Gluten-free Pasta : Technology and Quality Evaluation

Gluten forming proteins are fundamental for the production of a great variety of foods, including pasta, most appropriately made from durum wheat. The replacement of gluten network, in order to produce gluten-free pasta (GFP), is a major technological challenge, and ingredients that imitate the viscoelastic properties of gluten are always required. The first attempts in the search for substances able to imitate the viscoelastic properties of gluten exploited starch gelatinization and retrogradation phenomena, modifications that can be obtained during the technological process or using pre-gelatinized starches or starchy flours as raw materials. Later on, other ingredients have been considered in GFP formulation: rice and corn flours, flours from pseudocereals, starches from different sources, vegetable proteins, emulsifiers, hydrocolloids. The technological process also plays an important role on the final quality of GFP. The traditional process for making rice noodles involves the presence of many heating and cooling phases aimed at reorganizing the starchy matrix; the batch process can be switched to a continuous one with the use of the extrusion technology performed at high temperature; the same process and the same equipment employed in the production of durum wheat pasta can be used if pregelatinized materials are used. In consideration of such a large variety of formulations and technologies, the aim of this study was to evaluate the characteristics of as much as possible commercial GFP (spaghetti shape), in order to get a wide view of what is actually available on the Italian market. The study regarded the chemical, biochemical and physical characterization of the samples, focusing the attention on starch and protein organization. Cooking behaviour and textural characteristics of cooked pasta (at different cooking times) were also evaluated. The overview on GFS samples presented in this study highlighted the wide variety of raw materials and technologies adopted in this sector, indicating the on-going research of solutions providing for the gluten-network absence. At the same time, it came out how all these factors can directly influence the final structure and quality of the products. Phenomena related to starch retrogradation certainly have a central role on the final texture of the products, but also the origin of the protein included in the formulation plays an important role in the definition of the protein-protein interactions, especially in those samples including proteins from different vegetable sources.