# Optimized Continuous Thermosonication for Sustainable Pasteurization of Orange and Dried Black Lime Juices: Techno‐Functional, Physicochemical, and Microbial Assessment

## TL;DR

A new continuous thermosonication system was developed to efficiently and sustainably pasteurize orange and dried black lime juices while preserving quality and enhancing nutrients.

## Contribution

The development of a continuous thermosonication system that reduces energy use and improves juice quality during pasteurization.

## Key findings

- The CTS reduced energy consumption by 29.71% in orange juice and 30.51% in dried black lime juice compared to traditional pasteurization.
- Physicochemical and sensory properties of the juices were preserved with no significant differences compared to untreated fresh juice.
- Microbiological inactivation was complete, and bioactive compound content was enhanced in CTS-treated juices.

## Abstract

In pursuit of sustainable and efficient food processing solutions, a batch thermosonication system was successfully upgraded into a continuous thermosonication system (CTS) to improve pasteurization performance for orange juice (OJ) and dried black lime juice (DBLJ). The newly developed CTS integrates five core components: thermal heating, pumping, heat exchange, pasteurization, and electrical control units. Using response surface methodology, the effects of power (1.676–1.764 kW), mass flow rate (0.0142–0.0016 kg/s), and processing temperature (30°C–50°C) on the techno‐functional, physicochemical, and microbiological attributes of the juices were optimized. At optimal conditions, the CTS reduced specific energy consumption by 29.71% in OJ and 30.51% in DBLJ, relative to traditional pasteurization (TP: 90°C for 60 s), while improving energy efficiency and process productivity. No significant differences (p > 0.05) were observed in pH, titratable acidity, or sensory characteristics compared to untreated fresh juice. Moreover, the residual activity of pectin methylesterase was effectively reduced to 7.48% ± 0.11% (OJ) and 6.42% ± 0.074% (DBLJ). Microbiological analysis revealed complete inactivation of total bacterial count, psychrotrophic bacteria, coliforms, and yeasts and molds. Additionally, RP‐HPLC analysis confirmed enhancement in the bioactive compound content in CTS‐treated juices compared to both fresh and TP samples. These findings demonstrate that the CTS approach offers a sustainable, energy‐efficient, and quality‐preserving alternative for juice pasteurization, highlighting its potential application in modern food processing industries.

The study developed a continuous thermosonication system (CTS) for the sustainable pasteurization of orange and dried black lime juices. CTS reduced energy consumption by 30% compared to traditional pasteurization while preserving physicochemical, sensory, and microbiological quality. It also enhanced bioactive compounds, proving its potential as an efficient and quality‐preserving juice processing technology.