Kumquat

By Ken Love

Family: Rutaceae

Scientific name: Fortunella sp

Origin: Southern China

Introduction

Kumquat (cumquat) in Cantonese Chinese, means golden (Kum) and “Quat” meaning good fortune. A potted Kumquat tree with fruit is the ornament of choice during the Chinese New Year celebration in S.E. Asia, a tradition similar to the display of Christmas trees. The fruits are used in many Asian ceremonies and as offerings on the home altar. In Mandarin Chinese, it is known as jinju and in Japanese, kinkan. Kumquat was described in Chinese literature as early as 118 BC, and was first mentioned in European literature in the early 1600s. Chinese immigrants probably introduced kumquat to Hawaii, perhaps as early as 1825.

Varieties

There are a number of kumquat varieties, Meiwa (Fortunella crassifolia), and Nagami (Fortunella margarita), the two most common species grown in Hawaii. Hong Kong Wild (Fortunella hindsii), Marumi (Fortunella japonica), Fortunella obovata and Fortunella polyandra are other species found from Southeast Asia to Japan.

Environment

Considered a sub-tropical tree, the kumquat can be grown from lower elevations up to 5000 feet. Newly planted trees at lower elevations benefit from shading until well established. Kumquats are slow growing and will enter periods of winter dormancy. They rarely achieve heights greater than 15 feet.

Culture

Kumquats are sensitive to drought and flooding but are tolerant of a wide range of temperatures. They are often used as decorative hedges in Japan and planted as close as 3 feet apart. Orchard plantings in California place the trees from 5 to 12 feet apart. Quarterly fertilizing with 6-6-6 organic or all-purpose citrus fertilizer will keep the tree healthy and producing as will irrigation during periods of extended drought.

Pests and Diseases

Kumquat is a fruit fly host. Following the Hawaii Areawide Fruit Fly Pest Management Program (HAW-FLYPM) is highly advisable. Phyllocnistis citrella, the citrus leafminer, can be a problem. Petroleum sprays help to discourage egg laying but need to be repeated every 2 weeks when the plant flushes. Phytophthora citrophthora or fruit rot and Lasiodiplodia theobromae, fruit and stem rot, also affect the plant. Initial symptoms are yellowing and browning of leaves on some branches. These branches as well as any dead wood should be pruned off and disposed of.

Propagation

Kumquat is rarely grown from seed as seedling roots do not grow well. Commercial orchards in China use shield budding on trifoliate rootstock although rangpur lime and grapefruit rootstocks are also acceptable. Air layers and other forms of grafting are also possible. Lemon and sweet orange are not used as rootstock as they grow too vigorously for the slow growing kumquat.

Harvesting and Yield

Fruit is harvested when fully ripe and orange. Fruit should be free of defects and inspected carefully for damage from fruit flies. In Hawaii, Meiwa kumquats are sometimes confused with calamansie, a small round orange colored lime. The Meiwa has a much thinner skin and much sweeter taste than the lime. The tree is also not as prolific as calamonsie (Citrus microcarpa), which often produces large clusters of limes. China is the largest producer with more than 18,000 tons of kumquats harvested yearly.

Postharvest Quality

When stored from 36 to 39 degrees F. kumquats keep well for 1 to 2 months, or 2 to 3 weeks in a home refrigerator. Juice and whole or sliced fruit can be frozen for future use. At room temperature the fruit will last only a few days. The thin-skinned fruit should be packaged no more than 3 inches deep in blister packs to prevent compression damage.

Cost of Production

The project kumquat tree produced an annual marketable yield of 40.0 pounds. The average market price was $5.25 per pound, and therefore the tree generated a gross revenue of $210.00 for the year. Growing costs (fertilization, irrigation, pruning and all weed and pest control) amounted to $20.42, and harvesting costs (picking, packing and delivery to market) totaled $85.10. (All labor to grow and harvest the kumquats was assumed to be paid at an hourly wage rate of $16.00, including withholding, FICA and benefits.) Thus, the total annual operating costs, sometimes referred to as “variable costs,” were $105.52. The gross margin (gross revenue minus all operating costs) was $104.48.

The kumquat gross margin is the amount of money available to pay all the ownership costs associated with the kumquat enterprise. Ownership costs, sometimes referred to as “fixed costs,” include the value of land used (rent or rent equivalent or mortgage and property taxes), the value of the capital investment (such as the tree establishment cost and buildings and vehicles), the value of the management, and the value of any unpaid labor. (All paid labor is already included in the gross margin.) Ownership costs, unlike operating costs, will vary substantially from farm to farm and will depend largely on how the farming operation is financed and on economies of scale. Each grower will have to calculate his total farm ownership costs and then allocate an appropriate portion of these costs to each enterprise on the farm. Now the profitability of the kumquat enterprise can be determined by subtracting the kumquat enterprise’s share of the total ownership costs from the gross margin for kumquats.

The cost and return data are what was obtained from the 12 Trees Project site and other locations. Yields and costs were based on optimal growing conditions for one or more trees at various locations; different results will be obtained under different growing conditions. The prices used were actually obtained in 2005 and 2006. There is no guarantee that these prices will continue, especially if production increases significantly. These costs and returns are simply a starting point for growers to make their own estimates.

