Relationship Between Soft Wheat Flour Physicochemical Composition and Cookie‐Making Performance

Nowadays in Argentina, cookies, crackers, and cakes are made of flour obtained from bread wheat with additives or enzymes that decrease the gluten strength but increase production costs. The present research work aims to study the relationship between flour physicochemical composition (particle size average [PSA], protein, damaged starch [DS], water soluble pentosans [WSP], total pentosans [TP], and gluten), alkaline water retention capacities behavior, solvent retention capacities profile (SRC) and cookie‐making performance in a set of 51 adapted soft wheat lines with diverse origin to identify better flour parameters for predicting cookie quality. Cookie factor (CF) values were 5.06–7.56. High and significant negative correlations between sucrose SRC (–0.68), water SRC (–0.65), carbonate SRC (–0.59), and CF were found, followed by lactic SRC that presented a low negative but significant correlation (r = –0.35). The flour components DS (r = –0.67), WSP (r = –0.49), and TP (r = –0.4) were negatively associated to CF. PSA showed a negative correlation with CF (r = –0.43). Protein and gluten were the flour components that affected cookie hardness, but no significant correlation were found with pentosan or DS content. A prediction equation for CF was developed. Sucrose SRC, PSA, and DS could be used to predict 68% of the variation in cookie diameter. The cluster analysis was conducted to assess differences in flour quality parameters among genotypes based on CF. Clusters 1 and 4 were typified by lower CF (5.70 and 5.23, respectively), higher DS, pentosan content, and SRC values. Cluster 2 with a relative good CF (6.47) and Cluster 3 with the best cookie quality, high CF (7.32) and low firmness, and the lowest DS, TP, WSP content, and sucrose SRC values.     

Influence of Amylose Content on Cookie and Sponge Cake Quality and Solvent Retention Capacities in Wheat Flour

Reduced amylose wheat (Triticum æstivum L.) produces better quality noodles and bread less prone to going stale, while little is known about the relationships between amylose content and the quality of soft wheat baking products such as sugar snap cookies (SSC) and Japanese sponge cakes (JSC). Near‐isogenic lines developed from wheat cultivar Norin 61, differing in their level of granule‐bound starch synthase (Wx protein) activity, were used to produce wheat grains and ultimately flours of different amylose contents. These were tested with regard to their effect on soft wheat baking quality and solvent retention capacities (SRC). Amylose content was strongly correlated to cookie diameter (r = 0.969, P < 0.001) and cake volume (r = 0.976, P < 0.001), indicating that the soft wheat baking quality associated with SSC diameter and JSC volume were improved by an incremental increases in amylose content. Among the four kinds of SRC tests (water, sodium carbonate, sucrose and lactic acid), the water SRC test showed the highest correlation with amylose content, SSC diameter, and JSC volume. When the regression analysis was conducted between the nonwaxy and partial waxy isogenic lines that are available in commercial markets, only water SRC was significantly correlated to amylose content (r = –0.982, P < 0.001) among of four SRC tests. This suggests that, unlike udon noodle quality, high‐amylose content is indispensable in improving soft wheat baking quality, a process requiring less water retention capacity.     

Pan Bread and Chinese White Salted Noodle Qualities of Chinese Winter Wheat Cultivars and Their Relationship with Gluten Protein Fractions

Improvement of food processing quality has become a major breeding objective in China. Nineteen Chinese leading winter wheat cultivars with improved quality and two Australian cultivars with high bread and noodle-making qualities were sown in four locations for two years to investigate dough properties, pan bread, and Chinese white salted noodle (CWSN) qualities, and their association with the quantity of protein fractions. The results indicated that genotype, environment, and genotype-by-environment interaction significantly affected most of quality traits and amount of protein fractions. Genotype mainly determined the quantity of gluten protein fractions and pan bread quality parameters, while environment was the most important source of variation for the noodle quality parameters. Chinese cultivars were characterized by acceptable protein content (11.1–13.4%), medium to strong dough strength (maximum resistance 176.9–746.5 BU), medium to poor dough extensibility (166.5–216.4 mm), fair to very good pan bread qualities, and good to very good CWSN qualities. Gliadin contributed more in quantity to protein content (r = 0.80, P < 0.001), however, glutenin and its subgroups were more important to dough strength. The quantity of glutenin, HMW-GS, and LMW-GS were highly and significantly correlated with dough strength-related traits such as farinograph development time, stability, extensigraph maximum resistance, and extension area (r = 0.70–0.91, 0.65–0.89, and 0.70–0.91, respectively; P < 0.001). The quantity of LMW-GS could explain 82.8% of the total variation of dough maximum resistance. The quantity of gliadin and the ratio of HMW-GS to LMW-GS determined dough extensibility (r = 0.75 and r = –0.59, respectively; P < 0.001 and P < 0.01, respectively). Higher quantity of glutenin and lower ratio of gliadin to glutenin resulted in higher bread score with r = 0.70 (P < 0.001) and r = –0.74 (P < 0.001), respectively. However, protein content and its fractions have a moderate undesirable effect on CWSN parameters such as color, firmness, and taste. Therefore, both allelic variation and quantity of storage protein fractions should be considered in breeding cultivars with improved pan bread making quality.     

