Nutrients, bioactive compounds and antinutritional properties of marigold genotypes as promising functional food
Hasina Sultana, Khaled A. Alakeel, Jahidul Hassan, S. Mallick, Mohammad Zakaria, Emrul Kayesh, Joydeb Gomasta, Md. Zubayer, Muhammad Mustakim Billah, Yukio Ozaki, Alanoud T. Alfagham, Saud Alamri
Abstract
The rising demand for health promoting functional foods has sparked interest in diversifying diets by incorporating innovative items like edible flowers. Considering this, the nutritional composition, bioactive properties and antinutritional factors of the flowers of eight marigold genotypes (M 1 to M 8 ) were quantified and compared to elucidate their value and safety as functional food. The study outcomes highlighted significant differences among the genotypes for most of the attributes. Anthocyanin, carotenoid and lutein contents were observed within a range of 0.02 to1.90 mg/100 g, 5.02 to 11.08 mg/100 g and 0.19 to 9.78 µg/g, respectively. The content of sugars, β-carotene, vitamins (C and E) and minerals (sodium, potassium, calcium, magnesium and iron) were also found to be present in substantial amounts. The analysis of bioactive compounds revealed the richness in total phenolic (TPC) (428.58 to 592.71 mg gallic acid equivalent (GAE)/100 g) and flavonoid content (TFC) (135.06 to 233.39 mg quercetin equivalent (QE)/100 g). Among the assessed antinutrients, alkaloid, tannin and saponin exceeded permissible limits in the studied genotypes, while phytate remained within the safe range. However, the elevated levels of these antinutrients would not pose any problem if processed through methods such as soaking, boiling or cooking. Out of eight genotypes, M 1 had the highest content of anthocyanin (1.90 mg /100 g), reducing sugar (21.63 mg/100 g), and antioxidant activities. M 5 stood out with the highest levels of TSS (6.10 °Brix), β-carotene (0.50 mg/100 g), vitamin C (28.61 mg/100 g), Ca (225.33 mg/100 g), and TPC (592.71 mg GAE/100 g), while M 6 contained significant amounts of carotenoids (11.08 mg/100 g) and TFC (232.41 mg QE/100 g). Principal component analysis and cluster dendrogram findings further confirmed that among the eight studied genotypes, M 1 , M 5 and M 6 genotypes were found as the most prominent with the remarkable contributions of the majority of the studied variables. Hence, these marigold genotypes could be considered as promising options to improve and diversify healthy diets, potentially serving as valuable sources of dietary supplements and functional food ingredients.