Research background: Herbs and spices used in traditional medicine are nowadays increasingly used in combinations to create functional food formulations aimed at treating specific symptoms and disorders. Among herbs originating from the Mediterranean region, extracts of myrtle (Myrtus communis L.), bay leaf (Laurel nobilis L.) and fennel (Foeniculum vulgare Mill.) are traditionally used for gastrointestinal disorders. When considering how to incorporate these extracts into products, dairy-free milk alternatives provide an excellent base with almond-based drinks being among the most popular within this group.
Experimental approach: The aim of this study is therefore to optimise the formulation of an almond drink fortified with a 25 % (on dry mass basis) aqueous herbal extract containing myrtle, bay leaf (25 % each) and fennel seed (50 %) extracts. A central composite design with 20 formulations varied the content of φ(aqueous herbal extract)=2-6 %, lecithin as emulsifier 0.15-0.45 and xylitol as sweetener 2-5 % (m/V), while antioxidant activity, total phenolic content and sensory properties were determined as dependent variables.
Results and conclusions: The antioxidant activity and total phenolic content of the prepared almond drink formulations increased with the amount of added concentrated aqueous herbal extracts, as did the colour, herbal odour and flavour, bitterness and aftertaste. The addition of lecithin resulted in a darker colour and the sweetness was increased by the xylitol content. All formulations had good overall attractiveness, which increased with higher xylitol content.
Novelty and scientific contribution: The current work offers new insights into the optimisation of fortified dairy-free alternatives. The addition of myrtle, bay leaf and fennel seed extracts to almond drink-based formulations resulted in a 12-fold increase in antioxidant activity. Xylitol masks the potential bitterness of the phenolic compounds so that higher amounts of extracts can be added.
Keywords: almond drink; antioxidant activity; herbal extract; phenols; sensory analysis.
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