Melanie Bennett



“At what stage of the ripening process is a banana at its peak in terms of simple and complex carbohydrate levels for a long distance runner’s consumption?”By Melanie BennettLong distance runners rely on food to fuel their body to perform their best. Bananas are popular among runners because it is high in carbohydrates. During the ripening process, does the level of simple and complex carbohydrates change? And if so, should athletes be consuming a ripe or unripe banana? There were a number of key findings that helped shape the outcome of my research.Relative to the long distance running aspect of the question, long distance running is described as continuous running of distances anywhere from 5 to 42 kilometres long (Australian Institute of Sport 2009). Running long distances require a certain amount of stamina and aerobic conditioning (Mackenzie, B 1997). Running long distances is commonly found in athletics. Relative to a runner’s consumption aspect of the question, nutrition is important for human functioning. Cells are the smallest organism and are the building blocks of the body (Campbell et. al. 1999, p. 102). Cells maintain the bodies functioning, however, also need their own energy for their own functioning (Campbell et. al. 1999, p.p. 102-121). Without energy; the cell would die and the body would not have the appropriate cells to function. A key concept is that proper nutrition is particularly essential for runners. What a runner consumes is important because it affects how they perform (Australian Institute of Sport 2009). Running causes the body to work harder than at a rest state and more energy is required (Thompson et. al. 2010, p. 132).Food contains nutrients that provide the energy used by all cells in the human body. Nutrients are chemicals in food which are useful to the human body (Thompson et. al. 2010, pp. 9-10). There are six nutrient categories but only three of these can be used as fuel for the body to maintain physiological functioning (Thompson et. al. 2010, pp. 9-10). Nutrients that are used as fuel in the body are called macronutrients and include carbohydrates, lipids and proteins (Thompson et. al. 2010, pp. 9-10).Nutrients provide the energy used by cells in the body (Thompson et. al. 2010, p. 10). Before cells can use food, it has to be broken into particles that are able to be absorbed into the intestinal wall (Christenson 2011). From the mouth to the intestinal tract; digestive enzymes including amylases, reduce the food into absorbable pieces (Christenson 2011). Once nutrient particles are small enough to absorb into the intestinal wall, some are transported to cells, while some undergo processing in the liver (Christenson 2011). In the liver, fats are made water soluble, sugars are converted into glucose and proteins are reduced into amino acids; they are then delivered to the cells, where they are converted to ATP (Adenosine Triphosphate) molecules (Christenson 2011). ATP is a high energy molecule that can be transferred into the mitochondria and provide energy for cells (Thompson et. al. 2010, p.573).Carbohydrates are a type of macronutrient found in food. Although some cells in the body only use lipids and protein for energy, the brain, nervous tissues, red blood cells and muscles rely on glucose (Thompson et. al. 2010, p.131). A key finding was that carbohydrates are the primary source for fuel for physical activity. Bell (2013, email, 19th September) said that the estimated Acceptable Macronutrient Distribution Ranges for carbohydrates is that 45-65% of total energy intake should come from carbohydrates. During exercise the body tries to deliver more oxygen to the working muscles (Thompson et. al. 2010, pp.131-132). Breathing quickens in an attempt to take in more oxygen for muscles (Thompson et. al. 2010, pp.131-132). Oxygen helps provide energy for cells in muscles by assisting in the breakdown of ATP (Thompson et. al. 2010, pp.131-132). However, some exercise requires energy quicker than bodies can deliver oxygen. This is when the lactic acid system is essential; it provides energy to cells without the involvement of oxygen. The system only works with glucose provided by carbohydrates through the process of glycolysis. Glycolysis is an enzymatically controlled deterioration of glucose into pyruvate acid (Mackenzie, B 1999). Once the process of glycolysis occurs, pyruvate acid and hydrogen ions are formed (Mackenzie, B 1999). Pyruvate acid molecules then take part in oxidisation in the mitochondria to begin the Krebs cycle (Mackenzie, B 1999). The Krebs cycle produces energy through the oxidisation of acetate drawn from macronutrients into carbon dioxide (Mackenzie, B 1999).A popular food for athletes is the banana. Bananas contain approximately 23g of carbohydrates per 100g; an easy source of carbohydrates for athletes ( n.d.). The fruit also has an antacid reaction when eaten which helps ease a nervous stomach before a run (Holcomb 2011). Bananas suppress the acid secretions in the stomach, causing cells to form a protective barrier against acids in the lining of the stomach (Holcomb 2011). Lastly, bananas contain magnesium and potassium; two electrolytes that prevents cramping in muscles; which are often lost due to sweat during running (Holcomb 2011). During the ripening process of a banana, the molecular structure of the carbohydrates in bananas changes. Ripe is defined as being developed to the point of readiness for eating (Koning 1994). The plant hormone responsible for the ripening process is a gas called ethylene (Koning 1994). Ethylene is a hormonal trigger in plants which affects the growth, ripening and aging of plants (Koning 1994). Ethylene causes bananas to go from hard and green to yellow and soft. Ethylene triggers enzymes to be made and these enzymes ripen fruits. The enzyme hydrolyses breaks down chemicals inside fruits and Amylase digests starch to make sugar (Koning 1994).A banana is a fruit its main source of carbohydrates is from simple carbohydrates including fructose and sucrose (Thompson et. al. 2010, p.119). However, before the ripening process amylase wouldn’t have digested the starch into sugars; at this stage the banana would have more complex carbohydrates. Therefore, a banana has the ability to have simple and complex carbohydrates.