Effect of processing on the in vitro and in vivo protein quality of red and green lentils (Lens culinaris)

- Influence of processing on lentil protein quality was studied in vivo and in vitro.
- Protein content was not altered by baking, boiling or extrusion.
- Extruded lentils had higher protein quality scores than baked or boiled.
- A significant correlation was found between in vivo and in vitro protein quality.

In order to determine the effect of extrusion, baking and cooking on the protein quality of red and green lentils, a rodent bioassay was conducted and compared to an in vitro method of protein quality determination. On average, the Protein Digestibility-Corrected Amino Acid Score of red lentils (55.0) was higher than that of green lentils (50.8). Extruded lentil flour had higher scores (63.01 red, 57.09 green) than either cooked (57.40 red, 52.92 green) or baked (53.84 red, 47.14 green) flours. The average Digestible Indispensable Amino Acid Score of red lentils (0.54) was higher than green lentils (0.49). The Protein Efficiency Ratio of the extruded lentil flours (1.30 red, 1.34 green) was higher than that of the baked flour (0.98 red, 1.09 green). A correlation was found between in vivo and in vitro methods of determining protein digestibility (R2 = 0.8934). This work could influence selection of processing method during product development.