Encapsulation of polyphenols in baked goods: a strategy for enhancing stability and antioxidant activity

The object of this study was polyphenol-rich extracts obtained from black tea, grape seeds, green tea, and blueberries, incorporated into bakery matrices in both encapsulated and non-encapsulated forms. The research addressed the critical problem of thermal degradation of polyphenolic compounds during baking, which drastically reduces their antioxidant capacity and limits their application as functional ingredients in food systems. Experimental results demonstrated that microencapsulation using food-grade biopolymeric carriers – especially sodium alginate – significantly enhanced the thermal stability and retention of polyphenols during high-temperature processing. Non-encapsulated samples retained only 42–60% of their initial polyphenol content post-baking, while encapsulated forms preserved up to 90%, showing a clear technological advantage. Antioxidant activity, assessed via DPPH and FRAP assays, decreased by up to 45% in non-encapsulated products, whereas encapsulated variants maintained 75–90% of their original activity. HPLC analysis confirmed that encapsulation reduced the thermal degradation of individual compounds such as catechins, flavanones, and anthocyanins. These protective effects are attributed to the formation of a stabilizing polymeric matrix that shields bioactives from oxidation, limits interactions with gluten and starch, and ensures more uniform retention within the food matrix. Sensory analysis further demonstrated that the addition of encapsulated polyphenols enhanced aroma, texture, crumb softness, and color, especially in samples enriched with grape seed and green tea extracts. These findings confirm the practical feasibility of polyphenol encapsulation in commercial bakery workflows for producing clean-label, antioxidant-enriched functional baked goods with improved nutritional and technological properties and extended shelf life.