The yellow passion fruit is a distinctive fruit. Of the 400 known species of passion in fruit, about 30 possess edible fruit. For centuries yellow passion fruit has grown in tropical climates and have been cultivated to eat fresh from the vine or to make beverages.

Passion fruit is known by several names, depending which country is producing the crop. Some of the names include: Parcha, maracuya, cibey, and granadilla, and lilikoi. The yellow variety is the most commercial variety in many parts of the world primarily due to its ability to grown in a variety of soils and produce a hardy yield. It tends to grow larger fruits and is used for making jam, juice, passion ice cream, and alcoholic beverages. Passion fruit is one of the leading tropical juices which include pineapple, banana, and mango. In some South American cultures, passion fruit are used for their sedative or diuretic properties and may have potential in the growing field of medicinal botanicals used in dietary supplements. Each variety posses a unique composition that alters the aroma, flavor, and health benefits of the fruit and juice.

There are several varieties of passion fruit:

• Australian Purple a variety grown in Australia and Hawaii, it has a mild sweet flavor.
• Pratt Hybrid has a sweet flavor, but is susceptible to rot and plants do not produce a hardy yield.
• Sevcik Selection native to Hawaii but the juice has a woody taste, and is subjected to rot.
• Yee Selection is highly disease resistant, but the fruit has thick rind and low yield of juice
• Pintado is a variety found in the northern part of South America, particularly Ecuador and Colombia. This is perhaps the best variety in yield and flavor which ITI exclusively represents.

Yellow passionfruit flowers are perfect but self sterile. In controlled pollination studies it was found that the yellow variety has 3 types of flowers according to the curvature of the style: totally curved (tc), partially curved (pc), and upright styled (sc). TC flowers are most prevalent, carpenter bees will efficiently pollinate tc and pc flowers. Honey bees were much less efficient. Wind is ineffective because of the heaviness and stickiness of the pollen. SC flowers have fertile pollen but do not set fruit. Carpenter bees will not work the flower if the nectary is wet. If rain occurs in 1 ½ hours after pollination, there will be no fruit set, but if 2 hours pass before the rainfalls, it will not have a detrimental effect. The fruit is global shaped, grows in a perennial vine, and it has a hard thick shell. Both varieties are round, about 4-7 cm in diameter. Fruit occurs only on the current years growth, hence selective pruning is beneficial. Seed planting to flowering takes 6 months and flowering to ripe fruit takes 70-80 days. The fruit falls to the ground when it is ripe. Id does not attract flies or ants, but needs to be collected daily to avoid spoilage from soil organisms. Fruit must never be picked from the vine, as open wounds can result in viruses. The harvest in Ecuador is year round.

Passion fruit makes up the family Passifloracae and is a close relative to violets. There are more than 500 species of passiflorace, 50 of these species are edible, only the passion fruit is grown commercially.

Passionfruit vines are grown in many soil types but light to heavy sandy loams of medium texture are most suitable. The pH should be from 6.5-7.5. If the soil is too acid, lime must be applied. Good drainage is essential to minimize rot.

Passion fruit is generally grown from seeds. It is also easy to make cuttings, but they can carry viruses. Passion fruit flowers are cross pollinated by carpenter bees and many plantations have decaying logs among the vines to provide nesting places for them. The cross-pollination produces varied offspring better able to cope with a changing environment. Passion fruit requires a mild climate free from extremes of heat and cold with plenty of rain.

Passion fruit is achieving increase importance in the US, Asia, and Europe as a source of juice. Because of its unique intense, aromatic, acidic characteristics it has been described as a natural concentrate. Passion fruit is a highly palatable Beverage when sweetened and diluted and blends well with other juices. In Germany, one of the biggest juice consuming countries in the world, passion fruit concentrate and banana puree are the base of every "Multijuice vitamin juice" after apple juice which is the most popular juice in Germany.

We at ITI, work with perhaps the worlds largest processor of passion fruit juice, the description given below pertains to our supplier Quicornac, but I'm certain most other processing plants have similar procedures.

