Fruit quality
There is a very small market for the yellow granadilla in Europe, but at least 95% of demand is for the purple fruited form of passion fruit.
The General Standard specifications are as follows, but note that with the many different cultivars and hybrids now available, detailed specifications should be established in advance with the intended market. Where the yellow granadilla is required, specifications are broadly the same although sizing, of course, differs.
Varieties: Cultivars of P.edulis f. edulis
Appearance: Entirely purple. Fully developed, glossy and ripe.
Size: 40 - 50mm diameter, though a narrower range may be specified with different counts per carton. Min 30g. Max 50g.
Shape & Aspect: Globose. Preferably round and not ovoid. Light wrinkling is permitted, but should not be excessive, nor distorting the shape. The fruit stalk of 2-4mm may be required or permitted.
Condition: Free from splits or cracks in the skin. Free from pests and disease. Free from blemishes.
Taste & Texture: Fruits at least 80% full. Flesh yellow/orange, juicy with brown/black seeds, characteristically aromatic. No taints, off-flavours or fermentation.
Storage: 7-10°C. Susceptible to chilling injury. Note that passion fruit produces much ethylene - beware of mixed loads of produce.
Presentation: Boxes should contain fruit of uniform size.
Passion fruits contain numerous small, black wedge-shaped seeds that are individually surrounded by deep orange-colored sacs that contain the juice, the edible part of the fruit. Passion fruit is either eaten fresh or used in commercial juice production. Passion fruit is a high acid food (pH~ 3.2) due to the predominance of two acids, citric (~93-96 % of total) and malic (3-6 % of total) acid. Passion fruit also contains about 14.45 g sugar/100g of edible portion, including fructose, glucose and sucrose, along with seven others in trace amounts. The acids and sugars add to the unique taste and serve as a preservative nature for the tropical fruit.
Both the yellow and purple passion fruits contain ascorbic acid with the purple passion fruit variety containing a slightly higher content of ascorbic acid. Ascorbic acid is an organic acid with good antioxidant properties and is a good source of Vitamin C. The purple passion fruit has a sugar:acid ratio of 5:1. The yellow passion fruit has a sugar:acid ratio of 3:8. The purple passion fruit is generally sweeter than the yellow passion fruit. Passion fruit is high in potassium, vitamin A, vitamin C, niacin and fiber and it is low in sodium, cholesterol and saturated fats.
There are 3 primary groups of active chemicals in passion fruit: alkaloids, glycosides and flavonoids. A large amount of variability is noticed with regards to the incidence and quantity of particular phytochemicals within the same species of passion fruit. There is a lot of evidence that the passion fruit could be a powerful medicinal source but much more research needs to be done to unlock these potentially potent remedies.