of wheat (Triticum aestivum L.) flour affects food product quality due to the temperature-dependent interactions of starch with water during gelatinization, pasting, and gelation. The objective of this study was to determine the fundamental basis of variation in gelatinization, pasting, and gelation of prime starch derived from seven different wheat cultivars: Kanto 107, which is a partial waxy mutant line, and six near-isogenic lines (NILs) differing in hardness. Complete pasting curves with extended 16-min hold at 93°C were obtained using the Rapid Visco Analyser (RVA). Apparent amylose content ranged from 17.5 to 23.5%; total amylose content ranged from 22.8 to 28.2%. Starches exhibited significant variation in onset of gelatinization. However, none of the parameters measured consistently correlated with onset or other RVA curve parameters that preceded peak paste viscosity. Peak paste viscosity varied from 190 to 323 RVA units (RVU). Higher peak, greater breakdown, lower final viscosity, negative setback, and less total setback were associated with lower apparent and total amylose contents. Each 1% reduction in apparent or total amylose content corresponded to an increase in peak viscosity of about 22 and 25 RVU, respectively, at 12% starch concentration. Of the seven U.S. cultivars, the lower amylose cultivars Penawawa and Klasic were missing the granule-bound starch synthase (GBSS; ADPglucose starch glycosyl transferase, EC 2.4.4.21) protein associated with the Waxy gene locus on chromosome 4A (Wx-B1 locus). Kanto 107 was confirmed as missing both the 7A and 4A waxy proteins (Wx-A1 and Wx-B1 loci). The hardness NIL also were shown to be null at the 4A locus. Apparent and total amylose contents of prime starch generally corresponded well to the number of GBSS proteins; although the hardness NIL tended to have somewhat higher amylose contents than did the other GBSS 4A nulls. We concluded that reduced quantity of starch amylose due to decreased GBSS profoundly affects starch gelatinization, pasting, and gelation properties.  相似文献   

16.
Five Canadian oat genotypes were grown at six environments in Manitoba to assess the effects of genotype, environment, and genotype‐by‐environment interaction on oat starch properties and end‐product quality. Genotypic variation was significant for total starch, amylose content, starch swelling volume (SSV), Rapid Visco Analyser (RVA) pasting viscosities, differential scanning calorimetry (DSC) thermal properties, and starch gel texture as well as the quality of flakes and cooked oatmeal made by laboratory‐scale methodologies. Environment was the dominant factor contributing to the total variation of starch content, RVA pasting viscosities, SSV, and DSC thermal properties. Most measurements of starch gel and oatmeal texture were not affected by growing environment. Cross‐over analysis revealed that changes in the ranking of genotypes across environments occurred for starch RVA hot paste, breakdown and shear thinning viscosities, work of gel compression, flake hydration capacity, and the proportion of large flakes, indicating that breeding for these traits would require multiple testing sites. Trends were observed between oatmeal texture and several flake and starch gel properties, warranting further study. Results of this study indicated that there is a potential to breed Canadian oat cultivars with improved functional end‐product quality for use in the milling and food manufacturing industries.  相似文献   

17.
This study describes the effect of starch properties of Japanese wheat flours on the quality of white salted noodles (WSN). Starch was isolated from 24 flours of 17 Japanese cultivars and amylose content was determined along with pasting properties by Rapid Visco Analyser (RVA), thermal properties by differential scanning calorimetry (DSC), and the distribution of amylopectin chain length by high‐performance anion exchange chromatography (HPAEC). Twenty flours were used to prepare WSN. As expected, 5–6% lower amylose content was associated with good WSN quality (higher scores in softness, elasticity, and smoothness). RVA analysis indicated that the pasting temperature had the greatest influence on WSN quality, while breakdown and setback showed slight effects on WSN quality. DSC results showed that lower endothermal enthalpy (ΔH) in the amylose‐lipid complex was associated with good WSN quality. Chainlength distribution of amylopectin by HPAEC was not an important factor in relation to WSN quality.  相似文献   

18.
Up to 15% modified potato starch (MPS) is often added into Korean instant noodle formulas to improve the cooking and eating quality. However, the addition of MPS leads to higher raw material costs. The effect of phosphate salts (PS) on Korean instant‐fried noodle pasting properties was investigated in this research. When 33% of total MPS in the regular Korean instant noodle formula was substituted by a small amount of PS (≤0.3%), the results clearly indicated that all the PS improved the pasting properties of noodle dough and ground instant‐fried noodle powder, especially the peak viscosity of the Rapid ViscoAnalyser (RVA) curves. However, the pasting temperature was affected little by PS except that tripotassium phosphate increased it significantly. The RVA results showed that the pasting properties of ground instant noodle powder were significantly improved when 33% of MPS was substituted by 0.300% dipotassium phosphate. Meanwhile, the pasting properties were close to those of the regular formula ground instant noodle powder when 33% of MPS was substituted by 0.030% monosodium phosphate or 0.300% disodium phosphate. Therefore, we suggest that MPS used in Korea instant‐fried noodle could be partially substituted by the blends of selected PS.  相似文献   

19.
To determine the effect of amylose content on the starch properties, the amylose content, pasting properties, swelling power, enzymatic digestibility, and thermal properties of partial and perfect waxy types along with their wild‐type parent were analyzed. As expected, amylose content decreases differently in response to the loss of each Wx gene, showing the least response to Wx‐A1a. Most of the characteristics, except the thermal properties of the amylose‐lipid complex in differential scanning calorimetry (DSC), differed significantly among the tested types. Furthermore, the breakdown, setback, and pasting temperatures from the Rapid Visco Analyser (RVA) and the enzymatic digestibility, swelling power, peak temperature, and enthalpy of starch gelatinization from DSC showed a correlation with the amylose content. The relationships between the peak viscosity from the RVA and the onset temperature of starch gelatinization determined by DSC with amylose content of the tested materials were not clear. Waxy starch, which has no amylose, showed a contrasting behavior in starch gelatinization compared with nonwaxy starches. Among the nonwaxy starches, lower setback, lower pasting temperature, higher enzyme digestibility, higher peak temperature, higher enthalpy of starch gelatinization, and higher swelling were generally associated with low amylose starches.  相似文献   

20.
Relationships among soft wheat quality parameters relating to sponge cake volume and sensory tenderness were investigated. Sixteen soft wheats from the 2008–2009 crop and 11 from the 2009–2010 crop, including Japanese soft wheat cultivars, advanced breeders' lines, and western white wheat imported from the United States, were milled and evaluated for protein content, sucrose solvent retention capacity value, specific surface area, flour pasting properties, batter pasting viscosity, sodium dodecyl sulfate sedimentation (SDSS) volume, farinograph properties, specific cake volume, and sensory tenderness score to investigate their relationships. Batter pasting viscosity was measured with a Rapid Visco Analyzer (RVA) at 2 min after reaching 90°C in heating a mixture with equal weights of flour, sucrose, and water. RVA minimum viscosity of flour suspension in water was the most influencing factor and positively correlated to specific cake volume, and RVA batter pasting viscosity and SDSS volume were negatively correlated. Meanwhile, protein content and SDSS volume were strongly negatively correlated with sensory tenderness score. Stepwise multiple regression analysis selected protein content and specific cake volume as independent variables to predict sensory tenderness score; however, SDSS volume and farinograph properties relating to protein strength were not selected. Protein content affected sponge cake tenderness independently of specific cake volume, which was related to differences in cake density.  相似文献   

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