Internet version [Naruhodo no Mori] Vol.35

by Yumiko Mori

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Vol. 35     December 15th, 1997

Syrup Oranges

Home science experiments for mothers of elementary school children

Tae: "Oh, no! What is this? It doesn't taste right."
Mom: "We peeled orange and then we removed segment skins by boiling them in baking soda (sodium bicarbonate). You can dip them into syrup."
Tae: "The name 'baking soda' is familiar to me. When did we use before?"
Mom: "We used it when we made Japanese sugar cake."
Tae: "That's right. We used baking soda to make cake rise."
Mom: "Baking soda also can be used for cleaning, because it can get rid of grease."
Tae: "Baking soda is really all-purpose. It's interesting."
Mom: "Do you want to remove segment skins from oranges, Tae?"
Tae: "Yeah! I want to make a lot of syrup oranges and eat them with parfait."
Mom: "That's good idea. I bought ice cream yesterday. It's in the fridge."
Tae: "Satoshi, leave some oranges for us! Don't eat all!"

Materials

Orange	1	(Sour oranges are OK too.)
Baking soda	2 grams	(Sodium bicarbonate)
Water	400 ml	(2 cups)
Syrup		(Sugar water, or use juice from canned orange)
A glass cup
A pot
A slotted spoon
A bowl
A sieve

Preparation

• Peel orange skin and separate into segments. (Try not to break segment skin.)
• Put enough water in the bowl.

How to make syrup orange

1. Boil 2 cups of water (400 ml) and 2 grams of baking soda in the pot.
2. Place 3-5 orange segments on a slotted spoon and dip them into the boiled water.


3. Shake the segments in the boiled water for 2 minutes. For the beginning you see the segment skins become visibly white and later turn to yellow as a sign of skin melting.
   Then the water also become yellowish. If you boil orange segments too long, not only segment skins but also segments can melt.
4. Keep orange segments on the slotted spoon, transfer gently into cold water in a bowl, and rinse off the baking soda solution.
   Sieve orange segments and, then transfer segments to syrup juice.

• Depending on the baking soda concentration or the thickness of segment skins, the time necessary for the skins to melt may vary.

• When heated, baking soda become more alkaline and can soften orange fibers.
  When we boil bracken or mugwort (Both are commonly eaten wild plants in Japan), we use baking soda for the same reason.

• In the syrup orange factories, diluted chloric acid is used to remove segment skins and neutralized by sodium hydroxide.

• Bruised oranges tend to damage surrounding oranges too.
  The reason for this is that bruised oranges emit a plant hormone, ethylene gas which in turn damage the surrounding oranges.
  This ethylene gas is used to turn green bananas into yellow.

   Today we are surrounded by all sorts of processed food. Recent development in biotechnology has brought new kinds of food. We hear discussion about the safety of these new food items more frequently. We, consumers, always have to watch out for unsafe food. But, when I listened some discussion, I was completely perplexed by different opinions of the industry, the scientists, and the consumer groups. I wish someone can explain to me more plainly whether food is safe or not.

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