Actinidia deliciosa, commonly known as the fuzzy kiwifruit, is a fruit-bearing vine originally native to China, particularly from the forests of the Yangtze river valley. It is part of the Actinidiaceae family and widely cultivated for its edible fruit, which is known for its brown, fuzzy skin and bright green flesh with a unique tangy-sweet flavor. This species is often simply referred to as "kiwi."

Botanical Classification

Kingdom: Plantae
Clade: Angiosperms
Class: Eudicots
Order: Ericales
Family: Actinidiaceae
Genus: Actinidia
Species: A. deliciosa

Plant Characteristics

Actinidia deliciosa is a robust and fast-growing vine that can extend over 9 meters in length. It features large, rounded leaves that are slightly heart-shaped at the base. The plant is dioecious, meaning separate male and female plants are needed for pollination. The female plants produce the characteristic kiwi fruit after being pollinated by the flowers from male plants. The flowers themselves are white to creamy-white and have a pleasant aroma.

Chemical Composition and Structure

Kiwi is exceptionally rich in vitamin C, often higher than that found in oranges. It also contains significant amounts of vitamin K, vitamin E, and dietary fiber. The fruit is a good source of antioxidants such as carotenoids and flavonoids, which help mitigate oxidative stress. Kiwis also contain a natural enzyme called actinidin, which can break down proteins and aid in digestion.

How to Cultivate It

To obtain this fruit, two plants are needed: a male and the other female that will be pollinated by bees.

1. Soil: Prefers well-drained, acidic to slightly alkaline soil, rich in organic matter.
2. Light: Needs full sun for optimal growth and fruit production, though it can tolerate partial shade.
3. Water: Requires regular and consistent watering to maintain moist soil conditions, particularly during the growing season.
4. Temperature: While it is somewhat frost tolerant, young plants are vulnerable to frost damage. It thrives best in temperate climates.

Uses and Benefits

The kiwifruit is predominantly consumed fresh but is also widely used in culinary applications such as in salads, desserts, smoothies, and as a meat tenderizer, thanks to its actinidin content. Medically, the high vitamin C content makes kiwi beneficial for boosting immune system function, supporting skin health, and enhancing cardiovascular health.

Applications

• Culinary: The fruit's attractive appearance and refreshing taste make it popular in a variety of dishes.
• Nutritional Supplements: Used in health supplements for its rich vitamin and antioxidant profile.
• Cosmetic: Kiwi extract is used in skin care products for its vitamin C content and antioxidant properties, which are beneficial for maintaining healthy skin.

Environmental and Safety Considerations

Actinidia deliciosa should be cultivated with care to avoid becoming invasive, particularly outside its native range. Proper management and control are necessary to prevent it from overtaking local flora. Generally, kiwi fruit is safe for most people to consume, though it can cause allergic reactions in some, particularly those who are allergic to other fruits, latex, or have asthma. Handling the plant, especially during pruning, can cause skin irritation due to its sap, so protective gloves are recommended.

Studies

Kiwis contain on average:

• Vitamin C Ascorbic acid in the following measures (Cultivar Actinidia chinenssis Plach, Gaivard): mg/g 5,44 in the juice, 1,14 in the skin, 4,20 in the pulp (1).
• Vitamin E
• Potassium

It has good antioxidant and anti-inflammatory properties due to the presence of ascorbic acid.

Flavonoids, vitamin C and carotenoids have a preventive effect against cardiovascular diseases (2).

Kiwi has proven effective in relieving chronic constipation (3) with these benefits:

• decreased in days of laxative used
• satisfaction of bowel habit
• improvement in transit time
• improvement in rectal sensation

Kiwi studies

Attention: those suffering from Crohn's disease must abstain from consuming it.

References__________________________________________________

(1) Kvesitatdze GI, Kalandiia AG, Papunidze SG, Vanidze MR. Use of HPLC for identification and quantitative determination of ascorbic acid in kiwi fruit. Prikl Biokhim Mikrobiol. 2001 Mar-Apr;37(2):243-6. Russian. PMID: 11357433.

(2) Jung KA, Song TC, Han D, Kim IH, Kim YE, Lee CH. Cardiovascular protective properties of kiwifruit extracts in vitro. Biol Pharm Bull. 2005 Sep;28(9):1782-5. doi: 10.1248/bpb.28.1782. 

Abstract. It is currently accepted that the consumption of fruit-derived antioxidants such as vitamin C, carotenoids, and flavonoids provides a preventive effect against cardiovascular disease. The purpose of the present study was to investigate potential cardiovascular protective properties of aqueous and 70% ethanol extracts from kiwifruit by analyzing the antioxidative, antihypertensive, hypocholesterolemic, and fibrinolytic activities in vitro. Aqueous and 70% ethanol extracts at 50 mg/ml showed DPPH-radical scavenging activities of 72.31% and 70.75%, respectively. Total antioxidant activity in linoleic acid emulsion was 85-88% at 10 mg/ml and 96-98% at 50 mg/ml of kiwifruit extract. Inhibitory activities against angiogensin I-converting enzyme of kiwifruit extracts were 21-26% at 10 mg/ml and 46-49% at 50 mg/ml, and inhibitory activities on HMG-CoA reductase were 13-14% at 10 mg/ml and 19-30% at 50 mg/ml. Fibrinolytic activity of kiwifruit was also observed at a high concentration of 100 mg/ml in both aqueous and 70% EtOH extracts. Based on our results, kiwifruit have potential cardiovascular protective properties in vitro.

(3)  Chan AO, Leung G, Tong T, Wong NY. Increasing dietary fiber intake in terms of kiwifruit improves constipation in Chinese patients. World J Gastroenterol. 2007 Sep 21;13(35):4771-5. doi: 10.3748/wjg.v13.i35.4771. 

Abstract. Aim: To investigate if increased dietary fiber, in terms of kiwifruit, is effective in Chinese constipated patients. Methods: 33 constipated patients and 20 healthy volunteers were recruited for a 4-wk treatment of kiwi fruit twice daily. Response during wk 1-4 was defined as an increase in complete spontaneous bowl, motion (CSBM) > or = 1/wk. Secondary efficacy included response during wk 1-4, individual symptoms and scores of bowel habits and constipation. Responses were compared with the baseline run-in period. Colonic transit time and anorectal manometry were performed before and after treatment.....Conclusion: Increasing dietary fiber intake is effective in relieving chronic constipation in Chinese population.