fruit leather

Fruit leather is also called a fruit bar or a fruit slab, and it is a dehydrated fruit-based confectionery dietary product which is often eaten as a snack or dessert. The origin of fruit leathers may go back to the Persian Empire. They are known as “Pestil” in Turkey, “Bastegh” or “Pastegh” in Armenia, “Qamar al deen” in Lebanon, Syria and other Arab countries and “Fruit roll” or “Fruit leather” in the United States. Basically, fruit pulps are mixed with appropriate quantities of sugar, pectin, acid, and color and then dried into sheet-shaped products by hot air drying oven. Due to its novel and attractive structure, and for being products that do not require refrigeration, they constitute a practical way to incorporate fruit solids.
It is chewy and flavorful, naturally low in fat and high in fiber and carbohydrates, and it is also lightweight and easily stored and packed for kids and adults. One commercial all-natural fruit leather strip counts as a ½ serving of fruit and contains no added sugar. A 14g serving provides less than 50 calories and 0g of fat. Some even offer about 10 percent of the daily value of vitamin C, based on a 2,000-calorie diet. Picky kids who are reluctant to eat whole fruit might be willing to try fruit leather as an alternative. In recent years, their popularity has increased, transforming from a homemade preparation into an industrial product.

How to Make Fruit Leather by Hot Air Tray Drying Machine

industry drying machine for making fruit leather
fruit leather making machine
hot air drying oven for fruit leather

Fruit leathers are restructured fruit made from fresh fruit pulp or a mixture of fruit juice concentrates and other ingredients after a complex operation that involves a dehydration step. Dehydration of fruit leather is a process which involves simultaneous heat and mass transfer. Various methods of drying and drying conditions affecting the quality of fruit leathers have been previously studied. Traditional sun drying allows the production of fruit leather with a live color and translucent appearance. However, the drying time is long and dependent on environmental contamination. Today, the conventional hot-air drying process is still the more common technology which has been used for making fruit leathers with better color and flavor. And researches on hot air drying processes of popular fruit leathers are as follows.

Dehydration of strawberry leather
The strawberry puree, corn syrup, pectin, and citric acid were blended together in 200:40:2:1 ratio and then spread the mixture into thin layers on an aluminum weighing dish. The thin layers were then dried in a hot air drying oven at various temperatures(60℃,70℃,80℃). The drying times for the strawberry leather samples to reach the safe-storage moisture content of 12% (wb) varied from 80 to 600 minutes in terms of the different drying temperatures and sample thickness.
Dehydration of pear leather
The pear leather was prepared in different formulations homogeneously blending pectin (16%, 20%, and 24% w/w), water (4%, 6% and 8% w/w), and corn syrup (0%, 8% w/w) at different levels with pear juice concentrate. Then the mixture was put into the tray and dried in the oven. The weight in each tray was about 35g so the height of the fruit leather sheet could be about 2.85mm. The final leathers were made by placing the containers of the mixture in a hot air drying oven at 70℃ for 8 hours.
Dehydration of mango leather
The mango bars were prepared by washing and peeling the mangoes, then pulping and heating the pulp at 91℃ for 2 minutes. Then Mango puree, potassium metabisulfite, soy protein concentrate, skim milk powder, and sucrose were mixed,and the total solids of the mango puree were raised to 30%. The mango puree was spread uniformly on aluminum trays and dried for 14–16 hours in a hot air dryer at 60±2℃. Besides that, The drying was also carried out in an oven at 60-80℃ until the moisture content of the mango leather reached 15–18%. Additives significantly reduced the drying rate of mango leather. Sucrose improved its color and the product containing 4.5% skim milk powder and 4.5% sucrose deserved highest acceptability by the sensory panel.
Dehydration of pineapple leather
The pineapple puree was prepared by removing the stalk and rinsing each whole pineapple, then removed the skin, divots, and leafy crown, then rinsed the treated pineapple flesh with tap water, cut them into pieces, and chopped for 30s into a puree. Pineapple puree was heated at about 85℃ while stirring with an automatic pot stirrer at a speed of 57rpm for 15 minutes and then mixed with pectin, glucose syrup, sugar (fixed at 15%), and maltodextrin (fixed at 2%). The puree was heated and stirred for another 80 minutes to obtain pineapple paste. The flat pineapple paste was placed on a conveyor belt lined with a polypropylene plastic sheet, cut, and then dried in a hot air dryer at 60℃ for 10 hours to form the pineapple leather.
Dehydration of guava leather
The guava leather was prepared by washing ripe guava, then crushing, extracting them through a pulper to get a puree, and added 20% sugar, 0.2% citric, and 0.1% sodium benzoate until the concentration of the pulp was 80%. The treated pulp was boiled, cooled, and spread on trays that were previously oiled with glycerol. The pulp mixture was then poured into stainless steel trays and dried in hot air dryer at 60℃ for 8 hours until the moisture level of the pulp reached 15–20%.
Dehydration of kiwifruit leather
The basic ingredients of this fruit leather were pectin powder, sugar, salt, citric acid, water, and glucose syrup. Fruit puree and glucose syrup were mixed in a blender for 2 minutes before adding the other ingredients. The ingredients were mixed for additional 2 minutes and immediately spread onto stainless steel drying trays when the blend was consistent. The mixture was dried by using hot air at 70 ℃ for 12 hours, which had been preheated at least 0.5 hours before drying.
Dehydration of papaya leather
The papaya leather was prepared by peeling the fresh fruits and adding 20% sugar, 0.2% citric acid, and 0.1% sodium benzoate to a concentration of 80% pulp. The pulp was then boiled, cooled, and spread on trays that had been previously oiled with glycerol and then dried at 60℃ for 8 hours by hot air drying oven.
Dehydration of tomato leather
The tomatoes were washed, cut, seeds removal and heated 100℃ for 5 min. Using tomato puree 84.3g, aqueous solution of polydextrose (44.4%w/w) 12.95g, high methoxyl pectin 1g, citric acid 0.25g, hot air dryer dried 6.5h at 60℃ (2 m/s) for tomato leather, then final product characteristics were: pH= 3.7; aw= 0.85; m.c.= 0.42 d.b.