Handling and storing fruits and vegetables

First, let's talk a bit about handling and storing fruits and vegetables.

The deterioration of a harvested vegetables can be noted within a few hours of picking. This is due to the plants' cells effort to stay alive. Plant cells consume themselves and accumulate waste products, thus affecting their taste and texture. Corn and peas use their sugars for energy, celery uses its water to retain turgid pressure. Give them long enough and they lose their flavor and crispiness as they begin to die.

In contrast, fruits may get better after harvesting because they continue to ripen. But past ripening, they too run out of energy and die.

Spoilage is further brought on by microbes. Vegetables are mainly attacked by bacteria (Erwinia, Pseudomonas - "soft rot"). Fruits resist bacteria due to their acidity but are attacked by yeasts and molds (Penicillin, Botrytis).

For best results, it is important to know how to choose, handle, and store produce.

Produce with high metabolism will spoil faster: mushrooms, berries, apricots, figs, avocados, and papayas.

Lethargic produce such as apples, pears, kiwi, cabbage, and carrots are good keepers.

Moldy fruit or vegetables should be discarded immediately, as it can lead to "an infection"and spoil the rest of the produce faster. Clean out fridge drawers and fruit bowls often to reduce the microbial population.

It's best to keep produce in restricted spaces within the fridge to slow down moisture loss, but since produce exhales carbon dioxide and water, it's important to also avoid too much condensation. (Now I get why the fridge drawers are labeled "high/low moisture!") Tip: Line containers with paper towel.

Restricted spaces will also limit access to too much oxygen, which increases metabolic activity, but not so much that the cells go into anaerobic metabolism, which generates alcohols (think fermentation) and leads to tissue damage.

It's a tricky balance because keeping produce in a closed bag will create a favorable environment of higher CO2 and low O2, but it will also trap ethylene, a plant hormone that advances ripening and accelerates aging. Permanganate inserts destroy ethylene, so inserts may extend storage life.

Cooling extends the life of produce by: 1. slowing metabolism, 2. slowing microbial growth. But beware of refrigerating fruits and vegetables that are native to warmer regions. The cold leads to cell malfunction, uncontrolled enzyme action, and tissue injury. Foods to better keep at room temperature include: melons, eggplants, squash, tomatoes, cucumbers, peppers, beans, bananas, avocados, and citrus fruits.

Freezing kills plant tissue in two ways: 1. as the water crystallizes, enzymes and other reactive molecules become concentrated and react abnormally. 2. water crystals puncture cell walls and membranes, causing a physical disruption. Flash freezing at extreme low temperatures creates smaller crystals, thus lessening the damage.

Blanching is a technique where the food is rapidly immersed in boiling water for a minute or two, then rapidly immersed in cold water, and then frozen. The boiling will inactivate enzymes, the cold water will stop the food from continuing to cook and softening the cell walls.

Sugar syrup can prevent enzymatic browning in fruit (when accompanied by ascorbic acid) and improve the texture of the frozen fruit by stiffening the cell walls when absorbed.

Frozen produce should be wrapped in air- and watertight containers to minimize freezer burn (which is caused by sublimation of water molecules).

Phew! So many Do's and Don'ts just to keep good tasting (and nutritious) fruits and vegetables.