Functionalization of yogurts with Agaricus bisporus extracts
The extensive use of synthetic additives in foods, some of them recognized as carcinogenic substances, has alerted consumers towards the need of adopting healthier habits. Moreover, their appetence for functional foods, i.e. foods promoting positive effects on health in addition to their basic nutritional purposes, is progressively increasing.
•Preparations of crosslinked citric acid-maltodextrin protected mushroom extracts.
•The assayed carriers, prepared by spray-drying, were innovatively used in yogurt.
•Free and microencapsulated extracts gave significant differences in yogurt bioactivity.
•Extract-loaded microspheres submitted to post-thermal treatment gave the best results.
•The assayed system assured the gradual release of the extract along storage time.
Mushrooms represent interesting sources of bioactive compounds with potential application in functional foods. They can provide immunomodulating, antitumour, anti-hypercholesterolemic, antibacterial, antifungal, anti-inflammatory, antiviral, anti-diabetic, and cardioprotective effects to consumers.
The formulation of functional foods, namely dairy beverages, with A. bisporus extracts was reported to increase their bioactivity, as indicated by in vitro studies that validated the antioxidant activity and cytotoxicity against tumor cells. However the poor solubility of its major compound, ergosterol, both in lipophilic and hydrophilic media, may limit the application of those extracts.
In a recent study, alcoholic extracts of Agaricus bisporus were studied for their bioactivity and viability as functional ingredients in a food product with high water content (yogurt). Extracts were microencapsulated (to improve their stability and hydrophilicity) by spray-drying, using maltodextrin crosslinked with citric acid as encapsulating material. The effect of thermal treatment (after atomization) on crosslinking and bioactivity of microspheres was tested. The incorporation of free and thermally untreated forms resulted in yogurts with higher initial antioxidant activity (EC50 values: 214 and 272 mg.mL−1) that decreased after 7 days (EC50 values: 248 and 314 mg.mL−1). Contrarily, thermally treated microencapsulated extracts showed higher antioxidant activity after the same period (EC50 values, 0 days: 106 mg.mL−1; 7 days: 48.7 mg.mL−1), in result of an effective protection provided by microencapsulation with crosslinked maltodextrin and citric acid.
Results showed that the use of spray-drying technique and the occurrence of crosslinking of the encapsulating material are efficient to promote the protection, assuring a gradual release of the extract under the tested storage time. Functionalized yogurts showed an overall maintenance of nutritional properties.
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