Fermentation in food may lead to changes in the dietary and biochemical qualities relevant to the original ingredients. The fermented foods encompass enzymes from raw ingredients that may interrelate with the fermenting microorganism’s activities related to metabolism. The microbes involved in fermentation offer an exceptional strategy to attain food stability through various physical and biochemical alterations in fermented foods. Studies have reported that such foods may provide consumers with numerous benefits in comparison to conventional food items in various aspects such as antioxidants, production of peptides, probiotic properties, and antibacterial activity. It may also help in keeping an account of antinutrients and toxin levels. In fermented foods, both manufacturing methods and storage conditions play a crucial role in maintaining the beneficial microbial population. The present chapter is an attempt to highlight the ongoing studies on biochemical alterations in the process of fermentation of foods and showcasing the significant contribution of microbial fermentation to improve and enhance the quality of ethnic fermented food products.