Passion Fruit Processing is performed in the following manner:

Fruit is transported directly from farms to processing plant, and they undergo a selection process. The selected fruits are washed and brushed by means of high pressure jets. This removes extraneous matter, leave and dirt that may have adhered to the peel. The accepted fruit now ready for extraction, is transported to a group of specialty designed extractors where the cleanest juice is obtained. The product is then immediately screened to remove seed fragments, peel, and other unwanted soils.

Next the juice is centrifuged, de-aerated and pasteurized in a pre-steriled circuit. If the resulting juice meets all the requirements, it is packed as juice or concentrate to the desired brix level. In the concentration step, water is removed from the juice at a low temperature taking as little as 2 seconds. During this process, up to 99% of the volatile aroma is rescued by an independent recovery system and later joined and homogenized with the concentrated juice thus restoring the important sensory and nutritional profile typical of fresh fruit.

Finally the product is ready for filling. The filling room is separated from the rest of the processing equipment. Here drums and plastic bags are fully irradiated with ultra violet light and filled with product. Bags are securely closed and put into drums. Each drum is labeled and stored at at minus 18C.

In order for our processor to secure an abundant supply of first quality fruit, a team of experienced agronomists work 7 days a week providing both small and large farms with technical assistance. The major nutrient found in yellow passion fruit vary according to growing conditions and geographic locations. Yellow passion fruit possesses refreshing and sweet attributes due to its large water and carbohydrate content.

Approximately 84% of the juice is water, with the remaining elements contributing to aroma, flavor and energy. Passion fruit juice is not a significant source of fat or protein contributing 3% to 4% of the total calories. The juice of the yellow fruit contains marginal amounts of fiber and although the total soluble fiber is low, passion juice does contain some pectin. Pectin is a soluble fiber that has been shown to help lower cholesterol. The purple variety is preferred for consumption.

Carbohydrates constitute the major source of kcal. It can be divided into three sugars. Glucose and fructose are the predominant sugars, the quantity of fructose is higher in the purple variety. Quantitative measurements of sugar content influences total sweetness. Fructose is at least 1.5 times sweeter than sucrose, therefore purple passion fruit is much sweeter than the yellow variety. One distinctive quality of the yellow variety is the high citric acid content. Like lemon and lime juice, passion fruit juice is quite acidic. Citric acid comprises all of the non-volatile acid content ranging from 93% to 96% of the total acid, and malic acid from 4% to 7% of the total. The physical benefit of citric acid is that it may be a facilitator of zinc or other trace minerals. The juice is also found to be free of salicyclic and benzoic acids. The keeping quality of the juice has thus been contributed to its high acidity.

Exotic fruits have become quite popular in the US. Better packing, processing, handling and shipping techniques have contributed to this. Health conscious Americans now have a broader choice of fruits and their beverage and can improve the nutritional value of their diet because of the varieties now available to them. Taste and flavor are still however the most important attributes. The juice of the yellow passion fruit appears to have many beneficial health quantities that can be attributed to its micronutrient profile which include vitamins, minerals, and phytochemicals. Like other exotic fruits, passion fruit provides a significant source of several nutrients.

Passion fruit provides a significant source of vitamin C and can be considered an alternative source of this nutrient besides the commonly eaten citrus fruits. Vitamin C is a water-soluble vitamin that primarily acts as an anti oxidant. It protects the watery areas of the body, but also has the ability to protect plasma lipids and LDL Cholesterol from free radical damage. In addition vitamin C plays an important role in maintaining a healthy immune system and has even been reported to reduce some of the symptoms of the human cold. One glass of passion fruit juice provides about 50% of the dietary intake for adult men and 60% for women for vitamin C. Labeling requirements would allow passion fruit juice to be labeled as an excellent source of vitamin C. the only other fruits which have a higher level of vitamin C are papaya and kiwi.