Solvent Retention Capacities of Indian Wheats and Their Relationship with Cookie‐Making Quality

Ninety‐two wheat genotypes including 50 cultivars released in India and 42 germplasm lines were subjected to solvent retention capacity (SRC) tests using 1 g of flour and 1 g of whole meal to see the relationship with cookie‐making quality and the utility in breeding programs. Very high negative correlations (P < 0.001) were observed between cookie diameter and spread factor and alkaline water retention capacity (AWRC), and solvent retention capacities of both flour and whole meal samples. Multiple regression analysis showed that AWRC explained 43.8%, sodium carbonate SRC 27.3%, lactic acid SRC 15.1%, and protein content 13.8% of the total variability (multiple r = 0.87) in cookie diameter. Total variability (multiple r = 0.85) in spread factor was explained 40.3% by AWRC, 27.4% by SODSRC, 14.5% by LASRC, and 17.8% by protein content. When the technique was further used to reduce the number of parameters contributing to cookie diameter, AWRC explained 67.2% of the total variability (multiple r = 0.85) and the rest by lactic acid SRC and protein content. Surprisingly, multiple regression analysis of whole meal samples exhibited that lactic acid SRC and sodium carbonate SRC explained 88 and 12%, respectively, of the total variability (multiple r = 0.76) in cookie diameter and 78 and 22%, respectively, of the total variability (multiple r = 0.71) in spread factor. Among the soft wheat flour samples selected based on W > 7.70 cm, pentosan content as revealed by sucrose SRC explained 87.7% of the total variability (multiple r = 0.54) of cookie diameter and 83.8% of total variability (multiple r = 0.52) in spread factor. Clustering of genotypes based on SRC profiles using both flour and whole meal produced clusters with similar average cookie diameter and spread factor. The data clearly demonstrate that whole meal tests can be used in screening the recombinant lines as well as in selecting desirable genotypes for making crosses to enhance cookie‐making quality.     

Rheological Properties of Wheat Flour Dough and the Relationship with Bread Volume. I. Creep‐Recovery Measurements

The rheological properties of 17 pure European wheat cultivars were analyzed and evaluated in relation to the bread volume. Rheological testing included two empirical rheological methods, farinograph and alveograph, and more fundamental creep‐recovery experiments at shear stresses of 100 and 250 Pa. Principal component analysis on the farinograph and alveograph results showed that a wide range of rheological properties was present among the wheat cultivars. Correlation analysis pointed out that creep‐recovery parameters showed significant correlations with protein content, Zeleny sedimentation value, farinograph water absorption, alveograph extensibility, and bread volume. Among the rheological parameters, maximum recovery strain at a shear stress of 250 Pa showed the highest significant correlation with the bread volume (r = 0.790**). Variables were combined to predict the bread volume by multiple linear regression. A combination of protein content, farinograph water absorption, and alveograph P/L showed the best prediction (r² = 0.80). When taking into account the creep‐recovery parameters, the best prediction of the bread volume (r² = 0.74) was obtained for a combination of the maximum recovery strain at a shear stress of 250 Pa with one other quality parameter (Zeleny sedimentation value, farinograph water absorption, or alveograph W).     

