Optimizing the Nutritional, Phytochemical, and Techno-functional Profiles of Pigeon Pea Seed (Cajanus cajan L.) Flour through Spontaneous Fermentation

Abstract

Pigeon peas, although they contain two to three times more protein than cereals, are not widely used due to low digestibility, antinutritional properties, and difficult cooking characteristics. This study evaluated the effect of spontaneous fermentation on the nutritional and techno-functional characteristics of pigeon pea seed (Cajanus cajan L.) flour. Pigeon pea seeds obtained from Tanda, Côte d’Ivoire, were sorted, washed and divided into several batches. One batch was used as a control sample, while the rest were allowed to ferment spontaneously in distilled water at room temperature (28 ± 2 °C) for 24, 48 or 72 h. The flours obtained from the different treatments were analyzed for antinutritional factors, total polyphenols, flavonoids, individual phenolic compounds, vitamins and water/oil absorption capacities. The results showed a substantial decrease in tannins, oxalates and phytates after 72 hours of fermentation, which indicates a reduction in the  antinutritional factors. The total polyphenol and flavonoid content of the flours varied with fermentation time, with the highest content observed after 72 hours. Furthermore, HPLC analysis revealed that phenolic compounds such as chlorogenic acid, catechin and hydroquinone were the compounds that changed the most in concentration. Fermentation also influenced the vitamin content of the flour, notably increasing the levels of riboflavin (B2) and pyridoxine (B6). A greater water absorption capacity and a lower oil absorption capacity of the pigeon pea seed flour were observed after fermentation. Overall, it was found that spontaneous fermentation modifies the nutritional, phytochemical and functional characteristics of pigeon pea seed flour, which could improve its suitability for use in food formulations. However, further research into the product's safety, digestibility and sensory perception is required before it can be used.