## 1 Introduction  
Vegetables play a crucial role in a healthy and balanced diet, providing essential nutrients, vitamins, minerals, and dietary fiber [1]. Among the widely consumed vegetables, bell peppers (_Capsicum annuum_) are highly regarded for their vibrant colors, distinct flavors, and nutritional benefits. Bell peppers are known for their high content of vitamins A, C and E, as well as various phytochemicals with antioxidant properties [2].  
Raw bell peppers possess several pro-healthy ingredients that contribute to their nutritional value. Bell peppers play a vital role, e.g., in collagen synthesis, immune function, and antioxidant defense. Additionally, they contain carotenoids such as \(\beta\)-carotene, lutein, and zeaxanthin, which have been associated with reducing the risk of chronic diseases, including cardiovascular disease and certain types of cancer. The presence of phenolic compounds, such as flavonoids and phenolic acids, further enhances the antioxidant capacity of bell peppers [2].  
However, the nutritional quality and bioactivity characteristics of bell peppers can be influenced by cooking methods [3, 4]. Cooking methods greatly affect the sensory attributes, texture, and nutritional composition of vegetables. The most typical cooking methods for preparing vegetables, including bell peppers, are boiling, steaming, frying, baking, and microwaving. Each method has a unique impact on the final product, altering the taste, texture, color, and nutritional properties. Understanding the effects of these cooking methods on the nutritional quality of vegetables is essential for promoting optimal dietary choices and preserving the bioactive compounds present in raw bell peppers.  
While traditional cooking methods like boiling have been widely used to prepare vegetables, microwaving has gained both popularity and controversy in recent years.  
Microwaving offers a convenient and time-saving approach to cooking, but its impact on the nutritional composition of bell peppers is often questioned. Despite being demonized by some due to misconceptions, microwaving can be a healthy alternative to traditional cooking methods as it requires minimal water and shorter cooking times, thereby reducing nutrient loss (e.g., the decrease in ascorbic acid content by boiling in hot water was observed up to 34% from the original content) [5; 6; 7].  
However, the existing literature lacks a comprehensive and merit-based comparison of the real impact of microwaving on the nutrient composition of bell peppers, especially at different ripening stages [8; 9]. Many studies have focused on other cooking methods or have provided conflicting results, making it challenging to draw conclusive evidence regarding the effects of microwaving on the nutritional quality and bioactivity characteristics of bell peppers. Therefore, there is a need for further research to investigate the specific changes that occur in the nutrient composition and bioactive compounds of bell peppers when subjected to microwave cooking.  
The present study aims to address this research gap by evaluating the impact of boiling in water and microwaving on the bioactivity characteristics of bell peppers at different ripening stages. To the best of our knowledge, this is the first study comparing the effects of cooking and heating in a microwave oven on various physicochemical parameters of bell pepper fruits representing different stages of ripening.