Cuajinicuil (Inga Jinicuil) seeds as a novel source of starch: morphological, structural, and thermogravimetric characteristics of isolated fractions

This study aimed to analyze three fractions obtained from starch extraction from cuajinicuil (Inga jinicuil) seeds, to determine their physicochemical composition and potential functionality. The proximal, morphological, structural, and thermogravimetric characteristics of CF_U, CF_I, and CF_A fractions were determined. CF_U had high fat and fiber content, CF_I had high protein values and CF_A had high carbohydrate content. The size and shape of the particles seen in the micrographs, the intensity of the signals in the infrared spectrum, and the thermogravimetric behavior suggest that the CF_U fraction does not correspond to starch, but rather contains impurities related to lignin, since the particles had polyhedral shape, size larger than 50 µm, a signal at 1530 cm⁻¹ and a band at 600 °C, which are characteristic of lignin. The CF_I fraction contained starch granules embedded in larger polyhedral portions and exhibited a behavior more similar to starch, but with impurities. The CF_A fraction showed uniform granule size, infrared spectra, crystallinity, and thermogravimetric behavior characteristic of purified native starch. Cuajinicuil seeds are a new source of high-quality purified starch, as well as other fractions with potential applications in the food and pharmaceutical industries. This represents a regional, sustainable, and economically viable alternative for utilizing this important plant resource.