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The ability to modulate direct expanded product structures improves the versatility and range of product applications. The effect of nucleating agents, namely, talc and calcium carbonate (CC), on the expansion characteristics of pea starch extrudates as impacted by screw speed was explored. Pea starch blends with increasing levels of nucleating agents (0.25%, 1%, and 2%) at 18% moisture (w.b.) were extruded across a range of screw speeds (150, 250, 350, and 450 rpm). The water absorption index, water solubility index (WSI), expansion ratio (ER), unit density, and cell count were determined to evaluate the performance of nucleating agents. The nucleating efficiency of CC, as assessed by cell count, improved with increasing screw speeds. In contrast, the nucleating efficiency of talc was influenced by inclusion levels irrespective of screw speed. ER values ranged from 2.10 to 2.88, where higher nucleating agent inclusions and screw speeds corresponded with lower ER values. Increased nucleating agents and screw speeds corresponded to higher WSI values suggesting the nucleating agents promoted starch degradation. The nucleating agents appeared to promote flow instabilities indicated upon assessment of the extrudate surface. Practical Application: This study provides helpful information on the expanded extrudate structure of pea starch as influenced by screw speed and nucleating agents. These findings may help the food industry select processing parameters and appropriate nucleating agent inclusion levels when producing new expanded products with unique textures. [ABSTRACT FROM AUTHOR]

Fortification of direct‐expanded products with insoluble fiber generally leads to decreased expansion. Understanding the interactions between starches and fibers can help to include more fiber into puffed products. A pressure vessel setup is developed to allow for a small‐scale expansion process. Because trends for the expansion ability during the simulated process are similar to those during extrusion, the setup has been proven to be suitable for understanding the occurrences during extrusion. Elimination of hydroxyl groups through starch methylation can help to understand the role of hydrogen bonding during expansion. Nonmethylated and methylated starch are tested for their expansion at cellulose levels of 0%, 5%, and 20% on a weight basis. The specific volume of the obtained samples is used to determine the degree of expansion. The nonmethylated starch sample exhibits a specific volume of 16.3 ± 1.8 cm3 g−1, which is almost three times higher than the one of the methylated sample (≈6.0 cm3 g−1). Possible reasons for this decrease are the elimination of hydroxyl groups capable of forming hydrogen bonds or the significantly higher viscosity of the methylated starch. While fortification with 5% cellulose does not affect the expansion, 20% cellulose greatly reduces the specific volume for both starches. [ABSTRACT FROM AUTHOR]

Plant‐based meat analog products, including those produced by extrusion processing, have become increasingly popular. Complete comprehension of the texturization mechanism and the formation of fibrousness would help improve existing products and extend the variety of plant sources used. Therefore, this study aimed to provide improved insight into the mechanism of texturization during the processing of high‐moisture meat analog (HMMA) products. Blends with different wheat and pea protein ratios (100:0, 80:20, 60:40, 40:60, 20:80, and 0:100 wheat:pea) were extruded at a screw speed of 400 rpm, two different moisture contents (50% and 55%), and a feed rate of 90 g/min using a co‐rotating twin‐screw extruder. Extrudates were analyzed for their texture, free sulfhydryl groups, disulfide bonds, and solubility in different extractants relative to the raw ingredient blends. In addition, a sensory analysis was conducted using the rapid and cost‐effective "rate‐all‐that‐apply" (RATA) methodology. The interplay between the two protein types had synergistic effects on the system parameters torque, pressure, and specific mechanical energy, as well as on some textural and sensory parameters. Molecular analyses were not influenced by the interplay between wheat and pea protein as the molecular analyses followed linear trends with the pea inclusion level. Analysis of protein solubility suggests that the texturization mechanism differs slightly depending on the protein type. It is suggested that the texturization of wheat protein depends highly on disulfide bonds, whereas the texturization of pea protein relies on the combination of disulfide bonds and non‐covalent interactions. Additionally, RATA was found to be a valuable tool for HMMA products. [ABSTRACT FROM AUTHOR]

This study analyzed the effect of the inclusion of legume‐derived proteins, specifically pea and fava bean protein, with varying solubility levels on the expansion of corn starch. Three different proteins exhibiting low, medium, or high solubility were mixed with corn starch to obtain blends containing 15%, 25%, and 35% (w/w) of the protein. Extrusion was performed on a twin‐screw extruder at three different screw speeds (200, 400, and 600 rpm), a moisture content of 16% (w.b.), and a die temperature of 140°C. Obtained extrudates were analyzed for their expansion, unit density, and hydration properties, namely, water solubility index (WSI) and water absorption index (WAI). Extrudates containing the protein with the highest solubility showed different patterns than those that had proteins with low or medium solubility. Expansion ratio (ER) increased from a maximum of 3.55 ± 0.24 for pure corn starch up to 5.45 ± 0.43 when incorporating 35% of the protein with medium solubility but significantly decreased down to 1.24 ± 0.08 when incorporating 35% of the most soluble protein. The influence on the system parameters, as well as on the hydration properties, was also greatest for the blends containing the protein with the highest solubility. Even though significant Pearson correlations were observed between protein solubility and ER (r = −0.579), unity density (r = 0.614), WSI (r = −0.634), torque (r = −0.612), as well as specific mechanical energy (r = −0.451), further research is needed to evaluate if the solubility is indeed the reason for certain behaviors or if other protein characteristics are more critical for expansion. Practical Application: This manuscript provides practical information on the influence of the addition of legume‐derived proteins with different solubility levels on direct expansion. The obtained results may help the industry with the selection of the appropriate proteins for inclusion levels in producing high protein direct‐expanded extruded food products. [ABSTRACT FROM AUTHOR]

Ten novel breeding lines of quinoa (Chenopodium quinoa Willd) suitable to be grown in the Pacific Northwest of the United States were developed and utilized for extrusion processing. Understanding how a particular breeding line performs during food processing and which properties determine its performance can promote the use of quinoa as an ingredient in value‐added products, such as extruded snacks. In this study, extrusion characteristics of the whole seed flours of the novel quinoa breeding lines were evaluated using a co‐rotating twin‐screw extruder at two temperatures (110°C and 125°C), three screw speeds (200, 350, and 500 rpm), and a moisture content of 18% (w.b.). The expansion ratio (ER) ranged from 1.15 to 2.33 and was negatively influenced by the fat content in the flours. Breeding line 11WAQ‐104.88 (WAQ10) exhibited the greatest potential for use in direct expanded foods as it had the highest ER for all conditions studied. Strong correlations were found between ER and pasting properties of the flours, proving the usefulness of the pasting test for flour quality evaluation before extrusion processing. The results demonstrate the potential of using quinoa for producing direct expanded food products and highlight the importance of selecting specific breeding lines for desired product characteristics. Practical Application: This study provides the extrusion processing characteristics of 10 new quinoa breeding lines. Based on the information gained, it will be easier for the food industry, including breeders as well as processors, to select the right quinoa variety based on their requirements, and may further help to enhance the use of quinoa. [ABSTRACT FROM AUTHOR]