Effect of Growing Environment of Soft Wheats on Amylose Content and Its Relationship with Cookie and Sponge Cake Quality and Solvent Retention Capacity

The effect of growing environments of soft wheat on amylose content and its relationship with baking quality and solvent retention capacities (SRC) was investigated. Near‐isogenic soft wheat lines of Norin 61 differing in granule‐bound starch synthase (Wx protein) activity and grown in three different regions of Japan: Hokkaido (spring‐sown) for 2006 and 2007, Kanto (autumn‐sown), and Kyushu (autumn‐sown) for 2007 were evaluated. Spring‐sown samples produced grains of greater protein content (10.9–12.4%) than autumn‐sown samples (7.3–9.1%). In contrast, spring‐sown samples of 2007 with higher maturing temperature had lower amylose content (25.5% for Norin 61) compare to the autumn‐sown and spring‐sown samples of 2006 (27.6–28.4% for Norin 61). Amylose content was strongly correlated to sugar snap cookie (SSCD) diameter (r = 0.957–0.961; n = 10, all samples; P ≤ 0.001, r = 0.701–0.976; n = 7 partial waxy and nonwaxy samples; and Japanese sponge cake (JSCV) volume r = 0.971–0.993; n = 10; P≤ 0.001, r = 0.764–0.922; n = 7 partial waxy and nonwaxy samples), regardless of seeding season and growing conditions. The strength of the JSVC‐amylose relationship (slope) was similar among the three regions, whereas the strength of the SSCD‐amylose relationship was slightly weaker for spring‐sown samples and slightly stronger for partial waxy and nonwaxy autumn‐sown samples. Among of the four solvents (water, solutions of sodium carbonate, sucrose, or lactic acid), water‐SRC showed the greatest correlation to amylose content (r = –0.969 to –0.996; n = 10; P ≤ 0.001, r = –0.629 to –0.983; n = 7 partial waxy and nonwaxy samples), indicated that amylose content can be accurately estimated from the water‐SRC within the samples from the same grown environment.     

Use of a Rhizosphere-Based Method for the Assessment of Heavy-Metal Bioavailability in Soils Amended with Polluted Sewage Sludge

A rhizosphere-based method (a low-molecular-weight organic acid solution) was evaluated for the assessment of cadmium (Cd), chromium (Cr), and lead (Pb) bioavailability to barley (Hordeum vulgare) roots from rhizosphere soils (n = 36) following a 15.71 g dry weight kg^?1 application of a metal-spiked sewage sludge under greenhouse conditions. Statistically significant correlation coefficients were found: r = 0.758, P < 0.001 for Cd, r = 0.762, P < 0.001 for Cr, and r = 0.723, P < 0.001 for Pb. The correlations were greater in acidic soils (n = 6; r = 0.983, P < 0.001 for Cd, r = 0.888, P < 0.01 for Cr, and r = 0.898, P < 0.01 for Pb). This extraction failed to assess heavy-metal bioavailability in basic soils (n = 30; r = 0.111, P > 0.05 for Cd, r = 0.002, P > 0.05 for Cr, and r = 0.037, P > 0.05 for Pb). The overall predictability was greatly improved when soil properties were considered (n = 36; r² = 0.730, P < 0.001 for Cd, r² = 0.800, P < 0.001 for Cr, and r² = 0.719, P < 0.001 for Pb), and texture was observed in all the prediction models.     

Prediction of Specific Japanese Sponge Cake Volume Using Pasting Properties of Flour

In Japanese soft wheat (Triticum aestivum L.) breeding programs, protein content (PC), and specific surface area (SSA) of flour have been used as important factors for the baking quality of Japanese sponge cake. We proposed batter pasting viscosity (BPV) as a parameter to predict the baking quality of Japanese sponge cake. BPV was measured using a Rapid Visco‐Analyser (RVA) with a modified heating profile. Twenty soft wheat samples from the 2006‐07 season and 22 from the 2007‐08 season, including Japanese soft wheat cultivars, advanced breeders' lines, and Western White (WW) imported from the United States, were milled and evaluated for solvent retention capacity (SRC) values of four solvents, batter pasting properties, flour pasting properties, PC, SSA, and specific cake volume (SCV) to investigate their relationships. BPV was the most strongly correlated of the parameters to SCV (r = –0.90, P < 0.001). Stepwise multiple regression analysis selected BPV and minimum viscosity (MV) of flour pasting as significant independent variables to predict SCV (corrected R² = 0.848). The variability in BPV related to cake batter expansion was highly explained by PC and sucrose SRC (corrected R² = 0.854, P < 0.001). MV was correlated to SSA (r = 0.56, P < 0.001) and might be related to the prevention of sponge cake shrinkage during baking.     

