Postharvest application of oxalic acid to preserve overall appearance and nutritional quality of fresh -cut green and purple asparagus during cold storage: a combined electrochemical and mass-spectrometry analysis approach

The effect of oxalic acid (OA) treatment on visual properties and bioactive compounds of two green and one purple cultivars of fresh asparagus was investigated during twelve storage days at 5 °C. Cold storage and OA treatment positively affected the overall appearance of the investigated cultivars. Cut-end dehydration increased, all along the storage period, in all cultivars but, the negative effect of the storage, clear on control samples, was mitigated by OA. The most represented compounds in Grande and Vegalim cultivars were: quercetin rutinoside, feruloyl quinic acid and cumaroyl quinic acid. Cyanidin glucosyl rutinoside, cyaniding rutinoside and peonidin rutinoside were identified in Purple Passion cultivar. The bioactive compounds seemed to be affected by storage but not by OA treatment. The sensor-biosensor system indicated that the antioxidant activity is negatively affected by storage but not by OA. The decrease of antioxidant activity coincided with the reduction of ascorbic acid levels in all the cultivars.