The role of gluten in a sugar-snap cookie system: A model approach based on gluten–starch blends

The cookie making properties of dough made from blends of commercial wheat starch and gluten were determined. Higher gluten levels decreased dough piece weight, its density, stickiness and hardness. The largest spread was obtained when no gluten was added. However, this resulted in cookies of unacceptable structure. Higher gluten contents increased spread onset time, decreased cookie spread but generally had little impact on set time while additional water lowered spread onset time and likewise had no statistically significant impact on set time. The results showed that the final cookie diameter is quite dependent on the spread onset time which itself depends on the amount of water available to the non-gluten constituents in the system. Size-exclusion high performance liquid chromatography showed that during baking, proteins aggregated. This indicated that during the process the added gluten acquired the necessary mobility for interaction. However, because increasing levels of gluten increasingly decreased the relative level of water available to itself, and because the set time, and, hence, the set temperature, did not depend on the gluten level, we concluded that cookie dough setting was not determined by an ‘apparent’ glass transition. Furthermore, more protein aggregation went hand in hand with less spread.     

The role of gluten in a sugar-snap cookie system: A model approach based on gluten–starch blends

The cookie making properties of dough made from blends of commercial wheat starch and gluten were determined. Higher gluten levels decreased dough piece weight, its density, stickiness and hardness. The largest spread was obtained when no gluten was added. However, this resulted in cookies of unacceptable structure. Higher gluten contents increased spread onset time, decreased cookie spread but generally had little impact on set time while additional water lowered spread onset time and likewise had no statistically significant impact on set time. The results showed that the final cookie diameter is quite dependent on the spread onset time which itself depends on the amount of water available to the non-gluten constituents in the system. Size-exclusion high performance liquid chromatography showed that during baking, proteins aggregated. This indicated that during the process the added gluten acquired the necessary mobility for interaction. However, because increasing levels of gluten increasingly decreased the relative level of water available to itself, and because the set time, and, hence, the set temperature, did not depend on the gluten level, we concluded that cookie dough setting was not determined by an ‘apparent’ glass transition. Furthermore, more protein aggregation went hand in hand with less spread.     

Properties of sugar-snap cookies as influenced by lauric-based shortenings

The objective of this work was to assess the effect of different lauric-based shortenings with varying solid fat content (SFC) on sugar-snap cookie dough properties and cookie quality. Shortenings were produced by blending high oleic sunflower oil, palm kernel oil and palm stearin in different ratios, obtaining shortenings with different SFCs. It was observed that the SFC of the shortening largely influences the rheological properties of the cookie dough. At small deformations, fat crystals add elasticity to the dough; while at large deformations, fat-structure is disrupted, and it does not contribute to dough hardness. Fats with intermediate SFCs decrease dough resistance due to an enhanced shortening ability. Nevertheless, this effect is only obtained when shortening is homogeneously distributed in the dough. The SFC of the shortening influences dough and cookie structure by preventing gluten polymerization which was observed by a decrease in cookie break strength. A prerequisite for this effect is that shortening is finely dispersed in the dough. Good quality cookies were obtained using lauric-based shortenings, and best results were obtained with SFC between 20 and 25%. Higher SFC (around 45–50%) led to the production of unacceptable sugar-snap cookies.     

Influence of reducing agents on properties of thermo-molded wheat gluten bioplastics

The present work aims to study the influence of reducing agents of sodium bisulfite, sodium sulfite and thioglycolic acid on the equibiaxial extensional deformation of glycerol plasticized wheat gluten and the properties of gluten bioplastics thermo-molded at 125 °C. Moisture absorption, weight loss and water uptake, uniaxial tensile properties (Young's modulus, tensile strength, elongation at break and tensile set), and morphology observations were performed to characterize the physical properties of the thermo-molded gluten bioplastics. The results showed that reducing agents facilitated the viscous flow and restrained the elastic recovery of the plasticized gluten while not hindering the crosslinking reaction of gluten proteins during thermo-molding. On the contrary, reducing agents do not significantly influence moisture absorption, Young's modulus, tensile strength and the morphology of the gluten bioplastics thermo-molded at 125 °C. It is shown that reducing agents are highly effective for tailoring the flow viscosity of the plasticized gluten dough and the mechanical properties of thermo-molded gluten bioplastics.     

