Effect of heat treatment on the microbiology and quality of fresh filled pasta

The industrial processing of the pasta comprises one or more heat treatments. The fresh pasta is first treated with steam. The product is then transferred to another chamber, in which the pasta is dried with hot air to a moisture content of 30–32%. The product is then packaged in modified atmosphere packaging. The second treatment, which generally utilises microwave energy or hot air, is carried out on the packaged product. The aim of the heat treatment is to maintain product hygiene and quality. As a part of the processing procedure, the product is usually pasteurised to kill mould spores and spoilage microorganisms. This thermal process, however, affects the quality of the pasta on a macromolecular level due to reciprocal interactions between proteins and starch. These interactions can be detected by colour changes, a decrease in water activity, an increase in the starch gelatinisation level, and a change in the quantity of water absorbed in the cooking phase. The heat treatment can also lead to a reduction in the nutritional value of the food as a result of the Maillard reaction, which makes amino compounds biologically unavailable.