Novel Incorporation of Red-Stage Haematococcus pluvialis Wet Paste as a Colourant and Enhancer of the Organoleptic and Functional Properties of Filloas †

Haematococcus pluvialis Flotow is a microalga used as a nutraceutical, due to its high content in bioactive compounds, mainly carotenoids, in which astaxanthin stands out [1]. Furthermore, H. pluvialis has shown a high antioxidant potential, and combined with its intense red colour, this microalga could have dual functionality: as a colourant and a bioactive ingredient [2]. The process to obtain this ingredient involves several transformation steps—namely, lyophilisation and saponification—raising the costs to develop and obtain free astaxanthin, which paradoxically presents greater instability and solubility than its esterified counterpart [3]. Thus, this study provides an alternative approach for the application of red, astaxanthin-rich, H. pluvialis wet paste as a partial substitute for wheat flour (7% and 13% w/w) in the preparation of filloas (Galician pancakes), a typical dessert from the northwestern region of the Iberian Peninsula. To evaluate its power as a natural pigment, the stability of colour over time (3, 6, and 9 days) was measured, and the results were compared with those of a commercial colourant. At the same time, its physicochemical properties such as the microbiological profile were measured to determine its functionality as a food preservative. As a result, redness stability (a*) of 8% higher than that of the commercial colourant was obtained for the maximum concentration of H. pluvialis analysed. The texture showed a significant response (p < 0.02), improving its properties as the concentration of the microalga increased, which showed a tenacity of 3.23 N and extensibility of 15.10 mm during the first 6 days, i.e., a 52% and 19% improvement, respectively, in relation to the control group. In turn, an enrichment of carotenoids, fatty acids, and phenolic compounds, in combination with a potential moderator of microbiological degradation by this unicellular organism, gives added value to this food matrix.