Properties of Starch Noodles as Affected by Sweetpotato Genotype

Starch was extracted from 14 sweetpotato genotypes from the Philippines. The Rapid Visco-Analyzer (RVA) viscoamylographs of the starches showed Type A pasting curves, characterized by a high pasting peak followed by a high degree of shear-thinning. The major difference among genotypes was in the sharpness of the peak, with some showing a very sharp peak while others showed a broad peak. This difference was related to time from onset of pasting to peak viscosity, and to stability ratio (holding viscosity/peak viscosity), which were also highly correlated (r = 0.84, P < 0.01) to each other. Stability ratio was also correlated to noodle firmness (r = 0.95, P < 0.01), rehydration (cooked weight) (r = -0.89, P < 0.01), and swelling volume of the starch (r = -0.62, P < 0.05). The amylose content was correlated significantly only to peak viscosity (r = -0.84, P < 0.01). Significant differences in texture and cooking quality of the starch noodles produced from the different genotypes was found. It was shown that the RVA viscoamylographs could be used to detect differences in pasting characteristics of sweetpotato starch which are related to quality of noodle produced.     

Physicochemical Properties Related to Quality of Rice Noodles

Eleven rice genotypes with diverse Rapid Visco Analyzer (RVA) pasting characteristics were evaluated for their physicochemical and gel textural characteristics relative to their suitability for making rice noodles. Apparent amylose content (AC) was highly correlated with swelling power (r = -0.65, P < 0.05), flour swelling volume (FSV) (r = -0.67, P < 0.05), noodle hardness (r = 0.74, P < 0.01), gumminess (r = 0.82, P < 0.01), chewiness (r = 0.74, P < 0.01), and tensile strength (r = 0.72, P < 0.05). Solubility showed an inverse relationship with the pasting parameters and noodle rehydration, and a positive relationship with cooking loss, noodle hardness, and gumminess. FSV and most of the pasting parameters were negatively correlated with noodle hardness. RVA parameters and textural parameters of gels formed in the RVA canister were well correlated with actual noodle texture and may, therefore, be used for predicting rice noodle quality during early screening of genotypes in breeding programs.     

Effects of Protein Content,Glutenin‐to‐Gliadin Ratio,Amylose Content,and Starch Damage on Textural Properties of Chinese Fresh White Noodles

The independent effects of flour protein and starch on textural properties of Chinese fresh white noodles were investigated through reconstitution of fractionated flour components. Noodle hardness decreased with decreased protein content, whereas it unexpectedly increased as protein content decreased to a very low level (7.0%). Noodle cohesiveness, tensile strength, and breaking length increased with increased protein content. Higher glutenin‐to‐gliadin ratio resulted in harder and stronger noodles at constant protein content. Increased starch amylose content resulted in increased flour peak viscosity. When water absorption remained the same during noodle making, hardness and cohesiveness of cooked noodles also increased with increased starch amylose content, while springiness did not vary significantly. Increased starch damage of ≈5.5–10.4% effectively improved noodle hardness; however, starch damage >10.4% decreased it. Increased starch damage also enhanced noodle springiness while it decreased cohesiveness.     

Genetic Diversity in Properties of Starch from Zimbabwean Sorghum Landraces

Starch was isolated from 95 sorghum landraces from Zimbabwe using an alkali steep and wet‐milling procedure. The physicochemical properties of sorghum starch were examined for potential use in Southern Africa. All the landraces evaluated had a normal endosperm indicated by the amylose content of the starches. Starch properties were not correlated to most of the physical grain quality traits evaluated. Grain hardness was weakly correlated to starch gel adhesiveness (r = 0.36) and amylose content (r = 0.38) (P < 0.001). The mean peak viscosity (PV) of the sorghum starches was 324 Rapid Visco Analyser units (RVU) compared with 238 RVU in a commercial corn starch sample; PV was 244–377 RVU. Some landraces had low shear‐thinning starches, implying good paste stability under hot conditions. Pasting properties were highly correlated among the sorghum starches. The starch gel hardness showed considerable variation (44–71 g) among the landraces. Gelatinization peak temperatures were 66–70°C. The thermal properties of starches were not correlated with starch swelling and pasting properties. Genotype grouping by highest and lowest values in each category would allow selection of sorghums based on a specific attribute depending on the desired end use.     

