Effect of thermal and high hydrostatic pressure treatments on mango bars shelf-life under refrigeration

Ready-to-eat mango bars, previously developed, were packaged using a heat-sealable multilayer material (PET/PE aluminium film). They were then subjected to two types of preservation treatments: thermal treatments (TT) (80 and 90 °C for 120 and 300 s) and high hydrostatic pressure (HHP) (500 MPa for 120 and 240 s), in order to compare their impact on flavour release and microbial stability of the mango bars. A similar effect of both thermal and non-thermal treatments on the referred bars characteristics was observed. As such, TT at 80 °C for 120 s was selected as ideal for bars treatment, as it is the one carried out at lower temperature and lower period of time. For bars treated with this TT, parameters such as, hardness, cohesiveness, springiness, total colour difference, browning index, sensory quality, microbial growth (aerobic colonies and yeasts and moulds) and microbiological safety (detection of Listeria monocytogenes) of the bars were monitored under refrigerated conditions (5 °C). Results indicated the TT of 80 °C, for 120 s, as the more adequate to extend the shelf-life of the mango bars. The bars presented good stability during refrigerated storage, as the monitored parameters did not change significantly. The shelf-life of the untreated mango bars was estimated to be nine days, while the thermal treatment of the bars extended their shelf-life to 18 days at 5 °C.