A fruit is sugary water in a skin, with just enough vitamins for an animal to want to eat it and scatter its seeds further away. We are that animal.
What's inside
Water, mostly: 80 to 90% of the weight of fresh fruit. Watermelon and strawberries exceed 90%, an apple is about 86%, a banana 75%.
Sugars: fructose, glucose and sucrose, depending on the fruit. They provide most of its energy.
Fibre, including pectin, which makes jam set.
Acids: citric (citrus), malic (apple), tartaric (grape). They make fruit tart, and they're what allows fruit to be bottled without risk of botulism, see Les conserves en bocal.
Vitamins and minerals: vitamin C above all, potassium, and, in orange fruit, pigments the body turns into vitamin A.
Very little protein and almost no fat, with exceptions: avocado, olive, coconut.
Useful numbers (per 100 g of fresh fruit)
| Fruit | Energy | Vitamin C | What sets it apart |
|---|---|---|---|
| Apple | 52 kcal | 5 mg | Keeps for months in the cool |
| Banana | 89 kcal | 9 mg | Rich in potassium (358 mg) |
| Orange | 47 kcal | 53 mg | Travels well |
| Kiwi | 61 kcal | 93 mg | One of the best sources of vitamin C |
| Strawberry | 32 kcal | 59 mg | Very little pectin |
| Blackcurrant | 63 kcal | 181 mg | Europe's champion |
| Guava | 68 kcal | 228 mg | The tropics' champion |
| Grape | 69 kcal | 3 mg | Lots of sugar, few vitamins |
| Avocado | 160 kcal | 10 mg | 15 g of fat: the most filling |
| Dried date | 282 kcal | 0 mg | Concentrated energy, keeps for years |
| Dried apricot | 241 kcal | 1 mg | Concentrated iron and potassium |
Vitamin C is the reason fruit matters in hard times. About 10 mg a day is enough to prevent scurvy; recommendations for good health are around 100 mg. It is destroyed by heat, air and time: cooked or dried fruit loses a large part of it.
What's toxic
- The kernels inside the stones of apricots, peaches, plums and cherries, and apple pips, contain amygdalin, which releases cyanide when crushed or chewed. Swallowed whole by accident, they pass through. Bitter apricot kernels, sometimes sold as a "remedy", poison a child in small numbers.
- Black elder: raw berries, leaves and stems cause nausea. Fully ripe berries are eaten cooked (jam, syrup).
- Rhubarb leaves are rich in oxalic acid. Only the stalks are eaten.
- Grapefruit interferes with how many medicines are cleared (some for cholesterol, blood pressure, anxiety) and can push their level in the blood too high. If you take a treatment, check the leaflet.
- An unknown wild fruit isn't tasted: see Décider si quelque chose est comestible.
Ripening
Some fruits keep ripening after picking, because they give off a gas, ethylene, which speeds up their own ripening and their neighbours': banana, apple, pear, avocado, tomato, mango, kiwi. Others stop ripening once picked: citrus, grape, strawberry, cherry, pineapple.
Tips from people who store them
- To ripen a hard avocado or kiwi, shut it in a paper bag with a ripe banana or apple: the ethylene does the job in a day or two.
- To keep apples for months, choose sound ones, unbruised, picked by hand. Store them one by one, not touching, in the cool (1 to 5 °C), in a damp cellar. Remove any that start to rot every week: one bad apple speeds up all the others. And keep them away from potatoes and carrots, which ethylene makes sprout or taste bitter.
- Rose hips, the red fruit of the dog rose, stay on hedges all winter and contain several hundred milligrams of vitamin C per 100 g. They were Britain's vitamin C reserve during the war. Eat them as syrup or jam, without the hairs around the seeds, which are very irritating.
- Drying fruit concentrates its sugar and energy: it takes about 5 to 7 kg of fresh apricots for 1 kg of dried ones. See Le séchage.
- Pectin-rich fruit (apple, quince, redcurrant, citrus peel) sets the jams of fruit that lack it (strawberry, cherry): a few chopped apples in the pot are enough.
A little botany
To a botanist, a fruit is whatever holds the seeds. Tomato, pepper, cucumber and aubergine are therefore fruits; banana and avocado are berries. And the strawberry isn't really one at all: its flesh is the flower's receptacle, and its true fruits are the little seeds on its surface.