Solvent Retention Capacity Profile Research Articles

Prior roasting of wheat impacts on the functionality of flour prepared from it: Part 1. Wheat flour viscosifying properties

AbstractBackground and ObjectivesDry thermal treatment of wheat modifies the properties of wheat and of flour prepared from it. The objective of this study was to investigate the effect of wheat roasting on microstructural properties of wheat grains using confocal laser scanning, X‐ray diffraction (XRD), and scanning electron microscopy (SEM) techniques. The impact of roasting on the damaged starch contents, the solvent retention capacity profiles, and the pasting properties of the resulting flour prepared from roasted wheat were also studied.FindingsResponse surface models predicted wheat roasting at 115°C and 65 Hz (165 s) to enhance flour viscosifying properties. Roasting before milling resulted in grain puffing, slight damage to the starch granule surface, and destruction of the protein matrix, as observed using SEM. XRD analysis revealed that amylose–lipid complexation had occurred. As a result of roasting, the peak, hot paste, and final viscosities of flour from roasted wheat were significantly (p ≤ .05) higher than those of flour produced from control wheat.ConclusionsRoasting induces structural changes in wheat. Flour produced from roasted wheat can be used to produce gel structures with increased viscosities.Significance and NoveltyDry thermal treatment improves the viscosifying properties of flour milled from roasted wheat.

Wheat grain quality changes with water stress, zinc, and iron applications predicted by the solvent retention capacity (SRC)

Due to a lack of assessment tools for large samples, the effects of foliar Zn and Fe applications on grain nutritional and quality traits for wheat genotypes from diverse species and poloidal levels under water-limited conditions are less addressed. With the availability of simple/rapid solvent retention capacity (SRC) tests to assess a large number of samples for grain quality attributes, thirty-five wheat genotypes from 18 different species were field evaluated under four treatments of control, zinc (Zn), iron (Fe), and Zn + Fe foliar applications in two moisture regimes. Grain yield (GY) and thousand kernel weight (TKW) decreased due to water stress, while the grain quality traits including SRC values, flour protein content (FPC), Zn, and Fe content increased. Although diploid species showed higher FPC, grain Zn, and Fe than tetraploid (4x) and hexaploid (6x) species across all treatments, they presented much lower SRC values attributed to protein quality. Zinc application increased SRC profiles for 4x and 6x wheat and alleviated GY and TKW reduction due to water stress. A significant correlation between various grain and flour parameters confirmed the validity of the results and SRC quality predictions.

Effect of saline organic acid solutions applied during soft wheat tempering on microbial load and flour functionality

AbstractBackground and objectivesIn recent years, special concern has been raised about the safety of wheat‐based products. In light of several incidents of foodborne illness associated with flour, the objectives of this study were designed to (a) evaluate the efficacy of saline organic acids solutions to reduce the natural microbiota of soft wheat grain and flour, and (b) to assess the impact of these tempering solutions on the functional properties of soft wheat flour.FindingsThe microbial load of the tempered wheat was significantly reduced by all saline organic acid treatments. The combination of 5.0% lactic acid–NaCl was the most effective against aerobic mesophilic bacteria and Enterobacteriaceae, with average reductions of 3.1 ± 0.1 and 4.5 ± 0.0 log CFU/g, respectively. In addition, this tempering solution yielded flour with a significantly lower microbial load compared with the control. Tempering with saline organic acid solutions did result in minor, but significant, variations in the solvent retention capacity profile of some flours. However, the treatments did not cause significant changes in the pasting profile of flours or in the physical characteristics and texture profile of baked cookies.ConclusionsThe addition of organic acids and NaCl to the tempering water improved the microbiological quality of the wheat grain and the resulting flour without compromising its functionality.Significance and noveltyThis study evaluates the inclusion of antimicrobial agents in the water used to temper wheat grain prior to milling as a practical method to reduce the number of microbial contaminants in flour and flour‐based foods that are at risk for consumption without cooking or any killing step.

