Why Are Some Fruits Sweet and Some Sour and how does the Ripening of Fruit Affect It - Essay Example

Other sour tasting fruits include raw mangoes. According to Hulme (1970) fruits consist of different substances, including vitamins, sugars, starch, proteins, and organic acids in different proportions. The taste of a particular fruit depends on the concentrations of these substances. In sweet tasting fruits, the concentration of fructose, which is a simple monosaccharide, is higher than the concentration of sour substances such as organic acids. Fructose is a simple sugar and is highly soluble in water and hence it is a major component of fruit juices.

Naturally, bananas have high concentration of starch and as they ripen, it is converted into simple sugars such as fructose (Childers, 1978). This explains why ripe bananas have sweet taste while green bananas are not. In fruits, fructose could be in its simplest form or as a component of sucrose. Sour taste in fruits is caused by high concentration of hydrogen ions present in organic acids (Hulme, 1970). Some common organic acids in sour fruits include citric, malic and tartaric acids. Ripening of fruits affects the process of seed dispersal in various ways.

According to Mauseth, (2003) the major functions of the fruit are to protect the developing seed and enhance its dispersal. As the seed matures, the fruit ripens simultaneously. Fruits undergo different ripening processes that determine the eventual method of dispersal. In wind-dispersed seed, the fruit undergoes dehydration or desiccation, which reduces the weight of the seed. In other wind-dispersed seeds, the dehydration process enhances development of flight structures such as wings, which increases the floating ability of the seed in air (Mauseth, 2003).

Therefore, the desiccation process during the ripening of wind-dispersed seeds reduces the weight of the seed, which makes it possible for wind to carry and disperse the seed away from the parent plant. In animal dispersed seeds, the ripening process increases the attraction of the fruit to the consuming animal (Biale, 1954). During ripening of such fruits, the plant releases enzymes within the plant that enhances conversion of complex compounds such as starch into sweet tasting sugars. The enzymes enhance production of sweet smelling aromatic compounds to attract animals during the ripening process.

Some fruits such as tomatoes release ethylene that induces ripening, characterized by production of pink, reddish coloration and softening of the fruit (Mauseth, 2003). The appealing color, sweet taste and aromatic smell attract animals, which eat the fruit and disperse the seeds in the process. Therefore ripening of fruit enhances seed dispersal by promoting development of characteristics appropriate to the particular method of dispersal. Human beings interfere with the method of seed dispersal by consuming grains and fruits.

Consumption of immature seeds and fruits interferes with natural process of seed growth and development (Hulme, 1970). Therefore, when people eat the immature fruits and seeds, the natural process of seed dispersal and the eventual germination is interfered with because the seeds lose their viability to germinate. Besides consumption, human beings interfere with the process of seed dispersal by subjecting fruits and seeds to various techniques such as food processing and storage. Most food processing methods such as drying removes water in the seeds and the fruits.

This interferes with critical seed development processes that depend on water (Hulme, 1970). For example, drying seeds and fruits interferes with enzymatic and hormonal processes and reactions that promote ripening, development and eventual seed dispersal. Storage of seeds and fruits prevent other agents of dispersal such as wind and other animals from carrying