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  • December 2019
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CHAPTER 1 The Problem and Its Background Introduction The earliest method of dehydration is by sun drying. It is a relatively simple and inexpensive process. It is still the most common method of drying food products. However, several problems are associated with sun drying, such as susceptibility to contamination and subsequent spoilage as the product is exposed to elements. Sun drying is also considerably a long process compared to modern methods and it requires a very large area of operation. Dehydration of food is an effective weapon against microbial attack. Since the free water in food is essential for the proliferation of bacteria, preservation of food by drying has been practiced since the ancient times. But advances in food science and technology have created wholly new forms, such as composed freeze – dried foods that resume their original shapes or dehydration. Processed food by dehydration can now be found in the market. There are naturally dehydrated foods such as nuts, grains and peas. These foods are often finished commercially with artificial drying. Artificial drying helps in weight reduction b water loss. Water removal occurs at high or low temperatures. Statement of the Problem This research is conducted to produce a low cost food dryer. Specifically, it aims to answer the following questions: 1. How does the fabricated food dryer operate in terms of: a. Costing? b. Temperature? c. Time? 2. How effective is the machine in drying foods in terms of efficiency in drying and reliability? 1

Hypotheses The following are the basic assumptions of the researchers: 1. The fabricated food dryer is more efficient than sun drying in dehydrating foods such as fruit, vegetables and others. 2. Lowering the cost of the food dryer is possible by substituting the dry bulb into a heating coil as a heater. Significance of the Study Technological Aspect A food dryer minimizes the large area used for sun drying food and shortens the long procedure in sun drying. A food dryer is a very convenient way to dehydrate food. Economic Aspect Small entrepreneurs who cannot afford expensive food dryers can now avail one. Most available food dryers are bulky because they are intended for mass production which makes them reasonably expensive. Small entrepreneurs will benefit by using the fabricated food dryer since with it, it takes shorter time to dry products than sun drying. Also, the process of drying would not be delayed during calamities like rain storms which can result to loss of profit. Health Aspect Drying, as applied to food, is the removal of moisture so that the unfavorable environment for yeast, molds and bacteria will not be obtained. The food dryer will achieve the dehydrated state of a given product in the shortest time possible to minimize the chances of spoilage.

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Scope and Delimitations of the Study This study is only focused on the construction of a portable food dryer and its efficiency. The product is visualized for the household level mainly as it can be used more efficiently and to its full extent even in the simple confine of a house. The food dryer may be used in businesses with performance developments but this aspect will not be discussed in this research paper. The research took place at San Sebastian, Tarlac City and Tarlac Montessori School from November 2008 to March 2009.

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CHAPTER 2 Review of Related Literature This chapter deals with the related literature and studies of the portable food dryer. RELATED LITERATURE Food Preservation Food preservation is the process of treating and handling food to stop or greatly slow down spoilage (loss of quality, edibility or nutritive value) caused or accelerated by microorganisms. Some methods, however, use benign bacteria, yeasts or fungi to add specific qualities and to preserve food. While maintaining or creating nutritional value, texture and flavor is important in preserving its value as food. This is culturally dependent, as what qualifies as food fit for humans in one culture may not qualify in another culture. Preservation usually involves preventing the growth of bacteria, fungi, and other microorganisms, as well as retarding the oxidation of fats which cause rancidity. It also includes processes to inhibit natural ageing and discoloration that can occur during food preparation such as the enzymatic browning reaction in apples which causes browning when apples are cut. Some preservation methods require the food to be sealed after treatment to prevent recontamination with microbes; others, such as drying, allow food to be stored without any special containment for long periods. Common methods of applying these processes include drying, spray drying, freeze drying, freezing, vacuum-packing, canning, preserving in syrup, sugar crystallization, food irradiation, and adding preservatives or inert gases such as carbon dioxide. Other methods that not only help to preserve food, but also add flavor, include pickling, salting, smoking, preserving in syrup or alcohol, sugar crystallization and curing.

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Drying Foods Drying or dehydration, the oldest method of food preservation, is particularly successful in the hot, dry climates found in much of New Mexico. Quite simply, drying reduces moisture necessary for bacterial growth that eventually causes deterioration. Successful dehydration depends upon a slow steady heat supply to assure that food is dried from the inside to the outside. Drying is also an inexact art. Size of pieces, relative moisture, and the method selected all affect the time required to dehydrate a food adequately. Methods of Drying Foods may be sun dried with or without a solar dehydrator, in a gas or electric oven, or with a portable electric dehydrator. Dehydrators with thermostats provide better control over poor weather conditions and food quality than sun drying. An effective solar dehydrator is the shelf above the back seat of a car. Clotheslines are another popular drying rack for ears of corn and strips of jerky. 1. Sun drying Prepared foods are placed on drying trays. Stainless steel screening and thin wood lath are good materials for home-constructed drying trays. As aluminum screening reacts with acids in the fruit, it is less desirable. Galvanized, copper, fiberglass, or vinyl screening should not be used. 2. Freeze Drying A freeze dryer works on the principle of sublimating ice from a frozen food product and removing the vapor in partial vacuum of about 27 Pa pressure. At this pressure, the product is below the triple point of water; hence, the vapor is removed without passing through the liquid phase. The removal of moisture from within the product in the vapor form results in limiting the 5

