Document Type : Research Article
Authors
Tarbiat Modares University
Abstract
Regarding to economical importance of kiwi fruit, its wastes such as highly ripe or partially dried up fruits can be used to produce more economically valuable products like fruit leather. Therefore, the aim of present study was the effective factor evaluation of kiwi fruit leather production. The samples were studied in two groups, raw and cooked fruits which were treated in a boiling water bath. Defined amounts of liquid glucose (10%, 17.5%, and 25% w/w), ascorbic acid (100 mg percent of homogenized fruit) and citric acid (0%, 0.5% and 1% w/w) were added to each group. The samples were then poured in a flat pan with 7 mm thickness and were dried at 70°C in a vacuum drier to reach 14±1% moisture content. This research showed that increasing the percentage of citric acid caused an increase in fruit leather acidity whereas increasing the amount of liquid glucose caused a decrease in it. The ratio of vitamin C in samples from raw fruit was lower than that of its amount in samples prepared from cooked fruit. Furthermore, the amount of browning index in the fruit leather had a significant increase in comparison with the primary mixture before drying. Texture analysis showed that the tensile strength of the selected sample was significantly less than those of in the three other samples which are available in the market. Also, elongation of the selected sample was higher in comparison to the other samples. In the present study, regarding to the three decision variables, the acidity, the browning index and the ratio of vitamin C, six appropriate samples were selected for sensory evaluation and the most suitable sample was the sample obtained from cooked kiwi fruit which contained 25% and 0.5% of liquid glucose and citric acid, respectively.
Keywords: Kiwi fruit leather, Browning index, Vitamin C, Sensory evaluation
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