Application of edible coatings to partially dehydrated pineapple for use in fruit–cereal products Original Research Article

The present work analyzes the application method and the effectiveness of edible coatings based on caseinates or chitosan in partially dehydrated pineapple for its use in dry fruit–cereal products. Commercial breakfast cereals and partially dehydrated pineapples prepared by osmotic dehydration and vacuum impregnation were used for the experiments. Four coating application techniques, working at atmospheric pressure or applying vacuum impregnation, were used for coating the pineapple samples. Coated and uncoated samples were stored, at 20 °C with breakfast cereals and were subsequently analyzed weekly during 6 months. Critical water activity and critical water content for the glass transition of the cereals at 20 °C were estimated as 0.60 and 9.1 g water/100 g of product, respectively. Results show that the application of coatings by vacuum impregnation and sample air drying after coating, considerably extends the shelf-life of the pineapple–cereal system when caseinate based coatings are used. Chitosan based coatings are less effective to limit water vapor transfer and the critical moisture content of cereals are reached during the storage period.