Effect of Freeze Concentration on the Process Parameters, Physicochemical Properties, Total Bioactive Compounds and Antioxidant Capacity of Almond Milk

Abstract

The objective of this study was to evaluate the application of centrifugal block freeze concentration (CBFC) in fresh almond milk to obtain a concentrated liquid sample with enhanced chemical composition, total bioactive compounds (TBC), antioxidant activity, and process parameters, preserving its physicochemical characteristics. As the cycles progressed, the chemical composition (protein and lipid content), TBC (total polyphenol, flavonoid and protein (albumin) content), and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC)) significantly increased, reaching 5.2% and 3.3%, 3.16 mg gallic acid equivalents/100 mL, 0.2 mg catechin equivalents/100 mL, 33.5 mg albumin/100 mL, and 55.9, 71.4, and 65.1 µM Trolox equivalents/100 mL, respectively. The separation efficiency and solute yield reached values close to 87% and 72%, respectively. In solute terms, a significant threefold was noted, maintaining an attractive color very similar to that of the fresh sample. Thus, CBFC is an efficient low-temperature concentration method for liquid foods, with lower degradation of TBC than evaporation technology. Hence, the concentrated sample has potential for applications as a functional food and nutraceutical ingredient due to its increased TBC and antioxidant capacity, while its preserved physicochemical stability and chemical composition also suggest feasibility for cosmetic formulations.