Modeling of Byssochamys nivea and Neosartorya fischeri inactivation in papaya and pineapple juices as a function of temperature and soluble solids content

- Inactivation of B.nivea and N.fischeri in pineapple and papaya juice was studied.
- Temperature, T, (78-92 °C) and soluble solids, SS, (10-30°Brix) were factors assessed.
- Linear and quadratic effects of T, SS and their interaction were significant on δ.
- Fixed p-values for each strain were obtained and may allow estimation of F-values.

This study aimed to model the inactivation of B. nivea and N. fischeri ascospores in pineapple and papaya juices as influenced by temperature (78, 80, 85, 90 and 92 °C) and soluble solids concentration (10, 13, 20, 27 and 30 °Brix). First, a primary model was used to fit the Weibull model to inactivation data obtained from a combination of temperature and soluble solids concentration and to calculate δ (time for the first decimal reduction) and p (shape parameter). Then, a secondary model was used to describe how the inactivation kinetic parameters of these fungi in pineapple and papaya juices varied with the changes in temperature and soluble solids concentration. The shape parameter (p) was fixed for each strain and at temperature and soluble solids concentration studied. The results indicated that both linear and quadratic effects of temperature as well as the interaction between temperature and total soluble solids were deemed significant on δ value for both B. nivea and N. fischeri (except for B. nivea in papaya juice). This study contributes to the field by bringing new predictive models describing the influence and interactions of mild temperature conditions and soluble solids contents of fruit juices on the inactivation kinetics of heat-resistant fungi.