Abstract: The effect of pre-treatment methods on drying kinetics and quality attributes of air-dehydrated pineapple slices was investigated. Smooth cayenne pineapple specie obtained from Nigeria Institute of Horticultural Research (NIHORT), Ibadan was used for the study. A 2 factor-factorial experimental design of 3-levels of 3 pre-treatment methods (sucrose, blanching and sulphiting) and 1-level of drying temperature/ drying time resulting into 27 treatments was used for the study. The physico-chemical qualities of the fresh pineapple fruit were determined before hand peeling and slicing to spherical slices of 5 cm radius/0.5 cm thickness. The slices were air-dried in a cabinet direr; the moisture and ascorbic acid content were monitored during drying and the physical and chemical qualities of the dried products analysed at the end of drying. The data obtained were analysed statistically using the Statistical Analysis System. The results revealed that there were significant effect (p<0.05) of the pre-treatments on moisture, pH, TTA and ascorbic acid of the samples before drying. Sample pre-treated with S02 absorbed moisture from 82.41% of fresh pineapple to 83.53% while the 60% sucrose sample had a reduction to 81.70%. The quality attributes showed that there were significant differences (p<0.05) between the mean values of the samples. The 60% S/60°C B/2500 ppm S02 at 70°C drying had the least value of moisture content of 8.75%; 25.16 mg/100 g of ascorbic acid and 1.19% fibre. The result of the web diagram of the sensory evaluation indicated that the 60% S/2500 ppm S02, 40% S/60°C B/2500 ppm S02 and 60°C B/2500 ppm S02 ranked the first, second and third on overall quality acceptability, while the control sample was rated the least in all the evaluated sensory attributes. The statistical analysis revealed that there were significant effects of the pre-treatment methods on the quality attributes of the samples.
O.R. Karim , S.O. Awonorin and L.O. Sanni , 2008. Effect of Pretreatments on Quality Attributes of Air-Dehydrated Pineapple Slices. Journal of Food Technology, 6: 158-165.