Impact of packaging and storage conditions on colour and β-carotene retention of pasteurised mango purée

The effects of light and oxygen on β-carotene, vitamin A value, and colour stability of mango puree during storage were evaluated. Non-aseptic production at a pilot-plant scale, involving continuous high-temperature-short-time (HTST) heating, caused significant 13-cis-β-carotene formation, resulting in a pro-vitamin A retention of 82.3–89.6%, while peroxidase (POD) activity was reduced to residual levels of 0.4–2.6% in the pasteurised puree. Since oxygen removal from the package headspace by flushing with superheated steam or N2 marginally affected β-carotene stability during storage, hot-filling was most crucial for exhausting the air. Irrespective of the packaging material, pro-vitamin A loss during storage was chiefly caused by oxidative degradation of β-carotene. Additional photo- isomerisation under exposure to light became manifest in the relative increase in 9-cis-β-carotene with associated decline in the 13-cis isomer portion. Despite photoisomerisation, pro-vitamin A retention was up to 90.9% in bottled puree after 168 days of light-exposed storage, with deaeration of the puree resulting from hot-filling. Marked colour loss mainly caused by accumulation of brown oxidation products was monitored by a rising degree of discolouration (Dd). Although additional headspace deaeration of cans and bottles improved colour retention, dissolved residual oxygen and other reactive compounds provoked browning and β-carotene degradation. As regards pro-vitamin A and colour, headspace minimisation was much more effective than its deaeration. Due to smaller headspace volumes, bottling proved superior to canning under the prevailing conditions, irrespective of light-exposed storage.