Different Sequence of High-Hydrostatic Pressure and Mild-Heat Treatment on the Colour and Sensory Characteristics of Strawberry Puree

The effect of high pressure processing (300 and 600 MPa) combined with mild heat treatment (55 and 75 8C) on the colour parameters, anthocyanin content, and sensory characteristics of strawberry puree were examined after the treatments and 2 weeks of cold storage at 2 and 15 8C. As on an industrial scale the simultaneous implementation of these treatments remains a challenge, the HHP and heat treatments were carried out consecutively in different sequences. The colour parameters and the anthocyanin content did not change significantly due to the treatments, but decreased during cold storage, at 15 8C storage the changes were more intensive than at 2 8C. Regarding the sensory test results, the different sequence of the 600 MPa-75 8C combined treatments is not detectable even after 2 weeks of storage at 15 8C, but in case of 300 MPa-55 8C, the enzyme inactivation is probably not sufficient enough as differences between the samples were detected

Instrumental Analysis of Strawberry Puree Processed by High Hydrostatic Pressure or Thermal Treatment

High hydrostatic pressure (HHP) processing technology offers the possibility to preserve quality attributes. Objective test methods describing quality in a complex form have an important role in the development of new products and in the quality assurance of different technologies. Therefore, research was performed to compare the effects of HHP treatment and heat pasteurization on visual appearance, volatile composition, taste and texture properties of strawberry purees measured by sensorial and objective methods. Sensory evaluation did not show significant differences between samples. Similar result was obtained from the color measurements. Viscosity of purees changed only slightly as a result of the treatments. Electronic nose and electronic tongue were found to be promising tools for discrimination of strawberry purees treated by different levels of high hydrostatic pressure or thermal treatment. Canonical discriminant analysis showed that control and “600 MPa for 5 minutes” samples were quite similar. Samples treated by 600 MPa for 15 minutes were distinguished from the above mentioned ones. The heat treated samples (80°C for 5 and 15 minutes) were definitely separated from the control samples. Fusion of the data from the electronic nose and tongue showed the same trend and improved the classification of the treated puree samples