Relationship Between Solvent Retention Capacity and Protein Molecular Weight Distribution,Quality Characteristics,and Breadmaking Functionality of Hard Red Spring Wheat Flour

This research aims to investigate the relationship between the solvent retention capacity (SRC) test and quality assessment of hard red spring (HRS) wheat flour samples obtained from 10 HRS cultivars grown at six locations in North Dakota. The SRC values were significantly (P < 0.05) correlated with flour chemical components (protein, gluten, starch, and damaged starch contents, except arabinoxylan); with farinograph parameters (stability [FST], water absorption, peak time [FPT], and quality number); and with breadmaking parameters (baking water absorption [BWA], bread loaf volume [BLV], and symmetry). Differences in locations and cultivars contributed significantly to variation in quality parameters and SRC values. Suitability of SRC parameters for discriminatory analysis of HRS wheat flour is greatly influenced by molecular weight distribution (MWD) of SDS‐unextractable proteins. SRC parameters, except for sucrose SRC, showed significant (P < 0.01) and positive correlations with high‐molecular‐weight (HMW) polymeric proteins in SDS‐unextractable fractions, whereas only lactic acid SRC exhibited significant (P < 0.01) correlations with low‐molecular‐weight polymeric proteins. HMW polymeric proteins also exhibited positive associations with FPT, FST, BWA, and BLV. The discrepant variation in association of SRC parameters with respect to MWD of SDS‐unextractable proteins could improve segregation of HRS wheat flour samples for quality.     

Association of Barley Kernel Hardness with Physical Grain Traits and Food Processing Parameters

Kernel hardness is not a well‐characterized food quality trait in barley. Unlike wheat, not much is known about the effect of barley kernel hardness on food processing. Ten barley genotypes differing in single kernel characterization system hardness index (SKCS‐HI) (30.1–91.2) of dehulled kernels were used to determine the association of barley HI with other physical grain traits and food processing parameters. Thousand kernel weight (TKW) values of 10 genotypes were 29.7–38.1 g. Values for bulk density of grains were 721.1–758.9 kg/m³. Crease width and depth values were 0.9–1.3 mm and 0.4–0.7 mm, respectively. Barley HI showed no significant association with TKW, bulk density, or kernel crease dimensions. Kernel loss due to pearling after 325 sec of abrasion was 28.8–38.4% and showed significant negative correlation with HI (r = –0.87, P < 0.01). Proportion of barley flour particles >106 μm had values of 34.5–42.0%, and starch damage values were 1.8–4.5% among those 10 barley genotypes. HI showed significant positive correlations with both proportion of barley flour particles >106 μm (r = 0.93, P < 0.01) and starch damage (r = 0.93, P < 0.01). Water imbibition of barley kernels and cooked kernel hardness did not show significant correlation with HI.     

Solvent Retention Capacity Values in Relation to Hard Winter Wheat and Flour Properties and Straight‐Dough Breadmaking Quality

Solvent retention capacity (SRC) was investigated in assessing the end use quality of hard winter wheat (HWW). The four SRC values of 116 HWW flours were determined using 5% lactic acid, 50% sucrose, 5% sodium carbonate, and distilled water. The SRC values were greatly affected by wheat and flour protein contents, and showed significant linear correlations with 1,000‐kernel weight and single kernel weight, size, and hardness. The 5% lactic acid SRC value showed the highest correlation (r = 0.83, P < 0.0001) with straight‐dough bread volume, followed by 50% sucrose, and least by distilled water. We found that the 5% lactic acid SRC value differentiated the quality of protein relating to loaf volume. When we selected a set of flours that had a narrow range of protein content of 12–13% (n = 37) from the 116 flours, flour protein content was not significantly correlated with loaf volume. The 5% lactic acid SRC value, however, showed a significant correlation (r = 0.84, P < 0.0001) with loaf volume. The 5% lactic acid SRC value was significantly correlated with SDS‐sedimentation volume (r = 0.83, P < 0.0001). The SDS‐sedimentation test showed a similar capability to 5% lactic acid SRC, correlating significantly with loaf volume for flours with similar protein content (r = 0.72, P < 0.0001). Prediction models for loaf volume were derived from a series of wheat and flour quality parameters. The inclusion of 5% lactic acid SRC values in the prediction model improved R² = 0.778 and root mean square error (RMSE) of 57.2 from R² = 0.609 and RMSE = 75.6, respectively, from the prediction model developed with the single kernel characterization system (SKCS) and near‐infrared reflectance (NIR) spectroscopy data. The prediction models were tested with three validation sets with different protein ranges and confirmed that the 5% lactic acid SRC test is valuable in predicting the loaf volume of bread from a HWW flour, especially for flours with similar protein contents.     