Technological performance of various flours obtained through multigrain milling

This study was focused on multigrain flours consisting on wheat-rye-triticale and wheat-rye-hulled oat, obtained by using an experimental Buhler roller mill after blending the cereals at different levels. For all investigated multigrain blends the extraction yield of the first reduction passage was lower compared to wheat. The flour yields at the break roll passages decreased in the flowing order: blends with triticale, wheat and blends with hulled oat. The multigrain milling resulted in increased ash, crude fiber and fat contents, and decreased protein content compared to wheat. The solvent retention capacity profile varied with the type of blend, and important correlations were established with Mixolab parameters, mainly related to starch gelatinisation and breakdown. Texture measurements performed on breads prepared with multigrain flours indicated increased hardness and decreased springiness values with increasing the wheat substitution level. These results might allow better exploitation of different cereals through the efficient milling of multigrain blends. Multigrain milling could be a way to improve the milling quality and performance of some cereals like triticale, hulled oat and hulled barley. Blending these cereals with wheat in different ratio followed by milling with roller mill can result in multigrain flours with different extraction rate and functional profile. Multigrain flours or some mill streams can be used for obtaining particular baked products.

Evaluation of carbohydrate properties and end-use quality of hexaploid triticale and its relationship to solvent retention capacity

Triticale is a competitive grain in foraging, but it has only limited usage in the food industry due to its relatively unfavorable end-use quality. Improvement of carbohydrate characteristics could be an option to partially compensate for its weaker protein quality and to have positive influences on technological properties. In the present study, carbohydrate composition and its relation to baked bread properties of triticale whole meal flour were studied, and utilization of the solvent retention capacity (SRC) method to predict bread-making quality was evaluated. Carbohydrate composition of the analysed triticale genotypes exhibited notable genetic variance with advantageous carbohydrate composition. Many carbohydrate parameters, including damaged starch, total starch, total dietary fiber and sugar concentrations and arabinoxylans levels, influenced the baked bread characteristics and SRC profiles of the triticale. Values for triticale whole meal bread properties were between those of wheat and rye, and triticale genotypes, with bread properties most similar to wheat, showed the same SRC profile as wheat. Therefore, SRC values could be used to predict bread-making quality of triticale genotypes; in particular, based on results of correlation analyses, lactic acid SRC % is a more specific test, for assessing bread-making quality.

Milling, functional and thermo-mechanical properties of wheat, rye, triticale, barley and oat

The milling potential of hulled barley, hulled oat, triticale, rye and wheat was studied using a long tempering process and a laboratory four-roller mill. Regardless of the investigated cereal, the results indicated a significant influence (p < 0.05) of volume per surface area ratio on the milling yield and ash contents of the flour. The lowest milling yield was obtained in case of hulled oat. Solvent retention capacity profiles were determined for all investigated whole cereals and flours for predicting the contribution of different polymers to the functionality of samples. For all solvents higher values were obtained for the whole cereals compared to the corresponding flour. Thermo-mechanical properties of the whole cereals and refined flours were also investigated. If in case of wheat the gluten proteins play an essential role on dough behaviour during kneading at 30 °C, in case of triticale, rye, hulled barley and hulled oat, the fibers play a major role as well. Thermo-mechanical properties of starch registered a large variation between cereals and/or flours. The lowest torque value corresponding to starch gelatinization (C3) was registered in case of the hulled oat flour, 1.92 Nm, while the highest value in case of rye flour, 2.65 Nm.

Influence of jet milling and particle size on the composition, physicochemical and mechanical properties of barley and rye flours

Finer barley and rye flours were produced by jet milling at two feed rates. The effect of reduced particle size on composition and several physicochemical and mechanical properties of all flours were evaluated. Moisture content decreased as the size of the granules decreased. Differences on ash and protein contents were observed. Jet milling increased the amount of damaged starch in both rye and barley flours. True density increased with decreased particle size whereas porosity and bulk density increased. The solvent retention capacity profile was also affected by jet milling. Barley was richer in phenolics and had greater antioxidant activity than rye. Regarding colour, both rye and barley flours when subjected to jet milling became brighter, whereas their yellowness was not altered significantly. The minimum gelation concentration for all flours was 16%w/v. Barley flour gels were stronger, firmer and more elastic than the rye ones.

