kris ulland

Your Nutrition Partner

Most fruit can only ripen on the plant but there are some fruits like avocados which only ripen after picking. Only when the fruit on a plant reaches physiological maturity, can the fruit ripen.

Fruit and vegetables are categorized as climacteric or non-climacteric. Climacteric fruit reach a certain developmental stage and once attaining that stage, continue to develop to full physiological maturity, even when removed from the plant.

Climacteric fruit such as peaches, plums, cantaloupe, bananas, pears and tomatoes continue to gain flavor and get sweeter by changing starch into sugar. Many also go from firm to soft and juicy (peach and plum), or at least softer (avocado and cantaloupe). They are also sensitive to ethylene gas, which they self-generate, further aiding the ripening process.

Climacteric fruit can be left at room temperature until consumed or mature and then refrigerated. Since many climacteric fruit soften as they ripen, to minimize bruising during shipment and extend shelf life, they are harvested firm and physiologically immature. If not left to fully mature before refrigerating, you will have crunchy peaches, nectarines and plums; green, starchy bananas; and bland tasting cantaloupe.

If left at room temperature for a few days, these fruits will develop more flavor and sweetness. Peaches, nectarines and plums reach optimum flavor when soft and juicy, bananas are tastiest when they are yellow and have brown speckling on the skin and cantaloupe is best when the fruit is somewhat soft.

You can use the trick of putting unripe, mature fruit in a paper bag with an apple or banana to get it to ripen faster. Don’t use plastic, as the fruit needs to breathe. This only works for fruits that naturally produce ethylene gas which helps convert starch into sugar both on the plant and after picking.


  • Apple – Unlike some fruits, apples continue to ripen long after they are picked off the tree. This ripening (or over-ripening affects the texture not the taste of the fruit. (ie. They won’t get sweeter just softer).
  • Apricot
  • Avocado – Avocado matures on tree, but only ripens after picking.
  • Bananas – Bananas are picked when green and artificially ripened after shipment by being exposed to ethylene. Calcium carbide is also used in some countries for artificially ripening fruit.
  • Cantaloupe – If you’ve cut open a melon and found it to be underripe, the natural enzymes that break down a melon and turn it to compost will soften it slightly even as it rests in the refrigerator. That softens and improves the texture, though it’ll do little for its flavor. Slicing or dicing the melon helps or toss it with lemon or orange juice, a sprinkling of sugar, sweet white wine or a favorite fruit-flavored liqueur. You can maximize the flavor of any melon, ripe or not, by bringing it back to room temperature before you serve it. Sniff a melon in the store before buying it. A melon that’s odorless will usually be flavorless, while a melon that smells ripe and fragrant probably tastes that way, too. The stem end should be smooth and round, without stray fibers that show it was reluctant to be picked. The opposite, or blossom, end should have a small amount of “give” but not be soft or mushy.  Cantaloupe should be heavy for their size, which tells you they’re juicy. Avoid melons that smell fermented, have soft spots or are deeply bruised. Those are usually overripe. The skin should be a pale tan color, with little green. A green hue generally shows that the melon isn’t quite ready yet.
  • Chile pepper
  • Date
  • Guava
  • Honeydew melon
  • Jackfruit
  • Kiwi
  • Mango
  • Mulberry
  • Nectarine
  • Papaya
  • Passion fruit
  • Pawpaw
  • Peach
  • Pear
  • Persimmon
  • Plantain
  • Plum
  • Quince
  • Sapodilla
  • Sapote
  • Tomato 
  • Winter squash  – can sweeten after picking


Non-climacteric fruit are fruit that need to stay on the plant to reach full physiological maturity. Once removed, they will not continue to mature, gain flavor or sugar. Their highest eating quality is at harvest. For food safety, it is important that once all whole fruits and vegetables are cut-up, they need to be eaten or refrigerated within 2 hours.

Some fruit are ethylene sensitive. As a gas, ethylene is hard to contain and many things respond in negative ways if stored with ethylene generating fruit. Cabbage and Brussels sprouts will turn yellow or crack and start to grow, carrots develop a bitter flavor due to ethylene-induced isocoumarin production and cucumbers deteriorate quicker.

It’s ideal to get these fruits at a market where you can taste test them first because they’re not going to improve at home. In some instances, these fruits may soften after picking as they begin to breakdown (rot, really), but flavor won’t improve.

