Effect of Hydrostatic High Pressure and Thermal Treatments on Two Types of Pumpkin Purée and Changes during Refrigerated Storage

Abstract

High pressure processing (HPP) is an alternative to the traditional thermal treatment. The physicochemical composition, instrumental color and bioactive compounds (carotenoid and phenolic compounds) were evaluated in two pumpkin purées after processing (HPP: 400–600 MPa and thermal treatment) and after storage. One sample of purée was taken in the industry after the first sieve and before the thermal blanching, and the other was taken after deaeration and before pasteurization. HPP of pumpkin purée presented some advantages compared to the thermal treatment such as lower color modifications after processing and during storage, and higher nutritional value (some carotenoid and polyphenol contents were higher in HPP). The application of initial pretreatments reduces the original color intensity of the purées, and thus diminishes the differences of HPP and the thermal treatment in this aspect. However, the application of pretreatments is a necessary step for the stabilization of pumpkin purées during storage. Practical Applications Hydrostatic high pressure is a real alternative to thermal processing in determinate food products. Every year, new high pressure-processed products are in the market. However, only a few studies have evaluated the application of this technology in an industrial line of vegetable processing, which present some particularities (thermal pretreatments and additives are usually added). This paper presents valuable information for the application of high pressure processing at industrial level.