Nature
Ananas comosus, popularly known as pineapple, belongs to the family of Bromeliaceae and is considered as the second most essential tropical fruit, after banana (1). It is widely consumed across the world due to its remarkable succulent nature, vivid flavor and for its nutritional value (2). Pineapple plant is a long-lasting herb that grows up to a height of about 1.5 m (3). The sword-shaped leaves (~80 leaves on a mature plant) are organized in spiral pattern on the cylindrical stem with flowers at the terminal end, developing into an edible fruit. This plant possesses both underground as well as aerial roots which are adventitious and help in vegetative propagation (1).
Pineapple has unique inflorescence with 50 to 200 bisexual flowers forming a thick bract with the leaves. The color of the bracts may change i.e., from lavender to purple to even red, based on its variety. The pineapple fruit is distinctive from other fruits as it is technically named as ‘sorosis’, meaning a multiple large fruit formed by fusion of many fruits together (coalesced berries). It is naturally produced without fertilization of ovules, making the fruit seedless. The outer skin of the fruit is hard and composed of hexagonal segments (called eyes), that are arranged in Fibonacci numbers (1, 3). Its color may vary from green to yellow to orangish-yellow to red during its maturation process (1).
Globally, it is either consumed fresh, or cooked or even extracted for its juice. It is used in wide variety of edible items, such as fruit salads, candies, syrups, yogurt, desserts, jam, beverages, vinegar, pineapple chips or its puree. Pineapples can also be preserved and used as canned products. The green pineapples are generally used for preparing pickles. Further, the soft leaves and the left-over after juice extraction is used for livestock feeding (2).
Habitat
Pineapple is a fruit crop that prefers warm-humid condition, and hence grows well in tropical and subtropical zones of the hemisphere. This essential crop can grow at both sea level as well as at altitudes of >1400 m above sea level, that is devoid of cold icy climate (1, 4). The annual rainfall required for the favorable growth of the plant is between 760 and 1,000 mm, with the temperature ranging between 20 and 30℃. It grows best on sandy or clay loamy soil with an acidic pH and loaded with organic material and potassium (4).
Taxonomy
The taxonomy of pineapple has evolved over several years and has now been simplified by classifying all the pineapples under one genus i.e., Ananas, which is further categorized into five different varieties. The edible pineapple constitutes of Ananas comosus var. comosus, while the others include var. microstachys, parguazensis, erectifolius and bracteatus (1).
The taxonomic tree of edible pineapple as accessed on February 19, 2021 is as below (5):
| Taxonomic tree of Pineapple (5) |
|---|
| Domain |
Eukaryota |
| Kingdom |
Plantae |
| Phylum |
Spermatophyta |
| Subphylum |
Angiospermae |
| Class |
Monocotyledonae |
| Order |
Bromeliales |
| Family |
Bromeliaceae |
| Genus |
Ananas |
| Species |
Ananas comosus |
| Taxonomic tree of Pineapple (5) |
|---|
Tissue
Pineapple fruit may induce immunoglobulin (Ig) E-hypersensitivity reactions with bromelain, a proteolytic enzyme and a major allergen of pineapple responsible for its allergy (6, 7). Apart from the fruit, bromelain has extensively been found in other parts of the plant, which include its stem, leaves as well as peel of the fruit. The stem and fruit possess high quantities of bromelain allergen, which has wide biotechnological applications in the field of food, medicine and cosmetic industry. Interestingly, the bromelain content in stem is more than that of fruit (8).
