Kinetics of thermal and high-pressure inactivation of avocado polygalacturonase

• Published in: Innovative food science & emerging technologies Vol. 26; pp. 51 - 58
• Main Authors: Bermejo-Prada, Ana, Van Buggenhout, Sandy, Otero, Laura, Houben, Ken, Van Loey, Ann, Hendrickx, Marc E.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-12-2014
• Subjects: Atmospheric pressure; Avocado; Barometric pressure; Foods; High-pressure processing; Inactivation; Inactivation kinetics; Mathematical models; Polygalacturonase; Polygalacturonases; Purees; Surface layer; Texture; Thermal processing; Avocado; Polygalacturonase; Thermal processing; Inactivation kinetics; High-pressure processing
• ISSN: 1466-8564; 1878-5522
• DOI: 10.1016/j.ifset.2014.05.005

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/0.1MPa or at 20°C/350–500MPa, 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 (10min/70°C/0.1MPa or 15min/20°C/450MPa). PG inactivation models developed for PG in crude avocado extract could predict PG inactivation in avocado purée relatively well.
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 purée and sauces during the storage.
•Thermal and pressure inactivation kinetics of avocado PG were described.•No thermal or pressure resistant fractions were detected in avocado PG.•First-order models to describe thermal and pressure PG inactivation were obtained.•Inactivation models developed in crude extract can predict PG inactivation in purée.•Avocado PG can be inactivated at pressure levels currently applied in the industry.