The hypothesis in this Cheese Lab was the following: if pH of milk with the enzyme, rennet, increases, then the time it takes for the curd to form would increase as well because rennet catalyzes reactions well in acidic environments. After the lab was conducted, a positive linear trend was seen between the curdling time and the varying values of pH of the milk with the rennet in Figure 4. The milk contained casein micelles, composed primarily of casein proteins, calcium and phosphate (Swinscoe, 2013). Specifically, a protein in the casein micelle named kappa casein was negatively charged, which repelled the other micelles, allowing the milk to be a liquid substance (Swinscoe, 2013). When rennet was added to milk, it caused the negative part of the kappa casein to …show more content…
Specifically, when the rennet was added to the milk solutions with pH rennet to increase and stretch (Bowen, 1996). This allowed the rennet to catalyze the reaction efficiently and therefore, the curds formed faster (Bowen, 1996). Hence, as a result of lowering pH in the milk solution with the rennet, the curds formed faster. For instance, at a pH of 6, shown in Table 4, the time it took the curd to form was 215 seconds (s) and at a pH of 8, the time it took the curds to form was 475 s. Furthermore, the pH of the milk used was about 6.7, hence slightly acidic (Guadgnolo, 2016). With the addition of drops of hydrochloric acid (HCl), the pH of the milk became lower (to values of pH 2 and 4). This was because when the hydrogen ions (from the addition of HCl) were released into the milk solution, they neutralized the negative charge on the k-casein protein, allowing the casein micelles to coagulate (Sam Adam-Day, 2015). Due to the presence of calcium, the curds could be formed in the acidic solutions, before the addition of the rennet (Sam Adam-Day,
In this gummy bear lab, the goal was to see the movement of water in cells depending on the concentration of solutes in the environment. The control group was the type of water used. The research question for this experiment was, how does concentration of solute in the environment affect water movement in cells? The hypothesis thought of for this question was that the salt water would enlarge the gummy bear the most. The distilled water would not enlarge the gummy bear as much as the salt water.
Question: What will happen to a gummy bear if it is left in water for 24 hours?
Given the background, we hypothesized that for the first experiment, the lactase will break down lactose in milk and have a similar effect to sucrose. We also predicted that the Milk + Lactase reactant would have more glucose, the Milk + Water reactant would have a little bit of glucose broken down, the Sucrose + Lactase reactant would have less glucose than the Milk + Water reactant, and the Sucrose + Water reactant would have little to no glucose at all. As for the first procedure of the second experiment, we had hypothesized the more basic the solution would become, then the more glucose there would be. Our prediction for the first procedure of the second experiment was that there would be no glucose found in the solutions containing pH 4 and pH 7. For the second procedure of the second experiment, our hypothesis was that glucose would be present in the reactants at 4ºC and 25ºC while the reactant that had been in the hot water bath at 100ºC would have little to no glucose because it would have evaporated. We predicted that for this temperature experiment, the glucose would evaporate at 100ºC and would remain at 4ºC and 25ºC. For the first experiment we had found that a reactant of Milk + Lactase have high levels of glucose, while the other three reactants do not. As for the second experiment, for the first procedure, amounts of glucose were found in
The time in the water bath was also controlled to ensure that the enzymes were left to react for the same amount of time, making the experiment
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
This demonstrates that raw milk contains a lot of bacteria even after multiple serial dilutions.
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 purpose of this lab is to examine the specificity of the lactase enzyme to a specific substrate and how it can denature due to the rise in temperature.
We then tested the last set of test tubes containing milk and lactase, we did this to find which ones would present the most glucose concentration results, when placed in different temperatures, 4°C, boiling and room temperature. What we wanted to know was how far temperature could affect lactase to perform its enzymatic activity. We hypothesized that if the lactase is placed in a high or low temperature outside its active range, the temperatures would have a negative impact on the functions of the enzyme. If the temperature has an affect on lactose then we would see some temperatures in which lactase will be function able. We came to a conclusion that enzymes work at a temperature that is closest to body temperature (25°C); boiling water (100°C) denatures the enzyme, while the enzyme is not able to function properly if
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
Title: What Is The Effect Of Vinegar On Curd Mass? Purpose: This experiment was conducted to show the difference in mass of curd with and without vinegar added. Background Information Curd is a thick and white product that is formed usually when milk goes bad, and sometimes is used as the basis for cheese. Many things can be found in curd including saturated and unsaturated fats. On average of nearly fifty grams of fat is found in curd, while thirty-five grams out of the fifty are saturated fats.
-VariablesoIndependent:The temperature of the milkoDependent:The time taken for the milk to solidifyoControlled:The same amount and type of milk usedThe same amount and concentration of enzyme mixture usedThe same test tube sizeResults:-TableAmount of enzyme mixture (mL)Amount of milk (mL)Temperature (oC)Time for milk to clot (min)Ex: 1 Ex: 2 Average2.551060+60+60+2.552034.2036.0035.12.55303.554.203.882.55402.102.252.182.55505.004.454.73Discussion:The experiment showed that changing the temperature did affect the rate at which the milk solidified. At low temperatures of 10oC and 20oC the milk took the longest to solidify and at 10oC did not even go lumpy after an hour. As the temperature increased the speed at which it reacted got faster until it reached around 40oC where the speed began to drop.
In this lab or experiment, the aim was to determine the following factors of enzymes: (1) the effects of enzymes concentration the catalytic rate or the rate of the reaction, (2) the effects of pH on a particular enzyme, an enzyme known and referred throughout this experiment as ALP (alkaline phosphate enzyme) and lastly (3) the effects of various temperatures on the reaction or catalytic rate. Throughout the experiment 8 separate cuvettes and tubes are mixed with various solutions (labeled as tables 1,3 & 4 in the apparatus/materials sections of the lab) and tested for the effects of the factors mentioned above (concentration, pH and temperature). The tubes labeled 1-4 are tested for pH with pH paper and by spectrophotometer, cuvettes 1a-4a was tested for concentration and cuvettes labeled 1b-4b was tested for temperature in four different atmospheric conditions (4ºC, 23ºC, 32ºC and 60ºC) to see how the enzyme solution was affected by the various conditions. After carrying out the procedures the results showed that the experiment followed the theory for the most part, which is that all the factors work best at its optimum level. So, the optimum pH that the enzymes reacted at was a pH of 7 (neutral), the optimum temperature that the reactions occurs with the enzymes is a temperature of 4ºC or