How did Appert's canning method compare to older methods like salting regarding product quality?

It aimed for preservation with minimal change to the original quality

Traditional food preservation techniques such as salting, drying, or fermentation were highly effective at extending shelf life by removing water or introducing an environment hostile to microbial growth. However, these older methods inevitably resulted in drastic alterations to the food’s fundamental characteristics—taste became excessively salty or acidic, and texture changed significantly. Appert's goal, even without modern analytical tools, was to keep the food product tasting and appearing as close to the fresh state as possible. His technique of heat sterilization followed by sealing aimed to achieve long shelf life while retaining the flavor and nutritional profile of the original ingredients with only low to moderate alteration.