Evaluation of Hard Red Spring Wheat Mill Stream Fractions Using Solvent Retention Capacity Test

Quality and functionality of flour is dependent on chemical components, including protein, gluten, starch and arabinoxylans. The suitability of solvent retention capacity (SRC) for assessment of hard red spring (HRS) wheat quality was evaluated for mill stream flour samples. The HRS wheat sample was milled using a Buhler mill to produce six different flour streams. Flour samples were analyzed using AACC-I approved methods. The farinograph stability had very highly significant (P < 0.001) correlations with the water SRC (−0.96) and the gluten performance index (GPI) (0.93). There was very highly significant (P < 0.001) correlation between wet gluten content and GPI (0.89). The starch damage showed very highly significant (P < 0.001) correlation with water, sodium carbonate, and sucrose SRCs and GPI. Bread loaf volume had very highly significant (P < 0.001) correlations with GPI (0.83). The results of this study show that SRC may be useful for evaluation of mill streams for their use in targeted end product applications. Practical Applications Solvent retention capacity (SRC) has been implemented as a quality test for soft wheat flour used for making cookies and pastries. The SRC profiles for soft wheat applications have been well established; however, hard red spring (HRS) wheat has unique applications and characteristics. A few studies have been conducted on SRC for hard wheat flour, which have determined that SRC and gluten performance index (GPI) may also be implemented as a quality test for hard wheat flour. More investigation is needed to link appropriate SRC profiles and GPI with HRS wheat end product requirements. Further development of the SRC method would be beneficial to the milling and baking industries for hard wheat flour. The following study is important for determining the usage of the SRC method as a quality assurance measure for millers, specifically to determine quality characteristics of mill stream fractions when blending flour for specific end product applications.

Evaluation of Model Wheat/Hemp Composites

Model cereal blends were prepared from commercial wheat fine flour and 5 samples of hemp flour (HF), including fine (2 of conventional form, 1 of organic form) and wholemeal type (2 of conventional form). Wheat flour was substituted in 4 levels (5, 10, 15, 20%). HF addition has increased protein content independently on tested hemp flour form or type. Partial model cereal blends could be distinguished according to protein quality (Zeleny test values), especially between fine and wholemeal HF type. Both flour types affected also amylolytic activity, for which a relationship between hemp addition and determined level of Falling Number was confirmed for all five model cereal blends. Solvent retention capacity profiles (SRC) of partial models were influenced by both HF form and type, as well as by its addition level. Between both mentioned groups of quality features, significant correlation were proved - relationships among protein content/quality and lactic acid SRC were verifiable on p &lt;0.01 (-0.58, 0.91, respectively). By performed ANOVA, a possibility to distinguish the HF form used in model cereal blend according to the lactic acid SRC and the water SRC was demonstrated. Comparing partial cereal models containing fine and wholemeal hemp type, HF addition level demonstrated its impact on the sodium carbonate SRC and the water acid SRC.

Impact of Heat Treatment on Wheat Flour Solvent Retention Capacity (SRC) Profiles

ABSTRACTThe impact of heat treating wheat flour (for 2 or 5 h at 80 or 100°C) on its functional properties was studied with solvent retention capacity (SRC) tests and related to changes in individual groups of flour constituents. Heat treatments increased the overall water retention capacity (from 55.6% for control flour to 62.4% for flour heated 5 h at 100°C) as well as sucrose SRC (from 85.0 to 113.5%), although no changes were observed in sodium carbonate SRC. The decrease in lactic acid SRC values (from 113.1 to 97.4%) indicated that heat treatment restricted swelling of the protein network. As deduced from a decrease in both the level of proteins extractable in sodium dodecyl sulfate–containing medium and the level of free sulfhydryl groups, the restricted swelling was related to protein cross‐linking within the flour particles. Such upfront polymerization prevented proper hydration and gluten network formation during mixing. Starch (swelling) properties were also affected by heat treatment. Finally, the impact of heat treatment on flour SRC profiles was comparable to that noted when chlorinating wheat flour.

