Hot and Cold Integrated Process to Obtain Chia Seed Oil, Mucilage, and Protein Concentrates

An integrative extraction of chia seed (Salvia hispanica) byproducts (mucilage, oil, and proteins) was applied under both hot and cold conditions, followed by an evaluation of the resulting chia protein concentrates. Hot conditions enhanced protein solubilization during the mucilage extraction step, which reduced the protein recovery in the subsequent protein extraction, producing a hot chia protein (HCP) with a lower protein content (22.9%) than cold chia protein (CCP) (77.4%). Furthermore, CCP exhibited a higher denaturation temperature (92.3 °C), fewer free sulfhydryl groups (30.8 μmol L–1 g–1), and a slightly higher ζ-potential than HCP, which contributed to improving emulsifying properties in emulsions containing 3% protein at pH 3. Heating induced conformational changes in the HCP. β-Sheets were transformed into β-turns, α-helices, and aggregate structures due to denaturation, exposing hydrophilic groups and enhancing the water absorption capacity of HCP. Therefore, the selection of extraction conditions should be tailored to obtain food ingredients with desirable characteristics.