BACKGROUND The protein‐rich fractions of pulses and pseudocereals exhibit a well‐balanced amino acid profile, particularly when combined in different portions, and are therefore high‐value ingredients for the production of extruded snacks. However, the impact of a combination of pulses and pseudocereals on the physical and sensory qualities of extruded snacks has not been investigated up to now. Native or preconditioned protein isolates and concentrates from pulses – as single ingredients or in combination with protein‐rich flours of pseudocereals – were analyzed regarding their thermal and functional properties in relation to extrusion characteristics. Low moisture extrusion cooking was used to investigate the impact of protein source (lentil, lupin, faba bean), pseudocereal source (quinoa, amaranth, buckwheat) and protein content (30%, 50%, 70%) on sectional expansion, specific hardness, density and sensory properties of the snacks. RESULTS With increasing protein content from 30% to 50%, the sectional expansion decreased and the density and specific hardness of the extrudates increased, which could be counteracted by preconditioning of the protein‐rich ingredients. Lupin protein‐based extrudates exhibited satisfactory texture and sensory properties. Extruded mixtures of pulses and pseudocereals (70% protein) exhibited a smaller sectional expansion compared to pulses as single ingredients (30%, 50%), regardless of pseudocereal type. However, the texture and sensory properties of the extruded blends were satisfactory. CONCLUSIONS We show for the first time that protein‐rich fractions of pulses and pseudocereals can be processed into expanded snacks with favorable texture and nutritional properties such as increased protein contents (70%) and balanced amino acid profiles. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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In order to valorise food by-products into healthy and sustainable products, extrusion technology can be used. Thereby, a high expansion rate is often a targeted product property. Rapeseed press cake (RPC) is a protein- and fibre-rich side product of oil pressing. Although there is detailed knowledge about the expansion mechanism of starch, only a few studies describe the influence of press cake addition on the expansion and the physical quality of the extruded products. This study assessed the effect of RPC inclusion on the physical and technofunctional properties of starch-containing directly expanded products. The effect of starch type (native and waxy), RPC level (10, 40, 70 g/100 g), extrusion moisture content (24, 29 g/100 g) and barrel temperature (20–140 °C) on expansion, hardness, water absorption, and solubility of the extrudates and extruder response was evaluated. At temperatures above 120 °C, 70 g/100 g of RPC increased the sectional and volumetric expansion of extrudates, irrespective of starch type. Since expansion correlates with the rheological properties of the melt, RPC and RPC/starch blends were investigated pre- and postextrusion in a closed cavity rheometer at extrusion-like conditions. It was shown that with increasing RPC level the complex viscosity |ƞ*| of extruded starch/RPC blends increased, which could be linked to expansion behaviour.

Due to the increasing global population and unsustainable meat production, the future supply of animal‐derived protein is predicted to be insufficient. Currently, edible insects are considered as a potential and “novel” source of protein in the development of palatable meat analogues. This research used high moisture extrusion cooking (HMEC), at a screw speed of 150 rpm, to produce meat analogues using full‐ or low‐fat cricket flours (CF) and soy protein isolate (SPI). Effects of water flow rate (WFR), cooking temperature (9 and 10 ml/min; 120, 140, and 160°C, respectively), and CF inclusions levels of 0, 15, 30, and 45% were analyzed. Cooking temperature and CF inclusion had a significant effect (p < .05) on both tensile stress in parallel and perpendicular directions, while WFR had no significant effect (p = .3357 and 0.7700), respectively. The tensile stress increased with temperature but decreased with CF inclusion at both WFRs. Comparatively, the tensile stress was stronger at WFR of 9 ml/min than at 10 ml/min; however, the tensile stress in parallel was mostly greater than tensile stress in perpendicular directions. Fibrous meat analogues with high anisotropic indices (AIs) of up to 2.80 were obtained, particularly at WFR of 10 ml/min and at inclusions of 30% low‐fat CF. By controlling HMEC conditions, full‐/low‐fat cricket flours at 15% and 30% inclusions can offer an opportunity to partially substitute SPI in manufacturing of fibrous meat analogues.

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