Effect of wheat flour characteristics on sponge cake quality

To select the flour parameters that relate strongly to cake-making performance, in this study the relationship between sponge cake quality, solvent retention capacity (SRC) profile and flour physicochemical characteristics was investigated using 38 soft wheat samples of different origins. Particle size average, protein, damaged starch, water-soluble pentosans, total pentosans, SRC and pasting properties were analysed. Sponge cake volume and crumb texture were measured to evaluate cake quality. Cluster analysis was applied to assess differences in flour quality parameters among wheat lines based on the SRC profile. Cluster 1 showed significantly higher sponge cake volume and crumb softness, finer particle size and lower SRC sucrose, SRC carbonate, SRC water, damaged starch and protein content. Particle size, damaged starch, protein, thickening capacity and SRC parameters correlated negatively with sponge cake volume, while total pentosans and pasting temperature showed the opposite effect. The negative correlations between cake volume and SRC parameters along with the cluster analysis results indicated that flours with smaller particle size, lower absorption capacity and higher pasting temperature had better cake-making performance. Some simple analyses, such as SRC, particle size distribution and pasting properties, may help to choose flours suitable for cake making.

Solvent retention capacity values in relation to the Czech commercial wheat quality

SummaryTechnological quality in the sets of eighty commercial wheat samples was evaluated by grain milling traits (test weight, thousand kernel weight, grain hardness as Particle Size Index, one‐stream flour yield) and common analytical parameters (wet gluten and protein contents, Zeleny test value, falling number) together with the solvent retention capacity (SRC) method (AACC 56‐11). For the commercial wheat, the latter analytical procedure (originally designed for flour quality analysis) was verified also for grain wholemeal. Within the mentioned sample group, anova revealed the strongest effect of the harvest year, both for milling and for technological parameters. For the SRC profiles, the effect of the sample form used dominated the crop year influence. The grain SRCs were correlated with the milling traits foursome, while an agreement between the flour SRC profiles and technological quality data was not so tight. However, the flour lactic acid SRC was associated with the wet gluten and protein contents (r = 0.24, P &lt; 0.05), and the protein quality as Zeleny value with the flour water SRC (r = 0.24, P &lt; 0.05). Relationship between Zeleny's value and flour lactic acid SCR was confirmed by nonlinear Spearman correlation (R = −0.26, P &lt; 0.05).

Suitability of solvent retention capacity tests to assess the cookie and bread making quality of European wheat flours

A solvent retention capacity (SRC) profile of flour consists of its water RC (WRC), sodium carbonate SRC (SCSRC), sucrose SRC (SuSRC) and lactic acid SRC (LASRC) values. SRC tests have been designed to assess flour quality of North American soft wheats, but the value of these tests for European flour which is generally from harder wheats is rather unclear. We here studied the ability of the SRC values to assess the cookie and bread quality of nineteen European commercial flours and compared their predictive value with that of some conventional flour quality parameters. WRC value was a better parameter to assess the cookie diameter than Farinograph or Mixograph water absorption capacities and Alveograph dough tenacity values. In contrast, Zeleny sedimentation values and some rheological data were better to assess bread volume than LASRC values. When LASRC values were corrected for the contribution of non-glutenin polymers, they could assess bread volume to a comparable extent as the Zeleny sedimentation readings. In conclusion, the SRC tests are good alternative tests to assess the cookie and bread quality of European wheat flours. Furthermore, it is not always necessary to determine the entire SRC profile to sufficiently assess flour quality for a specific end-product.

