Effect of ultrasound for postharvest preservation of carrot from an economic and environmental perspective: Experimentation and deterministic optimization

Abstract

The promising potential of organic agents in elevating food preservation during the minimal processing of fruits and vegetables has surfaced as a notable trajectory. The objective of this work was to evaluate the effectiveness of citric acid and ultrasounds power during carrot sanitization considering various acid concentration and exposition times. To this end, optimization and mathematical modeling tools are employed to assess the implementation of ultrasound technology (US) and citric acid for improved carrot preservation, considering both economic and environmental perspectives. The foregoing is based on an Mixed-Integer Nonlinear Programming (MINLP) optimization problem which allows the selection of which conditions of citric acid concentration and ultrasound time are economically suitable as well as the evaluation of their environmental impact. The model and optimization were generated from experimental data obtained at different sanitization treatments of carrots with citric acid (150, 400, and 900 ppm for 0, 15, 30, 45, 60, 90, and 120 min) in static and Ultrasound baths. Citric acid content, color parameters, and growth of microorganisms in the carrots during storage at 4°C (days 0, 3, 6, and 9) were evaluated. The citric acid and moisture content in carrots increased with the concentration of citric acid in sanitizing solution. Ultrasound increased the citric acid content in carrots by up to 17 %, particularly during the treatment process. However, the optimization results showed that, at 900 ppm of citric acid, both with and without ultrasound technology, similar improvements in shelf life were observed, including lower microbial loads and reduced color changes up to the sixth day of storage. However, the use of US technology increased the cost and environmental impact.