Bioacessibilidade de compostos bioativos em biomassas de microalgas dulcícolas para aplicação em alimentos

Abstract

Microalgae are microscopic organisms, usually unicellular, which carry out photosynthesis, converting solar energy into chemicals. Among them, dulcicolous species stand out, which have various bioactive compounds including amino acids, fatty acids, phenolic compounds and pigments. These compounds can exert different biological activities, such as anti-inflammatory, anti-diabetic, anti-hypertensive, antimicrobial and antioxidant. However, for bioactive compounds to exert their activity in the human body, they must be bioaccessible. Bioaccessibility refers to the fraction of a nutrient or bioactive compound present in a food that is released from the food matrix during the digestion process and thus becomes available for absorption in the gastrointestinal tract. Determining bioaccessibility is fundamental to establishing the possible beneficial effects of a food. Studies on the bioaccessibility of freshwater microalgae are still scarce in the literature. This study determined the profile of amino acids, fatty acids and phenolic compounds present in the biomass of freshwater microalgae (Chlorella vulgaris, Spirulina platensis, Scenedesmus acuminatus, Desmodesmus maximus and Tetraselmis sp.) and the bioaccessibility of these compounds after in vitro digestion. The antioxidant, antidiabetic and antihypertensive activity of the fractions intestinal obtained after in vitro digestion was also evaluated. The results obtained indicate that the biomasses of the microalgae studied have essential amino acids in their composition, with threonine, phenylalanine and lysine predominating before digestion. The bioaccessibility of the amino acids identified in the microalgae studied ranged from 25 to 257%. Saturated (palmitic, myristic and stearic), monounsaturated (palmitoleic and oleic) and polyunsaturated (linoleic and linolenic) fatty acids were also found, with a higher concentration in S. platenses. The bioaccessibility of fatty acids was over 70% in Tetraselmis sp, with the presence of essential fatty acids (omega 9), (omega 6) and (omega 3) standing out. The microalgae biomass also showed high concentrations of phenolic compounds before digestion, but the bioaccessibility values were less than 20%. The intestinal fractions of the microalgae evaluated showed excellent results for antidiabetic activity (20-96%), with Tetraselmis sp standing out, as well as for antihypertensive activity (13-53%). They also showed high antioxidant activity (1313-1821 μM eq Trolox/g), with D. maximus standing out, followed by Tetraselmis sp. The study demonstrated the rich nutritional composition of microalgae and highlighted D. maximus and Tetraselmis sp. (p < 0.05), which showed a higher amount of bioactive compounds compared to the other microalgae analyzed in this study. The results obtained demonstrate the functional potential of the microalgae biomassstudied, reinforcing the viability of its use in the preparation of high value-added foods, favoring the production and marketing of these products. This could help to meet the growing interest and demand from consumers for foods that appeal to their health and functionality.