Evaluation of the integrated application of two types of modified atmosphere packaging and hot water treatments on quality retention in the litchi cultivar ‘McLean’s Red’

Abstract

SummaryThe efficacy of modified atmosphere packaging (MAP), Xtend® (XF) or biorientated polypropylene (BOPP), and hot water dip treatments on quality retention in the litchi cultivar ‘McLean’s Red’ was evaluated as an alternative to SO2-fumigation. Fruits were dipped in hot water at different temperatures and time regimes [50°C 2 min; 55°C 1 min; or 60°C 1 s] and packed in XF or in BOPP. The XF bags were closed with rubber bands, while the BOPP bags were heat-sealed to modify the atmosphere around the fruit. Packed fruits were placed in commercial cardboard cartons and stored at 2°C and 95% RH for 34 d to simulate commercial export conditions. Commercial SO2-fumigation, and fruit without any hot water dip treatment packed in XF or BOPP were included as controls. Weight loss, firmness, pericarp browning, severity of decay, Hunter colour values, titratable acidity, fruit pH and soluble solids concentrations were determined after storage. Sensory analysis was carried out to determine colour retention of the pericarp and aril, flavour qualities, taste, odour, juiciness and overall consumer acceptability. Fruit packed in BOPP showed reduced weight loss, colour deterioration and decay, and retained excellent eating quality during long-term storage due to the high RH and higher O2 concentrations (17%) around the fruit. Hot water dip treatments at 50°C for 2 min, or at 55°C for 1 min, caused deleterious effects on pericarp colour, surface structure and quality parameters.