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).     

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.     

Responses of phosphatases and arylsulfatase in soils to liming and tillage systems

This study was carried out to investigate the long‐term influence of lime application and tillage systems (no‐till, ridge‐till, and chisel plow) on the activities of phosphatases and arylsulfatase in soils at four research sites in Iowa, USA. The activities of the following enzymes were studied: acid and alkaline phosphatases, phosphodiesterase, and arylsulfatase at their optimal pH values. With the exception of acid phosphatase, which was significantly (P < 0.001) but negatively correlated with soil pH (r ranged from –0.65** to –0.98***), the activities of other enzymes were significantly (P < 0.001) and positively correlated with soil pH, with r values ranging from 0.65** to 0.99*** for alkaline phosphatase, from 0.79*** to 0.97*** for phosphodiesterase, and from 0.66*** to 0.97*** for arylsulfatase. The Δ activity/Δ pH values were calculated to determine the sensitivity of each enzyme to changes in soil pH. Acid phosphatase was the most sensitive and arylsulfatase the least sensitive to changes in soil pH. Activities of the enzymes were greater in the 0 – 5 cm depth samples than those in 0 – 15 cm samples under no‐till treatment. With the exception of acid phosphatase, enzyme activities were mostly significantly (P < 0.001) and positively correlated with microbial biomass C (C_mic), with r values ranging from 0.28 (not significant) to 0.83*** and with microbial biomass N (N_mic), with r values ranging from 0.31 (not significant) to 0.94***. Liming and tillage systems significantly affected the activities of some enzymes but not others, as was evident from the specific activity values (g of p‐nitrophenol released kg^–1 C_org h^–1).     

Use of Solvent Retention Capacity Profile to Predict the Quality of Triticale Flours

The solvent retention capacity test (SRC) was used to evaluate flour functionality for end use applications and select wheat for production of flour with required functionality, but there is little information about SRC test application on triticale flour quality. The ability of flour to retain a set of four solvents produces a flour quality profile for predicting bakery performance. The objective of this study was to evaluate the capacity of SRC and its micro test to determine the potential quality of 25 triticale flours, as well as studying the relationship between the SRC parameters and flour chemical composition. The SRC parameters of triticale flours were correlated with the flour components that have been proposed by the method: sucrose SRC‐pentosan (r = 0.57), carbonate SRC‐damaged starch (r = 0.80), lactic SRC‐glutelin (r = 0.42), water SRC‐all hydrophilic constituents (damaged starch [r = 0.72], protein [r = 0.61], glutelin [r = 0.66], pentosan [r = 0.46]). Triticale flours have shown higher water and sodium carbonate SRC, similar sucrose SRC, and lower lactic SRC values than published results of typical flours used for cookie production. Summarizing, the high level of association found between SRC and micro SRC parameters with flour composition and quality flour tests evidence that either the SRC profile or the micro test SRC could be used to determine the potential quality of triticale flours.     

Enzymic involvement in the biogeochemical responses of a Welsh peatland to a rainfall enhancement manipulation

 Microbial enzyme activities were followed during a field-based experimental simulation of the effects of higher rainfall in a Welsh peatland. The treatment did not significantly affect the activities of the carbon cycling enzymes, β-glucosidase, esterase or xylosidase. In contrast, the activity of the enzyme sulphatase decreased by 44% (P<0.001) in response to the wetter conditions. The manipulation suggests that should climate change cause conditions to become wetter in peatlands, then (with the exception of sulphatase) current levels of wetness may be sufficient to limit decomposition processes, and thus any further increase in wetness is unlikely to induce a further decrease in decomposition rates. Correlations were found between the esterase activity and both nitrous oxide flux (r=–0.44, P<0.05), and methane release (r=0.53, P<0.01). Likewise, there was a correlation between xylosidase activity and both carbon dioxide emission (r=0.52, P<0.01) and aluminium concentration (r=0.58, P<0.01). All of the enzymes correlated positively with dissolved organic carbon (range r=0.53, P<0.01 sulphatase to r=0.61, P<0.001 glucosidase). Together, the correlations lend support to recent hypotheses suggesting that enzymes exert an influence over wetland biogeochemical properties. Received: 29 May 1997     

