Use of humectants for the stabilization of pesto sauce

Summary The stabilisation of preserves through the lowering of water activity ( a w ) and the reduction of pH value are studied as alternatives to the traditional pasteurising/sterilising treatments. a w of samples of pesto has been reduced using two binary systems of humectants: KCl–fructose and KCl–saccharose. The microbiological stability of samples was assessed through the inoculation of Clostridium perfringens spores. Moreover, pH values, a w and colour parameters were measured. The results have pointed out that a w reduction and controlled temperature of storage inhibited the development of C. perfringens . In particular, run 1 ( a w 0.92 and temperature 25 °C) allowed a significant increase of the stability time of the samples. The reduction of a w may be a valid alternative to the traditional treatments of stabilisation in maintaining the organoleptic characteristics of the fresh product.