英文科學讀本 第二冊·Lesson 10 Starch for Food

Lesson 10 Starch for Food

If someone had told me a week ago, said Willie, "that we eat starch every day, it would have sounded like a joke. But we know now that it is true, for our bread and puddings and cakes and potatoes all contain starch."

Teacher was talking about sago, arrowroot, and tapioca, said Fred. "He says they are almost pure starch."

I have seen mother make sago and tapioca puddings, said Norah. "Can you tell me anything about them, Fred?"

I'll try, said Fred.

Let us think about the sago first. Mother gave me some in this saucer. Look at it. It is like little round balls. Teacher says it comes from a tree called the Sago Palm, that grows in very hot lands. It is got from the soft matter in the stem, which we call the pith.

When the tree is fully grown, it is cut down, and the soft pith is taken out. This pith then looks something like the inside of a dried apple. It is rather sticky, too, like gum. The pith is first crushed into powder, and then washed and kneaded in water. This presses all the starch out, just as we did out of the flour in the muslin bag.

When the water settles, the starch is left at the bottom. It is first partly dried, and then it is pressed through a sieve with small round holes.

Oh, then, said Norah, "this is why we always see it in little round balls."

Quite right, said Fred. "Now let us look at the arrowroot. This too is almost pure starch. It comes from the underground stem of a plant that grows in hot lands. It is got by breaking this stem in pieces, and kneading it up in water, as they knead the sago pith. When dried, it forms this white powder.

Tapioca is just the same sort of thing. It is almost pure starch. It is got from the root of a plant. The root must be broken up, and treated just like the sago pith and the arrowroot. The starch, that is left at the bottom of the water, is dried on hot plates. As it dries, it is stirred about with an iron rod. This makes it form in lumps as we see it here.

SUMMARY

Our bread, puddings, cakes, and potatoes all contain starch. Sago, arrowroot, and tapioca are nearly all starch. Sago is made from the pith of the Sago Palm, which grows in hot lands. Arrowroot is made from the underground stem, tapioca from the root, of a plant.