Light mediated red colour degradation of the pomerac (Syzygium malaccense) in refrigerated storage

The pomerac (Syzygium malaccense) is a highly perishable tropical fruit. Harvested fruit keep for 4-6 days under ambient conditions (28 degrees C) after which they deteriorate rapidly with increased fading of the fruit's bright, strikingly red skin colour. Exposure to light increased greatly red skin colour loss compared to dark storage when fruit were kept at 5 degrees C for 30 days. After 30 days, pomeracs stored under lit conditions were light red (Hunter 'a' value of 19.8) with an anthocyanin absorbance reading of only 0.019 and a yellow or tan discolouration within regions of red skin colour loss (Hunter 'b' value of 16.8). Under dark storage, degradation of red skin colour and hence yellowing was reduced. After 30 days, lit stored fruit were light red (anthocyanin absorbance reading of 0.166) with traces of yellow and with Hunter 'a' and 'b' values of 26.2 and 13.7, respectively. Total colour difference (Delta E) Values also changed with both the rate and extent of Delta E changes being greater for fruit stored under lit conditions, compared with dark storage. (C) 2000 Elsevier Science B.V. All rights reserved.