Response of internal browning in pineapple fruit vacuum infiltrated with solutions of calcium chloride or strontium chloride

The development of internal browning (IB) was studied in pineapple fruits treated with CaCl2 and SrCl2. ‘Smooth Cayenne’, ‘73-50’ and ‘Gold’ grown in Queensland, Australia were vacuum infiltrated at 30 kPa for 2 min in aqueous solutions of 0.18 M CaCl2 or 0.18 M SrCl2, stored at 13 or 20°C (80-90% RH) for 14 days, and assessed for IB after 3 days at 20°C. In Australian grown ‘Smooth Cayenne’, black heart (BH), a form of IB is a common disorder found in the fruit maturing during the winter months. Storage at 13°C increased IB in ‘Smooth Cayenne’ fruit harvested in March, September and December 2007 and in February 2008 but there was a low incidence of IB only in ‘Gold’ harvested in September 2007. Fruit of ‘73-50’ harvested in September 2007 had a high incidence of IB but no IB developed in fruit of this cultivar harvested in December 2007. Vacuum infiltration did not significantly increase the calcium content in the core or adjacent flesh tissue and treatment with calcium or strontium had no effect on the incidence or severity of IB