Drying improves shelf life by all except which of the following?

Drying is an effective preservation technique primarily because it decreases the moisture content of food products. Lower moisture levels hinder the growth of microorganisms, which can spoil food and lead to foodborne illnesses. Additionally, reducing moisture contributes to the overall stability and longevity of food products by preventing chemical reactions and enzymatic activity that can cause spoilage.

While drying can enhance flavor in some cases, such as with concentrated fruits or herbs, it's essential to note that this isn't its primary purpose. Instead, the main goal of drying is to create a shelf-stable product by lowering moisture to a point where spoilage and degradation are minimized.

Changing the quality attributes of a product can occur as a result of drying, but these changes are not necessarily a means to improve shelf life. Instead, they may affect the food's texture, flavor, and nutritional profile, which can be seen as either positive or negative depending on the product.

Thus, while decreasing moisture content, enhancing flavor, and reducing microbial growth directly contribute to improving shelf life, changes in quality attributes are not aimed at extending it and can even detract from the product’s appeal in some cases.