2018 ASHS Annual Conference

Post-harvest technologies play a key role in enhancing shelf life and maintaining quality characteristics of tender fruits such as nectarines (Prunus persica [L.] Batsch var. nectarina). This research investigated the effects of an ‘Enhanced Freshness Formulation’ (EFF) with hexanal as the key ingredient to improve shelf life of nectarines. Pre-harvest sprays of EFF on ‘Fantasia’ nectarines, conducted at two commercial orchards in the Niagara region, ON, showed a general improvement in shelf life. Application of EFF delayed the incidence of chilling injury symptoms (internal browning and mealiness/woolliness) by one week. Treated fruits maintained significantly higher firmness until 38 days post-harvest. There were no differences in total soluble solids, titratable acidity and color values between treated and control fruits, suggesting an otherwise normal ripening behaviour. The volatile analysis study (GC-MS) indicated for the first time that hexanal is naturally present within the nectarine fruit. Further, it was observed that reduced levels of volatile compounds associated with fruit ripening such as lactones, and an increased level of acetates associated with unripe fruit, were present in EFF treated fruit. qRT-PCR was conducted to evaluate the expression levels of 22 genes potentially involved in ripening, to understand the regulatory effects of the hexanal formulation. EFF application induced a highly significant reduction in transcript levels of three Phospholipase D genes, five N-glycoprotein group genes, and other genes involved in ripening and softening processes. These findings indicate that, a delay in the ripening process caused by EFF, may be associated with the modulation of the expression of key ripening related genes, enhancing shelf life and quality of nectarines.