Physicochemical Properties of Flours that Relate to Sorghum Couscous Quality

Flours from eight sorghum cultivars were evaluated for their couscous-making ability with the objective of finding predictive relationships between flour physicochemical properties and couscous quality. Chemical composition, physical characteristics, and pasting and gelatinization properties of the flours were determined. A laboratory procedure was used to prepare couscous. Couscous properties were evaluated and compared to a laboratory-prepared and a commercial durum wheat couscous. Hard grain produced flours containing a high proportion of coarse particles with low ash and high damaged starch content and yielded a higher proportion of desirable sorghum couscous granules. A variety of colors ranging from brown to yellow were obtained when flours were processed into couscous. Cooked sorghum couscous stickiness was positively correlated (r = 0.89, P < 0.01) with the amount of damaged starch in flour. Cooked couscous hardness correlated positively (r = 0.79, P < 0.05) with apparent amylose content of flour and correlated negatively (r = -0.75, P < 0.05) with flour peak viscosity. Durum wheat couscous was lighter and had more yellow color than sorghum couscous. Sorghum couscous was stickier and harder than durum wheat couscous. Addition of 2% oil to the cooking water considerably improved the texture of some sorghum couscous to a level comparable to that of durum wheat couscous.     

Effects of LAB Fermentation on Physical Properties of Oat Flour and Its Suitability for Noodle Making

Flour was obtained from oats fermented with lactic acid bacteria (LAB) to study the effect of fermentation on the physical properties and the suitability of fermented oats for use in starch noodle production. The results showed that fermented samples had a significantly lower pH than control samples. Gel strength and amylose content initially increased and then decreased (P < 0.05) with fermentation time. The peak viscosity, breakdown, final viscosity, and setback value decreased with fermentation time. Fermented noodles showed a higher hardness and springiness. In particular, Lactobacillus plantarum (LP) induced the highest springiness, cohesiveness, gumminess, chewiness, and resilience over 12 hr of fermentation. The cooking quality evaluation indicated that fermentation improved the quality of oat starch noodles. Fermented oats resulted in noodles with low cooking loss and higher cooking weight compared to noodles made from fresh flour. The use of LP for 12 hr of fermentation time yielded noodles of the best quality.     

Starch Properties and Stability of Club and Soft White Winter Wheats from the Pacific Northwest of the United States

Based on examination of 192 club and soft white winter (SWW) wheat samples, club and SWW wheat flours showed comparable levels of starch damage and flour peak viscosity, while differing significantly in starch content. Varietal differences and growing conditions had strong influence on the characteristics of both classes of wheat flour. Club wheat flour exhibited better stability in starch content and starch damage than did SWW wheat flour. A significant correlation between starch damage and cookie diameter in both club and SWW wheat was observed (r = -0.480, P < 0.0001 for club wheat and r = -0.430, P < 0.0001 for SWW wheat). Sponge cake volume was positively correlated with starch content in both classes of wheat (r = 0.362, P < 0.01 for club wheat and r = 0.181, P < 0.05 for SWW wheat). When wheat samples were grown in one location over three years, club and SWW wheat flours had comparable starch content. However, flour and prime starch peak viscosities were significantly different in club than in SWW wheat. Club wheat flour had lower starch damage and amylose content, as measured by high-performance size-exclusion chromatography (HPSEC), than did SWW wheat flour. Crop year and varietal differences had significant effect on amylose content, starch damage, and flour and starch peak viscosities, but not on starch content, in both classes of wheat flour. When wheat samples were grown in one year over seven locations, club wheat flour was higher in starch content, lower in starch damage, and comparable in amylose to SWW wheat flour. Both flour and prime starch viscosities were significantly higher in club wheat than in SWW wheat. Varietal differences and growing location had strong influence on starch properties in both classes of wheat. Peak viscosity of the isolated starch did not correlate well with the corresponding flour, indicating that flour pasting property does not reflect the pasting property of starch. The fine structure of isoamylase-debranched amylopectins from club and SWW wheats had a similar tri-modal pattern, with maximum at ≈DP 15 and two valleys at ≈DP 20 and 45, respectively. Although wheat flour samples differed widely in their prime starch peak viscosity, no significant difference between debranching patterns was obtained. These results indicate that the fine structure of amylopectin might not be responsible for the large differences in prime starch pasting property.     

