Quality of french fried potatoes as influenced by coating with hydrocolloids

Potato french fries were coated with a combination of calcium chloride and either pectin or sodium alginate at different levels. The best treatment was selected for the second coating with different hydrocolloids. Qualities of single- and double-coated french fries were evaluated. Potato french fries coated with sodium alginate as a first coating had less oil reduction and less quality than those coated with pectin. Single-coated french fries with a combination of 0.5% calcium chloride and 5% pectin had the highest reduction of oil content as well as the highest moisture content. Also, coated french fries at these levels exhibited higher red and yellow colours and were firmer than the control. Coated french fries with 0.5% calcium chloride and 5% pectin had higher sensory scores for all attributes compared to the control. French fries coated with carboxy methyl cellulose (CMC) as a second layer were more effective than those coated with pectin or sodium alginate in reducing the oil content. The incorporation of CMC at 1.5% level as a second layer reduced the oil content by 54%; however, the single coating with 0.5% calcium chloride and 5% pectin reduced the oil content by 40%. Double-coated french fries had higher moisture contents and firmer structures than the single coated french fries. Increasing the level of the hydrocolloid forming the second coating up to 1.5% resulted in non-significant differences in the sensory scores for all attributes. Scanning electron microscope photographs indicated that the single- or double-coating process was effective in protecting the cellular structure of potato tissues from the damage produced during deep-fat frying. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.