Page:Foods and their adulteration; origin, manufacture, and composition of food products; description of common adulterations, food standards, and national food laws and regulations (IA foodstheiradulte02wile).pdf/403

 Within the pod is found a dark-colored pasty material, closely attached to the seed sacks and joined to the stem of the pod by coarse fibers. This pasty material constitutes the edible portion of the fruit and has a very sour taste which serves to mask the large amount of sugar, sometimes as much as 30 percent, which it contains. The tamarind is remarkable as having the highest content both of acid and sugar of any of the edible fruits which are in common use. It contains more acid, for instance, than the sourest lime and more sugar than the sweetest fruit. The tamarind is not very largely used directly for edible purposes but is a component of many refreshing summer beverages and is used for flavoring other products. It has mild purgative properties, and hence its intermittent use in small quantities tends to keep in proper regulation the mechanical movements which are so necessary to normal digestion.

Composition of the Tamarind.—

Water,   47.47 percent Acid,     6.03    " Sugar,    31.43    " Protein,  1.36    " Ash,       1.56    "

The above data show that the tamarind is essentially of a carbohydrate nature, its chief food value being in the sugar which it contains. On account of its high acidity very little of the sugar which is present is in the form of sucrose or cane sugar, but is mostly in an invert condition.

Preparation of Tamarinds.—Tamarinds are not only used directly but most extensively in the form of tamarind paste which is made up chiefly by the addition of cane sugar to the pulp; as much as 75 percent of sugar is often added to the making of paste. Another form of preparation is called tamarind pulp, which has practically the same composition as the paste. These two bodies may be called tamarind preserves. The proportion of pulp to added sugar is about as 20 to 80.

Mineral Constituents of Tropical Fruits.—The mineral content of the edible portions of fruits is important, both from a dietetic and chemical point of view.

The mineral substances in fruits not only add to their palatability but also have important functions in digestion and assimilation. The lime and phosphoric acid which the ash of fruits contain are foods that nourish certain tissues of the body, such as the bones. The other mineral ingredients of fruits take an active part in the circulation of the fluids of the body. Since the modern development of physiological chemistry, what is known as osmotic force, or the power that causes solutions to pass through membranes, is believed to be due largely to the mineral constituents of the juices of the body. These mineral constituents are therefore necessary in the food. The following