Use of Elongational Viscosity to Estimate Cookie Diameter

Cookie diameter is a function of spread rate and set time during baking. Dough viscosity appears to control cookie spread rate and, thus, will affect final cookie diameter. The technique of lubricated uniaxial compression was used to measure the elongational viscosity of cookie dough. Full-formula cookie doughs made with a commercial hard wheat flour had a significantly higher elongational viscosity (5.88 × 10⁶ ± 9.17 × 10⁴ Pa·S) than cookie doughs made with a commercial soft wheat flour (2.17 × 10⁶ ± 1.05 × 10⁴ Pa·S). Elongational viscosity correlated significantly (P < 0.05) with the diameter (r = -0.796) of cookies made with flours from various soft wheat cultivars. Using a simplified cookie formula decreased the testing time without greatly changing the correlation coefficient (r = -0.738). Thus, lubricated uniaxial compression appears to be an appropriate technique to measure the viscosity of cookie doughs and may be useful for predicting the cookie baking quality of soft wheat flours.     

Levels of Protein and Protein Composition in Hard Winter Wheat Flours and the Relationship to Breadmaking

Protein and protein fractions were measured in 49 hard winter wheat flours to investigate their relationship to breadmaking properties, particularly loaf volume, which varied from 760 to 1,055 cm³ and crumb grain score of 1.0–5.0 from 100 g of flour straight‐dough bread. Protein composition varied with flour protein content because total soluble protein (SP) and gliadin levels increased proportionally to increased protein content, but albumins and globulins (AG), soluble polymeric proteins (SPP), and insoluble polymeric protein (IPP) levels did not. Flour protein content was positively correlated with loaf volume and bake water absorption (r = 0.80, P < 0.0001 and r = 0.45, P < 0.01, respectively). The percent SP based on flour showed the highest correlation with loaf volume (r = 0.85) and low but significant correlation with crumb grain score (r = 0.35, P < 0.05). Percent gliadins based on flour and on protein content were positively correlated to loaf volume (r = 0.73, P < 0.0001 and r = 0.46, P < 0.001, respectively). The percent IPP based on flour was the only protein fraction that was highly correlated (r = 0.62, P < 0.0001) with bake water absorption followed by AG in flour (r = 0.30, P < 0.05). Bake mix time was correlated positively with percent IPP based on protein (r = 0.86) but negatively with percent SPP based on protein (r = ‐0.56, P < 0.0001).     

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.     

Modified Dough Preparation for Alveograph Analysis with Limited Flour Sample Size

Dough rheological characteristics obtained by alveograph testing, such as extensibility and resistance to extension, are important traits for determination of wheat and flour quality. A challenging issue that faces wheat breeding programs and some wheat research projects is the relatively large flour sample size of 250 g required for the standard alveograph method (AACCI Approved Method 54‐30.02). A modified dough preparation procedure for a small flour sample size was developed for the alveograph test method. A dough was prepared by mixing 80 g of flour with 60% water absorption (2.5% salt solution) for 4 min in a 100 g pin mixer; it was then sheeted and cut into three patties of defined thickness. Data generated by the modified dough preparation method were significantly correlated with the results from the approved alveograph method. The correlation coefficients (r) for each of six alveograph dough characteristics of 40 different advanced breeding lines and wheat varieties were 0.92 for P (mm H₂O), 0.73 for L (mm), 0.83 for W (10^–4 J), 0.90 for P/L, 0.90 for le (%), and 0.76 for G. The modified dough preparation was easier and more convenient than the approved method, and test time for the modified dough preparation was shorter by 20–25 min. This modified dough preparation procedure for the alveograph may be useful for wheat breeding programs as well as an alternative to the approved alveograph method for milling and baking industries and wheat quality research.