Effects of extrusion screw speed, feed moisture content, and barrel temperature on the physical, techno-functional, and microstructural quality of texturized lentil protein.

Utilizing lentil protein as a novel ingredient for producing texturized vegetable proteins (TVPs) can provide new opportunities for the production of next-generation hybrid meat products. TVPs from lentil protein isolate were manufactured using low-moisture extrusion cooking at different combinations of screw speed (SS), feed moisture content (MC), and barrel temperature (BT) profile. In total, seven different combinations of processing treatments were tested, and the resulting TVPs were characterized for their physical (rehydration ratio, texture profile analysis, color, and bulk density), techno-functional (oil and water holding capacities), and microstructural properties. The processing conditions of higher SS and lower MC resulted in increased values of several textural profile attributes (springiness, cohesiveness, and resilience), increased water holding capacity (WHC), and decreased bulk density. Compared to raw lentil protein, TVPs showed enhanced oil holding capacity, though WHC either decreased or remained constant. The extrusion response parameters (die pressure, torque, and specific mechanical energy) showed positive correlations with several physical properties (texture, WHC, and total color change), revealing their potential for serving as important TVP quality indicators. TVPs produced at SS, MC, and BT of 450 rpm, 30%, and 140°C, respectively, showed relatively better overall physical and techno-functional quality and can be used as meat extenders in hybrid meat patties. Overall, this research evidenced the viability of lentil protein as a potential ingredient for producing low-moisture TVPs.

Utilization of Intermediate Wheatgrass (Thinopyrum intermedium) as an Innovative Ingredient in Bread Making.

Intermediate wheatgrass (IWG; Thinopyrum intermedium), a nutritionally dense and sustainable crop, is a promising novel ingredient in bakery applications. The main aim of this study was to investigate the potential of IWG as a novel ingredient in breadmaking. The second aim was to investigate the characteristics of breads substituted with 15, 30, 45, and 60% IWG flour compared to control bread produced using wheat flour. The gluten content and quality, bread quality, bread staling, yellow pigment, and phenolic and antioxidant properties were determined. Enrichment with IWG flours significantly affected the gluten content and quality and bread characteristics. Increased levels of IWG flour substitution significantly decreased the Zeleny sedimentation and gluten index values and increased the dry and wet gluten contents. The bread yellow pigment content and crumb b* colour value increased with the increasing level of IWG supplementation. IWG addition also had a positive effect on the phenolic and antioxidant properties. Bread with 15% IWG substitution had the highest bread volume (485 mL) and lowest firmness values (654 g-force; g-f) compared to the other breads, including the control (i.e., wheat flour bread). The results indicated that IWG has great potential to be used in bread production as a novel, healthy, and sustainable ingredient.

Enhancing the Techno-Functionality of Pea Flour by Air Injection-Assisted Extrusion at Different Temperatures and Flour Particle Sizes.

Industrial applications of pulses in various food products depend on pulse flour techno-functionality. To manipulate the techno-functional properties of yellow pea flour, the effects of flour particle size (small vs. large), extrusion temperature profile (120, 140 and 160 °C at the die) and air injection pressure (0, 150 and 300 kPa) during extrusion cooking were investigated. Extrusion cooking caused the denaturation of proteins and gelatinization of starch in the flour, which induced changes in the techno-functionality of the extruded flour (i.e., increased water solubility, water binding capacity and cold viscosity and decreased emulsion capacity, emulsion stability, and trough and final viscosities). In general, the large particle size flour required less energy input to be extruded and had higher emulsion stability and trough and final viscosities compared to the small particle size flour. Overall, among all of the treatments studied, extrudates produced with air injection at 140 and 160 °C had higher emulsion capacity and emulsion stability, making them relatively better suited food ingredients for emulsified foods (e.g., sausages). The results indicated air injection's potential as a novel extrusion technique combined with modification of flour particle size distribution and extrusion processing conditions to effectively manipulate product techno-functionality and broaden the applications of pulse flours in the food industry.

Butterfly Pea Flower as a Novel Ingredient to Produce Antioxidant-Enriched Yellow Pea-Based Breakfast Cereals.

Butterfly pea flower (BP) is a rich source of bioactive components and can potentially be utilized to produce appealing, wholesome foods. Antioxidant and dietary fiber-enriched breakfast cereals were produced by extrusion cooking using blends of BP and yellow pea flour (YP). BP was added to YP at 0%, 5% and 10% levels (w/w), respectively, and extruded at two temperature profiles with die temperatures of 130 and 150 °C. Incorporation of BP significantly (p < 0.05) improved the total phenolics content, antioxidant properties, and insoluble and total dietary fiber content of the extrudates, with 10% BP extrudates showing the highest values. At a die temperature of 150 °C, the extrudates had a higher expansion ratio, a lower dry hardness, and a higher dry crispiness as compared to those at 130 °C. The color of BP-incorporated extrudates was darker and bluer as compared to the no-BP extrudates. The 10% BP extrudates retained relatively more of their hardness, crispiness, and crunchiness after soaking, indicating a better bowl-life and, therefore, better suitability of this blend formula for breakfast cereal production. Overall, this research shows that healthier breakfast cereals with appealing color and relatively longer bowl-life can be produced using BP, making BP a potential novel ingredient for extrusion formulations.

Development of Cellular High-Protein Foods: Third-Generation Yellow Pea and Red Lentil Puffed Snacks.

