Saponins, phytic acid, tannins and protease inhibitors in quinoa (Chenopodium quinoa, Willd) seeds

Abstract

The seeds of quinoa (Chenopodium quinoa, Willd), a food crop of the Andean region of Latin America, contain protein of good quality and high amounts of carbohydrates, fat, vitamins, and minerals. An industrial process for manufacturing infant food using quinoa as a basic raw material is being developed. The presence of antinutrients are of importance in this context, and this paper deals with saponins, phytic acid, tannins and protease inhibitors in quinoa seeds. The samples of quinoa analysed in this experiment contained two main types of saponins. The amount of saponin A (β-d-glucopyranosyl-[β-d-glucopyranosyl-(1 → 3)-α-l-arabino-pyranosyl-(1 → 3)]-3-β-23-dihydroxy-12-en-28-oate methyl ester) was 0·7% of the dry weight and that of the saponin B (β-d-glucopyranosyl-[β-d-glucopyranosyl-(1 → 3)-α-l-arabino-pyranosyl-(1 → 3)]-3-β-23-dihydroxyolcan-12-en-28-oate was 0·2% of the dry weight. These were the major saponins found in the quinoa bran collected while polishing the seeds. After scrubbing and washing, the level of saponin-A remaining in the seeds decreased to 0·31% of the dry weight, and saponin-B was completely removed by this process. The content of phytic acid in the quinoa seeds was about 1% of the dry matter, and scrubbing and washing reduced the phytic acid content of the seeds by about 30%. Neither protease inhibitor nor tannins were detected in the quinoa seeds. © 1993.