So sweeeet!

Luohan guo, the sweetest fruit on earth, can be grown in North India, says Chiranjit Parmar

LUOHAN guo is the sweetest fruit on earth. It does not contain any sugar. This unique fruit was originally grown in southern China and northern Thailand. With time, the plant also travelled to a few more countries in the South-East Asia. But most parts of the world are still unaware of it. In fact, the world came to know about this fruit barely a hundred years ago. This is also called arhat fruit or monk’s fruit.

Luohan guo, or Siraitia grosvenorii, belongs to the botanical family Cucurbitaceae. Vegetables like lauki and kaddu too belong to this family. Luohan guo is, however, a perennial plant and not a seasonal vine like its Indian relatives. The sweetness of luohan guo is due to the presence of a chemical mogroside in its pulp. Mogroside is 300 times sweeter than sugar. The pulp of luohan guo contains around one per cent mogroside making it the sweetest fruit on earth.

Luohan guo is a vine. Being a climber, it requires support to grow. The vine reaches a height of three to five metres. It has 10 to 20 cm long, narrow, heart-shaped leaves. The vine is a vigorous grower and a prolific bearer. However, for getting optimum yield, it has to be given the right kind of support and made to grow on trellis or bowers. The plant has a life span of five to seven years. The cultivation is simple and does not require specialised skill. Luohan guo fruits are round, measuring five to seven cm. The fruits are green in the beginning but turn slightly brown by maturity. Each fruit contains numerous seeds. The fruit cannot be eaten fresh nor can it be kept for long since it starts rotting very soon. So after harvest, it is dried slowly in the oven. It turns black after drying. The fruit is sold in shops only in that form.

For eating, the dried fruit is cut into half and put into a bowl. Then boiling water is poured on it. The water is decanted after two to three minutes and then drunk like juice.

The Chinese believe that the fruit has a beneficial effect on human health and increases age. That is why the fruit is also called a "longevity fruit" in China. In addition to being a general health tonic, the fruit is also used to cure respiratory ailments and sore throats. Though a number of products are being prepared from the fruit, its real potential lies in the manufacture of non-sugar sweeteners, whose demand is increasing everyday. Plant-based sweeteners have been rated better and safer than the synthetic chemical sweeteners. Procter and Gamble has already standardised and patented a technique for mogroside extraction from luohan guo fruits.

Luohan guo should be able to grow successfully in North India. In fact, one of its relative species, Siraitia sikkimensis, already grows in the Eastern Himalayas. The plant grows from seed which can be imported at a low cost. The bearing starts in a few months. So there will not be a long gestation period, besides low initial cost. The fruit should be introduced and tried in North India at the earliest.

At present, stevia is being promoted in India to meet the demand of plant-based non-sugar sweeteners. But the cultivation of stevia has limitations in Haryana, Punjab and Himachal Pradesh. Stevia is a tropical plant whereas the area has a subtropical climate. So the yield is quite low. But luohan guo is not a tropical plant. The target part in this case is the fruit which are borne normally in a subtropical climate.