Effects of cold‐pressing conditions on physicochemical and functional properties of cold‐pressed tigernut oil and starch isolated from press‐cake

Abstract

Summary Tigernut tuber is a peculiar source of oil because it has high amounts of starch. To collect tigernut oil and obtain high‐quality starch from pressed cake, a comprehensive validation of the cold‐pressing method was conducted. At 40–60 MPa, from one pressing, 67.18–73.97% of total oil content can be obtained; with three pressings, 77.38–82.34% of total oil can be obtained. Starch yields from solvent extraction of cold‐pressed press‐cake are significantly higher ( P < 0.05) compared with native tigernut flour. For oils from different pressings, the fatty acid and total tocopherol contents had no obvious difference. Structural and functional analysis of the starch showed that cold‐press pretreatment had little effect on the particle size and molecular chains of the starch, while the syneresis and storage modulus (G′) of starch gel increased slightly. Overall, cold‐pressing is a potential processing method for effectively developing tigernut oil and starch as industrial resources.