Osmotic dehydration of mango and its effect on quality
1990
Ballon, Gracia Logo Maria
Investigations were made on the effect of different types of sugars at three concentrations on the kinetics of osmosis during the osmotic dehydration of mango. Moisture loss, weight loss and solids gain were the parameters investigated. Volume changes during the process was also investigated using the platform method. Quality aspects were investigated by subjecting the osmosed sample to freezing and drying treatment. Browning, ascorbic acid content, total sugars and sensory evaluation tests were conducted for both samples. For the dried samples, dehydration ratio, moisture content and texture evaluations were done while drip loss and freezing-thawing experiments were performed on the frozen samples. Results of the sensory evaluation tests were related to objective measurements. Results obtained from this study showed that the sucrose/sorbitol combination gave the highest reduction in moisture (48.70 %) and was found to have acceptable quality. Sucrose has the highest K value. Glucose syrup and its combined form gave the lowest reduction in moisture and rendered the product unacceptable because of the dark coloration of the flesh. Salt in combination with sucrose increased the rate of moisture and weight loss but not the solids gained in the process. Mathematical relationships were established on the effect of sugar concentration and temperature using these results and the plot of the experimental and calculated values was found to be highly correlated. Volumetric changes were related to the moisture loss and were not apparently affected by the size of the sample. From the results of sensory evaluation tests, the quality of the osmosed samples subjected to freezing and drying treatments were found to be highly acceptable.
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