Protein quality of pigeonpea (Cajanus cajan (L.) Millsp.) as influenced by seed polyphenols and cooking process.

True protein digestibility (TD), biological value (BV), and net protein utilization (NPU) of low-polyphenol pigeonpea cultivars (Nylon, BDN 2, and ICPL 87067) were significantly higher than those of the high polyphenol cultivars (C 11, ICPL 87, and ICPL 151) when whole-seed samples were compared. Most of the polyphenols (80-90%) were concentrated in the seed-coat. Dhal (decorticated split cotyledons) samples of low (Nylon) and high (C 11) polyphenol cultivars revealed no large differences in TD, BV, and NPU values of these cultivars. This indicated an adverse affect of seed-coat polyphenols on protein quality of pigeonpea whole-seed. The cooking process significantly increased TD in both whole seed and dhal samples. BV of both whole-seed and dhal samples was reduced remarkably by cooking. However, NPU of the cooked whole-seed and dhal samples was significantly higher than in the raw samples. No noticeable differences due to cooking were observed in amino acid composition of whole-seed and dhal samples of these cultivars.