Antioxidant Activity, Total Polyphenol Content, and Mineral Composition of Milk Beverages Fortified with Spice Mixtures (Clove, Cinnamon, and Turmeric) and Natural Sweeteners (Erythritol and Stevia): Evidence of Synergistic or Antagonistic Effects of Compounds.

Extensive research is underway on a variety of functional foods that support consumer health. A promising combination is milk (a drink with high nutritional value), fortified with spices (naturally rich in antioxidant compounds) and supplemented with low-calorie, health-promoting sweeteners. The aim was to analyze the antioxidant activity (AA), total polyphenol content (TPC), and mineral composition of milk beverages fortified with a mixture of spices and sweeteners and to verify the interactions between these ingredients. Twenty-four variants of milk drinks were prepared with the addition of three types of spice mixtures (1:1) of clove (Cl), cinnamon (Ci), and turmeric (Tu) with the shares of 2.5%, 5%, 7.5%, and 10%, and two types of sweeteners-erythritol (E) and stevia (S)-as well as six control samples, including three 10% aqueous solutions of spice mixtures. AA was measured using the ABTS, FRAP, and DPPH methods. TPC was determined using the Folin-Ciocalteu method. Mineral content (Ca, Mg, Fe, Cu, and Zn) was assessed using the FAAS/FAES method. The highest AA was demonstrated for beverages with Cl-Ci and Cl-Tu, whereas the highest TPC was found in those with Cl-Tu. AA and TPC values increased with the increase in the share of spices in the beverages, and both measurements were significantly higher in beverages with erythritol compared to those with stevia. Despite the 4-5 times lower TPC, 3-8 times higher AA was demonstrated in beverages with the addition of 10% spice mixtures than their corresponding control samples (aqueous solutions with the addition of 10% spice mixtures), which suggests the great role of interactions between nutrients in food. For beverages with 10% Cl-Ci/Cl-Tu mixtures, significantly higher ABTS, FRAP, and DPPH were observed than would result from the simple sum of AA of the components (synergistic effect). The opposite (antagonistic) effect was observed for beverages with Ci-Tu. AA was positively correlated with the content of Fe, Mg, and Cu; negatively with Ca; and not correlated with Zn. The results suggest that the most health-promoting properties are exhibited by the milk drink with the addition of 10% Cl-Tu and erythritol, demonstrating the highest AA and TPC, the strongest synergistic effect of the components, and the highest content of Mg and Zn. This study highlights the importance of carefully selecting and combining ingredients to maximize the antioxidant properties of functional beverages. However, further research is needed to expand knowledge on this issue.