Passion fruit is also an excellent source of vitamin A. many of the carotenoids found in passion fruit have varying degrees of vitamin A activity. Vitamin A is an essential fat soluble vitamin that is important in vision, skin health, growth, and reproduction. It is estimated that one cup of juice provides 6000 I.U. of vitamin A. this represents a significant source of this nutrient and the label panel could clearly state that the juice is an excellent source of this vitamin.

Passion fruit also provides a significant source of the mineral potassium, an important electrolyte in aiding heart muscle contraction, acid-base balance and blood pressure control. Passion fruit excels as an alternative to other foods such as banana, and oranges. Nutrition experts recommend that men and women consume approximately 1.6 - 2g of potassium per day. One cup of passion fruit juice provides 34-72% of this estimated recommendation.

Passion fruit also contains 10-13% of the daily requirements for magnesium, a mineral that also contributes to blood pressure control.

Folic Acid is a vitamin that is receiving a great deal of attention currently. It plays a role in cardiovascular health. Folic acid has also been identified as the single most effective nutrient to prevent neural tube defects in infants. Women of childbearing age are recommended to consume at least 400 micrograms of this nutrient per day. Passion fruit juice is a fair source of this nutrient, having approximately 5% of the daily value.

Passion fruit juice contains a variety of yellow and orange pigments. The different carotenoids can be converted to vitamin A with different degrees of efficiency and therefore each carotenoid has its own vitamin A activity. Considering the many potential health benefits that carotenoids posses, there is a worldwide effort to obtain analytical data on these substances. Over 500 different lipid-soluble carotenoids have been identified, and to date passion fruit contains about 13 of them in enough quantity to identify. Humans derive the benefits from carotenoids in 2 ways: as pro-vitamin A or as an oxidant. Of all the carotenoids beta carotene possesses the greatest pro-vitamin A activity. The carotenoids in general especially beta-carotene help protect cells from the destructive radical damage and may help to prevent the formation of pre-cancerous cells. Diets rich in carotenoids have shown to be associated with a reduce risk of breast, cervical, lung, skin and stomach cancer. The antioxidant activity of the carotenoids may also be important in reducing the risk of cardiovascular disease and cataracts.

Plant sterols are found in all plant foods and have been reported to have an ability to lower blood cholesterol. Increasing the consumption of plant foods that are high in sterols may have a positive impact on health, although the benefits may also be due to other factors in the plants such as the amount of soluble fibers. Passion fruit contains the highest amount of total plant sterol compared to other fruits eaten in the US, Compared to broccoli, brussel sprouts, cauliflower and black olives, passion fruit is a sweet alternative to these other sterol dense vegetables. Although passion fruit has a relative high amount of plant sterol, a very large amount of juice would have to be consumed to see a cholesterol lowering effect.

Many South American countries report that various species of passion fruit have tranquilizing or sedative effects. In the 1970's many pharmacological studies were undertaken to better understand the chemicals that might be responsible for these effects. Alkaloid and flavanoid content of the passion fruit were examined. Studies showed that the primary alkaloid found to be responsible for the calming effect in the juice is called Harman. Seven total alkaloids were found, 3 were unidentifiable, and the other were identified as Harmin, Harmol, and Harmalin.

The new dietary recommendation for healthy Americans encourages the intake of fruits and vegetables due to their anti-cancer and other health promoting properties. Five servings of fruit and vegetables are recommended. Meeting this amount of fruit consumption is quite difficult. Passion fruit juice is an excellent source to meet these dietary recommendations as it is an excellent source of antioxidants, and minerals.

Literature Cited

1. USDA Nutrient Laboratory
2. Arjona HE, Matta FB. Post harvest quality of passion fruit as influenced by harvest time and ethylene treatment. Hortscience 1991;26:1297-1298
3. Chassagne D, Crouzet J, Bayonove CL. Glycosidical bound eugenol and methyl salycilate in the fruit of edible Passiflora species. J.Ag.Fd.Chem 1997;45:2685-2689
4. Gould M.N. Cancer chemoprevention and therapy by monoterpenes. Environmental Health Prespectives 1997;105:977-979