-14605662940In relation to the simple and complex carbohydrate levels aspect of the question, an experiment conducted supported information obtained on the breakdown of starch into simpler sugars in bananas during the ripening process. There were two key findings from the experiment. The first key finding related to the levels of starch present in bananas at different stages of the ripening process. After testing the starch in six bananas from different stages Figure one clearly showed that as the ripening stages progressed, the colour reaction decreased; a decrease in colour change meant that there was less starch present (Ophardt 2003). Figure 1: Colour change related to the starch content of bananas at different stages of the ripening process.405066530480The second key finding related to the levels of sugar present in bananas at different stages of the ripening process. After testing the sugars in six bananas from different stages of the ripening process figure two clearly showed that as the ripening stages progressed, the colour reaction increased. The colour change related to the sugar content of the bananas; the more sugar in the banana, the more the colour of the banana solution changes. A banana with little or no sugar present will turn blue, a banana with some sugar present will turn a yellow colour and a banana with higher amounts of sugar will progress to an orange or red colour (Doc Ireland’s Webspace 2012).Figure 2: Colour change related to the sugar content of bananas at different stages of the ripening process.The results from the investigation described the levels of simple and complex carbohydrates in bananas at different stages of the ripening process. As The Science of Nutrition notes (Thompson et. al. 2010, pp. 9-10) Simple and complex describe the two types of carbohydrates. Simple carbohydrates (sugars) are made up of one or two molecules. Complex carbohydrates (mainly starch) can be made up of hundreds or thousands of molecules. The difference between simple and complex carbohydrates is the number of molecules which make up the carbohydrate. Simple carbohydrates are composed of less molecules, resulting in them breaking down and digesting quickly. On the other hand, complex carbohydrates are made of more molecules, making it a longer process for enzymes to breakdown and digest them.As The Science of Nutrition notes (Thompson et. al. 2010, pp. 120-130) the main aim in digestion is to break down larger carbohydrate molecules into smaller ones which are more easily digestible. Enzymes are responsible for breaking down carbohydrates. After broken down into sugars, they enter the bloodstream; this causes blood sugar levels to rise. The pancreas then has to produce a hormone called insulin. Insulin triggers cells to absorb the sugar in the blood for storage or for energy. As the blood sugar begins to absorb, the blood sugar levels decrease back to normal. According to The Science of Nutrition (Thompson et. al. 2010, pp. 120-130) simple and Complex carbohydrates have different effects on blood sugar levels. Simple Carbohydrates have a simpler chemical structure. This means that the breakdown of the simple carbohydrates is a quicker process; leading to blood sugar levels and insulin production to rise quickly. Complex carbohydrates have a more complex chemical structure. Complex carbohydrates also contain vitamins, fibre and minerals. This causes complex carbohydrates to take longer to break down in to easily digestible sugars. This then causes blood sugar levels to rise slowly compared to simple carbohydrates.How types of carbohydrates rank on the glycemic index relates to what type of carbohydrates a runner should consume. The glycemic index ranks food according to the speed in which carbohydrate based foods raise blood sugar levels after digestion (Thompson et. al. 2010, pp. 129-131). Foods with a higher glycemic index are absorbed into the blood stream quickly; causing a quick rise in blood sugar and insulin (Thompson et. al. 2010, pp. 129-131). Insulin is released when sugar levels are too high. Insulin then takes the high amounts of glucose to the liver and fat storage (Zaino 2003). As a consequence, the sugar levels are brought right down by the insulin; causing low blood sugar; low blood sugar can lead to hypoglycaemia (Zaino 2003). Runners cannot perform their best with hypoglycaemia because it can cause excessive sweating, confusion and heart palpitations (Brent 2011). Foods rating low on the glycemic index are digested slowly and gradually raise blood sugar levels (Zaino 2003). Conversely, food ranking low on the glycemic index does not spike blood sugar levels due to the gradual breakdown of the sugars (Zaino 2003). In conclusion, bananas in their early stages of the ripening process are at their peak in terms of simple and complex carbohydrate levels for a runner’s consumption because enzymes have not yet broken down the starch into sugar. Starch is considered a complex carbohydrate which will not spike blood sugar levels; preventing hypoglycaemia. Using interviews, literature reviews and experiments I could determine at what stage of the ripening process a banana was at its peak in terms of simple and complex carbohydrates for a runners’ consumption.(1810 Words)BibliographyAustralian Institute of Sport 2009 ‘Distance Running’, Australian Sports Commission, accessed 3 September 2013, <; Bell, L. 2013.?Interview on Carbohydrates, Interviewed by Melanie Bennett [Email], 7-19 September n.d., ‘Food Nutrients Database: Bananas, Raw’, accessed 20 September 2013, <, M 2011, ‘Long distance running: Low Blood Sugar, accessed 26 October 2013, <, NA, Reece, JB & Mitchell, LG 1999, ‘Biology’, 5th edn, Banjamin/Cummings, an imprint of Addison Wesley Longman, Inc. California, pp. 102 – 121Christenson, S 2011, ‘How Does Our Body Change Food Into Energy We Can Use?’ Live strong, accessed 20 October 2013, < Ireland’s Webspace 2012, Lab Manual, Doc Ireland’s Webspace, accessed 20 September 2013, <, K 2011, ‘Does eating a banana help with running?’ Live strong, accessed 25 October 2013, <, RE 1994 ‘Fruit Growth and Ripening’, accessed 20 September 2013, <, B 1997, ‘Conditioning’, accessed 25 July 2013, < , B 1999, ‘Lactic Acid’, accessed 10 September 2013, <, E. C. 2003, Starch – Iodine, Elmhurst College, accessed 16 September 2013, <, LJ, Manore, MM, & Vaughan, AL 2010, ‘The Science or Nutrition’, 2nd edn, Pearson Benjamin Cummings, New York, pp. 9 – 573Zaino, C 2003, ‘Carbs are not created equal’, accessed 26 October 2013, <; ................
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