EVALUATION OF ALTERNATIVE MODELS FOR RESPIRATION RATE OF READY-TO-EAT STRAWBERRIES (cv. ‘Ágata’)

The actual growing demand for ready-to-eat (RTE) fruit and vegetables is driven both by consumers' quest for convenience and by an increasing demand for healthy food options, transforming consumption habits all over the world. Modified atmosphere packaging (MAP) is an essential technology for maintaining quality attributes and extending fresh-cut products’ shelf-life. When designing MAP conditions, it is necessary to determine the influence of internal gaseous atmosphere (oxygen-O2 and carbon dioxide-CO2) and temperature on fresh-cut metabolism, allowing us to predict the best conditions for shelf-life extension. While respiration rate models for various strawberry cultivars are well documented, there is limited literature specifically addressing fresh-cut strawberries. The aim of this work was to evaluate alternative models for the respiration rate (RR) of ready-to-eat strawberries as a function of O2, CO2, and temperature. Strawberries (cv. Ágata) were washed, sanitized (peracetic acid - 80 ppm), dehulled, and dried. The effect of gaseous atmosphere and temperature on RR was determined in a total factorial experiment where 45 treatments were obtained by combining factors: oxygen (0-22%) and carbon dioxide (0-15%) concentration at three levels and temperature (4 - 26ºC) at five levels. Different mathematical models were used to fit RR data using both phenomenological (Michaelis--Menten and Langmuir) and non-phenomenological (exponential, power, and linear) approaches. The temperature effect was modelled by Arrhenius, exponential, and power models. Model selection was performed based on R2-adjusted, RMSE, IAC, and BIC indicators. Models with an R2 greater than 0.80 and higher AIC and BIC were selected. An integrated mathematical model based on strawberry respiration activity and the influence of oxygen, carbon dioxide, and temperature was obtained, allowing its use for MAP modelling.