Pasta from pulses : conventional extrusion or extrusion-cooking?

Nowadays, consumer demand for healthy foods with low environmental impact is growing. Pasta from pulses represents a potential solution that the food industry could offer to meet current consumer needs. Indeed, pulses are rich in fibre and proteins and are more sustainable than cereals. Moreover, the absence of gluten makes them suitable for people suffering from celiac disease and/or gluten intolerance. It is known that gluten free pasta production from rice or corn is produced by conventional extrusion of pregelatinized flour (labelled here as process A) or by extrusion-cooking of native flour (process B). In the case of pulses, limited information is available regarding which technology is better (process A or B) to obtain a product with desirable quality. To answer this question, this work focused on understanding the relationship between raw materials and processing conditions and their effect on pasta quality. Pasta from rice and red lentils was prepared using two technologies. Process A consisted in a conventional extrusion of flour from pregelatinized grains, while process B involved extrusion cooking of native flour. The effect of processing on starch properties was assessed by measuring starch susceptibility to α-amylase hydrolysis (AACCI 76-31.01) and by evaluating pasting properties (MVAG, Brabender©). The weight-increase of cooked pasta, the loss of solids in cooking water and textural characteristics were evaluated. The pasta-making process significantly affected starch properties, promoting a high degree of gelatinization which was notable by the increase in starch susceptibility to alpha-amylase hydrolysis and by the decreased capacity to form a gel during the MVAG test. However, the extent of starch modifications differed according to the type of raw materials (rice and red lentils) used. This could be due to differences in composition (i.e. amount of fiber, proteins, and starch) and/or starch organization. Finally, both pasta-making processes were found to be effective in obtaining gluten-free pasta from either rice or red lentils. However, samples from process B resulted in pasta with a non-homogeneous structure, showing some non-hydrated points that might affect both water absorption and textural properties. Based on the results process A seems to be the more suitable process for producing pasta from red lentils.