Fruit Drying(Apple,Pineapple)

Drying or dehydration is the removal of substances that can evaporate, such as water or moister, in order to slow down or stop the growth of microorganisms or chemical reactions. During this process, there are a number of changes in the physical and chemical properties of the dried product. These may include features such as shape, hardness, color, aroma, taste and nutritional value. In conventional drying methods,during the drying process,due to temperature difference between the surface and the cold interior,heat is transferred by stages through the surface of the dried material towards the interior. This situation causes the heat between the surfaces of the product to be unequally distributed.In the microwave drying process, as the electromagnetic field influences the material as a whole, unlike conventional drying methods,a selective heating is performed by targeting the water molecules in the material. In this method, heat is formed directly in the product. Moisture in the product is heated and evaporated in a very short time process.The moisture transfer is from the inside out due to the vapor pressure difference which occurs in the inside and outside. So, the problem of heat transfer in conventional drying methods has been solved in the microwave drying process. Increasing problems with product quality and production costs have guided to researches about these problems and encouraged the industry to adopt combination drying technologies.

Table 1. Comparison of convective and microwave drying of grape

Advantages of combinational drying with microwaves include shorter drying times, improved Drying or dehydration is the removal of substances that can evaporate, such as water or moister, in order to slow down or stop the growth of microorganisms or chemical reactions.

During this process, there are a number of changes in the physical and chemical properties of the dried product. These may include features such as shape, hardness, color, aroma, taste and nutritional value. In conventional drying methods,during the drying process,due to temperature difference between the surface and the cold interior,heat is transferred by stages through the surface of the dried material towards the interior. This situation causes the heat between the surfaces of the product to be unequally distributed.In the microwave drying process, as the electromagnetic field influences the material as a whole, unlike conventional drying methods,a selective heating is performed by targeting the water molecules in the material. In this method, heat is formed directly in the product. Moisture in the product is heated and evaporated in a very short time process.The moisture transfer is from the inside out due to the vapor pressure difference which occurs in the inside and outside. So, the problem of heat transfer in conventional drying methods has been solved in the microwave drying process. Increasing problems with product quality and production costs have guided to researches about these problems and encouraged the industry to adopt combination drying technologies.

Advantages of combinational drying with microwaves include shorter drying times, improved product quality and flexibility in producing a wide variety of dried products.[2] Thus,the original flavor can be preserved. Depending on the short drying time, the heat loss is also minimized.[1] Microwave related drying techniques examples are MW-hot air,MW-vacuum,MW-freeze and MW-osmotic.These can be applied to foods; particularly to fruits and vegetables. Fruit drying is the process of removing moisture. Fresh fruits or vegetables last for few days; if we use the drying methods for fruit preservation then they can be stored for months or even years. The benefit of drying fruits and vegetables is not only to preserve crops as food but also reduce package and transport cost in terms of weight and volume, while offering the possibility of adding value to harvested goods. Dried fruits are highly nutritious.

One piece of dried fruit contains about the same amount of nutrients as the fresh fruit, but condensed in a much smaller package.By weight, dried fruit contains up to 3.5 times the fiber, vitamins and minerals of fresh fruit.Therefore, one serve can provide a large percentage of the daily recommended intake of many vitamins and minerals.[5]

Figure 1. Dried Apples

Microwave Drying Of Apple

Dried fruits are widely used as ingredients in many food formulations such as pastry, confectionery products, ice cream, frozen desserts and yoghurt. Dried apples are an important raw material for many food products among other dry fruits. The drying process was progressed through two stages.in the first stage the samples were put in a microwave oven and in this period, approximately 55% of the water was removed. After that, at the second stage, the apple samples were put in forced draft oven to reach the final moisture content. [3]

One of the main benefits of dehydrated apples is their dietary fiber content. A half-cup serving of the dried fruit contains 3.7 grams of dietary fiber. If you follow a 2,000-calorie diet, the snack provides 13 percent of your daily fiber according to the Colorado State University research.[3] It also slows digestion, preventing blood sugar spikes that leave you tired and hungry shortly after your meal.

Dried apples also provide a source of beneficial vitamins for your health. They contain several B vitamins that collectively support your metabolism and they feed your liver and skin. According to the Linus Pauling Institute, a half cup of beverage contains about 6 percent of daily B-6 vitamin consumption and 3 percent of daily B-5 vitamin intake. Both vitamins help to build neurotransmitters, which are chemicals needed for brain function.

Dried apples are beneficial because of their mineral content. Potassium, another mineral that is useful for the health of the nervous and brain functions, is found in a lot of dry apples. Each half-cup serving contains 4 percent of your daily recommended intake of potassium. In the dried apples there is a small amount of iron and we use it to make new red blood cells.So, our tissues can get a fresh supply of oxygen from your bloodstream.

Figure 2. Dried Pineapples

Microwave Drying Of Pineapple

Dried pineapple is a delicious snack that contains low calorie but rich in vitamins and minerals. The natural sweetness and chewiness make dried pineapple the perfect ingredient for candy. The dehydrating process does not effect the pineapple’s nutrient value. So,dehydrated pineapple is a healthy addition to anyone’s diet. With the consuming of dried pineapple, you gain 32 milligrams of calcium, 30 milligrams of magnesium, 20 milligrams of phosphorus, 270 milligrams of potassium, 119 milligrams of vitamin C, 45 milligrams of folate, 144 international units of vitamin A and 6 micromilligrams of vitamin K. In addition, each service contains a small amount of sodium, iron, zinc, thiamine, vitamin E, vitamin B-6, riboflavin and niacin. [4]

REFERENCES

1. Microwave Fruit and Vegetables Drying, International Advanced Research Journal in Science, Engineering and Technology Vol. 4, Special Issue 2, January 2017, Rohini K Parit, Ms. Chatali S. Prabhu

2.Meyve ve Sebzelerin Mikrodalga Destekli Kurutma Sistemleri ile Kurutulması,Sevil KARAASLAN (2012), Süleyman Demirel Üniversitesi Ziraat Fakültesi Dergisi 7 (2):123-129, http://dergipark.gov.tr/download/article-file/308755

3.Tremblay, Sylvie. “Are Dehydrated   Apples Healthy?” accessed July 24, 2018. http://healthyeating.sfgate.com/dehydrated-apples-healthy-5756.html

4. Styles, Serena. “Dehydrated Pineapple Nutrition” last modified July 20, 2017. http://healthyeating.sfgate.com/dehydrated-pineapple-nutrition-2060.html

5.Dried Fruit: Good or Bad?, Adda Bjarnadottir, June 4 2017, https://www.healthline.com/nutrition/dried-fruit-good-or-bad#section1

By |2018-07-26T13:10:44+00:00July 25th, 2018|Categories: Uncategorised|Comments Off on Fruit Drying(Apple,Pineapple)