Influence of reducing agents on properties of thermo-molded wheat gluten bioplastics

The present work aims to study the influence of reducing agents of sodium bisulfite, sodium sulfite and thioglycolic acid on the equibiaxial extensional deformation of glycerol plasticized wheat gluten and the properties of gluten bioplastics thermo-molded at 125 °C. Moisture absorption, weight loss and water uptake, uniaxial tensile properties (Young's modulus, tensile strength, elongation at break and tensile set), and morphology observations were performed to characterize the physical properties of the thermo-molded gluten bioplastics. The results showed that reducing agents facilitated the viscous flow and restrained the elastic recovery of the plasticized gluten while not hindering the crosslinking reaction of gluten proteins during thermo-molding. On the contrary, reducing agents do not significantly influence moisture absorption, Young's modulus, tensile strength and the morphology of the gluten bioplastics thermo-molded at 125 °C. It is shown that reducing agents are highly effective for tailoring the flow viscosity of the plasticized gluten dough and the mechanical properties of thermo-molded gluten bioplastics.     

Significance of furosine as heat-induced marker in cookies

The effects of recipe formulation in terms of leavening agents (ammonium and sodium bicarbonates), sugars (sucrose and glucose), initial moisture content, and baking conditions (temperature and time) on furosine formation in cookies were studied. The cookies were baked at different temperatures for different times to monitor the progress of the early stage of the Maillard reaction. Change in furosine levels as an indicator of the Amadori products showed a typical kinetic behavior with a rapid increase to an apparent maximum followed by exponential decrease during baking. Initial water activity of cookie dough had no remarkable effect on the apparent maximum, but lowering the water activity decreased the time required to attain it. In addition, levels of furosine in the final product are highly correlated to the initial water content of dough at the same baking conditions. The levels of furosine attained were significantly lower in cookies composed of sucrose than in cookies composed of glucose. Early stage of the MR is rapidly overcome during baking as the Amadori product degraded in the advanced stage. Among the leavening agents, ammonium bicarbonate was the most effective for the progress of the Maillard reaction in cookies during baking.     

Significance of furosine as heat-induced marker in cookies

The effects of recipe formulation in terms of leavening agents (ammonium and sodium bicarbonates), sugars (sucrose and glucose), initial moisture content, and baking conditions (temperature and time) on furosine formation in cookies were studied. The cookies were baked at different temperatures for different times to monitor the progress of the early stage of the Maillard reaction. Change in furosine levels as an indicator of the Amadori products showed a typical kinetic behavior with a rapid increase to an apparent maximum followed by exponential decrease during baking. Initial water activity of cookie dough had no remarkable effect on the apparent maximum, but lowering the water activity decreased the time required to attain it. In addition, levels of furosine in the final product are highly correlated to the initial water content of dough at the same baking conditions. The levels of furosine attained were significantly lower in cookies composed of sucrose than in cookies composed of glucose. Early stage of the MR is rapidly overcome during baking as the Amadori product degraded in the advanced stage. Among the leavening agents, ammonium bicarbonate was the most effective for the progress of the Maillard reaction in cookies during baking.     

Phytate negatively influences wheat dough and bread characteristics by interfering with cross-linking of glutenin molecules

The influence of added phytate on dough properties and bread baking quality was studied to determine the role of phytate in the impaired functional properties of whole grain wheat flour for baking bread. Phytate addition to refined flour at a 1% level substantially increased mixograph mixing time, generally increased mixograph water absorption, and reduced the SDS-unextractable protein content of dough before and after fermentation as well as the loaf volume of bread. The added phytate also shifted unextractable glutenins toward a lower molecular weight form and increased the iron-chelating activity of dough. It appears that phytate negatively affects gluten development and loaf volume by chelating iron and/or binding glutenins, and consequently interfering with the oxidative cross-linking of glutenin molecules during dough mixing. Phytate could be at least partially responsible for the weak gluten network and decreased loaf volume of whole wheat flour bread as compared to refined flour bread.     

