Comparative Study of the Nutritional Composition and Bioactive Characteristics of Low-Grade Fresh Cacao Fruit (Theobroma cacao L.) and Its Anatomical Parts

Large quantities of low-grade fresh cacao fruits (Theobroma cacao L.; pod weight < 250 g) are generated as by-products during cocoa processing and remain largely underutilized, despite their potential as sources of nutrients and bioactive compounds. To address this gap, this study aimed to provide the first comprehensive comparative evaluation of the proximate composition and biological activities of distinct anatomical parts of low-grade cacao fruits, including cocoa beans, pulp, pod husk, and whole fruit. Proximate composition was determined using standard analytical methods, while ethanolic extracts of each fruit part were evaluated for total phenolic content (TPC), total flavonoid content (TFC), antioxidant capacity (DPPH, ABTS, FRAP, and metal chelating assays), as well as hypoglycemic, tyrosinase inhibitory, and antimicrobial activities. The proximate composition varied significantly among the different parts, with carbohydrates (67.12% - 90.03%) being predominant, while fat (1.38% - 20.08%), ash (3.44% - 11.40%), and protein (4.64% - 8.89%) were present in lower and variable proportions. Significant differences in biological activities were observed among fruit parts (p < 0.05). Pod husk showed the highest TPC, ABTS radical scavenging activity, FRAP, metal chelating capacity, and tyrosinase inhibition, whereas cocoa beans had the greatest TFC and DPPH radical scavenging activity (p < 0.05). Pulp and pod husk exhibited strong α-amylase and α-glucosidase inhibitory effects, respectively. Pod husk extract showed the most pronounced tyrosinase inhibitory effect (IC₅₀ = 2.83 mg/mL) and the highest antimicrobial activity against Staphylococcus aureus and Staphylococcus epidermidis. These results highlight the nutritional and functional potential of low-grade cacao fruits, particularly the pod husk, as a valuable source of natural antioxidants and bioactive compounds that may be exploited in the development of functional foods, food-related products, and cosmetic formulations. However, as all biological activities were assessed exclusively under in vitro conditions, further in vivo investigations are necessary to verify their physiological efficacy, bioavailability, and safety. Overall, this study supports the sustainable valorization of cocoa by-products for potential applications in food, nutraceutical, cosmetic, and pharmaceutical sectors. HIGHLIGHTS The study compares nutrients and bioactivities of cacao fruit components. Carbohydrates dominate, while other nutrients vary across fruit parts. Pod husk shows highest phenolics; beans contain the most flavonoids. Pod husk and beans exhibit strong antioxidant activities in all assays. Pod husk shows potent antidiabetic, tyrosinase, and antimicrobial effects. GRAPHICAL ABSTRACT