The physicochemical characteristics and the activity of the polyphenol oxidase from piñuela fruit juices were determined at two ripening stages. The antioxidant capacity was evaluated by the superoxide anion yield. The ripening stage showed greater ability to inhibit ( $O_2^{. -}$ , 35.3 %). The inhibition of superoxide dismutase was higher for both ripe (88.29 %) and unripe (95.94 %) states. The rheological behaviour of the juice was satisfactorily described using Herschel-Bulkley model (R2 > 0.99). The concentration effect on the rheological parameters was described by the potential law model, and the temperature effect on the viscosity was described based on the Arrhenius equation, finding activation energy values from 11.94 and 17.80 kJ/mol. These results make Bromelia karatas L. a promissory fruit due to their content of secondary metabolites and its antioxidant activity, which could be associated to the presence of phenolic compounds, specifically flavonoids. Variations in these metabolites could also account for structural changes, physicochemical properties, the integrity protection of the fruit against adverse and an alternative to food products.

Input-output tables (IOTs) provide a relevant picture of economic structure as they represent the composition and interindustry relationships of an economy. The technical coefficients matrix (A matrix) is considered to capture the technological status of an economy; so, it is of special relevance for the evaluation of long-term, structural transformations, such as sustainability transitions in integrated assessment models (IAMs).The A matrix has typically been considered either static or exogenous. Endogenous structural change has rarely been applied to models. The objective of this paper is to analyze energy intensity, a widely used variable in IAMs, and its role as a driver of structural change. We therefore identify the most relevant technical coefficients in the IOTs time series and estimate an econometric model based on the energy intensity of five different final end-use energy sources. The results of this analysis show that energy intensity has a significant influence on the evolution of the A matrix and should therefore be taken into consideration when analyzing endogenous structural change in models.