A new lean no time test baking method with improved discriminating power

In response to customer concerns related to gluten strength in commercial baking, the Canadian Grain Commission assessed whether the Canadian Short Process (CSP) test bake method was generating useful data related to intrinsic strength of wheat varieties. Assessment of CSP loaf volume data for Canadian variety trials spanning 2003 to 2013 showed very little correlation with dough strength parameters as measured by farinograph and extensigraph. A lean no time (LNT) test baking method was developed that can better discriminate genotypes and provide objective indicators of the effect of intrinsic dough strength on baking quality. From early method development, through method validation and verification using diverse sets of samples targeting different Canadian wheat classes and grown in three different crop years, results showed the LNT method to be more discriminating and easily adopted by other laboratories. In 2015, the LNT method was adopted as the method of choice in future Canadian variety registration trials. The LNT method is fast, simple and well-suited to high throughput test baking conditions encountered in the evaluation of large numbers of breeder lines. A new objective parameter, loaf top ratio, was also introduced and found to correlate well with dough strength and dough handling properties.     

A new lean no time test baking method with improved discriminating power

In response to customer concerns related to gluten strength in commercial baking, the Canadian Grain Commission assessed whether the Canadian Short Process (CSP) test bake method was generating useful data related to intrinsic strength of wheat varieties. Assessment of CSP loaf volume data for Canadian variety trials spanning 2003 to 2013 showed very little correlation with dough strength parameters as measured by farinograph and extensigraph. A lean no time (LNT) test baking method was developed that can better discriminate genotypes and provide objective indicators of the effect of intrinsic dough strength on baking quality. From early method development, through method validation and verification using diverse sets of samples targeting different Canadian wheat classes and grown in three different crop years, results showed the LNT method to be more discriminating and easily adopted by other laboratories. In 2015, the LNT method was adopted as the method of choice in future Canadian variety registration trials. The LNT method is fast, simple and well-suited to high throughput test baking conditions encountered in the evaluation of large numbers of breeder lines. A new objective parameter, loaf top ratio, was also introduced and found to correlate well with dough strength and dough handling properties.     

Suitability of full fat and defatted rice bran obtained from Indian rice for use in food products

The effect of blending different types of rice bran in wheat flour on the rheological, pasting and baking properties is reported. Dough development time and strength as measured through farinograph decreased with the blending of unstabilized full fat and defatted bran; whereas, blending of stabilized fullfat and defatted bran improved the dough strength. Pasting properties revealed an increase in gelatinization temperature and decrease in paste viscosities and set-back values with the blending of various types of rice bran. Bread volume and cookie spread decreased with blending of different types of rice bran; however, the decrease was more pronounced with the defatted bran. Muffin volume improved with the blending of rice bran. Stabilized fullfat rice bran up to 20% level and unstabilized fullfat or stabilized defatted rice bran up to 10% was found suitable in various food products.     

The impact of redox agents on further dough development,relaxation and elastic recoil during lamination and fermentation of multi-layered pastry dough

The role of gluten proteins during lamination and fermentation of multi-layered wheat flour pastry dough was examined by including oxidizing or reducing agents in the recipe to respectively strengthen or weaken the gluten protein network. Pastry burst rig textural measurements showed that dough strength increases during lamination up to 16 fat layers. However, further lamination up to 64 and 128 fat layers decreases the dough strength, most likely due to destruction of layer integrity. Redox agents strongly affect dough strength. Furthermore, fermentation and spread tests showed that they strongly influence elastic recoil immediately after lamination and during relaxation. Moreover, elastic recoil consistently occurs to a greater extent in the final direction of sheeting. None of the observed changes in dough strength and relaxation behaviour could be linked to changes in the levels of protein extractable in sodium dodecyl sulfate containing medium (SDS-EP). This suggests that changes occur preferentially either within the SDS-extractable or within the non-SDS-EP fraction and that they do not render non-extractable protein fractions extractable or vice versa. Furthermore, elastic recoil is most likely caused by reformation of inter- and intramolecular hydrogen bonds and hydrophobic interactions.     

