The Effect of Antioxidant Polysaccharide Based Coatings on Optimum Immersion Time, Vitamin C Content and Salt Adsorption of Quince Cylinders during Osmotic Dehydration

In this study، the effects of carboxymethyl cellulose-low methyl pectin based edible coatings containing ascorbic acid antioxidant were investigated on optimum immersion time during osmotic dehydration of quince sheets. The selection of coating type was based on natural composition of fruits peel، (i. e cellulose) and pectin and the osmotic solutions were formulated on the basis of natural ingredients in fruits (fructose، citric acid and calcium ions). The results showed that solid gain trends have been incremental until 240 min in both coating types; however، the coated samples showed lower solid gain in all testing times. The optimum immersion time was found to be 180 min based on the water loss (W. L)، solids gain (S. G)، process efficiency index and weight reduction (W. R). In next stage، the absorption of salt and citric acid from osmotic solution and loss of vitamin C from quince cylinders (dried by hot air) were measured. Absorption of salt and citric acid in the coated samples was smaller than the non-coated samples and coated and osmotic quince cylinders indicated smaller vitamin C losses than the uncoated and non-osmotic samples.