Effects of enzymatic extraction on the simultaneous extraction of oil and protein from full-fat almond flour, insoluble microstructure, emulsion stability and functionality

Abstract

Lipid and protein extractability from food matrices has been challenged by the use of several sequential unit operations and flammable solvents to produce defatted flours. The effects of enzymatic extraction on the simultaneous extraction of lipids and proteins from full-fat almond flour, insoluble microstructure, and oil recovery from two different emulsion destabilization strategies (enzymatic and pH-shift) were evaluated. The physicochemical and functional properties of emulsion proteins were evaluated to elucidate the impact of both demulsification strategies on oil recovery and composition. Enzymatic extraction achieved 67% of oil and 77% of protein extractability while generating smaller protein fragments and a more porous insoluble structure. Enzymatic destabilization increased the degree of hydrolysis of the emulsion proteins from 8 to 22% while reducing their hydrophobicity from 1205 to 688. Moreover, it increased emulsion protein solubility from 33 to 50% (pH 5) while reducing its emulsification capacity from 731 to 324 g oil/ g. The changes observed in the physicochemical and functional properties of the emulsion proteins led to a 93% recovery of the extracted oil, highlighting the potential mechanisms involved during the emulsion breakdown. The almond oil fatty acid composition was not affected by the destabilization strategies evaluated, evidencing that enzymatic extraction followed by enzymatic destabilization of the emulsion is an effective and green strategy to maximize the extractability and recovery of oil and proteins from full-fat almond flour.

Keywords

• proteolysis
• emulsion
• oil recovery
• protein
• full-fat almond flour