Effects of storage and packaging materials on some physicochemical properties and sensory and microbiological parameters of pineapple juice (Ananas comosus)

Physicochemical,microbiological and sensory parameters of concentrated pineapple juice stored in cans and glass bottles were studied over a period of ten weeks. there was slight increase in ph from 4.2 to 4.7 and to 4.8 and decrease in titratable acidity from 8.1 to 5.1 and to 4.6 mg/100 ml,whereas total solids (%) decreased from 76.23 to 65.47% and to 60.38% in canned and bottled pineapple concentrates,respectively. over 90% loss of vitamin c was observed,with the bottled samples retaining more vitamin c than the canned samples. the microbial counts ranged from 2.0 × 103 to 2.4 × 104 cfu/ml whereas fungi and mesophilic bacteria,were not detected to 6 × 103 cfu/ml. freshly prepared single strength juices of pineapple were better in terms of taste and colour,while the bottled reconstituted juice concentrate competed favourably with the fresh one in colour. the canned samples lost their colours within 10 weeks of storage. the glass bottled samples had a characteristic desirable aroma. thus concentrated juice in glass bottles stored at room temperature enhanced the keeping quality of the juice and compared more favourably with the fresh juice than the canned concentrated juice.