Investigating the Browning of a Fruit or Vegetable
Aim: To design, carry out and report on an experiment which
investigates the browning of red delicious, pink lady, granny smith,
braeburn and royal gala apples with regard to temperature and pH
levels.
Hypothesis: It is expected that each apple will brown at a faster rate
at warmer temperatures and at an optimal pH level. The degree and
speed at which each apple portion browns will depend upon the strength
and amount of the enzyme phenolase present in each portion.
Background Information: Apples will turn brown when cut and exposed to
air. This can be partly attributed to the action of enzymes which are
organic catalysts. They speed up chemical reactions without taking
part in the reaction. Enzymes are sensitive to temperature and pH and
have optimal levels of each variable at which they will function at
the fastest rate.
For the browning reaction of an apple to occur, three conditions are
necessary;
1. The enzyme know as phenolase must be present
2. The target/substrate of the phenolase called phenols must be
present
3. Oxygen must be present in the surrounding atmosphere.
Apple browning occurs close to the fruit's flesh surface. This is
because cells beneath the fruit's skin are damaged and exposed to
oxygen. In whole apples, the phenolase and phenols are kept separate.
However, when one cuts or bites into any type of apple, the cells are
opened and the enzyme and target are free to react with one another.
The phenolase proceeds to combine the phenols and oxygen into the
different chemical of polyphenol oxidase which is yellow/brown in
colour. This ty...
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...e to superficial harvest
bruising meaning larger harvests and increased profits.
Processor Impact: Less product shrinkage due to bruising on packing
line. If apple is fresh cut, less flavour altering additives needed to
control browning process.
Retail Sector Impact: As bruising won't show as much, product cullage
will be significantly reduced to about 4% of total produce rather than
the current rate of 10%.
Consumer Impact: Gain access to apples that don't require additives to
control browning. Better health due to the more appetizing thought of
non browning apples
References:
www.ars.usda.gov/is/kids/mailbag/mushyapple/applemushanswer.htm
www.nysaes.cornell.edu/fst/faculty/lee/browning.html
www.urbanext.uiuc.edu/apples/preserving.html
www.madsci.org/posts/archives/feb99/917668893.Ch.r.html
Is there a difference in the rate of reaction of catalase activity between pinto beans and carrots? Based on our research, we believe that the catalase activity in pinto beans will increase more relative to the catalase activity in whole carrots because pinto beans are higher in protein. We conducted an experiment to test our hypothesis that if we increase the hydrogen peroxide concentration then we will see higher kinetic saturation in pinto beans over whole
Catecholase is an enzyme formed by catechol and oxygen used to interlock oxygen at relative settings, and it is present in plants and crustaceans (Sanyal et. al, 2014). For example, in most fruits and vegetables, the bruised or exposed area of the pant becomes brown due to the reaction of catechol becoming oxidized and oxygen becoming reduced by gaining hydrogen to form water, which then creates a chain that is is the structural backbone of dark melanoid pigments (Helms et al., 1998). However, not all fruits and plants darken at the same rate. This leads to question the enzymatic strength of catecholase and how nearby surroundings affect its activity. The catecholase enzyme has an optimal temperature of approximately 40°C (Helms et al., 1998). Anything above that level would denature the tertiary or primary structure of the protein and cause it to be inoperable. At low temperatures, enzymes have a slower catalyzing rate. Enzymes also function under optimal pH level or else they will also denature, so an average quantity of ions, not too high or low, present within a solution could determine the efficiency of an enzyme (Helms et al., 1998). Also, if more enzymes were added to the concentration, the solution would have a more active sites available for substrates and allow the reaction rate to increase if excess substrate is present (Helms et al., 1998). However, if more
This experiment was conducted to determine the effects of pH and temperature on peroxidase from a potato. The optimum temperature for peroxidase was determined to be 23°C, because it had a rate of absorbance of 0.3493, higher than the other temperatures evaluated. A temperature of 48°C is inefficient of speeding up peroxidase activity because its rate of absorbance was 0.001.
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The Effect of Temperature on the Activity of the Enzyme Catalase Introduction: The catalase is added to hydrogen peroxide (H²0²), a vigorous reaction occurs and oxygen gas is evolved. This experiment investigates the effect of temperature on the rate at which the enzyme works by measuring the amount of oxygen evolved over a period of time. The experiment was carried out varying the temperature and recording the results. It was then repeated but we removed the catalase (potato) and added Lead Nitrate in its place, we again tested this experiment at two different temperatures and recorded the results. Once all the experiments were calculated, comparisons against two other groups were recorded.
Enzyme peroxidase is essential in any cell metabolic reaction as it breaks down the harmful hydrogen peroxide to harmful products in the body. The report analyzed its effect on changes in temperatures by determining the optimum temperatures and the effects of its reversibility. Through the method of extracting the enzyme by blending it with potato tissue in phosphate buffer, the effects were analyzed on the effect of the dye guaiacol and the activity measured under different temperatures. The optimum temperature was obtained at 22.20C and above this temperature, the enzyme was denatured. Conclusively, increase in temperature increases
The Effect of Surface Area on the Rate of Reaction Between Catalase from a Potato and Hydrogen Peroxide
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