The development of new food products obtained by extrusion processing has increased in recent years. Extrusion is used by the food industry to produce a wide variety of food products, such as ready-to-eat foods (e.g., snacks), among others. Pulses have also gained popularity as novel food ingredients in the formulation of a variety of food and food products, due to their high content of macro and micronutrients, and bioactive compounds that improve the nutritional and functional properties of the final food products. In this review, the impact of extrusion variables on proteins, carbohydrates, vitamins, phenolics and antinutritional compounds in pulses and pulse-based formulations are highlighted. Particularly, the impact of the specific mechanical energy. Also, the preservation, increase and/or reduction in those functional compounds, as a consequence of different extrusion processing conditions, are discussed.

Tiger nut (TN) is a nutritious source of gluten-free flour, used generally in healthy beverages, but its incorporation in gluten-free extruded snacks has not been explored. TN flour was blended at different concentrations (up to 70%) with rice flour and soluble fiber, for the development of gluten-free snacks on a twin-screw extruder. The effect of TN inclusion in the formulations was evaluated on relevant physiochemical characteristics of the snacks. Viscoamylograph of the raw formulations showed that TN addition increased (p < 0.01) onset temperature and delayed peak viscosity. In the extruded flours, TN contributed to limit the starch degradation during extrusion. Diameter, expansion ratio, true density, and total pore volume of the extrudates were reduced (pf < 0.01) by the increased TN content in the formulations, while bulk density rose. The surfaces of the extruded snacks were modified by the increasing inclusion of TN in substitution of rice in the formulations. Extrudates containing 10% TN showed the best overall texture profile. Moreover, TN addition enhanced the ash and protein content of the snacks and increased their total antioxidant activity. This study demonstrated that incorporation of 10% TN flour into rice-based formulation was suitable for making gluten-free snacks with acceptable physical properties.

Extrusion cooking allows the development of value-added products from pulses, such as gluten-free snacks with added functional properties. The main objective of this study was to evaluate the changes induced by the extrusion process on the carbohydrate fraction (total carbohydrates, soluble sugars and oligosaccharides, dietary fiber, and arabinoxylans) of novel flour formulations based on chickpeas and rice enriched with different dietary fiber sources. Moreover, the influence of the addition of fiber-rich ingredients, such as Fibersol^® and passion fruit, on the analyzed compounds was also evaluated. Sucrose was the main soluble sugar found in analyzed formulations, and raffinose was the prevalent oligosaccharide, followed by stachyose. The content of total α-galactosides tended to be higher after extrusion cooking. As a consequence of the extrusion treatment, the content of total and soluble dietary fiber was statistically increased in most of the analyzed samples. In general, no significant changes were observed in total arabinoxylan content as a consequence of the extrusion process, while the content of water-soluble arabinoxylans was significantly increased in extruded formulations. It was observed that the content of total available carbohydrates, stachyose, and water-soluble arabinoxylans were significantly influenced by the addition of passion fruit, Fibersol^®, and both. The incorporation of these ingredients in gluten-free formulations based on chickpeas and rice allows one to obtain suitable functional formulations for the development of innovative, gluten-free, extruded snack-type products, which could be an interesting alternative for people with celiac disease.

The incorporation of pulse flour into gluten-free extruded snacks based on cereals improves the functional properties as well as the nutritional value of these types of products. The aim of this study was to investigate the changes induced by the extrusion process on the functional properties in terms of the concentration of total phenolic compounds (TPC), phenolic families (hydroxybenzoic acids, hydroxycinnamic acids, and flavonols), and non-nutritional factors (inositol phosphates and trypsin inhibitors) of extruded snack-type products developed from novel formulations based on rice-chickpea flours and fortified with different percentages of Fibersol^® and passion-fruit-skin flour. The in vitro antioxidant activity of the studied formulations was evaluated to explore their potential for developing sustainable snack-type products with added functional value. The results demonstrated that extrusion treatment caused a statistically significant (p < 0.05) decrease (12–30%) in TPC. Despite this reduction, the extruded formulations preserve an interesting content of these compounds, with hydroxybenzoic acids being the majority in the analyzed formulations. The extrusion process maintained or decreased the content of phytate and total inositol phosphates in samples fortified with passion fruit and Fibersol^®. A significant reduction (p < 0.05) of trypsin inhibitor activity (between 86.7% and 95.8%) was observed when comparing extruded samples to their raw counterpart. The antioxidant activity in vitro of the formulations was assessed. The results obtained by the Folin–Ciocalteu method indicated that extrusion caused a decrease in the antioxidant activity of 50% of the analyzed samples, while in the others, no changes were observed. DPPH and FRAP assays tended to demonstrate an increase in antioxidant activity. In general, the highest values were obtained by applying the DPPH method. Additionally, the effects of the ingredients used for fortifying the formulations were investigated. The results highlighted the complexity of the analyzed formulations, revealing that their composition is influenced not only by the presence of Fibersol^® and passion fruit but also by the interaction between these two ingredients.

To enhance the nutritional value of food products, new functional extruded products have been developed based on combinations of corn and lentil flour (70:30), with added salt (1.25%), sugar (5%), and resistant starch V (5–20%), and fortified winemaking by-products (fermented and unfermented pomace/pomace seeds) (5–20%). The formulations were processed through a 32 mm twin screw extruder. The developed extrudates were analyzed for bioactive content. The findings show that among the experimental formulations, those with the highest concentration (20%) presented the greatest amounts of the following functional compound total dietary fiber, total arabinoxylans, resistant starch, total phenols, total flavonols, and total anthocyanins, and the lowest content of raffinose and stachyose. These study results indicate that extrusion is an effective method for adding value to underutilized commodities, such as winemaking by-products. A future sensory evaluation study will be conducted on the extruded products with the highest amount of winemaking by-products of 20%.