Effects of Spontaneous Fermentation on Proximate Composition, Mineral Profile, and Amino Acid Modulations of Pigeon Pea (Cajanus cajan L.) Flours

Abstract

Aims: This study aimed to evaluate the effects of spontaneous fermentation on the proximate composition, mineral profiles and amino acid dynamics of pigeon pea (Cajanus cajan L.) flour to enhance its nutritional value for human and animal nutrition. Study Design: A controlled experimental study was conducted using a randomised design across four processing intervals (0, 24, 48 and 72 hours). Place and Duration of Study: The study was conducted in the Gontougo region (northeast Côte d'Ivoire) and the analyses were performed at the Biochemistry Laboratory of Peleforo Gon Coulibaly University in Korhogo and Nangui Abrogoua University, between 2023 and 2024. Methodology: Cleaned pigeon pea seeds were spontaneously fermented in sterilised, hermetically sealed stainless-steel containers at room temperature (28 ± 2 °C) for 24, 48 and 72 hours. Proximate parameters, total reducing sugars and mineral composition were quantified using standard AOAC and spectrophotometric methods. Total amino acid profiling was evaluated by high-performance liquid chromatography (HPLC) with post-column ninhydrin derivatisation. Results: Spontaneous fermentation significantly affected (P < 0.05) the nutritional matrix. Crude protein increased from 23.63% in the unfermented control to a peak of 32.37% at 24 hours, before gradually declining to 28.87% at 72 hours. Total ash decreased significantly from 3.16% to 2.60% at 48 hours (P < 0.05), while dry matter increased slightly. Total soluble sugars peaked at 24 hours (45.28%) and decreased significantly by 72 hours (30.77%). Reducing sugars showed a continuous downward trend from 23.59% to 18.68%. Essential amino acids such as tryptophan, lysine and histidine were substantially enhanced at 24 and 48 hours, while essential branched-chain amino acids (isoleucine and leucine) peaked at 48 hours. Conclusion: Spontaneous fermentation for 24 to 48 hours optimised protein quality, enhanced key essential amino acids and improved the nutritional profile of pigeon pea flour, indicating its potential use as an ingredient in infant flour formulations and functional livestock feed.