INTERPLAY BETWEEN RAW MATERIAL AND PROCESSING CONDITIONS FOR THE FORMULATION OF PULSE-BASED PRODUCTS

As modern consumers are becoming increasingly conscious about health and sustainability, they are demanding plant-based tasty and convenient food products. In this context, using pulses in food formulations has strongly grown owing to their agronomic, nutritional and health benefits. In the scenario of reformulating food products with pulses, extrusion plays a key role as it can lead to a wide range of products such as snacks, pasta, and meat analogues. Although some studies provided information on the suitability of pulse extrusion, it is still unclear which pulse performs better for each type of application and how to perform the process to obtain products with enhanced quality. This project focused on understanding the relationship between raw material, processing conditions and product quality, with the final goal of identifying the most suitable combination of type of pulse and extrusion process for the production of extruded products. Three extruded products were chosen as representative of the extrusion carried out at different moisture levels: snacks (10% moisture), pasta (30% moisture), and meat analogues (50% moisture). As regards snacks, a literature review was necessary to frame the industry (chapter 4.1.1). This revealed the lack of information regarding the use of pulses (as whole or fractions) in extruded snacks. Therefore, the research focused on the use of bran from chickpeas and green peas (at 15% and 30% enrichment level) on the chemical and physical characteristics of snacks (chapter 4.1.2). Although the enrichment with pulse bran affected the snack features, the developed products were preferred by the consumers compared to the control. These results lead to a focus on sensory aspects (chapter 4.1.3), highlighting that crumbliness and mild flavor positively influenced hedonic scores, whereas stickiness, dryness, hardness, and to a lesser extent visual aspect, affected them negatively. Comparing the extrusion aptitude of chickpeas, green peas, and red lentils, the latter gave the best results for both snacks and pasta products (chapter 4.1.4). In the case of pasta, the literature review showed great interest in using unconventional raw material (chapter 4.2.1). A picture of the pulse pasta market highlighted differences according to the type of pulse and brand (chapter 4.2.2), suggesting further investigation on processing. Comparing the conventional extrusion process with the extrusion-cooking (chapter 4.2.3), it was found that thermal treatment enhances pasta quality. Thus, the effect of pregelatinization on starch and proteins was studied (chapter 4.2.4) and related to the quality of pasta produced at lab- (chapter 4.2.5) and pilot- (chapter 4.2.6) scale. Finally, high moisture extrusion (50%) was considered. The aptitude of air-classified pulse fraction high in protein was proposed as a sustainable alternative to soy protein concentrates for meat analogues production (chapter 4.3.1). Overall, this PhD project provides evidence on how the extrusion process can be uniquely useful from a pulse-product reformulation perspective and what variables are responsible for determining product features.