Relative contribution of wheat flour constituents to Solvent Retention Capacity profiles of European wheats

Solvent Retention Capacity (SRC) tests have originally been designed to predict flour functionality of North American wheat flours. A SRC profile consists of its Water Retention Capacity (WRC), Sodium Carbonate SRC (SCSRC), Sucrose SRC (SuSRC) and Lactic Acid SRC (LASRC) values. As the value of such tests when considering European wheat flours is rather unclear, we studied the chemical composition and SRC profiles of nineteen commercial European wheat flours. Their WRC, SCSRC, SuSRC and LASRC ranged from 56 to 66%, 74 to 88%, 90 to 102% and 106 to 147%, respectively. Both WRC and SCSRC were mostly higher than those of North American soft wheat flours, but in the range of those of North American hard wheat flours. For the entire set of European flours, strong linear relations were observed between the flour damaged starch levels and WRC values, as well as with SCSRC values. Modifying specific flour constituent properties and levels illustrated the contribution of proteins, damaged starch and arabinoxylan (AX) to the SRC values. Flour proteins, especially glutenins, mainly contributed to LASRC, while damaged starch largely impacted flour SCSRC. Water-extractable AX only contributed to the SuSRC values, whereas the solvent-accessible AX generally contributed to all SRC values, and particularly to the SuSRC values.

Influence of damaged starch on cookie and bread-making quality

In this study two wheat and one triticale cultivars were milled in a disc mill to obtain different levels of damaged starch. The effects of the damaged starch content on physicochemical flour tests and cookie and bread-making quality were analyzed. The grain milling conditions in disc mill and grain hardness influenced the amount of damaged starch. The solvent absorption of flours, as measured by Solvent Retention Capacity Profile (SRC) and Alkaline Water Retention Capacity (AWRC), was significantly incremented by the damaged starch content. There was a consistent loss in cookie quality as the damaged starch content increased. In spite of the fact that the proteins were not affected by flour milling, bread quality decreased as the damaged starch content increased.

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

ABSTRACTThe 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.

Application of Wheat Meal Solvent Retention Capacity Tests Within Soft Wheat Breeding Populations

ABSTRACTThe solvent retention capacity (SRC) test is a relatively new AACC Approved Method (56‐11) for evaluating soft wheat flour quality. The test measures the ability of flour to retain a set of four solvents (water, 50% sucrose, 5% sodium carbonate, and 5% lactic acid) after centrifugation. The objective of this study was to evaluate the utility of wheat meal sodium carbonate and lactic acid SRC tests and SDS sedimentation volume within three populations of soft spring wheat inbred lines as tools for selecting for improved flour SRC profiles, flour extraction, and cookie and pastry quality. The populations were derived from the crosses Vanna/Penawawa, Kanto 107/IDO488, and M2/IDO470 and were grown in replicated, irrigated trials in 2000 and 2001 near Aberdeen, Idaho. Within each of the three populations, wheat meal sodium carbonate SRC effectively predicted straight‐grade flour sodium carbonate (r = 0.69–0.81) and sucrose SRC (r = 0.74–0.84). Wheat meal sodium carbonate SRC also was negatively correlated with flour extraction and sugar snap cookie diameter. Wheat meal lactic acid SRC predicted straight‐grade flour lactic acid SRC in only one population. In contrast, SDS sedimentation volume predicted straight‐grade flour lactic acid SRC in all three populations (r = 0.74–0.93). Moreover, SDS sedimentation volume and wheat meal sodium carbonate SRC were independent in two of the three populations. This suggests that the SDS sedimentation and sodium carbonate SRC may measure different intrinsic characteristics. Therefore, a combination of sodium carbonate SRC and SDS sedimentation volume analyses of wheat meal may be an efficient approach to selecting toward target SRC profiles, increased flour extraction, and larger sugar snap cookie diameter in soft wheats.

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

ABSTRACTNinety‐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 &lt; 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 &gt; 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.