Desenvolvimento de um estruturado alimentício vegano a partir de algas marinhas (Hypnea pseudomusciformis E Gracilaria caudata) e vegetais

Abstract

This study aimed to develop a food-structured product composed of red seaweeds (Hypnea pseudomusciformis and Gracilaria caudata) and various vegetables, used in their entirety, as bioactive and aromatic ingredients for food preparation. The hydrated seaweeds (25 °C/1.5 h) were subjected to NaOH pretreatments (0.1 M and 0.25 M) for 1.5 h at 25 °C, both at a 1:30 (w/v) ratio. A control formulation was also evaluated. The pH of the samples was adjusted to 7.5–8.0, and aqueous extraction was carried out in a water bath under stirring at 1.5 rpm (90 °C/1.5 h). The resulting extracts were freeze-dried and analyzed for carbohydrates, proteins, total phenolic compounds, and antioxidant activity. The vegetables were dehydrated at 50 °C and ground for hydroalcoholic extraction with 50% (v/v) ethanol at a 1:25 (w/v) ratio at 78 °C for 2 h, followed by concentration and ethanol removal by rotary evaporation. The concentrate was analyzed for total phenolic compounds and antioxidant activity. The food-structured product was prepared by combining (1:1) an aqueous solution of seaweed extracts (3%) with a vegetable concentrate base (90%) containing solid residues (10%). The mixture was molded and refrigerated (4 °C/24 h). The fresh and freeze-dried structured products were evaluated for color, antioxidant activity, rheological properties, chromatographic profile, volatile compounds using an electronic nose, and the bioaccessibility of phenolic compounds and carbohydrates. Regarding the initial characterization of the extracts, the highest protein content (4.22%) was observed in the Hypnea control, whereas the highest carbohydrate content (18.65%) was obtained for Gracilaria pretreated with 0.1 M NaOH. The concentrate exhibited an antioxidant activity of 139.9 μmol TE/g. The structured products showed a neutral pH, phenolic compound concentrations ranging from 29.79 to 51.98 mg GAE/g sample, and a predominant aromatic profile characterized by acetaldehyde. The dissolution time was 0.97 min for the fresh product and 15.61 min for the freeze-dried product, which was attributed to molecular rearrangement. Bioaccessibility results demonstrated how the food matrix and processing conditions influence the release of nutrients during gastrointestinal digestion, with the fresh product showing a peak phenolic bioaccessibility of 179.7% in the intestinal phase. This value above 100% indicates that simulated digestion released compounds previously bound to the food matrix, making them more available for absorption than in the initial state of the sample. The structured product represents a vegan food ingredient that combines practicality and sustainability while providing aroma and bioactive compounds to foods.