Microalgae-Enriched High-Moisture Meat Analogues: Improved Physicochemical, Functional, and Digestibility Properties

This investigation examined the effects of microalgae supplementation on the physicochemical properties, nutritional profile, and digestibility parameters of high-moisture meat analogues (HMMAs). The sustainability and nutritional potential of incorporating three microalgae species-<i>Arthrospira platensis</i>, <i>Haematococcus pluvialis</i>, and <i>Nannochloropsis oculata</i>-into diets were investigated at inclusion levels of 0.5% and 1.5% (<i>w</i>/<i>w</i>). Colour metrics, compositional analysis, antioxidant capacity, textural characteristics, and in vitro protein digestibility were also assessed. The findings demonstrated enhancements in nutritional quality, particularly in protein content. Antioxidant capacity was significantly elevated in the 1.5% inclusion samples. Samples containing 1.5% <i>A. platensis</i> exhibited the highest chlorophyll concentrations at 19.91 mg/mg, while 1.5% <i>H. pluvialis</i> displayed carotenoid levels at 34.59 µg/mg. These improvements correlated with increased efficacy in ABTS and FRAP radical scavenging assays. Colourimetric analysis indicated that elevated microalgae concentrations contributed to darker hues; 1.5% <i>H. pluvialis</i> markedly increased redness (a-value, <i>p</i> < 0.05), with the visual profile similar to conventional meat. Supplementation with 1.5% <i>A. platensis</i> consistently decreased hardness and chewiness, likely attributable to enhanced porosity. Conversely, 1.5% <i>N. oculata</i> promoted a honeycomb-like microstructure, thereby augmenting cut resistance and hardness. The diminished rehydration capacity observed in 1.5% <i>H. pluvialis</i> was ascribed to smaller pore sizes, but maintained a higher oil-holding capacity relative to the control. All microalgae-infused HMMAs retained excellent in vitro protein digestibility. These results underscored the potential of microalgae-particularly 1.5% <i>A. platensis</i> for nutritional and textural enhancements, 1.5% <i>H. pluvialis</i> for improved visual and antioxidant properties, and 1.5% <i>N. oculata</i> for elevated phenolic and chlorophyll contents-in advancing sustainable, plant-based meat alternatives.