Apple Juice
Introduction:
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.
Results:
Discussion:
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.
Results:
Discussions:
There are several tests we use in this experiment to test the component in the coke. The tests are Benedict test, iodine test, Biuret test and paper test. The red precipitate is formed when Benedict test is performed on the coke. This shows that the coke contains reducing sugars. When the iodine is added to the coke, yellow colour is observed. This means that the coke do not contain starch. There will be dark blue in colour if the coke does not contain starch. The coke also give a negative results for the Biuret test (colour unchanged) and the paper test (no transparent spot).
The table below shows the nutrition facts of the coke which we found from the internet: The nutrition facts of the coke also support our results which the coke is free of fat, protein, and starch. The coke also contains sodium as show in the table above.
Onions
Introduction:
Onion in the general sense can e used for any plant in the Genus allium but used without qualifiers usually means Allium cepa L, also called the garden onion. Onions are edible with a distinctive strong flavor and pungent odor which is mellowed by cooking. The special quality of onion is its smell (flavor) on account of which it is commonly used in the food preparations. The pungent taste of onion is due to volatile oil Alkyl Propyl Disulphide present in it. They generally have a papery outer skin over a fleshy, layered inner core. Used worldwide for culinary purposes, they come in a wide variety of forms and colors.
The origin of the name “onion” comes from the classical period when it was given the Latin name unio that means oneness or unity, or kind of single onion. The French call it oignon. Martin Elcort in his book The Secret Life of Food writes, “The word (onion) was created by adding the onion-shaped letter o to the word union, yielding a new spelling ounion. The letter u was later dropped to create the modern spelling. A union is something that is indivisible and which, if taken apart, is destroyed in the process, like an onion. “
In his experiment, the onion is going to be tested for the presence of reducing sugar, starch, protein and lipid (fat). To test the presence of these macromolecules, the Benedict’s solution, Iodine solution, Biuret solution and grease spot test are to be used respectively on the onion sample.
Result:
Discussion:
All the cells are composing of 4 different types of biological building blocks, or “macromolecules.” These are carbohydrates, lipids (fats), proteins and nucleic acids. But in this lab exercise, we will examine only three of the four macromolecules: carbohydrates, proteins and lipids. Both reducing sugar and starch fall under the category of carbohydrate, but in order to differ the both, Benedict’s and Iodine test is to be tested respectively on the onion sample. All of the experiments, except for the iodine-starch test, require that we use a sample solution. Therefore, if non-liquid sample is used, the sample must first be dissolved, mixed, or mashed in water (a few drops) before any reagent is added.
From the results, the Benedict’s test was successful. Onion juice contains glucose, and of course, glucose would test positive. Onion has both glucose (reducing sugar) and sucrose (non-reducing sugar). Meaning, onion juice contains both mono and disaccharides. All of these are carbohydrate compounds. When the Benedict’s reagent is combined with sugars at a boiling temperature, a color reaction will occur. Our independent cariable, Benedict’s reagent color is blue. For the positive result of the test, it will change to brick red precipitate, because all monosaccharide as well as some of the disaccharide sugars posses the capacity to reduce alkaline solutions of copper. These monosaccharide and disaccharide are called reducing sugars. A reducing sugar is a sugar with actual or potential aldehyde or ketone groups. Benedict’s solution is a mixture of CuSO4, Na2CO3 and sodium citrate. During the reaction, a complex series of reactions occur, but the visible end result is that Cu2+ is reduced; causing a color change from blue to brick red (this is the positive result). The solution will remain blue if no reducing sugars are present (negative result).Often, students will be surprised that there is sugar in onions because the taste is bitter due to acids present.
Soybeans
Introduction
The Soya bean is the seed of the leguminous Soya bean plant. Soya foods include tofu, Tempe, textured vegetable protein (chunks, mince etc), Miso, Soya sauces, Soya oil and margarine, and Soya dairy alternatives. Soybeans originate from China. In 2853 BC, Emperor Sheng-Nung of China named five sacred plants –soybeans, rice, wheat, barley, and mille. Soybean is an excellent source of high quality protein (soybeans contain on average 37% protein), is low in saturated fats (also high in polyunsaturated fatty acids), and is cholesterol free. Soy protein is the only vegetable whose protein is complete. Soybean is characterized by high lipid content: it contains about 20% fat. Soya is the richest natural vegetable food. The dried bean is 18-22% fat, 35% carbohydrate, and one hectare of Soya beans yields 162kg/357 1b of protein (compared with 9kg/20 1b per hectare for beef). There are more than 1000 varieties. Other than that, the protein of soybean contains all the essential amino acids in adequate amounts except methionine and cystine. Since it has majority of essential amino acid it is one of the best vegetarian food item as far protein content is concerned. Main advantage if Soya bean is that the iron absorption is decreased on a Soya bean diet compared to the diet of egg albumin or casein of milk. Supplementing vitamin C can increase the iron absorption. It is also rarely causes conditions like Soya milk goiter and Chinese restaurant syndrome.
In this experiment, the Soya milk is used because the sample to be tested with the reagents needs to be in solution form. Soya milk is an alternative to dairy milk, and it is most commonly made by soaking Soya beans in water which are then strained to remove the fiber. It can also be made from Soya protein isolate or Soya flour.
Result:
Discussion:
The purpose of this experiment was to determine the chemical composition of certain biological molecules. Four tests were performed: Iodine, Benedicts, Biuret, and grease spot test. Each test was looking for certain characteristics. In this experiment, two tests for carbohydrates will be used. The Iodine test will detect starch, and Benedict’s test will detect reducing sugars (small sugar subunits and individual sugar monomers). Biuret tested for the presence of protein. The grease spot test is tested for lipids.
From the results of this experiment, the Benedict’s, Biuret and grease spot test show positive results, while the iodine test is negative result. This shows that the reducing sugar, protein, and lipid are present, while starch does not. A positive test for iodine was to look for a purple or black precipitation. In the presence of starch the Iodine will break the glycosidic bonds to form the precipitate (an iodine-starch complex is formed causing a color change from reddish-brown to violet-black). Supposedly, the test for Iodine reagent with soybeans should produce a positive result. But unfortunately in this experiment, the soybeans do not contain much starch to proof that there’s starch present, so the reddish brown color remains unchanged. A reducing sugar is a straight chain sugar with free aldehyde or ketone at the end. A positive test for Benedicts was an orange or brick red precipitate. In Benedict’s test, Benedict’s reagent (a solution of sodium citrate and CuSO4) will produce an insoluble brick red or orangish Cu2O precipitate in the presence of reducing sugars (aldoses and some ketoses) and heat. In the presence of reducing sugars, he benedict’s solution will cause the precipitate because it reacts with the free aldehyde or ketone present at the end of the sugar chain. To detect protein, the Biuret test will be used. In this test, NaOH and CuSO4 are added to test solutions. In the alkali environment, the Cu2+ ions will oxidize. In the process Cu2+ ions reduced to Cu+1 producing a purple color whose intensity directly correlates with the amount of protein present. A positive test for Biuret was lavender to black precipitation, which depends on the amount of protein present. A positive test for the grease spot test was to see if there’s a translucent patch on the brown paper when it is dried.
In each of these, there were stronger test and some tests provide weaker results. Stronger corresponds to a higher amount of the substance present and weaker correspond with a lower or lowest amount substance present. For example, the potato will have a strong test towards iodine reagent \, whereas the soybean was barely positive. For the Biuret reagent, the soybean was a chunky purple, leading us to believe that it was the strongest result towards protein test. Each of these tests involved a chemical change, except for the grease spot test. In this case the change was a physical one.
