Kinetics of colour changes in pasteurised strawberry juice during storage

- Colour-related attributes of strawberry juice changed significantly during storage.
- Higher storage temperatures accelerated colour changes in strawberry juice.
- A higher oxygen availability resulted in a faster change of strawberry juice colour.
- Colour changes are the result of complex (non-)oxidative reactions.
- An ASLT-kinetics approach is a powerful strategy to study colour changes.

Colour changes during storage are an important quality defect of fruit-based products. Therefore, this work investigated the effect of storage time, storage temperature and oxygen availability (through the type of bottle) on changes in CIEL*a*b values, anthocyanin and ascorbic acid content of shelf-stable strawberry juice (produced with a spiral-filter press under vacuum conditions) using kinetic modelling. The colour-related attributes changed significantly during storage at ambient (20 °C) and accelerated temperatures (28-42 °C) in both types of bottles. The change in all attributes was accelerated at higher storage temperatures. A higher oxygen availability resulted in a faster change of all attributes. As oxygen availability was not fully controlling colour changes, they are caused by complex oxidative and non-oxidative reactions. The results of this work demonstrate the applicability of a kinetics-based accelerated shelf-life testing approach to obtain faster insight into colour changes of strawberry juice and to be used for shelf-life investigations.