ABSTRACT Microalgae, such as Tetradesmus obliquus , have gained attention as sustainable alternative protein sources for food. This study aimed to compare three protein extraction strategies: (P A ): ball milling followed by solubilization, (P B ): ball milling, solubilization, and isoelectric precipitation, and (P C ): ball milling combined with ultrasound, solubilization, and precipitation. We also aimed to establish the relationship between processing conditions, protein structural modifications, thermal behavior, and techno‐functional properties of the resulting products. Compared to the other samples, the P B extract exhibited the highest protein content (52.65% on a dry weight basis), although it demonstrated a lower protein recovery yield. In contrast, the P C extract achieved the highest extraction yield, corresponding to 21.1% of the total protein in the biomass. Structurally, P C exhibited a more ordered secondary structure, whereas P A exhibited a less‐ordered profile. Differential scanning calorimetry revealed greater thermal stability for P C , with a denaturation enthalpy of 136.6 J·g −1 , indicating stronger intermolecular interactions after ultrasound‐assisted processing and precipitation, which directly influenced its functional behavior. The P C exhibited lower water‐holding capacity (0.71 ± 0.06 g water/g protein), higher oil‐holding capacity (1.98 ± 0.20 g oil/g protein), and superior emulsifying performance, with creaming index values between 44.6% and 57.6% (vol/vol) and emulsifying activity index ranging from 47.2 to 89.4 m 2 /g at 1% (wt/wt) concentration across pH 3.0–9.0. The main finding of this study is the clear processing–structure–function relationship established for T. obliquus proteins, identifying P C strategy as the most effective method for producing protein‐rich concentrates with potential applications as functional food ingredients.
Silva et al. (Sun,) studied this question.