Ripe Fruit - choosing and storing for optimum ripeness

• Download ripe-fruit.pdf (713k).
  This single-page colour guide will help you choose and store fruit for optimum ripeness - aroma, sweetness, juiciness and colour.
  Alternatively, just read the guide on this current web page.
• [Italiano] Scaricare frutta-matura.pdf (709k).
  Questa guida, una pagina solo, ti aiuta ad acquistare e conservare la frutta matura. Così obteni l'ottima aroma, dolcezza, succosità e colore.

Sources. The categories of ripening are derived from "The Man Who Ate Everything" by Jeffrey Steingarten (at Amazon). Buying advice comes from that book and also from "Le Cordon Blue Complete Cooking Techniques" by Jeni Wright and Eric Treuille (at Amazon). A website worth reading is The Cook's Thesaurus: Fruit. The advice on grapes and pineapples is from own experience. I am Lucian Wischik.

Fruit on the tree grows to its intended size and shape - maturity
Then, within a week or so, it ripens in the following ways:

1.  Aroma. Bitter and astringent phenols fade away (their job was to discourage animals before the seed was ready), and nice aromas are produced (to encourage animals). This normally only happens while fruit still attached to tree. Ethylene gas is the "ripening hormone" that coordinates the ripening.
2.  Sweetness, in the form of sucrose or fructose. It can come as sweet sap while attached to the tree, or in some fruits by converting the fruit's stores of starch/glucose/acid.
3.  Juiciness and softness. The enzyme polygalacturonase attacks pectin in the cell walls making cells slide around (softness) and spill their contents (juiciness). Acids are used up in this, making the fruit less sour.
4.  Colour changes, brightens, forms a waxy sheen to slow loss of water. Look at the background colour, not the red blush which growers have bred so it appears even before ripeness.

Ripens after picking?	Fruit	Buying	Storage
		Buy from loose fruit rack, so you can smell it and check for no bruising or mould or musty damp. Handle little, since ripe fruit spoils easily.	Don't fridge before a fruit is ripe, since this ruins the ripening. Once ripe, or immediately for non-ripening fruit, eat. Otherwise, store in fridge to slow respiration, in plastic bag to stop moisture loss, but unsealed to avoid fermenting.
	avocado	(Won't even ripen on tree, because a chemical signal inhibits it). When ripe, it yields to gentle pressure but skin is not loose.	Store on tree! Or, after ripening, fridge it for up to a week.
	banana	Buy green, so they won't have been damaged during transport.	Ripen in paper bag until yellow with black specks. Then fridge what you can't eat.
	pear	Buy under-ripe. Firm flesh with no blemishes.	Unusually, fridge before ripening to avoid mushiness. Once ripe, their perfect ripeness lasts less than a day.
	apple kiwi mango papaya	Best if picked after maturity. Judge maturity by aroma. Apples smooth shiny skin, firm with no bruising, no blemishes. Papaya rich colour, gives slightly at room temperature.	(Apples lack polygalacturonase and so don't soften, instead remain crisp.)
	peach nectarine apricot plum	Buy mature: peaches etc. have fully-developed shoulders; sutures well-developed and just started to soften. Colour has no trace of green, nectarines have a slight sheen. No bruising.	Ripen in a sudden rush.
	passion-fruit fig blueberries	Buy mature. Blueberries plump with blue/green "bloom", firm not soft.	Most ripen in a sudden rush. Passion-fruit can be frozen.
	canteloupe galia charantais casaba	Round depression where stem was should be smooth, shows the fruit was ripe enough to fall off easily. Look for softness and aroma at opposite end. Cantaloupe skin not green. Fruit with netted skin should have netting raised. With smooth skin, it should be slightly waxy.	Ripen in a sudden rush.
	watermelon	Well-rounded at both ends, rinds firm but not hard, intense red flesh without white streaks, seeds dark not white.
	orange grapefruit lemon, lime	Buy fruit that feels heavy for its size (will be juicier with more dissolved solids in juice). Look for glossy smooth even-coloured fine-pored skin (smooth skin implies thin skin). In oranges, button should be green, and green skin is fine.
	grapes pineapple cherries berries	Choose fruits that already smell and taste ripe -- they will not ripen any further. Pineapple should have a strong sweet smell at its base.	Short storage lives. Store and handle berries carefully and briefly. Don't wash until last minute (to avoid damage/decay). Grapes keep okay in the fridge. Pineapple will not get any sweeter in storage, but it will become less tart as its acids are used up to soften the flesh.