Relationships Between Some Structures and Functionalities of Starches from Wheat Cultivars Grown in East China

Starches separated from 30 wheat cultivars grown in East China were studied for granule size, amylose content, degree of crystallinity, thermal, pasting, and gel textural properties. Average granule size and amylose content of wheat starches were 15.08–20.8 μm and 29.43–34.19%, respectively. The degree of crystallinity and enthalpy of gelatinization of samples was 29.54–42.12% and 5.2–9.95 J/g, respectively. The gelatinization temperature and pasting temperature were 59.45–62.2°C and 75.40–83.95°C, respectively. There was a wide range of gel hardness values (208.5–426 g). Various significant correlations between functionality and structural parameters were observed. Highly positive correlations were found between the gelatinization temperatures. Gelatinization peak temperature was significantly correlated to hardness of starch gels (r = –0.374, P < 0.05). Significant correlations were observed between amylose content and breakdown viscosity (r = –0.483, P < 0.01), hardness (r = 0.373, P < 0.05), and cohesiveness (r = 0.378, P < 0.05). Many significant correlations between the various pasting parameters were observed. The average granule size was positively correlated to peak viscosity, trough viscosity, and final viscosity (r = 0.369, 0.381, and 0.398, respectively, P < 0.05).     

Comparison of Flour Starch Properties in Half‐Sib Families of Opaque‐2 Maize (Zea mays L.) from Argentina

Since the discovery of the o2 mutation in maize, many studies have reported the characterization of the protein quality of opaque‐2 genotypes. However, few have reported the properties of their starch. The objective of this study was to characterize flour starch properties of 12 half‐sib families of opaque‐2 maize from Argentina. Chemical composition and thermal and pasting properties of whole grain flour were determined. Nonopaque genotypes were used as a control. Starch content of opaque‐2 genotypes did not show significant differences compared with nonopaque genotypes, yet amylose content was significantly lower. A high variability in pasting and thermal properties was observed in genotypes. Opaque samples showed a significantly higher peak viscosity and a lower pasting temperature compared with nonopaque samples, probably owing to larger and less compact starch granules in the floury endosperm. The higher the gelatinization enthalpy of opaque‐2 genotypes was, the lower the amylose content in relation to nonopaque varieties. Two retrogradation endotherms were observed in DSC analysis: one corresponding to amylopectin crystallization and the other to melting of amylose‐lipid complex. Both enthalpies were considered total starch retrogradation (ΔH _RT). A wide range of variation was obtained in ΔH _RT in opaque‐2 genotypes, but no significant differences between opaque and nonopaque genotypes were observed. The differences in starch properties found in this study would make it possible to identify opaque‐2 families with particular characteristics for the development of starchy food items adapted to specific processing traits.     

Sources of Variation for Starch Gelatinization,Pasting, and Gelation Properties in Wheat

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.     

