EVALUATION OF FACTORS AFFECTING SHELF-LIFE AND QUALITY BIOMARKERS OF IMPORTED AVOCADO FRUIT

Avocado is a subtropical fruit with ever increasing demand in the UK market. All year round consumption is supported by a wide range of suppliers across the world. Inevitably, disparities in preharvest conditions and differences in transit time result in undesired fruit quality variability throughout the year. In order to understand these differences, a scoping study was undertaken on fruit imported into the UK where not only demand but also costumer complaints are high. Fruit were harvested in Peru and South Africa (SA) in April-March (early season), June (middle) and August (late). Avocado fruits were transported at 5°C for 33-39 days when imported from Peru and for 25-36 days from SA. Each origin and season was individually investigated. During shelf life (18°C) mesocarp firmness was assessed as an indicator of fruit ripeness. Fatty acid profiles and sugar content was measured to evaluate whether fatty acids and sugar concentrations could be used to discriminate between fruits from different origin or harvest. Generally, higher firmness charac-terised fruit from SA and a faster softening process was noticed in late season fruit. The main biochemical markers also changed according to origin and harvest time. For instance, results showed a higher ratio between monounsaturated vs. saturated fatty acids in fruit from SA (between 2.7 and 3.0) compared to fruit from Peru (2.0-2.2). Moreover, the mannoheptulose content was higher in fruit from Peru when harvested early in the season (106 μg mg-1). However, regardless of origin and harvest season mannoheptulose content declined with fruit ripening, adding evidence to the previously hypothesised role of C7 carbohydrates in the regulation of avocado fruit ripening.