Design and Application of Radiofrequency and Nanocomposite Packaging for Preservation of Habanero Pepper: Effects of Frequency, Processing Time, and Film Thickness

Abstract

Preservation of vegetables by drying, freezing, and pickling often leads to alterations in their nutritional characteristics. To promote preservation, this research explores the design and examines the effects of Radio Frequency (RF) and starch-based nanocomposite (SISN) packaging on the quality of habanero peppers during refrigerated storage. RF device was designed and applied to treat peppers at frequencies of 15.5 MHz, 20.22 MHz, and 27.12 MHz for 2, 4, and 6 min. The frequency was varied using a microcontroller MOSFET equipped with a voltage-controlled oscillator (VCO), phase-locked loop (PLL), and a frequency synthesizer. The treated samples were packaged with SISN films made of Irish potato starch and African star apple nanoparticles in three thicknesses (15.6 μm, 21.22 μm, 30.4 μm) and stored for 30 days at 6 °C. Microbial and nutritional properties, including lycopene, carotene, total phenolic compounds, and antioxidant activity, were examined. The optimal process parameters were identified using the Box-Behnken Design methodology. Results showed thicker films had better barrier properties due to lower permeance values, while thinner films exhibited higher thermal stability due to their tightly packed structure. Samples treated at 27.12 MHz for 6 min showed superior nutritional properties and the lowest microbial counts (fungi: 2.9 × 10² CFU/g, bacteria: 3.5 × 10³ CFU/g) at p < 0.05. At optimal conditions (23.73 Hz, 2 min, 28.14 μm film), microbial counts were reduced (fungi: 3.67 × 10² CFU/g, bacteria: 4.76 × 10³ CFU/g) compared to the control. Under these conditions, lycopene (6.31 mg/kg), β-carotene (3.68 mg/kg), and vitamin C (87.61 mg/100 g) levels increased, while antioxidant activity slightly decreased to 147.47 µmol TE/100 g. Thus, applying RF treatment before SISN packaging effectively preserved the quality of habanero peppers and is recommended for vegetables preservation.