Harvest maturity, pre-cutting wash, and post-processing dip to improve quality of fresh-cut carambola fruit

Abstract

‘Arkin’ carambola (Averrhoa carambola L.) fruit harvested at color break or full yellow stage were washed with water or with an alkaline solution (pH 12), cut to 10-mm slices, and dipped in calcium ascorbate (Ca ASA), ascorbic acid (ASA), or water, packaged in perforated clamshells, and stored for up to 14 days storage at 4 °C. Surface color, flesh firmness, soluble solids content (SSC), titratable acidity (TA), and microbial population of the cut slices were determined on days 0, 7, and 14. The alkaline wash reduced microbial loads on the cut slices throughout the entire storage period. ASA and Ca ASA inhibited cut surface browning as indicated by lower a* value, higher L* and hue values, and higher scores in visual quality. Ca ASA-treated carambola also maintained a firm and crisp texture as shown by the high firmness break force. An informal sensory panel preferred slices treated with Ca ASA for reduced sour, astringent, and bitter tastes probably due to the binding of soluble oxalic acid to form insoluble Ca oxalate. But, care must be taken to avoid phytotoxicity caused by the alkaline pre-cutting treatment, and cut surface drying that was enhanced by the Ca ASA application.