---

The high levels of tomato production as well as its perishability, make the development of research on processing and improving the quality of existing products more evident. The aim of this study was to assess the effect of whole tomato heating treatment by steam on the physicochemical and structural properties of produced tomamto paste with different degree of Brix (°Br). The fresh tomatoes was washed with water followed by exposing to steam and the tomamto paste with different °Br (18-26) produced through hot breaking approach. The results showed that the color indexes, precentage of precipitation weight ratio, acidity, viscosity, consistency and microstructure of final products were significantly influenced by steam preheating. The color indexes of ^*a and b^* and precentage of precipitation weight ratio were negatively affected by steam preheating. The reason behind these observation is increasing the efficiency of heating process in hot breaking stage reulted in lycopene destruction. On the other hand, the viscosity and consistency of tomato paste were meaningfully increased. The images of scanning electron microscopy revealed that the steam preheating brought about solube pectin to migrate from cell wall, forming an amorph structure. Considering the acceptble range of color indexes as well as profound improvment in rheological characteristics of produced tomamto paste, in can be concluded that applying preheating treatment by steam would be of efficeint procedure in tomato paste production.
 

---

Currently, dissimilar metal joining processes are receiving considerable attention in various industries. The objective is to create composite structures that are both high-strength and lightweight, ultimately reducing the weight of the final product. Researchers have recently proposed friction drilling as a new method for creating joints between dissimilar metal sheets. This innovative technique offers potential advantages in achieving the desired outcomes. In this process, metal sheets are placed on top of each other and simultaneously subjected to friction drilling. As a result, this process not only creates an effective space for tapping but also establishes a frictional joint between the two sheets. Research has shown that preheating up to 350°C can have desirable effects on reducing the gap between the two sheets in the vicinity of the created joint between aluminum and stainless steel using the above-mentioned method. In the upcoming work, the effect of preheating on tool wear in simultaneous friction drilling of aluminum sheet AA6061T6 and stainless steel AISI304L using a tungsten carbide drilling tool has been experimentally analyzed, and the findings indicate that increasing the preheating temperature up to 350°C leads to a 13.77% increase in tool adhesive wear and a 0.46% increase in tool abrasive wear.