Influence of a post-harvest hot water treatment on the development of green mould [Penicillium digitatum (Pers.:Fr.) Sacc.] and on the quality of ‘Mandora’ fruit [Citrus reticulata Blanco Citrus sinensis (L.) Osbeck

Abstract

SummaryThe effect of a post-harvest hot water treatment (HWT) at 56° – 65°C for 1 – 3 min on the development of green mould [Penicillium digitatum (Pers.:Fr.) Sacc.] on inoculated ‘Mandora’ fruit [Citrus reticulata Blanco × Citrus sinensis (L.) Osbeck], and on rind colour and juice quality, were evaluated during post-treatment storage at 8.5°C and 90% relative humidity. Treatment duration was more influential than treatment temperature on the incidence of green mould (IGM) during post-treatment cold storage. ‘Mandora’ fruit demonstrated a relatively high thermal tolerance to HWT. Treatment for up to 3 min at 56°C did not result in any symptoms of rind discolouration or heat damage after 16 d of storage, while it reduced the IGM by 98.2%, 60.9%, and 16.2% after 8, 12, and 16 d of cold storage, respectively. The loss in fresh weight (FWL) for fruit treated at 56°C for 3 min was 15.7% higher than in untreated control fruit after 16 d of cold storage. The titratable acidity and soluble solids content of the juice were not affected by HWT, and no sensory defects were detected after storage. Post-harvest HWT may constitute a valuable, stand-alone application to control the IGM on organically produced ‘Mandora’ fruit, or as a pre-treatment for conventionally produced fruit. However, HW-treated fruit were prone to an increased FWL, indicating caution during the commercial application of HWT.