Sustainable valorization of unutilized marigold flowers for eco-friendly herbal gulal production and its storability...

Floral waste from temples, markets and public events poses a growing environmental concern due to its high biodegradability and disposal challenges. In this study, a sustainable approach was employed to valorize marigold (Tagetes erecta L.) flower waste into eco-friendly herbal gulal, offering a biodegradable and non-toxic alternative to synthetic colorants. The experiment followed a Completely Randomized Design (factorial) with two packaging materials (polythene bag and steel container), two storage conditions (ambient and cold storage at 4 °C), and three storage durations (4, 8, and 12 months), each replicated thrice. Gulal prepared from marigold petals of cv. 'Laddu Gainda', harvested in August and December, was assessed for physico-chemical and sensory attributes. Storage in steel containers under cold conditions for 4 months preserved the highest total phenolic and flavonoid contents, maintained optimal pH, and minimized IC₅₀, microbial load, and colour change (Δe). In contrast, prolonged storage in polythene bags under ambient conditions led to quality deterioration. Nonetheless, herbal gulal retained appreciable properties up to 12 months, remaining superior to commercial gulal that exhibited elevated pH, microbial contamination, and heavy metal residues. The findings demonstrate that value addition of floral waste through herbal gulal production supports circular bioeconomy principles and contributes to sustainable waste management.