Fruit Ripening

Why are some fruits sweet and some sour, whereas others have no specific taste?

Naturally fruit contains cellulose, proteins, starch, proteins, vitamins, certain acids and fructose (or sugar). When fruit ripens, a series of chemical changes occur in the fruit that result in either a sweet fruit, sweet and sour fruit, sour fruit or fruit with no specific taste. During these changes, the acids content in fruit becomes less and the fructose content increases thereby resulting in a sweet fruit (Coen, 2011). The more fructose that is present in a fruit, the sweeter it will be like in apples, mangoes, guavas and watermelon. When fruits have a more sour taste to them, this means that there is a higher level of acid in the fruit. No matter how much it ripens it will never have a sweet taste as with lemons and limes (Gemini Geek, 2011). For fruits like oranges and grapefruits there is a balance of sweet and sour, therefore an equal presence of acid and fructose in the fruit (Redding, 2010). Other factors that affect the taste of fruit is its growing conditions. The proper amount of sunshine can make fruit taste sweeter. As the sun shines on the fruit, it heats up the fruit which increases the sugar content in the fruit. In the growing seasons, where there is more rain than sunshine, the fruit will have a watered down taste (Redding, 2010).
How does the ripening of fruit affect the process of seed dispersal? As plants undergo the process of ripening, they produce their own ethylene. Ethylene is a simple gas that is produced when fruit ripens (Nemec, 2008). When the fruit is ripe it is responsible for seed dispersal by attracting animals to the fruit, who consume it and then the seeds are dispersed in their fecal matter or whatever remains of the uneaten portion of the fruit that is left on the ground will be absorbed into the soil (Mauseth, 2003). Another means of seed dispersal is the wind or the fruit disperse the seeds themselves. This takes place when the seeds are dry and light enough to be carried by the wind or through self-dispersal.
How do humans interfere in this process by consuming grains and fruits? When humans consume grains and fruits they interfere with process of the fruit ripening and seed dispersal. Eating these foods before the seeds are dispersed, hinders complete formation of the seeds and disrupts the conversion of acids into starch (Mauseth, 2003).
Does the seed use the fructose or starch in fruits for its metabolism?

In the book Botany: An Introduction to Plant Biology (2003), fructose and starch found in fruit is not used for metabolism. Fruit and seeds have separate storage places for food and receive nutrition from the endosperm. The endosperm is the nutritive tissue within seeds of flowering plants from which plants receive their nutrition. What seeds need primarily for metabolism is water. Also oxygen and temperature are important for seed 's metabolism (Jirage, 2011).

References

Coen, K. (August 11, 2011). Sweet vs. sour fruits. Retrieved from http://www.ehow.com

Gemini Geek. (2011). Why are some fruits sweet where others are sour? Retrieved from http://www.geminigeek.com

Jirage, R. (November 21, 2011). Steps of seed germination. Retrieved from http://www.buzzle.com

Mauseth, James D. (2003). Botany:an introduction to plant biology. pg. 271-273. Jones & Bartlett Publishers: Sudbury, MA

Nemec, J. (May/June 2008). What makes fruit ripen? Retrieved from http://www.grit.com

Redding, L. (August 4, 2010). Heat makes fruit sweet. Retrieved from http://www.fredericknewspost.com

References: Coen, K. (August 11, 2011). Sweet vs. sour fruits. Retrieved from http://www.ehow.com Gemini Geek. (2011). Why are some fruits sweet where others are sour? Retrieved from http://www.geminigeek.com Jirage, R. (November 21, 2011). Steps of seed germination. Retrieved from http://www.buzzle.com Mauseth, James D. (2003). Botany:an introduction to plant biology. pg. 271-273. Jones & Bartlett Publishers: Sudbury, MA Nemec, J. (May/June 2008). What makes fruit ripen? Retrieved from http://www.grit.com Redding, L. (August 4, 2010). Heat makes fruit sweet. Retrieved from http://www.fredericknewspost.com