  • Bell pepper
  • Berries
  • Blueberry
  • Blackberry
  • Blackcurrant
  • Cherry
  • Citrus fruit
  • Coconut
  • Cucumber
  • Eggplant
  • Figs
  • Gooseberry
  • Grape – Grapes do not continue to ripen once off the vine. It is the leaves of the grape that engender the sugars, which are then transferred to the fruit.
  • Grapefruit
  • Lemon
  • Lime
  • Longan
  • Loquat
  • Lychee
  • Mandarin
  • Muskmelon
  • Olive
  • Orange
  • Peppers
  • Pineapple – Pineapples may soften after picking but will not become sweeter.
  • Pomegranate
  • Prickly Pear
  • Rambutan
  • Raspberry
  • Strawberry – Strawberries are usually picked when they are not quite ripe and they do not continue to ripen after they are picked, at least not in terms of sweetness. Commercially-grown strawberries are bred for sturdiness so they can stand up to shipping. They’re usually picked when they are not quite ripe. They do continue to redden so they are looking good by the time they get to the store. Researchers in Japan have developed a strawberry-picking robot that can tell which berries are ripe and which ones aren’t.  The robot has two cameras that create a 3-D image of the strawberries and analyze them for color. If the berry is ripe enough a pincer cuts it off and drops it in a collection basket without damaging the fruit. The contraption can pick a berry in nine seconds.
  • Summer squash
  • Tamarillo
  • Tangerines
  • Watermelon

Fruits and Vegetables to Store at Room Temp

  • Bananas
  • Basil
  • Cucumber
  • Eggplant
  • Garlic
  • Grapefruit
  • Green beans
  • Lemons
  • Limes
  • Onnions
  • Oranges
  • Potatoes
  • Summer Squash
  • Sweet Potatoes
  • Watermelon
  • Winter squash
  • Zucchini

Store These on Your Counter, then Move to the Fridge When Ripe (Soften)

  • Apricots
  • Avocados
  • Kiwifruit
  • Mangos
  • Melons
  • Nectarines
  • Papayas
  • Peaches
  • Pears
  • Pineapple
  • Plums

Fruits and Vegetables to Store in the Fridge

  • Apples
  • Asparagus
  • Blueberries
  • Broccoli
  • Brussels sprouts
  • Cabbage
  • Carrots
  • Cauliflower
  • Cherries
  • Cilantro
  • Corn (whole ears in the husk)
  • Dark leafy greens
  • Grapes
  • Leeks
  • Lettuce
  • Parsley
  • Peas
  • Pomegranate
  • Raspberries
  • Strawberries


The plum is a stone fruit that grows on trees in the Prunus genus. Depending on the variety, a plum may be green, red, purple, or yellow, and all have smooth, edible skin and sweet flesh surrounding a pit.

The fruit is most often used in baked goods or boiled to create jams and sauces for both sweet and savory dishes. It can also be grilled, poached, roasted, or stewed. And, plums are delicious eaten raw.

Plums are a member of the rose family, Rosacea, and are related to peaches, apricots, nectarines and almonds. The plant is native to China, the Americas, and Europe. The fruit is classified as a drupe, meaning it has a pit (or stone) in the center, similar to a peach and apricot. Healthy plum trees are prolific and the fruits fill every branch and limb, often ripening all at once.

The plum ranges in size, shape, and color. Black and yellow plums have an amber-colored flesh under their skins.

Two types of plums, the European and the Japanese variants, originate from two different countries. European plums were first documented in the Caucasus, with Pompey the Great being known to have cultivated the trees as early as 65 B.C., while Japanese plums have been documented in China, with the philosopher Lao Tzu believed to have been born under a plum tree. 

Plums are relatively low in calories, but contain a fair amount of important vitamins and minerals. One plum contains the following nutrients:

  • Calories: 30
  • Carbs: 8 grams
  • Fiber: 1 gram
  • Sugars: 7 grams
  • Vitamin A: 5% of the RDI
  • Vitamin C: 10% of the RDI
  • Vitamin K: 5% of the RDI
  • Potassium: 3% of the RDI
  • Copper: 2% of the RDI
  • Manganese: 2% of the RDI

Additionally, one plum provides a small amount of B vitamins, phosphorus and magnesium.

As a stone fruit, plums can be divided into three categories: clingstone, semi-clingstone and freestone. These divisions vary mainly on the separation of the flesh from the stone, or the pit. Clingstone plums have flesh that adheres to the stone, while freestone plums have flesh free from the stone.

While prunes are usually described as dried plums, not all plums can be processed into prunes. Prunes are specifically produced with the Prunus domestica cultivar because its sugar content keeps it from fermenting during the drying process.

While prunes and plums come from the same plant, their nutritional components largely differ. For example, one cup of sliced, raw plums contains only 76 calories, while the same amount of prunes contains 418. Fresh plums are high in sugar with 16 grams per serving, while the dried variety has 66 grams.

Plums and prunes are rich in antioxidants, which are helpful for reducing inflammation and protecting your cells from damage by free radicals. They are particularly high in polyphenol antioxidants, which have positive effects on bone health and may help reduce the risk of heart disease and diabetes.

The significant amounts of flavonoid polyphenolic antioxidants in plums, such as lutein and cryptoxanthin, may help fight aging and disease by combating free radicals and reactive oxygen species. Red blood cell-formulating iron, heart- and blood pressure-regulating potassium and fat- and carbohydrate-metabolizing B vitamins, such as niacin, B6 and pantothenic acid, are important components in both plums and prunes.

Vitamin A and zeaxanthin in plums are eye-protective, because they absorb into the retina and filter ultraviolet light. In addition, the vitamin C content of plums may help protect LDL from oxidation, which is especially beneficial for people at risk for atherosclerosis (hardening of the arteries).