movement of soluble solids, maintaining the tissue structure and minimizing product shrinkage. Sublimation can take place at temperatures below 0 degrees Celsius. Hence, below this, foods can be dried without heat damage unlike other drying procedures. However, freeze drying is an expensive process and is suited mainly for special types of dried products. 3. Solar Drying Solar drying is an industrial process in many countries where outdoor temperatures reach 115°F or higher. In East Asia, spice crops and other exported plant materials are routinely solar dried. Solar drying is different form “sun drying”. Solar drying uses equipment to collect the sun’s rays in a unit designed to ventilate moisture. The temperature in the unit is usually 20° – 30° higher than in open sunlight. 4. Tray or Cabinet Dryers Tray dryers are small-capacity dryers that use hot air as the drying medium. The products being dried are often carried on trays that can be supported either by tray guides attached on the walls of the drying chamber or by tray trucks that could be rolled into and out of the dryer. Cabinet dryers are generally low-cost and easy to construct and operate. It is ideal for laboratory drying experiments and other drying tests because of its small size. 5. Tunnel Dryers Tunnel dryers consist of long drying chambers that can accommodate a train of carts loaded with a number of trays. The drying medium moves from one end of the tunnel to the other end in the process picks up moisture from the product. Auxiliary heaters are commonly installed at certain sections of the drying chamber because the drying air temperature tends to drop along the length of the tunnel. Tunnel dryers can also be designed for continuous operation by providing means of moving the tray carts from one end of the tunnel to the other. 6. Drum Dryers Drum dryers consist of rotating drums that are heated from within, generally by steam. During its rotation, the heated drum surface is allowed to come in contact with a pool of liquid material. The liquid immediately boils and sticks to the drum surface where it dries. The dried film of food sticking on the surface is removed from the rotating drum with a stationary scraper. 6

Drum dryers can provide high drying rates and economical use of heat. However, these are suited only for liquid or slurry foods that can stand high temperatures for short periods ranging from two to 30 seconds. In the food industry, therefore, drum dryers are used for milk, soups and baby food. 7. Vacuum Shelf Dryer Drying of heat-sensitive food products at temperatures below 100°C may be achieved using vacuum dryers. These dryers consist of an air-tight chamber with food products on plates heated at low pressures. The pressure ranging from 0.135 to 9.45 kPa allows evaporation of moisture from the product at low temperatures. Drying cost using this system is relatively high because additional work is needed to pull a vacuum within the drying chamber. 8. Bin Dryer Cereal grains, as well as other relatively dry granular products, are commonly dried in bin dryers. This type of dryer consists of a container bin with perforated flooring and drying air plenum underneath. Hot air is forced from the plenum through the flooring and through the bed of granular food product. Drying can take place only if the air can pass through the bed of goods being dried. Bin dryers generally require low capital and operating costs but they allow relatively low drying rates. 9. Spray Dryer Spray dryer are used mainly for drying liquid food products, such as milk and fruit juices, into powdered form. This is accomplished by atomizing the feed through a nozzle at pressures ranging from 3.6 to 48.4 MPa. The fine droplets produced are allowed to come in contact with hot air which moves within the drying chamber. Due to the very large surface area of contact between the droplets and the drying medium, very rapid rates are achieved. 10. Drying Times Drying time varies widely because of the method selected and the size and amount of moisture in food pieces. Sun drying requires the most time; an electric dehydrator requires the 7

least. Vegetables take from 4-12 hours to dry; fruits take 6-20 hours. Meats require about 12 hours. Making raisins from grapes may require days/weeks when dried outside. When testing foods for dryness, remove a piece from the center of the drying tray and allow it to come to room temperature. Fruits and meat jerky should be leathery and pliable; vegetables should be brittle. Nutritional Value of Dried Foods Dried foods retain their protein, mineral and vitamin A content fairly well if soaking water is also consumed. Because they are concentrated into a small mass, dried foods can also be high in calories. RELATED STUDIES Local Literature Sun drying is the earliest method of dehydration of foods in the Philippines. It is relatively simple and inexpensive, but it is still a common method in dehydration of foods. Drying by exposure in the sun is also a considerable longer process compared to modern methods of drying. Sun drying requires a large area of operation. It can be very a very unreliable procedure due to the intractability of weather conditions even during the dry season. Several problems of sun drying are exposure to contamination and susceptibility, subsequent spoilage as the product is exposed to the elements.

