Optimization of extraction process and development of clove essential oil based biodegradable biofilm for preservation of grapes

¹ Amity Institute of Horticulture Studies and Research, Amity University, Noida, Uttar Pradesh, India
² Amity Food & Agricultural Foundation, Amity University, Noida, Uttar Pradesh, India

^* Corresponding Authors: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

Grapes are highly perishable and prone to rapid deterioration after harvest, particularly from Alternaria alternata, a major pathogen in grape storage. This study explores the development and application of a clove essential oil (CEO)-based biodegradable biofilm to extend grapes shelf-life extension. Response Surface Methodology (RSM) was used to evaluate the combined effect of ultrasonic temperature (35–45 °C) and ultrasonic extraction time (25–35 min) on essential oil recovery. Optimized Ultrasonic Pre-treated Soxhlet Extraction (UPSE) produced a maximum clove extract yield of 7.41% within 3.15 h at 40 °C for 30 min treatment. Ultrasonic Pretreatment Hydro-distillation (UPHD) further increased oil recovery to 8.63% within 2.00 h under optimized extraction conditions. A 500 μL of the clove essential oil (CEO) based biofilm formulation or oil emulsion was aseptically added to the sterile medium to achieve a final concentration of 1000 ppm. The CEO was incorporated into a sodium alginate-based biopolymer solution at (CEO)-based biofilm coatings at different concentrations (2.5 %, 5 %, and 10%) under fungal inoculation conditions. DLS analysis of a 2.5% CEO nano emulsion confirmed its nanoscale properties, with a Z-average size of 109.7 nm and a bimodal distribution for stable nono-emulsions confirmed through Dynamic Light Scattering (DLS) analysis. Antifungal assays significantly inhibited A. alternata growth on grapes reduced fungal infection at the 2.5% concentration. This indicates that the CEO based formulations were effective in preventing fungal infection on both sterilized and unsterilized grape surfaces. The results suggest that CEO-based edible films are a promising alternative to to synthetic fungicides and plastic packaging.