Kinetics of thermal and high-pressure inactivation of avocado polygalacturonase

Abstract Despite high-pressure (HP) processed avocado products are nowadays commercialized, there is no information about the effect of pressure on avocado polygalacturonase (PG) yet. In the present study, PG inactivation kinetics in crude avocado extract was investigated under isobaric conditions at 20 °C. Moreover, PG inactivation kinetics under isothermal conditions at atmospheric pressure was also included to make comparisons with the processing technique usually employed in the industry. Both temperature and pressure inactivation of avocado PG, either at 60–70 °C/0.1 MPa or at 20 °C/350–500 MPa, could be mathematically described by first-order inactivation models. No thermal or pressure resistant fractions were detected. Thus, avocado PG appeared a rather labile enzyme which could be completely inactivated after relatively mild thermal or pressure treatments (10 min/70 °C/0.1 MPa or 15 min/20 °C/450 MPa). PG inactivation models developed for PG in crude avocado extract could predict PG inactivation in avocado puree relatively well. Industrial relevance High-pressure processed avocado products are, nowadays, commercially available, but no data exist about the effect of high-pressure on pectinases yet. This paper provides, for the first time in the literature, scientific data about kinetics of thermal and high-pressure inactivation of avocado polygalacturonase. Moreover, first-order inactivation models are issued to mathematically describe inactivation. All these data should be of high interest for the food industry since polygalacturonase can affect the texture of avocado halves and chunks and the rheological properties of guacamole, avocado puree and sauces during the storage.