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CHAPTER 3 Research Methodology This chapter explains the type of research design applied for this study. This chapter includes the data gathering used by researchers and what processes were involved in forming the final product. A part of this chapter is the procedures or experiments done to evaluate the final product. Research Design This study made use of the experimental method of research. During this experiment, researchers gained knowledge from a trial and error method. This is the most prestigious method for advancing Science and Technology and for the Research and Development for the reason that it is a production-oriented. Since this study is concerned with a portable food dryer, the experimental method helped in determining its efficiency in drying time based on the different products dried. Experimental Procedure I.

Fabrication of the Portable Food Dryer A. Conceptual Design B. Materials C. Assembly

II.

Testing the Portable Food Dryer First, gather all the materials to be dried. Weigh all the supplies using a measuring scale.

Now, the drying process can begin, starting off with the Saluyot leaves. Place 30 grams of Saluyot leaves inside the Portable Food Dryer and set the timer to three minutes. After that, weigh the Saluyot leaves again. This process will be repeated with each of the materials only differing in the length of time in drying. The banana chips should be dried for seven minutes. The sweet potato chips should be dried for four minutes. The shrimp should be dried for 12 minutes and the fish should be dried for 22 minutes. 9

Research Paradigm

DEPENDENT VARIABLE INDEPENDENT VARIABLE

Dried Saluyot leaves, banana chips, sweet potato chips, shrimp and fish at desired moisture content.

Portable Food Dryer

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CHAPTER 4 Presentation, Analysis and Interpretation of Data This chapter focuses on the presentation, interpretation and analysis of data based on the personal observations of the researchers upon experimentation and evaluation. The research projects was carefully prepared and planned by the researchers to achieve the desirable or expected outcome. After finishing the research projects, it was tested of its functions and table 1 shows the results of the observations on the food’s sensory attributes after drying. Table 1: Dehydrated Products at using Fabricated Food Dryer Product 1) Dried Saluyot

Initial Weight 30 grams

Drying Time 3 minutes

Drained Weight 15 grams

leaves 2) Dried Banana

40 grams

7 minutes

20 grams

Chips 3) Dried Sweet

25 grams

4 minutes

13 grams

Potato Chips 4) Shrimp 5) Dried Bangus

50 grams 75 grams

12 minutes 22 minutes

25 grams 38 grams

Table 1 shows the length of time wherein the products’ weight would be reduced to almost half of its original weight. For Saluyot leaves, it took about three minutes for 30 grams to become 15 grams. For the banana chips, seven minutes were needed for the 40 - gram sample to become 20 grams. For the sweet potato chips, it took four minutes for 25 grams to become 13 grams. On the other hand, for the 50 - gram shrimp, it took 12 minutes for it to become 25 grams and 22 minutes for the 75 – gram Bangus to become 38 grams. (These observations were perceived by the researchers while conducting the experiment).

CHAPTER 5 Summary, Conclusion and Recommendation 11

Summary The machine is effective in drying-up Saluyot leaves, Banana Chips, Sweet Potato, Shrimp and Bangus. The weight of each of the product was reduced to half of its original weight. The food dryer is more convenient than drying through sun. Using the food dryer is time efficient especially in cooking. Conclusion Based from the experimentation done, we can conclude that drying of food in the food dryer is more efficient and more convenient than sun drying since it requires less possible time in dehydrating food and it minimizes the large area used for sun drying food. Dehydrating of food in a food dryer is also more reliable than the process of sun drying. Sun drying can be a very unreliable procedure due to the inconsistency of weather conditions. The food dryer is not that costly since heating coils were used as the medium of heating. As for health concerns, drying reduces the moisture needed for bacterial growth which causes deterioration. With sun drying, another reason of its unreliability is that one of its problems is exposure to contamination and succeeding spoilage as the product is exposed to the elements. On the other hand, food dryer minimizes the chance of spoilage since the product will achieve its dehydrated state in the shortest time possible. Recommendation For the betterment of the food dryer, the researchers recommend the following: 1. The screen, tray for the product, should be changed into screen with thinner spaces so products put on the tray will not be dropped below the heating area. 2. Aside from Saluyot leaves, Banana, Sweet Potato, Shrimp and Bangus, next researchers can also focus on other leaves to be dried.

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3. Further studies can also be conducted to improve the food dryer.

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