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Dati pubblicati inerenti il tema di ricerca:1. Derossi A., De Pilli T., Severini C. 2007. Prediction of water activity in vegetable creams:note 2. J. Food Eng. 79(4): 1280-1286.Results were reported in note 1 on a simple empirical mathematical model for predicting water activity values(aw) in aqueous solutions for extract of mushroom and mushroom creams. In this paper we verified the equationobtained in note 1 on a different raw material (apple creams). Moreover, on the basis of the same method used inthe first part of this work a new mathematical model to forecast aw values using two different humectants wasproposed. Results showed a high accuracy for the proposed equation.2. Severini C., Corbo M.R., Derossi A., Bevilacqua A., Giuliani R. 2007. Use of humectants forthe stabilization of pesto sauce. Int. J. Food Sci. and Tech., 43: 1041-1046.The stabilisation of preserves through the lowering of water activity (a w ) and the reduction of pH value are studiedas alternatives to the traditional pasteurising ⁄sterilising treatments. aw of samples of pesto has been reducedusing two binary systems of humectants: KCl–fructose and KCl–saccharose. The microbiological stability ofsamples was assessed through the inoculation of Clostridium perfringens spores. Moreover, pH values, a w andcolour parameters were measured. The results have pointed out that a w reduction and controlled temperature ofstorage inhibited the development of C. perfringens. In particular, run 1 (a w 0.92 and temperature 25°C) alloweda significant increase of the stability time of the samples. The reduction of a w may be a valid alternative to thetraditional treatments of stabilisation in maintaining the organoleptic characteristics of the fresh product.3. Derossi A. E Severini C. 2007. Water food interaction: availability and mobility of water relatedto quality of food. In Food Engineering Research Developments, chp. 2, T.P. Klening(Ed.), pp. 25-66.Water is the most important compound of food. It affects chemical reactions, microbial growth and organolepticquality. Historically, the effects of water on food degradation have been related to its availability but the lack ofexact definition of this term has caused contradictory results. Nevertheless, it is well known that through the controlof “free” and “bound” water content it is possible to restrict degradation reactions and to improve foodquality.Nowadays different parameters to measure the state of water in food are available, but from industrial point ofview, the most important is the water activity (a w ). This term is used to indicate the ratio of the vapour pressurein equilibrium with a food and the vapour pressure of water at the same temperature and pressure. With the recognitionof the importance of this parameter, new knowledge and understanding of water-food interaction haveled to new methods to obtain shelf-stable food by reduction of water activity. Moreover, the importance of wateractivity led food scientists to study mathematical models to predict a w values in complex food.In this chapter we present results about osmodehydration and direct addiction of humectants as treatments toreduce water activity in food. We studied, in particular: i) the interactions of different humectants, the influenceof process variables and the development of mathematical models to predict a w values from a statistical and engineeringpoint of view; ii) the optimization of processes with the aim to obtain safe vegetable food with goodorganoleptic quality. Also, we review the new water-food interaction theories based on dynamic rather thanthermodynamic. In particular, we analyze the glassy transition temperature and translational diffusion coefficientsmeasured by DSC and NMR techniques and present some preliminary results obtained on apple osmodehydratedsamples.SISTAL - SOCIETA’ ITALIANA DI SCIENZE E TECNOLOGIE ALIMENTARIDipartimento di Scienze e Tecnologie Agroalimentari, Università degli Studi della TusciaVia San Camillo de Lellis, 01100 ViterboTel.: 0761- 35 74 94/7 , Fax: 0761- 35 74 98, e-mail: mmoresi@unitus.it154