Effect of high-pressure homogenisation on the structure and functional properties of micro algae Golden Chlorella (Auxenochlorella protothecoides)

Microalgae are valued for their high protein content (30-70%), essential amino acids, and fatty and acids making them valuable food supplements and promising natural ingredients. Golden Chlorella; GC ( Auxenochlorella protothecoides ) has recently gained attention as a functional microalgal ingredient owing to its nutritional value, functionality and sustainability characteristics. This study investigated the effects of high-pressure homogenisation (HPH), on the microstructure and functional properties of GC suspensions. GC dispersions were treated at 200, 500 and 1000 bar using one or two passes, and changes in microstructure and techno-functional characteristics were evaluated. Microscopy showed that increasing homogenisation pressure reduces the size of large agglomerates into smaller and more uniform fragments, thereby enhancing interactions within water and oil matrix. Water solubility of HPH processed GC increased by 22%, 35% and 54% after single-pass homogenisation at 200, 500, and 1000 bar, respectively, compared to untreated GC (12%). These HPH conditions also improved the oil adsorption capacity of GC by 46.4%, 61.0% and 67.4%, respectively, whereas foaming capacity improved by 8.0%, 19.5% and 28.0%. Viscosity of HPH-modified GC samples at 200 bar increased up to 1.5 times compared to untreated GC suspension. Overall, increasing pressure during HPH significantly enhanced the solubility, adsorption properties, viscosity and foaming capacity GC, demonstrating its potential as an effective technology to modify functional properties of microalgal ingredients. • HPH reduced the particle size of golden chlorella effectively. • HPH increased solubility with higher pressure and more passes. • HPH enhanced the oil absorption capacity of golden chlorella. • HPH increased viscosity with increasing pressure and number of passes.