The Extraction And Absorption Of Casein

The protein molecules in many foods provide the amino acid building blocks required by our own cells to produce new proteins. To determine whether a sample contains protein, a reagent called Biuret solution is used. Biuret solution contains copper ions. However, the chemical state of the copper ions in Biuret solution causes them to form a chemical complex with the peptide bonds between amino acids (when present), changing the color of the solution. Biuret solution is normally blue, but changes to pink when short peptides are present and to violet when long polypeptides are present.

Protein Assay: The Pierce BCA Protein Assay (Thermo Scientific) is a detergent-compatible formulation based on bicinchoninic acid (BCA) for the colorimetric detection and quantitation of total protein concentration. A series of standard solution of Bovine Serum Albumin (BSA) ranging from 0-2000 µg/ml was prepared from a stock solution of 2 mg/ml BSA. 25ul of diluted crude (1:500, 1:250), desalted (1:100, 1:50), and 6 peak fractions from cibarcon blue column (1:10, 1:5) were loaded in microplate along with 175ul of BCA working reagent. Microplate was incubated for 30min at 370C and then the absorbance was measured at 562nm.

Enzymes are proteins which can catalyse chemical reactions without changing themselves. The enzyme lipase breaks down the fat in dairy products such as full-cream milk for people who are lactose intolerant. Lipase acts on its specific substrate, lipids produces fatty acids. If enzyme concentration increases, random collisions between the substrates and active sites of enzyme increase due to the increasing amount of active sites which allow more collisions to happen, so the rate of breakdown of lipids to simpler substances will increase. During the experiment, sodium carbonate solution and pH indicator phenolphthalein will be added ahead of

The homogenates provided were made by homogenizing tissues in a sucrose phosphate buffer in a 1:20 ratio. The protein concentration in bovine cells was measured by diluting the homogenate with a 1:5 ratio; 50 microliters of homogenate and 200 microliters of water. Then 5 known protein concentration samples which were 0.4, 0.8, 1.2, 1.6, 2.0 mg/ml of bovine serum were used to determine absorbance with a spectrophotometer. Two additional samples were made; one was blank and the other was for the specific homogenate sample. Then 3 microliters of bradford assay reagent, which indicates the amount of protein present

It contains the mineral calcium, which build bones and keep them healthy. Osteoporosis is a condition where your bones are pourous and break or fracture very easily. Drinking milk and obtaining calcium helps prevent this in a major way. Protein is also found in milk, and is also extremely important.. Protein is used by your body to repair and make tissue, such as your hair and nails, and is also used to make enzymes, such as lactase, to speed up chemical reactions in your body. One last thing found in protein is potassium. Potassium helps maintain mineral and water throughout your body, can help control muscle growth and plays a big role in nerve function. Regular drinking milk is broken into four main types, with countless products branching off. These four types are whole milk, 1% milk, 2% milk, and skim milk. The types are divided by their fat contents (whole being the highest in fat, skim being the lowest). The brand of milk that will be used in this experiment is Horizon. This brand is part of the National Organic Program, so the cows producing the milk will not be genetically modified. This means the cows will not be given any hormones or preservatives, which could potentially effect the milk, and how the lactase responds to

How do various factors, pH, enzyme concentration, ionic concentration, substrate concentration, and temperature, effect turnip peroxidase absorbance/ transmittance rate? The initial experiment was testing the effects of pH buffers (3,5,7,9,and 11). If the pH buffers of 3, 5, 7, 9, and 11 are tested on the turnip peroxidase, the enzyme will function best, and the reaction rate will be the fastest, under conditions of a neutral pH because the cytoplasm of most cells has a pH of about seven and usually extreme pH’s in an enzymes environment usually denature the enzyme, restricting it from catalyzing the reaction. First, a baseline was tested to establish a standard control for a reaction to reference to when testing other factors, to

In part II of the lab six small glass tubes were obtained in a test tube rack. Ten drops of distilled water were then added to test tube 1, five drops to tubes 2-4, and no drops in tubes 5 and 6. Five drops of 0.1M HCl were added to test tube 5 and five drops of 0.1M NaOH to test tube 6. Five drops of enzyme were then added to all tubes except tube 1. Tube 3 was then placed in the ice bucket and tube 4 was placed in the hot bucket at 80-900C for five minutes, the remaining tubes were left in the test tube rack. After the five minutes five drops of 1% starch was added to every tube and left to sit for ten minutes. After ten minutes five drops of DNSA were then added to all the tubes. All the tubes were then taken and placed in the