Classified as phenols, neochlorogenic and chlorogenic acid are two unique phytonutrients in plums and prunes, and have been the subject of numerous clinical trials in recent years. This is because of their antioxidant effectiveness, especially against one of the most damaging free radicals: superoxide anion radical.

Both fresh and dried plums are known as a natural laxative, mainly due to their high sorbitol content. The fiber in plums and prunes may also play an important role in feeding the good bacteria in your gut. In a 2018 animal study in the journal Frontiers in Microbiology, researchers found that dietary fiber treatment may help improve gut health by promoting microbiota changes.

Plums have properties that may help with blood sugar control. Despite being fairly high in carbs, plums and prunes do not appear to cause a substantial rise in blood sugar levels after they’re eaten. This is attributed to their potential to increase levels of adiponectin, a hormone that plays a role in blood sugar regulation.

Additionally, the fiber in plums may be partly responsible for their effects on blood sugar. Fiber slows the rate at which your body absorbs carbs after a meal, causing blood sugar to rise gradually, rather than spike.

Luther Burbank, a pioneer in agricultural science, performed cross-breeding experiments on plums to produce a tree with all the right attributes, such as “stability, novelty, variety, hardiness, beauty, shipping quality and adaptability.” Burbank’s experiments with plums produced the “plumcot”, half plum and half apricot. He also produced the pluot, which was 75% plum and 25% apricot, and the aprium, a 75% apricot and 25% plum mix.

How to Buy

Most supermarkets and grocery stores stock fresh plum when the fruit is in season. The fruit can also be found at some farmers markets. Plum comes into season from the middle of summer into early fall. This will vary slightly with the climate, the weather that year and the specific variety. Sold individually by the pound, plums are inexpensive.

Plums are delicate and should be handled carefully to avoid bruising. When selecting a plum, give it a very gentle squeeze. It should give just a little bit, just like a peach. The skin should be a vibrant color and not have soft spots or bruising. Most plums have a bloom, a delicate dusty white matte powder on the skin that rubs or rinses off. This is a sign of ripe, freshly harvested fruit that has not been over-handled.

How to Store

A plum that is ripe and ready to eat can be kept at room temperature. Or, to keep it in good shape a bit longer, wrap the fruit loosely in in a tea towel and keep it chilled. For a plum that is still hard, allow it to soften by leaving it out at room temperature. To speed up the process, place it in a paper bag. Unlike some fruit, a plum won’t get sweeter; it stops developing sugars once plucked from the tree.

If you have too many to use right away, plums freeze well. Wash, peel, and pit the plum if you prefer. Cut it into smaller pieces, then flash freeze the fruit in a single layer on a baking sheet before transferring to an airtight container. Plum will keep in the freezer for six months to one year. Once frozen the fruit is best for smoothies, baked goods, or jams.

How to Cook

Besides eating raw out of hand, plums can be used in a variety of ways. They’re commonly found in baked goods such as cakes, pies, and tarts. Plum jam and chutney are very popular, as are sauces for desserts and savory meat dishes. The fruit is also used in beverages such as smoothies and can be juiced to drink as is or fermented to make plum wine. When you cook with black plum, the dark skin will give the entire dish a deep purple color.

To prepare plum for recipes, wash the outside well. Recipes will generally require you to cut the fruit into halves or quarters, then discard the pit. For recipes like dumplings, when you need to preserve the general shape of the plum, slit it in half, cutting along the pit, then remove the pit. Other recipes, like jams that require boiling, will call for chopped plums. Plum halves may also be grilled or roasted and quartered plums can be poached for a sweet fruit soup or compote.

Gluten Free Sugar Plum Tart

Sarcastic Cooking / Photo credit Stefanie of Sarcastic Cooking

6-8 Servings


For the Crust:

  • 2 ½ Cups Almond Meal
  • 5 Tablespoons Coconut Oil or vegan butter – melted
  • 1 flax egg – 1 tablespoon flax in 3 tablespoons water – let sit 5 minutes and stir
  • 2 Tablespoons Granulated Sugar (I use coconut sugar.)
  • Pinch of Sea Salt

For the Filling:

  • 4 Cups Pitted and Sliced Plums
  • 5 Tablespoons Corn Starch
  • 2/3 Cups Granulated Sugar
  • Pinch of Sea Salt
  • 3 Tablespoons Grated Ginger
  • Juice ½ Lemon
  • 1 Tablespoon Cold Vegan Butter


  1. Preheat the oven to 400 degrees F.
  2. Add crust ingredients to a medium mixing bowl. Mix until all ingredients are moist. Pour the crust mixture into the tart pan. Press into one even layer over the bottom and sides of the tart pan using your hands.
  3. In a separate medium mixing bowl, mix together the plums, corn starch, sugar, salt, lemon, and ginger. Pour the fruit filling over the crust. Arrange in one even layer. Dot the top of the fruit with the cold vegan butter.
  4. Bake the tart in the oven for 30-40 minutes until the crust is deeply golden. Check during the last ten minutes to make sure the top edges do not burn. Cool completely before slicing.



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