316: Effect of Shortwave Germicidal UV-C Radiation Pre-Treatment on Drying Dynamics, Kinetic Modeling, Physicochemical Characteristics, and Functional Attributes of Costus Pictus D. Leaves

Introduction

Modern dietary habits have increased the prevalence of chronic diseases like diabetes mellitus, necessitating sustainable strategies to improve food quality and functionality. Costus pictus D., known for its antidiabetic and antioxidant properties, remains underutilized despite its rich nutritional profile. Ultraviolet-C (UV-C) radiation offers potential beyond drying, including reducing postharvest fruit diseases, delaying ripening, and combating senescence. This study explores UV-C radiation as a nonthermal pre-treatment to enhance the drying process and preserve the bioactive properties of Costus pictus D. leaves.

Methods

Costus pictus D. leaves were subjected to UV-C radiation (Wavelength 254 nm, 10 min, 8 W) prior to drying at 40°C, 50°C, and 60°C, with untreated samples as controls. Drying methods such as conventional drying, vacuum drying, and freeze drying were compared. Drying kinetics were modeled to identify the best fit, and mass transfer parameters, including effective diffusivity and activation energy, were evaluated. Biochemical analyses measured bioactive compound retention and antioxidant activity. Structural changes were examined using Scanning Electron Microscopy (SEM), and Fourier Transform Infrared Spectroscopy (FTIR) validated the preservation of antioxidant-related functional groups.

Results

The Page model provided the best fit (R²=0.998), showing enhanced moisture removal efficiency. UV-C treatment significantly improved mass transfer parameters, including effective diffusivity and reduced activation energy. Vacuum drying retained bioactive compounds effectively, while UV-C pre-treatment (dose at 2.286 KJ/m2) further enhanced their levels, increasing antioxidant activity and functional properties. UV-C treatment reduced drying time, and freeze drying preserved the highest levels of bioactive compounds and structural integrity. SEM revealed UV-C-induced cell wall disruption, facilitating improved moisture release, while FTIR confirmed the preservation of antioxidant-related functional groups. UV-C application improved produce quality and extended shelf life.

Significance

This study demonstrates UV-C pre-treatment as a sustainable, scalable, and eco-friendly approach for enhancing drying efficiency and preserving bioactive compounds in Costus pictus D. leaves. UV-C radiation offers transformative potential for perishable food systems, contributing to sustainable functional food production.

Authors: Naveen Chandrakar, Mamoni Banerjee