(673a) Economic and Environmental Impact of Ultrasound-Assisted Carrot Preservation: Experimental Results and Deterministic Optimization

The use of organic agents in food preservation offers a sustainable alternative for minimally processed fruits and vegetables. For example, citric acid is commonly used in the disinfection and washing of carrots to control microbial growth, reduce browning, and decrease cellular respiration. However, ensuring effective uptake of citric acid is crucial, as its slow mass transfer through the carrot tissue can lead to longer processing times and higher costs (Phong et al., 2023). Recent advancements highlight ultrasound technology (US) as a promising method to accelerate this process (Bhargava et al., 2021). Ultrasound enhances mass transfer through cavitation, which disrupts cell membranes and generates microcurrents, thereby facilitating deeper and faster penetration of citric acid. This non-thermal, environmentally friendly technique not only improves the efficiency of the sanitization process but also helps maintain the sensory and nutritional quality of the products. Moreover, optimizing process variables through mathematical models and incorporating environmental impact assessments further supports sustainable scaling in industrial applications (Silva & Sanjuan, 2019). Such integrated approaches lead to innovative, efficient, and cleaner food preservation strategies that meet modern consumer demands.

In this context, this study explores a novel approach to carrot preservation by combining citric acid with ultrasonic technology, ensuring that nutritional and sensory qualities are maintained. The investigation is structured in two main stages. In the first one, an experimental evaluation is conducted to assess the effectiveness of using citric acid together with ultrasound for carrot preservation. Key output variables, such as citric acid concentration, color stability, and microbiological properties, are analyzed to determine the impact of the proposed combined treatment. The second stage leverages the experimental data to develop a modeling and optimization framework for process design. This analysis aims to identify the optimal operating conditions that minimize both operating costs and the environmental footprint of the process by targeting a real implementation of the carrot treatment proposed. In terms of economics, the capital (CAPEX) and operational expenditures (OPEX) of the various alternatives have been assessed. Concurrently, the environmental sustainability of these options is evaluated using the Eco-indicator 99 metric.

The study reveals how citric acid concentration and ultrasound technology affect carrot preservation. It shows that using a higher citric acid concentration (900 ppm) combined with US accelerates acid absorption and improves water transfer, leading to notable changes in moisture content and color parameters that remain within acceptable sensory limits. The treatment effectively reduces fungal and bacterial loads during initial storage, though its effectiveness decreases after six days, indicating a need for supplementary preservation strategies. While lower citric acid concentrations (150 ppm) are more cost-effective and environmentally friendly, higher concentrations yield superior preservation outcomes, although with increased processing costs and energy consumption from US. Overall, the study underscores the potential of these methods not only for carrots but also for other vegetables, contributing to the development of sustainable postharvest processing techniques that balance preservation effectiveness, economic feasibility, and environmental impact.

Acknowledgements

A.S. acknowledges the financial support of the “Consejería de Educación” of the “Junta de Castilla y León” under project SA085P24.

References

Bhargava, N., Mor, R. S., Kumar, K., & Sharanagat, V. S. (2021). Advances in application of ultrasound in food processing: A review. Ultrasonics sonochemistry, 70, 105293.

Phong, W. N., Payne, A. D., Dykes, G. A., & Coorey, R. (2023). Postharvest decontamination of fresh black truffle (Tuber melanosporum): Effects on microbial population and organoleptic qualities. Postharvest Biology and Technology, 197, 112191.

Silva, V. L., & Sanjuan, N. (2019). Opening up the black box: A systematic literature review of life cycle assessment in alternative food processing technologies. Journal of Food Engineering, 250, 33-45.