Tomatoes, owing to their rich nutritional content and their versatility in both raw and cooked forms, hold an integral place in our diets (Diantom, Boukid, Carini, Curti, & Vittadini, 2020). As per the latest data from the Food and Agriculture Organization (Food and Agriculture Organization of the United Nations (FAO), 2020), the worldwide production of tomatoes is on an upward trajectory, by 2019, it exceeded 186 million tons per year. This surge in production reflects the growing popularity of tomatoes, a testament to their beneficial components and their significant nutritional and medicinal values (Granger & Eck, 2018). Notably, tomatoes are a rich source of lycopene (C40H56), a carotenoid found in human plasma that lends the red color to fruits and vegetables. Remarkably, lycopene boasts an antioxidant activity that is tenfold greater than alpha-tocopherol and twice that of beta-carotene (Khan et al., 2021).

Since the human body cannot produce ascorbic acid on its own, it requires dietary consumption of this substance to meet its Vitamin C requirements. As an antioxidant, ascorbic acid or Vitamin C is crucial to the body's function and can be found in abundance in certain foods like tomatoes (Ferrada, Barahona, Salazar, Vandenabeele, & Nualart, 2020). A small portion of tomatoes is consumed fresh as a seasonal product, while the majority of tomatoes are processed into tomato paste and tomato juice. Tomato paste, along with tomato sauce and ketchup, is a key ingredient in many popular products. Tomato paste is produced through a process that relies on heat treatment, both in home and industrial settings. The heat treatment process can inadvertently modify the aroma profile of tomato juice, which can negatively impact the final quality of the tomato paste, posing a major hurdle (Zhu, Klee, & Sarnoski, 2018).

The filtration process divides the primary liquid product into multiple streams. The filtrate, or the substance that permeates the filter, is termed “permeate,” while the remainder, known as “retentate,” is left behind (Kazemi, Jahanshahi, & Peyravi, 2018). The potential application of membrane technology in the production of tomato juice concentrates has been under scrutiny since 1981. Despite its numerous advantages including aromatic compounds preservation, enhanced nutritional value, decreased energy consumption, heat degradation elimination, as well as savings in time, labor, and space, along with lower capital investment needs compared to thermal concentration techniques, membrane filtration still lags behind thermal methods in the tomato juice concentrate sector. This is primarily due to issues such as the high pressure prerequisites for reverse osmosis systems, and pore blockage in membranes (Ganorkar, Nandane, & Tapre, 2012). Research employing microfiltration membrane technology prior to juice concentration has demonstrated a marked decrease in the rate of membrane pore closure (Shanmuganathan, Nguyen, Jeong, Kandasamy, & Vigneswaran, 2015). The centrifuge method, though utilized for the separation of tomato juice pulp, has proven to be both inefficient and cost-intensive (Bahçeci, Akıllıoğlu, & Gökmen, 2015). Augmenting the efficiency of the reverse osmosis filtration method, and concurrently reducing the necessity and expense of filter maintenance, can be achieved through the separation of insoluble solids prior to filtration (Zhang & Feng, 2022).

The spiral filter press serves as an essential tool in the food industry, particularly in the dehydration of various fruits like apples, pears, pineapples, kiwis, watermelons, and tomatoes. This device functions by crushing the fruits and pressing them against the filter's surface to execute dehydration, following which the resultant pulp is directed to the outlet via the spiral movement. Consequently, the juice extracted is often high in pulp content. Spiral press filters are mostly used to separate water from solids that can move forward with spiral pressure. A significant advantage of this device lies in the movement of the material on the surface of the filter, which ensures its cleanliness and allows for continuous execution of the filtration process (Kips et al., 2016; Kips et al., 2017). A filter press serves as an instrumental device in the separation process of solid particles from a liquid saturated with excess water. It typically comprises a stationary plate, pressed against by a movable plate connected to a hydraulic jack. The mechanism works by pumping fluid and generating hydraulic pressure, which leaves the solid particles behind on the stationary plate and allows water droplets to pass through fabric holes. Consequently, the filter press enables the separation process. A significant advantage of the filter press is its lack of moving parts. The filtration process hinges on the hydraulic pressure of the fluid. However, the accumulation of solid particles on the filter surface can lead to the closure of membrane pores, necessitating a halt in the filtration and purification process for maintenance (Morsch et al., 2021; Sandoval et al., 2019). The majority of the pulp particles in tomato juice fall within the size range of 100 to 1000 μm (Kubo, Augusto, & Cristianini, 2013).

Dead-end filtration refers to a membrane process where the feed liquid passes through the membrane in a unidirectional flow. The liquid that permeates seeps through the membrane pores, while the suspended solids or particulates in the feed liquid are held back on the reverse side of the membrane, forming a filtrate cake. As this cake accumulates, it increases the pressure exerted on the membrane and eventually slows the permeate liquid flow to an insignificant level. At this juncture, it becomes necessary to cease the filtration process, eliminate the accumulated filtrate cake and clean the membrane thoroughly. Cross-flow filtration (CF) is a membrane filtration technique where the feed stream moves in a direction parallel to the membrane surface. It enables the separation of dissolved and suspended solids from the feed stream at a right angle to the membrane surface. CF's efficiency in material separation from the feed stream stems from its ability to inhibit filter cake formation on the membrane and reduce the potential for membrane clogging (Rivera et al., 2020).

Membrane clogging is a physical phenomenon that occurs when suspended particles within a liquid come into contact with and adhere to the membrane surface. This adherence results in a reduction in the membrane's permeability, thereby diminishing the overall efficiency of the membrane system. One of the pivotal factors influencing membrane clogging is the flow rate. A more elevated flow rate escalates the fluid's velocity in relation to the membrane, which in turn shortens the interaction duration between the fluid and the membrane. This sequence of events can potentially lower the probability of pore obstruction (Busatto et al., 2018).

In this study, it was capitalized on the benefits of the spiral filter press, which offers continuous filtration and cleaning, as well as the filter press, which facilitates filtration through fluid pumping and hydraulic pressure. It was designed and implemented a novel laboratory-scale spiral filter press system. This system utilizes tomato juice pumping as a driving force with a stable spiral path compared to a filter equipped with a 100 μm mesh size. The system is engineered to separate the pulp from the juice of the tomato, with adjustable controls for pressure levels and fluid temperature. The aim of the study was to scrutinize the impact of fluid pressure and temperature on the tomato juice filtration process. The ultimate objective was to fine-tune this process to enhance the permeate flux, lycopene, and vitamin C content, while also reducing the total energy consumption.