Significance of Starch Properties and Quantity on Sponge Cake Volume

We evaluated the qualitative and quantitative effects of wheat starch on sponge cake (SC) baking quality. Twenty wheat flours, including soft white and club wheat of normal, partial waxy, and waxy endosperm, as well as hard wheat, were tested for amylose content, pasting properties, and SC baking quality. Starches isolated from wheat flours of normal, single‐null partial waxy, double‐null partial waxy, and waxy endosperm were also tested for pasting properties and baked into SC. Double‐null partial waxy and waxy wheat flours produced SC with volume of 828–895 mL, whereas volume of SC baked from normal and single‐null partial waxy wheat flours ranged from 1,093 to 1,335 mL. The amylose content of soft white and club wheat flour was positively related to the volume of SC (r = 0.790, P < 0.001). Pasting temperature, peak viscosity, final viscosity, breakdown, and setback also showed significant relationships with SC volume. Normal and waxy starch blends having amylose contents of 25, 20, 15, and 10% produced SCs with volume of 1,570, 1,435, 1,385, and 1,185 mL, respectively. At least 70 g of starch or at least 75% starch in 100 g of starch–gluten blend in replacement of 100 g of wheat flour in the SC baking formula was needed to produce SC having the maximum volume potential. Starch properties including amylose content and pasting properties as well as proportion of starch evidently play significant roles in SC baking quality of wheat flour.     

Contribution of Wheat Flour Fractions to Peak Hot Paste Viscosity

The quality of many baked products, noodles, gravies, and thickeners is related to the pasting properties of wheat (Triticum aestivum L.) flour, yet different flours vary markedly in their pasting performance. The objective of the present research was to assess the role of the wheat flour fractions, gluten, water solubles, prime and tailing starches, in the contribution to peak hot paste viscosity among three selected wheat cultivars. Straight-grade flours were fractionated and reconstituted. Fractions were examined independently and were deleted in otherwise fully reconstituted flours. Fractions were exchanged between cultivars for reconstituting flours, and fractions were substituted individually into a common starch base. The flours from the cultivars Klasic, McKay, and Madsen differed markedly in their peak hot paste viscosities, and were fractionated and reconstituted with only a small effect on paste viscosity. Results clearly showed that prime starch was the primary determinate of flour paste viscosity, but the other fractions all exerted a significant effect. Tailing starch increased paste viscosity directly due to pasting capacity of starch or indirectly through competition for water. Gluten also increased paste viscosity through competition for water. The water-soluble fraction from different cultivar flours was more variable in effect.     

不同品种甘薯淀粉组分、物化及粉条品质的比较研究

为探讨不同品种甘薯淀粉特性与其粉条品质的关系,本研究选用济薯25、济薯26以及商薯19共3个品种于丘陵山地进行试验,收获后进行块根干物质含量、产量测定以及淀粉分离,分析淀粉组分、老化和糊化特性,并对粉条品质进行测定.结果表明,济薯25的薯千产量显著高于其他2个品种(P＜0.05),且3个品种的淀粉结晶结构、形态相似.3...     

Increase in Apparent Amylose Content and Change in Starch Pasting Properties at Cool Growth Temperatures in Mutant Wheat

Some mutant wheat lines with low‐amylose content were grown in a field and greenhouse (15 or 20°C) to compare apparent amylose content and starch pasting properties. The apparent amylose content of flour and starch increased and starch pasting parameters as measured by a Rapid Visco Analyser (RVA) changed in the greenhouse (at cool temperatures) during seed maturation. Densitometric analysis of the protein band separated by electrophoresis suggested that the increase in amylose content by cool temperature was related to the amount of Wx‐D1 protein. This data suggests that the Wx‐D1 gene was responsible for these changes. In wheat starch from Tanikei A6099 and Tanikei A6598 at 15°C, the value of final viscosity and total setback was higher than that from the field. In wheat starch from Tanikei A6599‐4 (waxy mutant with stable hot paste viscosity), the peak viscosity temperature was higher and time maintained >80% of the peak was shorter at 15°C than that from the field. Genetic analysis using doubled‐haploid (DH) lines from a combination of Tanikei A6599‐4 and Kanto 118 (low‐amylose line) showed that apparent amylose content increased and the starch pasting curve and properties changed in waxy progenies similar to Tanikei A6599‐4.     

