Classification of Food Materials in Biology
In foodstuffs, which are food sources that are usually derived from plants and animals, which can be eaten or consumed to meet human nutritional needs. Every living thing, especially humans, really need food to eat, because without food, humans will find it difficult to do their daily activities.
Food Material Classification
Food can help humans in getting energy, and help the body and brain growth. Even so every food has a different nutritional content. Protein, carbohydrates and fats are examples of nutrients that will be obtained from food.
Food Material Classification
In the foodstuffs that are around us can be classified into several types namely:
Based on Form
Fresh food is food that has not been processed.
Dry foodstuffs are foodstuffs with a dry texture, such as whole grains.
Processed foodstuffs are processed and processed food, both semi-finished and ready-made.
Based on Main Sources
Power sources are food sources that contain carbohydrates and fats.
Source of builder is a source of food containing protein.
Regulatory sources are food sources that contain vitamins and minerals.
Based on whether or not it is damaged
High Perishable Food is food that is very perishable, which can be damaged within 1-6 hours.
Perishable Food is perishable food which can be damaged within 1-2 days.
Semi Perishable Food is a food that is slightly durable, which is where this food can last for a period of 1 week at room temperature.
Non Perishable Food is food that is not perishable, where this food can last for a period of several months or even years.
Based on Nutrients
Carbohydrates are foods that contain carbohydrate elements such as: monosaccharides, disaccharides and polysaccharides.
Protein is a food that contains protein elements such as: vegetable protein and animal protein.
Fats are foods that contain fat elements, such as saturated fats and unsaturated fats.
Vitamins are food ingredients that contain vitamin elements such as: water-soluble vitamins and fat-soluble vitamins.
Minerals are foods that contain mineral elements such as micro minerals and macro minerals.
Test Results Using Reagents
In this practicum we use reagents that are used to determine food content, including:
Lugol
used to test whether a food contains carbohydrates (starch). If the food that drops lugol turns into black and blue, then the food contains carbohydrates. The darker the color means that the food contains a lot of carbohydrates.
Biuret
is a reagent used to test protein content. If the food contains protein then after reacting with biuret will produce a purple / violet color. That happens because there is a protein bond with a biuret that produces the following basic reactions: The coordination complex between Cu2 + with the -C = O and NH groups of peptide bonds in an alkaline solution will form a violet color.
Benedict
is a reagent used to test the glococci in food. The reaction results in a brick red color when Benedict's reagent is mixed and heated with glucose. Glucose has an electron to give, copper (one of the ingredients in the benedict reagent) will accept the electron and experience a reduction so that there is a change in color.
Frosted Paper
is a testing material for fat content. Because opaque paper easily absorbs water / oil so it is suitable for this test. In this fat test, mashed food is applied to opaque paper after which it is heated on a sepritus burner so that the water content is dry, if there is a transparent stain, the food contains fat.
Food Testing Results
From the observations we have obtained the following test results:
Test Bread
Test starch, bread in drops with lugol reagents react and produce a dark blue color. Therefore, bread contains starch.
Protein Test, bread does not contain protein because after dropping a green biuret reagent only slightly above and the rest only white.
Glucose test, after dropping benedict and heated over Bunsen turns brown. This shows that bread contains glucose.
Test of fat, bread that is applied to frosted paper leaves a transparent stain. This means that the bread has fat content.
Egg Test
In the starch test, egg whites in drops with the lugol reagent react and produce a yellow orange color. That means it does not indicate that the egg white has starch because if it has starch after testing it should have a blackish blue color.
Protein test, egg white contains protein because after dropping the biuret reagent the color turns purple.
Glucose test, egg white drops with benedict and then heated on a bunsen turns green. This shows that egg white contains a little glucose.
Test fat, egg whites that are applied to frosted paper do not leave transparent stains. Then the egg white does not contain fat.
Butter Test
Test the starch, the butter in the drops with the lugol reagent reacts and produces a black color. Therefore, bread contains starch.
Protein Test, butter does not contain protein because after a drop of blue biuret reagents.
Glucose test, after drops of benedict and heated over Bunsen does not change. This shows that butter does not contain glucose.
Test of fat, bread that is applied to frosted paper leaves a transparent stain. This means that the bread has fat content.
Butter is only used during fat testing. The results of our observations are that margarine has a fat content because when butter is applied to opaque paper it leaves a transparent stain.
Orange Test
Orange juice is only used when testing Vitamin C. The result, orange juice has a lot of Vitamin C.