Biochemical evaluation of spent Bixa (Bixa Orellana) seeds for potential application in the food industry

Biological raw materials and side-streams generated during food processing may contain chemically diverse compounds with biological activity, that can be harnessed towards food system and environmental protection. One of such side-streams is spent bixa seed, obtained after extraction of Annatto dye, much of which is often disposed into landfills. The objective of this research was to analyze biochemical components of spent bixa seeds in comparison to unprocessed bixa seeds, and explore their potential in upcycling into food products. Samples of raw and spent bixa seeds were collected from a bixa processing company in Kenya. Laboratory analysis for toxicological and biochemical components, including proximate, phytochemicals and antioxidative capacity was carried out using recommended protocols. The results of cardiac glycoside test turned negative for all samples. Nutritional components were significantly higher in raw bixa samples, indicating the effect of processing and storage. The spent bixa samples had protein content ranging 9–10%, starch of 27–60%, fibre of 9–10% and crude fat of 2–3% on dry weight basis. The seeds could also be a good source of linolenic fatty acid, which is essential in the diet. There was significant reduction of antioxidants after processing, especially flavonoids, indicating that it could be linked to the extracted annatto. Storage also had an impact, with an IC50 of about 10 mg/mL in samples that had stayed for 7 days. In conclusion spent bixa seeds can be valorized and utilized as whole food due to their balanced nutritional profile. Additionally, high starch can be extracted and used as a food ingredient.