Ascorbic acid helps keep kiwifruit from browning.Medioimages/Photodisc/Photodisc/Getty Images
When you slice kiwifruit, you may notice are the tiny black seeds neatly arranged amongst the stunning green flesh and creamy, white center. What you will never see amongst the seeds and flesh, however, is browning. Although kiwifruit, whole or sliced, is not susceptible to these unattractive brown spots, it is perishable and subject to other physical changes that occur as fruit comes in contact with oxygen in the air.
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Unlike fruits such as apples, bananas and pears, kiwifruit does not fall victim to the oxidation dilemma. Once cut, oxygen exposure turns the flesh of these fruits an unappetizing brown color. This color change, or browning, is the result of high levels of polyphenol oxidase activity. Kiwifruit has low PPO activity and high levels of ascorbic acid, which inhibits browning. Even when bruised, kiwifruit does not sustain brown patches. Instead, the fruit develops soft spots in the affected area.
Cut and Eat
Kiwifruit may not turn brown after slicing, but it does become mushy. The longer a kiwifruit sits after cutting, the soggier the fruit becomes. Since the skin of the kiwifruit is edible, consider eating the unpeeled fruit. Leaving the peel intact during storage keeps the kiwifruit fresher longer. If you must remove the skin or cut the kiwifruit, do it right before you plan to eat it.
What to Look For
Since kiwifruit does not turn brown when cut or bruised, differentiating between ripe and over-ripe is difficult. The key is in the texture and firmness of the kiwifruit. Ripe kiwi possesses a slight give when you apply pressure to the outer surface. As the kiwifruit continues to ripen, however, wrinkles develop and overtime the entire fruit wrinkles and shrivels, affecting quality and nutritional value.
While the whole fruit keeps for up to four weeks in refrigeration, once sliced, kiwifruit quickly begins to dry out and wrinkle. If you are unable to eat the kiwifruit immediately after cutting, wrap the sliced fruit tightly in plastic wrap and pop it in the refrigerator. The storage time for sliced kiwifruit is variable, dependent in part on the ripeness of the fruit prior to cutting.