The standard curve was plotted for FeSO4 with concentration range of 0.2-1mM, and there was a strong correlation between FeSO4 concentration and antioxidant capacity (R²= 0.992) and the equation was Y=0.1958X-0.2452. The standard curve displayed a linear trend between 0.2 to 1mM FeSO4. There was strong correlation between pectin concentration and antioxidant activity for all the pectin samples tested (R2=0.9778, 0.9885, 0.9742 and 0.9954), for the native, 100W, 200W and 400W degraded pectin respectively. Sonicated pectin had increased antioxidant activity with 400W treated pectin having 43% relative FRAP activity at 4mg/mL, the same concentration of native pectin had a lower relative FRAP activity 16.4% compared to FeSO4. There was generally increased antioxidant activity with increasing sonication power applied. The results are consistent with the previous observation by Pokora et al., [66], who reported that enzymatic hydrolysis of egg yolk protein and white protein improved their radical scavenging (DPPH) capacity, ferric reducing power, and chelating of iron activity. Native pectin is a complex molecule with complex side group structure, and during sonolysis the large molecule is depolymerized yielding low degree of polymerization pectin , thus exposing prior hidden functional groups and creating functional groups at the scission sites, e.g. carbonyl groups. The reducing agents mostly act as hydrogen/electron atom donors thus

Introduction: Enzymes are protein catalysts facilitating the conversion of substrates into products (Alexander and Peters, 2011). They go through a whole chemical reaction which starts off with the substrate and then ends up with a product. The only way this reaction can be adjusted or not even work is if they end up going through some sort of affect which only temperature and pH levels can do determining the environment. When enzymes are in an environment that is too acidic or alkaline, their chemical properties, sizes and shapes can become altered (Magher, 2015) Chemical modification of proteins is widely used as a too; to maintain a native conformation, improving stability (Rodriguez-Cabrera, Regalado, and Garcia-Almendarez, 2011) In this experiment, four trials were conducted and recorded every 15 seconds for 5 minutes in order to calculate the optimum levels and IRV.

The Effect of pH on the Digestion of Casein by Trypsin When planning the experiment, the equipment and method had to be well thought-out in order for the experiment to be accurate and efficient. Firstly, I have chose to use a 1% trypsin concentration then altered it to 0.8%, because a higher concentration means more trypsin molecules in the solution and therefore more enzyme substrate complexes are likely to occur with the casein in the milk, causing digestion of the casein to be faster. However, I don’t wantowever digestion to occur too quickly as I will not be able to analyse the effect of PH. Therefore, I chose a lower concentration which would allow me to test the percentage transmission at

The main purpose of this lab is to identify and separate the main components of milk. To do this an understanding of the properties of these components in needed to separate them from one another. We will be separating the components with their polarity or non-polarity and the temperature at which specific components precipitate. To do this we will be using hot plates, gravity filters and vacuum filters1, water and ice baths, and blot drying.

The results suggest that pasteurization kills most pathogens in milk by brief exposure to relatively high temperature. This was demonstrated most beneficially with the 10-6 and 10-7 dilutions wherein the raw milk exhibited 284,000,000 cells/mL and 440,000,000 cells/mL respectively and the pasteurized milk had too few cell colony forming units to even count. Unpasteurized milk is not healthy for people to drink. For example, in a study performed in December of 2001, the bacteria Campylobacter jejuni, a microaerophilic bacteria commonly found in animal feces, was found in unpasteurized milk at an organic dairy farm in Wisconsin and caused 75 people, ages 2 to 63, to become ill.

Rennin, also known as chymosin, is a protein digesting (coagulating) enzyme that curdles milk by transforming caseinogen into insoluble casein. Rennin is only found in the fourth stomach of cud chewing animals and if milk were not coagulated it would rapidly flow through the stomach. This would therefore result in the animal to miss the opportunity of the initial digestion of its protein, deriving no benefit from drinking the milk. Processed in the form of inactive pro-rennin, rennin is produced in large quantities instantaneously after birth where its production decreases to non existent by adolescence. Rennin’s importance is then decreased as it is then replaced by a digestive enzyme called pepsin, also produced in the stomach.

Lactoferrin (Lf) is a member of a 300-500 million years old transferrin family (Teng, 2002). It is a single-chain protein of approximately 690 amino acids and a molecular weight of 77kDa (Nuijens et al., 1996). Lactoferrin (also known as lactotransferrin) was first identified in 1939 as a red protein that was present in bovine milk (Sorensen and Sorensen 1939). Lf is a whey protein found in the milk and other biological fluids (including tears, pancreatic juice, mucous, saliva, bile, genital and nasal secretions and in circulating neutrophils) and other tissues of mammals (Bellamy et al., 1992). Other members of the transferrin families are serum transferrin, ovotransferrin, melanotransferrin, and the inhibitor for carbonic anhydrase Transferrins are iron-binding blood plasma glycoproteins and their function is to control the level of free iron in biological fluids such as the ones mentioned above (Crichton and Charloteaux, 1987). Lf is produced by mucosal epithelial cells in various mammals and recent studies have shown that LF is also produced by fishes and it is the second most abundant protein in milk (Torres et al., 2006). Lf has a high iron-binding affinity and is the only transferrin which can retain iron over a wide pH range even extremely acidic pH (Aisen and Leibman., 1972). Lf has a net positive charge and its distributed in various tissue which make it a multifunctional protein. It contributes to various functions in the body such as regulating

1. Thin slices of cooked egg white with same size (about 0.5 cm²) are placed in four test tubes.