Journal of Environmental Biology

High-shear optimized shade-dried marigold carotenoid extract: process optimization and stability kinetics

A.K. Rajeev¹, P. Anand¹*, A. Joshi², K.P. Singh¹ and M.C. Singh³     

¹Division of Floriculture and Landscaping, ICAR- Indian Agricultural Research Institute, New Delhi-110 012, India

²Division of Food Science and Postharvest Technology, ICAR- Indian Agricultural Research Institute, New Delhi-110 012, India

³Centre for Protected Cultivation Technology, ICAR- Indian Agricultural Research Institute, New Delhi-110 012, India

Received: 18 October 2025                   Revised: 21 January 2026                   Accepted: 16 April 2026

*Corresponding Author Email: prativa.anand0723@gmail.com                  *ORCiD: https://orcid.org/0000-0002-9678-1627

Abstract

Aim: To optimize a green-solvent, high-shear extraction protocol for carotenoids from shade-dried marigold (Tagetes erecta L.) petals and assess extract stability under varying temperature, light, and pH.

Methodology: Petals (cv. ‘Pusa Narangi Gainda’) were extracted using ethyl acetate 60% (v/v) formulated with acetone. A Box–Behnken Design under Response Surface Methodology (RSM) was employed, with spindle speed (10,000–20,000 rpm), extraction time (1–3 min), and temperature (10–40^°C) as independent variables. Responses included total carotenoid content, antioxidant activity (FRAP, CUPRAC), and color parameters. The optimized extract was subjected to stability testing under different storage temperatures (10–40^°C), light vs. dark exposure, and pH (2–8) over 7 days and degradation kinetics were fitted to first-order models.

Results: Optimal conditions (19,936.73 rpm, 2.98 min, 34.85^°C) predicted total carotenoid content of 1,936.94 mg 100 g-1 d.wt., FRAP of 369.08 µmol TE g^-1, and CUPRAC of 284.04 µmol TE g^-1. The maximum retention occurred at 10^°C, in darkness and near-neutral pH (6–7.5), while degradation accelerated under heat, light, and extreme pH.

Interpretation: High-shear ethyl acetate extraction is efficient and eco-friendly for marigold carotenoid recovery. Shade drying combined with low temperature, darkness, and near-neutral pH effectively preserves pigment stability, supporting sustainable industrial utilization.

Key words: Antioxidant activity, Carotenoids, Green solvents, High-shear extraction, Marigold, Stability kinetics

Copyright © 2026 Triveni Enterprises. All rights reserved. No part of the Journal can be reproduced in any form without prior permission. Responsibility regarding the authenticity of the data, and the acceptability of the conclusions enforced or derived, rest completely with the author(s).