Assessment of the nutritional quality of raw and extruded Pisum sativum L. var. laguna seeds

Pea (Pisum sativum L. var. Laguna) seeds were submitted to extrusion process at 129, 135 and 142 °C and modifications on the proximate composition and nutritional parameters were evaluated. Peas were a good source of protein (24 g/100 g), amino acids (sulphur amino acids were the limiting ones), dietary fibre (18 g/100 g), carbohydrates (53 g/100 g), energy (330 kcal/100 g), riboflavin and thiamine (0.1–0.2 mg/100 g). Pea seeds also contained non-nutritive compounds such as α-galactosides (4 g/100 g), phytic acid (0.4 g/100 g) and trypsin inhibitor activity (2 TIU/mg). Extrusion cooking caused a slight increase of protein and fat content, whilst it reduced dietary fibre, thiamine and α-galactosides, and led to negligible trypsin inhibitor activity (TIA) levels. The protein quality of pea measured by biological indexes (net protein utilisation, net protein ratio, relative net protein ratio, true protein digestibility and biological value) was not affected by extrusion treatments. Protein quality measured by chemical indexes (chemical score and protein digestibility corrected amino acid score) decreased in processed peas. Among extruded peas, those processed at 135 °C presented the highest chemical indexes. Therefore, the aforementioned condition could be considered adequate for the manufacture of novel pea-derived products with high nutritive value.