This study aimed to evaluate how extrusion cooking conditions and microwave heating play a role in enhancing physical and thermal properties of third-generation expanded cellular snacks made from yellow pea (YP) and red lentil (RL) flours for the first time. Increasing temperature and moisture content during extrusion resulted in darker, crunchier and crispier products with higher expansion index (EI). Microwave heating after extrusion led to an increase in cell size and porosity of YP and RL products when qualitatively compared to extrusion alone. Additionally, extrusion followed by microwave heating resulted in extensive damage to starch granular structure and complete denaturation of proteins. Using microwave heating, as a fast and inexpensive process, following partial cooking with extrusion was demonstrated to greatly improve the physical and thermal properties of YP and RL snacks. Microwave heating following mild extrusion, instead of severe extrusion cooking alone, can potentially benefit the development of high quality nutritionally-dense expanded cellular snacks made from pulse flours.

Physical and technofunctional properties of yellow pea flour and bread crumb mixtures processed with low moisture extrusion cooking.

The potential utilization of yellow pea flour and bread crumb blends was investigated to generate nutritionally-dense extruded products with superior physical and/or technofunctional properties. Yellow pea flour mixed with bread crumb at different ratios were processed using low-moisture twin-screw extrusion cooking conditions to examine the effect of blending ratios and feed moisture contents on physical (that is, radial expansion index, extrudate density, microstructure, texture, and color) and technofunctional (that is, emulsifying capacity, emulsifying stability, water solubility [WS], water binding capacity [WBC], oil binding capacity [OBC], and pasting) properties of the final products. Compared to the two feed materials alone, samples produced with yellow pea flour and bread crumb blends showed lower hardness and higher crispiness. Moisture content (12% to 18%) was found to significantly affect physical and technofunctional properties. With an increase in feed moisture content from 12% to 18%, the WBC of the extrudates increased while the WS decreased. Extrudates produced with higher feed moisture content, and higher yellow pea flour content had higher setback viscosity. Among all formulas and feed moisture contents studied, extrudates produced with 50% yellow pea flour and 50% bread crumb at 12% feed moisture content had the highest radial expansion and bigger cells with thinner cell walls. This study has shown that incorporation of yellow pea flour and bread crumb in extrusion cooking process could be used to develop nutritionally-dense foods with improved physical and technofunctional properties.

The effects of sodium reduction on the gas phase of bread doughs using synchrotron X-ray microtomography.

Globally, the bakery industry has a target of reducing sodium content in bread products. However, removing salt results in changes in the quality of bread through effects on dough's gas phase during the breadmaking process. Using synchrotron X-ray microtomography, the objective of this study was to investigate how sodium reduction induced changes in the gas phase parameters (i.e., gas volume fraction, bubble size distribution (BSD) and its time evolution) of non-yeasted doughs made from a wide range of formulations (i.e., wheat cultivar and water content) prepared with different mixing times. As salt content was reduced, a lower gas volume was retained in the dough by the end of mixing. Less gas bubbles were also retained if doughs were prepared from a stronger wheat cultivar, higher water content, and/or mixed for a shorter time. Rates of change in the median (R0) and the width (ε) of the fitted lognormal radius dependence of bubble volume fraction [BVF(R)] indicated that reduced sodium content permitted disproportionation to proceed more rapidly. Higher water content or longer mixing time also resulted in faster disproportionation, indicating that water content and mixing time can be manipulated as a means of increasing bubble stability against disproportionation during low-sodium breadmaking. An examination of relative changes in dough's gas phase parameters arising from sodium reduction demonstrated that wheat cultivar, water content and mixing time all affected dough's tolerance to sodium reduction. Therefore, attainment of good bread crumb cell structure in low-sodium bread formulas is a function of salt's effects on dough rheology in addition to its effect on yeast activity, so that dough formulation and mixing conditions also need to be considered.

Functional and thermal properties of yellow pea and red lentil extrudates produced by nitrogen gas injection assisted extrusion cooking.

BACKGROUND: There are excellent opportunities for greater incorporation into our diets of pulses, which are rich in proteins and dietary fibers, if their functional properties are modified to fit a wide range of applications in the food industry. The objective of this research was to produce high protein and fiber extrudates from yellow pea and red lentil flours using conventional and N2 gas injection assisted extrusion cooking methods. The effects of process variables on extrudate functional and thermal properties were also investigated. RESULTS: The cold viscosity of extrudates produced by N2 gas injection were higher than those produced by conventional extrusion, indicating that gas-assisted extrusion does affect the end-product pasting properties. At higher barrel temperatures (150-175 °C) extrudates did not exhibit any thermal transition in their thermograms, and thus their starches were completely gelatinized and proteins completely denatured during extrusion. In general, water solubility of extrudates produced by N2 gas injection was significantly (P < 0.05) higher than those produced by conventional extrusion. Emulsion capacity and stability of yellow pea extrudates were in the range of 44-50% and 42-47%, respectively, and the counterpart values of red lentil extrudates were very similar (in the range of 43-47% and 43-46%, respectively). CONCLUSION: Nitrogen gas injection assisted extrusion cooking can be used practically in development of pulse extrudates which contain high protein and dietary fiber. This novel and innovative technique is a reliable alternative method to the conventional CO2 gas injection assisted extrusion cooking methods in the snack food and food ingredient industries. © 2019 Society of Chemical Industry.

Ultrasound as a tool to study bubbles in dough and dough mechanical properties: A review.

Investigation of dough mechanical properties using low-intensity ultrasound is now reasonably well established. In this review, an introduction to the fundamentals of ultrasound propagation in non-scattering and in scattering media is followed by several examples of how low-intensity ultrasound is used as a research tool for exploring the bubble size distribution in breadmaking dough and evaluating dough's mechanical properties. Utilization of ultrasonic techniques for quantitative assessments of bubbly dough structure and characterization of dough mechanical properties as affected by dough formulation are pointed out.