Unveiling the enhanced bioactive and thermal properties of dark chocolates with tropical fruit enrichment

• The dominance of form V is attributed to both the incorporation of tropical fruits and controlled processing • Theobromine was the predominant methylxanthine, exceeding caffeine, characteristic of dark chocolates • The addition of fruits in chocolate acts as a fortifying strategy improving the bioactive profile The study aimed to evaluate the bioactive composition and thermal properties of dark chocolates formulated with cocoa from three countries (Peru, Mexico, and Brazil) and enriched with tropical fruits (cherimoya, pineapple, and soursop). The bioactive properties (polyphenol and flavonoid content and antioxidant activity), metabolite profile (methylxanthines, sugars, and amino acids), and thermal properties (crystallization and melting) were analyzed. The results showed that the addition of fruit increased the levels of polyphenols (52.4 mg GAE/g) and flavonoids (32.2 mg EC/g). Theobromine (12.0 mg/g) was the predominant methylxanthine compared to caffeine. Saccharose was identified as the major carbohydrate (22.6 mg/g). Likewise, the presence of amino acids such as aspartic acid, serine, glycine, arginine, alanine, valine, leucine, and phenylalanine was detected, while proline was found in low concentrations. Regarding the chocolates' thermal properties, they had a melting point between 32.9 and 33.3°C, showing a predominance of the stable Form V polymorph (60.2–70.7%). These findings demonstrate that the incorporation of tropical fruits into dark chocolates serves as a fortification approach that augments their bioactive profile and stabilizes their thermal properties.