Why are some fruits sweet and some sour, whereas others have no specific taste?
According to Hui, different types of fruits have distinct taste, which contrasts in some way from the taste of any other fruits. Consecutively, some fruits are sweet while others are sour whereas others do not have specific taste. The compounds present in the fruits accounts for the distinct taste of a fruit. Some fruits contain acids, others fructose, vitamins, protein starch or even cellulose. Moreover, the compounds may be mixed in a fruit although at different proportion in a range of fruits.
Sweeter fruits tend to have more fructose more than the other compounds in them. Despite the fruits having acidic juice in them, high levels of fructose neutralize the acidic effect leaving only the sweetness taste in them. Some of the sweet fruits may be sour before they ripen, after maturity, the amount of sugar increases. For instance, a raw banana has more of starch, but as it is ripening the starch changes to fructose, hence increasing the sugar content. Increase of sugar content indicates that the sweeter the fruit becomes.
On the other hand, sour fruits tend to contain more acid in them as compared to the sweet fruits. As this kind of fruit gets mature, it produces more acid. Subsequently, the acidic juice in them accounts for the sourness in the fruit. For instance, lemon fruit contains more citric acid than sugars. As a result, lemon fruit tastes sour thanks to the acid.
Most important, there are fruits without any specific taste. These fruits are neutral as they are not either acidic or sweet fruits. This is because they have equal amounts of fructose as well as acid in them. The same amounts of sugar and acid neutralize each other leaving the fruit without any specific taste.
Ripening of fruit affect the process of seed dispersal
The fruit ripening process has a direct link to the seed dispersal. As the fruit start to get ripe, a layer, mostly known as abscission zone, in the pedicel just next to the attachment point of the fruit to the stem also matures. Moreover, the ripening of the fruit also stimulates production of a new enzyme, pectinases, which unglues the cells in the abscission zone and eventually makes the cell to have weak connections (Copeland, 2001). Consecutively, the weight of the fruit becomes too much for the connection to bear, thereby the connection giving in, subsequently, the fruit falls. The falling of the fruit is the first stage of the dispersal. This is because the fruit can then be dispersed through different agents of dispersal such as animals, water (if it falls on water) or even wind.
How do humans interfere in this process by consuming grains and fruits?
Human beings constitutes to the agents of seed dispersal. This happens especially when they consume grains or fruits containing seeds viable for germination. There are some seeds which are consumed by the human beings which contain a protective coating which inhibits digestive enzymes in the human digestive track from working on them. Subsequently, the seeds move through the digestive track and as human beings defecate, the seeds also are ejected inform of waste. Henceforth, if the seeds fall in a ground with the essentials of germination it will germinate and grow to a plant. This means that human beings are also agents of dispersion.
Does the seed use the fructose or starch in fruits for its metabolism?
Seeds do not use fructose or starch stored in the fruits for their metabolism. However, the seeds obtain nutrients from the food stored in ether the endosperm or cotyledons (Bradford & Nonogaki, 2007). Monocotyledons like zee mays store their nutrients in the endosperm whereas the dicotyledonous store has their nutrients in the cotyledons. The starch stored in the seed oxidizes into glucose for the seed use. This is so because the fruit and the seed have different and separate places where they store their nutrients and so there is no dependence or sharing between the two. Henceforth, seeds do not consume the minerals stored in the fruits, but rather the nutrients found in the endosperm.