Instant coffee: Products and packaging systems characteristics

Abstract

The moisture gain cause instant coffee quality loss. In Brazil, these products are marketed in glass containers, with seals and screw caps, metal cans with easy-open lid and LDPE (low density polyethylene) over cap and flexible plastic packaging of multilayer film: PET (polyethylene terephthalate)/Al (aluminum) foil/LDPE. The aim of this study was to evaluate twelve instant coffees of three different types (freeze-dried, spray-dried agglomerated and powder) and their packages regarding to water activity, initial moisture, thermal analysis and moisture sorption isotherm, as well as some characteristics of the packaging systems - gas composition of the headspace, oxygen and water vapor transmission rate. All instant coffees evaluated presented similar characteristics of quality standard described in international literature. Products showed quality loss appearance with 10%-12% (d.b.) moisture content. Packaging systems presented oxygen transmission rate values greater than 1.000mL (STP)m-2.day-1 and water vapor transmission rate values less than 0.017g of water.package-1.day-1 (25 °C/75%RH) and 0.048g of water.package-1.day-1 (38 °C/90%RH).