Utilizing physicochemical and sensory analyses to guide development of a novel high-protein almond milk with environmentally-friendly processing methods

Despite its popularity, conventionally manufactured almond milk is low in protein (0.42%) and lipids (1%) compared to bovine milk. This presents an opportunity for the development of an improved almond milk. The objective of this research was to increase the protein and oil content of almond milk without negatively impacting its sensory properties and stability by using the Aqueous and Enzyme-Assisted Aqueous Extraction Processes (AEP/EAEP). A central composite design was employed to determine the combined impact of solids to liquid ratio (1:10 to 1:6) and pH (7-9 for AEP) or enzyme concentration (0.25-0.75% alkaline protease for EAEP) on the physicochemical and biological properties and acceptability of the resultant milks. Protein extraction yields of ~72% for AEP and ~90% for EAEP were achieved. Though the use of enzyme improved protein extractability, it also led to increased oil droplet diameter and decreased viscosity, indicating weaker emulsions compared to the AEP milk. Enzyme use also led to increased decreased almond protein immunoreactivity via ELISA tests (1.0 x 10⁵ vs 9.4x10⁶ mg amandin/kg skim protein). Descriptive sensory analysis was employed to analyze the sensory properties of the milks and compare them with other commercial almond milks. Some milk formulations were then evaluated by an untrained consumer panel to determine degree of liking of the milk. Sensory tests showed that the EAEP milks were perceived as bitter, which could be a result of bitter peptides created during enzymatic hydrolysis, and thus EAEP samples were reformulated to reduce enzyme concentration. Overall, consumers preferred milks with a high almond butter to water ratio. Final AEP and EAEP formulations yielded a milk with higher protein (3.5%) and lipid (8.8%) contents and consumer liking comparable to those of commercially produced almond milks,  offering processors a method of manufacturing a nutritionally improved almond milk that consumers would enjoy.