Effect of sodium chloride on gluten network formation,dough microstructure and rheology in relation to breadmaking

Sodium chloride (NaCl) is an essential ingredient to control the functional properties of wheat dough and bread quality. This study investigated the effect of NaCl at 0, 1 and 2%, (w/w, flour base) on the gluten network formation during dough development, the dough rheology, and the baking characteristics of two commercial flours containing different levels of protein (9.0 and 13.5%) and with different glutenin-to-gliadin ratios. Examination of the dough structure by confocal microscopy at different stages of mixing show that the gluten network formation was delayed and the formation of elongated fibril protein structure at the end of dough development when NaCl was used. The fibril structure of protein influenced the dough strength, as determined by strain hardening coefficient and hardening index obtained from the large deformation extension measurements. NaCl had a greater effect on enhancing the strength of dough prepared from the low protein flour compared to those from the high protein flour. The effect of NaCl on loaf volume and crumb structure of bread followed a similar trend. These results indicate that the effect of NaCl on dough strength and bread quality may be partially compensated by choosing flour with an appropriate amount and quality of gluten protein.     

Rheological properties of kafirin and zein prolamins

The possibility of forming dough from kafirin was investigated and laboratory prepared kafirin was formed into a viscoelastic dough system. Measurements with Contraction Flow showed that dough systems prepared from kafirin and from commercial zein had the required extensional rheological properties for baking of leavened bread. The extensional viscosity and strain hardening of the kafirin and zein dough systems were similar to those of gluten and wheat flour doughs. The kafirin dough system, however, unlike the zein dough system rapidly became very stiff. The stiffening behaviour of the kafirin dough system was presumed to be caused by cross-linking of kafirin monomers. SDS-PAGE showed that the kafirin essentially only contained α- and γ-kafirin, whereas the zein essentially only contained α-zein. Since γ-kafirin contains more cysteine residues than the α-prolamin it is more likely to form disulphide cross-links, which probably caused the differences in stiffening behaviour between kafirin and zein dough systems. Overall the kafirin dough system displayed rheological properties sufficient for baking of porous bread. Kafirin like zein appears to have promising properties for making non-gluten leavened doughs.     

施氮量对强筋小麦产量、氮素利用率和品质的影响

为探明协同提高强筋小麦产量、氮素利用率和品质的施氮量,以强筋小麦品种济麦20（中穗型）和洲元9369（大穗型）为材料, 研究了180、240和300 kg·hm^-2三个氮肥水平（分别用N180、N240和N300表示）对强筋小麦产量、氮素利用率、品质及其相关指标的影响。结果表明,相同施氮量下,洲元9369的产量、氮素利用率、面团形成时间、面团稳定时间、面包体积和面包评分均高于济麦20。当施氮量由N180增至N240时,2个品种的产量无显著变化,但沉降值、面团形成时间、面团稳定时间、面包体积和面包评分均显著提高;施氮量增至N300后,2个品种的产量和品质又都显著下降,籽粒总蛋白含量、谷蛋白含量、SDS-不可溶性谷蛋白含量、醇溶蛋白含量和谷蛋白聚合指数均明显降低,而SDS-可溶性谷蛋白含量和谷醇比却表现为上升趋势。经相关分析,SDS-不可溶性谷蛋白含量、谷蛋白聚合指数与面团形成时间、面团稳定时间、面包体积和面包评分均呈显著正相关。以上结果表明,谷蛋白聚合程度降低是过量施氮条件下强筋小麦品质下降的主要原因。综合考虑小麦产量、氮素利用率和籽粒品质,240 kg·hm^-2为本研究条件下的最佳施氮量。     

Aeration of bread dough influenced by different way of processing

The effect of steady shearing versus z-blade mixing on mechanical aeration and gas retaining ability of the dough during processing and subsequent proofing and bread baking stages was investigated. Reduction in moisture content led to reduction in both static and dynamic densities of z-blade mixed dough. At low moisture content, dough had higher consistency and tended to physically entrap more air bubbles upon processing, leading to a higher dough volume and, thereby a low density. The results showed that both processes led to similar mechanical aeration as measured by static dough density immediately after processing. Shearing at a low rotational speed, led to similar proofing dough volume as z-blade mixing did. Nevertheless, both dough expansion test and breadmaking trials showed a significant reduction in gas retaining ability of sheared dough, especially at higher rotational speeds. This is explained by the fact that higher shear rates could break up the gluten network and negatively influence gas retaining ability. The results revealed the influence of processing conditions; e.g. the type of deformation flow on dough aeration. Furthermore, it was shown that rotational speed in the shearing system influences the aeration and gas holding ability of the dough during proofing and baking processes.     