Quality Characteristics of Yellow Alkaline Noodles Enriched with Hull‐less Barley Flour

Roller milled flours from eight genotypes of hull‐less barley (HB) with normal, waxy, zero amylose waxy (ZAW), and high amylose (HA) starch were incorporated at 20 and 40% (w/w) with a 60% extraction Canada Prairie Spring White (CPSW, cv. AC Vista) wheat flour to evaluate their suitability as a blend for yellow alkaline noodles (YAN). The barley flour supplemented noodles were prepared using conventional equipment. Noodles containing 40% HB flour required less work input than the corresponding 20% blend noodles due to a higher water absorption at the elevated level of HB flour addition, which probably caused them to soften. The addition of any HB flour at either level to the CPSW flour resulted in significantly decreased brightness (L*) and yellowness (b*), elevated redness (a*), concomitant with a significantly greater number of specks per unit area of noodle sheet compared with the control flour. The addition of 40% HB flour to YAN decreased cook time and cooking losses. Noodle firmness, as determined by maximum cutting stress (MCS), was significantly increased by the addition of 40% HB flour. Noodle chewiness, as determined by the texture profile analysis (TPA), was affected by the type of starch in the barley samples; the addition of waxy and ZAW HB flour decreased chewiness, whereas normal and HA HB flour increased chewiness of composite noodles.     

Production of Bihon-type Noodles from Maize Starch Differing in Amylose Content

Maize starches extracted from selected maize cultivars with 0.2–60.8% amylose contents were used to produce bihon-type noodles. Starch dough using a pregelatinized starch binder was prepared and extruded through a laboratory-scale extruder simulating the traditional process of making bihon in the Philippines. The normal maize starches with amylose content of ≈28% were successfully used for bihon-type noodle production, but waxy maize starches with 0.2–3.8% amylose content and high-amylose maize starches with 40.0–60.8% amylose content failed to produce bihon-type noodles. Viscoamylograph profile parameters and swelling volume are significantly correlated to amylose content of maize starch samples evaluated. These physicochemical properties may be used to indicate that the starch samples at normal amylose levels may be used for bihon-type noodles. Starch noodles produced in the laboratory were not significantly different in terms of either cooking quality or textural properties from two commercially produced maize noodle samples, except for adhesiveness. The laboratory process and fabricated extruder can be used to produce bihon-type noodles.     

Evaluation of Starch Properties of Wheats Used for Chinese Yellow-Alkaline Noodles in Japan

The objective of the present research was to assess the functional properties of the starches isolated from Australian prime hard wheat (PH) and hard red winter wheat (HRW) in the United States. These wheats are favorably used in Japan for the production of Chinese yellow-alkaline noodles (YAN). Starches isolated from PH showed higher amylose content than those of noodle wheat but lower than bread wheat. Analysis of swelling power showed that PH starch had lower values than noodle wheat starches but higher values than bread wheat starches. By contrast, HRW starch showed relatively higher amylose content and lower swelling power. There were large differences in the starch pasting properties between PH and HRW. High-performance size-exclusion chromatography studies on the components leached from the starch (80°C, 20 min) showed that PH starch had a somewhat characteristic leaching profile. Its peak ratio of high molecular weight region to low molecular weight region was greater than that of HRW starch. PH starch also characterized by having lower endothermal enthalpy (ΔH) in amylose-lipid transition. The eating quality assessment for YAN revealed that PH had more elastic texture than HRW. Additional reconstitution studies showed that these quality differences could be attributable to its starch properties.     

