Everyday materials such as foods are composed of organic molecules such as carbohydrates, starch, proteins and lipids. It will be possible for us to determine if these organic substances are present by using the tests we learned in the last experiment. Various chemicals will be used in this practical to test for the presence of these molecules. Most often, we will be looking for a particular color change. If the change is observed, the test is said to be positive because it indicates that a particular molecule is present. If the color change is not observed, the test is said to be negative because it indicates that a particular molecule is not present.
In all of the procedures, we will need to include distilled water as a control. Usually, a control goes through all the steps of the experiment but lacks one essential factor (the experimental variable). The missing factor allows you to observe the difference between a positive result and a negative result. If the control sample tests positive, we know that our test is fail. All of the experiments below, except for the iodine test, require that you use a sample solution. Therefore, if you are using a non-liquid sample, we must first dissolve, mix or mash the sample in water (a few drops) before adding any reagent.
The nutritional benefits of apple juice (as well as applesauce and many other apple products) are often underestimated because these foods are “quietly virtuous.” When closely evaluating the nutritional composition of apple juice and other apple products, it becomes apparent that the lack of fat, cholesterol and sodium are just a few of the many reasons these products are an important part of a healthful dietary regimen.
Apple juice contains important phytonutrients as whole apples(e.g., quercetin, numerous other flavonoids). These nutrients are why a juice directly from the fruit, such as 100% apple juice, offers many of the natural nutrition benefits. Recent research also suggests that it is the antioxidants that are plentiful in apple juice which are responsible for improving cognitive function. An antioxidant is a chemical that prevents the oxidation of other chemicals. In biological systems, the normal processes of oxidation produce highly reactive free radicals. They can readily react with and damage other molecules: in some cases the body uses this to fight infection. In other cases, the damage may be to the body’s own cells. The presence of extremely easily oxidisable compounds in the system can “mop up” free radicals before they damage other essential molecules.
Fruit sugars such as those found in apple products like fructose can serve as an immediate source of energy. And because apple products taste so good, they are readily consumed by infants and children. Apple juice also serves as an excellent means of providing essential fluids to the body, and is unlikely to cause allergic reactions. A recent national survey of pediatric health professionals has confirmed that apple juice is most often recommended as the first juice for infants. It is easily accepted and pleasing to infants. Also, since babies love the sweet taste of apple juice, it may help motivate them to use a cup and accept new tastes and foods.
In this experiment, we use several test to test for the component in the apple juice. The tests are Benedict test, iodine test, Biuret test, and paper test. From the observation, apple juice only gives the positive test for the Benedict test which give the red precipitate after boiling. This shows that apple juice does not contain starch, protein, and lipid because it gives the negative results for the other three tests (iodine test, Biuret test and paper teat). From the resource we get from the internet, the nutrition facts for the apple juice is zero contain fat, protein and starch. This shows that our results are accurate. The diagram below is the nutrition
The nutrition facts of apple juice above show that apple juice not only contains sugars, but it also contains calcium, iron, and especially rich in vitamin C which is important source of antioxidants. There is an experiment we find in the internet which can support our results. This experiment use the Benedict test, Barfoed’s test and Selivanoff’s test to test the carbohydrate structure in pressed apple. Both Benedict and Barfoed tests determine reducing sugar presence and Selivanoff test determine the presence of aldose or ketose. A red precipitate is formed as the Benedict test is performed in apple juice. This indicates that the apple juice has free aldehyde or ketone groups and thus it is a reducing sugar. Apple juice is a nutrition drink because it is rich in vitamin C which is a water-soluble nutrient essential for life, used by the human body for many purposes.
Coke Introduction: Coke is a very popular carbonated cola soft drink sold in stores, restaurants and vending machines in more than 200 countries. It is also one of the most recognizable and widely sold commercial brands. It is generally agree that Coca-Cola can be harmful if consumed to excess, particularly to young children whose soda consumption competes with, rather than complements, a balanced diet. This is because coke contains high sugar and lack of essential nutrient such as protein and vitamin. Hence, it is calories-rich and nutrient-poor beverage. This high sugar soft drink also will cause obesity. Obesity is a condition in which the natural energy reserve of humans or other mammals, which stored in fat tissue, is expanded far beyond usual levels to the point where it impairs health.