Effect of structured lipid on alveograph characteristics, baking and textural qualities of soft wheat flour

The effect of substituting canola oil/caprylic acid structured lipid (SL) for partially hydrogenated shortening (at 0, 25, 50, 75, and 100% levels) on the rheology of soft wheat flour dough (28.4% total lipid on flour weight basis, 43% moisture) was determined using the Alveograph. The effect of SL substitution on baking and textural qualities of sugar-snap cookies was also investigated. Addition of shortening to soft wheat flour dough resulted in a significant (P<0.05) decrease in dough resistance to deformation (P), dough extensibility (L), and dough baking strength (W), suggesting a less developed gluten network. SL substitution for shortening did not affect P and W. The cookies incorporating SL (50 and 75% SL substitution) were similar (P<0.05) to the shortening control cookies in both baking and textural qualities, but exhibited some baking and textural quality differences at the 25 and 100% SL substitution levels. Correlations (P<0.05) were found between some Alveograph characteristics, and baking and textural qualities.     

Oat malt as a baking ingredient – A comparative study of the impact of oat,barley and wheat malts on bread and dough properties

Oat malt is a nutritionally rich ingredient mainly used in a small number of speciality products. The aim of this study was to evaluate the suitability of oat malt in wheat baking. The effect of oat malt on bread and dough properties at levels ranging from 0.5% to 5% was studied and compared with barley and wheat malts. The addition of all malts increased loaf specific volumes. Barley and wheat malts at levels above 2.5% led to a sticky and coarse crumb, but the effect of oat malt on the crumb grain was negligible. Rheological characterisation could not explain the superior baking performance of oat malt, as it increased extensibility and decreased resistance extensively indicating weakening of the extensional properties of the gluten network. The high lipolytic activity may have compensated for the loss of dough strength by improving the surface properties of gas cells. The results show that oat malt can be used in wheat baking to improve the loaf volume and nutritional quality without the detrimental effects associated with the excess amylolytic activity of barley and wheat malts.     

Oat malt as a baking ingredient – A comparative study of the impact of oat,barley and wheat malts on bread and dough properties

Oat malt is a nutritionally rich ingredient mainly used in a small number of speciality products. The aim of this study was to evaluate the suitability of oat malt in wheat baking. The effect of oat malt on bread and dough properties at levels ranging from 0.5% to 5% was studied and compared with barley and wheat malts. The addition of all malts increased loaf specific volumes. Barley and wheat malts at levels above 2.5% led to a sticky and coarse crumb, but the effect of oat malt on the crumb grain was negligible. Rheological characterisation could not explain the superior baking performance of oat malt, as it increased extensibility and decreased resistance extensively indicating weakening of the extensional properties of the gluten network. The high lipolytic activity may have compensated for the loss of dough strength by improving the surface properties of gas cells. The results show that oat malt can be used in wheat baking to improve the loaf volume and nutritional quality without the detrimental effects associated with the excess amylolytic activity of barley and wheat malts.     

面筋蛋白对小麦粉理化性质及面包烘焙品质的影响

为明确不同类型小麦的面粉改良方案,为我国优质面包专用粉的生产提供理论与技术支持,以三个筋力不同的小麦品种宁麦13、扬麦16和郑麦9023为材料,通过洗面筋法提取各供试材料的湿面筋,将其冷冻干燥后按照7%、8%、9%、10%、11%的添加比例与各自面粉进行配比,对配粉的面包烘焙品质、面粉理化性质和面团流变学特性进行了测定分析。结果发现,随着面筋蛋白添加量的提高,配粉的蛋白质、湿面筋、谷蛋白大聚体(GMP)含量和沉降值逐步上升;粘度参数和面团弱化度有所下降;糊化温度和糊化时间呈上升趋势。在同一添加量下,强筋小麦的烘焙品质和面粉理化性质始终优于中筋小麦和弱筋小麦。随着面筋蛋白添加量的提高,面包体积、弹性、回复性、内聚力增大,而硬度、咀嚼性减小,感官品质得到改善。面筋蛋白添加量超过一定范围(宁麦13、扬麦16添加9%,郑麦9023添加8%),面包品质改良效果变缓,且色泽不断加深。综上所述,适量添加面筋蛋白可改变面粉的理化性质,提高其面包烘焙品质;配粉的蛋白质含量为18%左右是最经济的面包烘焙品质改良方案。