Cryogenic freezing of fresh filled pasta: Case study

The partners

Founded in the hills of Modena as a small workshop producing tortellini and tortelloni, folded and packaged by hand, Il Matterello today has expanded its offerings to include artisanal pastas, ready-made meals, l'emiliana and whole-wheat pasta, both fresh and frozen, thanks to continuous-cycle systems. The growth of the company, recorded in recent years, has forced the search for new production models, capable of maintaining the peculiarities of typical Emilian pasta, but overcoming the limitations of mechanical freezing. Tortellinice, a reality specialized in enhancing the food excellence of the territory, has provided the necessary consulting support in optimizing processes, thanks also to the patent filed in 2018 precisely in the field of processing and preservation of fresh filled pasta. The SIAD Group, a producer of cryogenic gases and liquids, brought to bear its know-how in the field of cutting-edge applications and solutions for the food industry: in particular, it developed the most suitable technological solution, considering the needs of Mattarello. Completing the group was the University of Pollenzo, a university that places the greatest emphasis on multidisciplinary sciences related to the food supply chain, both in university education and in the Third Mission. The team of specialists included highly competent figures in the culinary and food technology sectors: Luca Bellocchio, process technologist for cryogenic systems at SIAD Spa; Marco Cornia, Tortellinice-System inventor; Erik Montorsi, Ceo of Il Matterello; and Gabriella Costi, supply quality manager. On the University of Pollenzo side, Carol Povigna, Food-Lab technical manager; Gabriele Cena, Relations and Partnerships manager; Luisa Torri, Sensory-Lab manager; and Chiara Nervo, Sensory Analyst Technician, were involved.

The intervention

The triangular test, one of the most widely used methods in the sensory evaluation of products, according to UNI EN ISO 4120, was held within the Sensory Analysis and Consumer Science laboratory of the University of Pollenzo. As per the normative reference model, each taster was given three samples, two equal tortellini and one different tortellini. At the end of the tasting, they were asked to indicate the product they thought was different from the others. In the present case, the evaluation focused on Tortellini Mutino-Bononiensi, offered in fresh and cryogenized versions. In the second case, the fresh stuffed pasta was treated with SIAD technology, a cryogenic deep-freezing system for fresh pasta, developed for the occasion thanks to pre-tests carried out in the previous months. The purpose of these tests was to identify the correct combination of two key factors in freezing: time and temperature. The optimum was found: blast chilling, lasting only 5 minutes, brought the core temperature of the product down to minus 20 degrees Celsius. Such rapidity, is made possible by the use of liquid nitrogen, a gas capable of reaching minus 90°centigrade in the freezing chamber. Next, both tortellini, fresh and frozen, were subjected to cooking within the University's Food Lab in a broth of the traditional recipe, with a different minute count: three minutes for the fresh, five for the frozen. At this point, it was on to the tasting.

The results obtained

At the taste test, the tasters stated that they were unable to distinguish the different tortellini, as predicted by the triangle test: the stuffed pasta, subjected to cryosurgitation, maintained a texture totally comparable with the fresh product. According to the experts, no alteration was recorded, especially with regard to texture and water release: this would be the case, however, in the case of standard freezing. The process of cryosefreezing (or cryogenic food freezing), through the sudden lowering of temperature, prevents the formation of ice macrocrystals, which are responsible, during thawing, for alteration of the product. The advantages of cryogenic freezing in fresh pasta affect both the product and the process: in the former case, the test demonstrated the maintenance of the nutritional, qualitative and sensory characteristics of the pasta without decay or alteration. With respect to the process, cooling, which within the production chain represents the most time-consuming phase, becomes extremely rapid thanks to cryogenic technology. This results, for the company, in faster production times and avoidance of the so-called “bottleneck.” Electricity consumption is minimized, compared with equipment that does not require large structural investments. Finally, the shelf-life of the product is significantly extended. In light of this, the plant initially created on a pilot scale has now joined the company on a permanent basis: consisting of a liquid nitrogen storage tank, a high-performance insulated line for liquid nitrogen distribution, and a cryogenic freezing cabinet, it is fully integrated with the line within the production hub located in the Modena hills.