Packaging, Pricing and Marketing

Kumquats sold in Asia and Hawaii are either sold loose, with or without leaves, or packaged in small blister packs. Packaged fruit should be free of defects and inspected for possible frit fly stings. Kumquats should be fully ripe and orange colored when packaged. If sold with leaves attached, the leaves should be free of insect damage. In Hawaii, kumquats are more commonly found in farmers markets but occasionally in larger grocery stores around the New Years holiday. Prices in Hawaii range from $2.50 to $7.00 per pound for both wholesale and retail. Chefs often request the best quality fruit for their culinary creations.

Food Uses and Nutrition

Nutritional Information- 100 grams of edible portion

Water 80.85

Energy kcal 71

Energy kj 296

Protein g 1.88

Total lipid (fat) g 0.86

Ash g 0.52

Carbohydrate, by difference g 15.90

Fiber, total dietary g 6.5

Sugars, total g 9.36

Minerals

Calcium, Ca mg 62

Iron, Fe mg 0.86

Magnesium, Mg mg 20

Phosphorus, P mg 19

Potassium, K mg 186

Sodium, Na mg 10

Zinc, Zn mg 0.17

Copper, Cu mg 0.095

Manganese, Mn mg 0.135

Vitamins

Vitamin C, total ascorbic acid mg 43.9

Thiamin mg 0.037

Riboflavin mg 0.090

Niacin mg 0.429

Pantothenic acid mg 0.208

Vitamin B-6 mg 0.036

Folate, total mcg 17

Folate, food mcg 17

Folate, DFE mcg 17

Vitamin A, IU 290

Vitamin A, RAE mcg 15

Vitamin E (alpha-tocopherol) mg 0.15

Carotene, alpha mcg 155 2 0

Cryptoxanthin, beta mcg 193 2 0

Lutein + zeaxanthin mcg 129 0 0

Health Benefits- A good balanced source of vitamins and antioxidants.

The cryptoxanthin, zeaxanthin and lutein are essential for eye and vision care.

Recipes

Kumquat, Ginger and Chinese 5 Spice Marmalade

By Chef Paul Heerlein

Chef Instructor Hawaii Community College-West Hawaii

8 cups thinly sliced kumquats

0.5 cup tangerine juice

6 oz pectin

5.5 cups sugar

3 T finely minced fresh ginger

1 tsp (heaping) Chinese 5 Spice

In a saucepan combine the kumquats, tangerine juice and bring to a boil. Slowly add the pectin while whisking and then bring to a second boil. Add sugar while whisking and bring to boil again. Turn off the heat, stir in the ginger, 5- Spice and bottle immediately.

Boil the filled jars for twenty minutes.

Kumquats are eaten fresh or made into jams, jellies, and pickles, candied and used in a wide variety of recipes.

Kumquat KimChee Kumquat Mongolian Beef

The 12 Trees Project

Is funded by the Western Sustainable Agriculture Research and Education (WSARE) USDA-CSREES competitive grants program. Fifty-four Hawaii Island chefs, fruit buyers and growers were invited to select the types of fruit they would like to see commercially available, based on their desire to utilize the fruit in culinary applications. In selecting the final 12 fruits, considerations were given to seasonality and harvest times so that the availability of harvested fruit and on-farm labor needs were spread out over the year.

Fruit trees were planted and brought into production at a demonstration orchard at the Kona Pacific Farmers Cooperative on Napoopoo Road in the South Kona District. During the course of the three-year project, fruit from this orchard, as well as additional fruit purchased from area farmers, were donated to the West Hawaii Community College culinary school. Culinary student chefs developed recipes to be published on the project web site < http://www.hawaiifruit.net/12trees.html> and in a book in the final year of the project. Members of the cooperative as well as members of the Hawaii Tropical Fruit Growers - West Hawaii association and any other interested growers were encouraged to plant these trees. The goals of this project were to increase profitable agricultural diversification and to develop a consistently high quality, year-around supply of tropical fruit for local markets.

References and Further Reading

Popenoe W. 1920. Manual of Tropical and Subtropical Fruits. The Macmillan Company

Morton, Julia F., 1987. Fruits of Warm Climates

PROSEA 1992 Plant Resources of South-East Asia 2 Pp 169-171

Spiegel-Roy Pinchas, Goldschmidt Eliezer E., 1996. The Biology of Citrus. Cambridge University Press

Internet References:

University of Hawaii Knowledge Master database

http://www.extento.hawaii.edu/kbase/crop/cropmenu.htm

Hawaii Areawide Fruit Fly Pest Management Program (HAW-FLYPM)

http://www.fruitfly.hawaii.edu/

USDA's National Nutrient Database for Standard Reference, http://www.nal.usda.gov/fnic/foodcomp/cgi-bin/list_nut_edit.pl accessed 2006 November 10.

Acknowledgements

The author is grateful to Drs. R. Bowen, B. Brunner, K Fleming, R. Paull and F. Zee for their valuable contributions to this manuscript.