Flour Particle Size,Starch Damage,and Alkali Reagent: Impact on Uniaxial Stress Relaxation Parameters of Yellow Alkaline Noodles

Three patent flours, each possessing three different levels of starch damage were prepared from a single hard white spring wheat. Each flour was sieved to yield three flours with different particle size distributions (85–110, 110–132, 132–183 μm). Raw alkaline noodles were prepared from the nine flours using either 1% w/w kansui (sodium and potassium carbonates in 9:1 ratio) or 1% w/w sodium hydroxide. Uniaxial stress relaxation parameters percent stress relaxation (SR%), initial rate of relaxation (k₁) and the extent of relaxation (k₂) were measured on the raw noodles immediately after production (t = 0 min) and at 60 min. Raw noodles after resting for 60 min were optimally cooked and stress relaxation parameters were measured. Raw noodles at t = 0 min exhibited SR%, k₁, and k₂ that were significantly (P < 0.0001) influenced by both the degree of starch damage and the type of alkaline reagent used. Flour particle size only influenced SR% and k₁ (P < 0.025) but had no impact on k₂. In raw noodles aged for 60 min, both SR% and k₂ were significantly influenced by alkaline reagent, particle size, and starch damage (P < 0.01) while k₁ was only affected by the degree of starch damage (P < 0.0001). Cooked noodle SR parameters were all significantly (P < 0.0001) influenced by alkaline reagent, particle size, and the degree of starch damage. Cooked noodles prepared from starch with low damaged flours within any given particle size range, regardless of the type of alkali employed, yielded the most rheologically elastic‐like (firmer) noodles. Two potential mechanisms by which the degree of starch damage influences noodle elastic like texture are discussed.     

Effects of Added Minerals on Pasting of Partial Waxy Wheat Flour and Starch and on Noodle Making Properties

Mineral content, as determined and expressed by ash content, serves as an index of wheat flour quality for flour millers and food manufacturers who prefer flour of low mineral content, even though the significance of mineral content on the functional properties of wheat flour is not well understood. We explored whether minerals have any influence on the functional properties of wheat flour and product quality of white salted noodles. Ash, obtained by incinerating wheat bran, was incorporated into two hard white spring wheat flours and their starches to raise the total ash content to 1, 1.5, or 2%. Pasting properties were determined using a rapid visco analyzer (RVA). Addition of ash increased the peak viscosity of the flours in both water and buffer solution but did not affect the peak viscosity of starch. Wheat flours with added ash showed lower pasting temperature by approximately 10°C in buffer solution. Mineral extracts (15.3% ash) isolated from wheat bran, when added to increase the ash content of wheat flour and starch to 2%, increased the peak viscosity and lowered the pasting temperature of flour by 13.2–16.3% but did not affect the pasting properties of the isolated starch. The mineral premix also increased peak viscosity of wheat flour but not in starch. Added ash increased noodle thickness and lowered water retention of cooked noodles while it exhibited no significant effect on cooked noodle texture as determined using a texture analyzer.     

Starch Pasting and Textural Attributes of Elbow Macaroni as Impacted by Dough Moisture,Dough Mixing Time,and Macaroni Cooking Time

The effects of dough moisture, mixing time, and cooking time on uncooked and cooked elbow macaroni by means of starch pasting and macaroni textural characteristics were investigated. In conventional elbow macaroni production, cooking time was found to have significant contributions to cooked macaroni starch pasting properties, indicating that degree of starch cook dependent on cooking time was the main influence on cooked macaroni starch pasting phenomena. Dough moisture also showed some significant (P < 0.05) relationships with cooked macaroni starch pasting properties; however, mixing time did not show significant effect. Cooked macaroni starch pasting properties showed significantly (P < 0.05) high correlations with cooked macaroni firmness and stickiness. Cooking time was the only major variable contributing to variations in cooked elbow macaroni starch and consequently in pasting and texture characteristics. Cooking time was highly related to firmness and stickiness of cooked elbow macaroni (P < 0.0001, R² = 0.8148; P < 0.0001, R² = 0.6215, respectively). In addition, dough moisture had a slight significant (P < 0.05) effect on cooked elbow macaroni firmness and stickiness. Cooked elbow macaroni firmness and stickiness were found to be highly correlated (P = 0.0001, R² = 0.8459). Increases in firmness increased cooked elbow macaroni stickiness. As a result, when elbow macaroni was cooked for shorter times, firmer and stickier macaroni was obtained.