|Kaukau variety Beerwah Gold|
As our population continues to grow at 2.3% per annum, there will be demands for increasing food production to ensure food security.
The main staple foods and their annual production are sweet potato or kaukau (2.9 million) banana (700,000), yam (300,000), taro (350,000) and cassava (80,000) tonnes respectively.
Globally, more than 133 million tonnes of sweet potato is produced annually, and it is the seventh most-important crop after wheat, rice, maize, potato, barley and cassava.
In PNG, it is the most important crop both in terms of production as well consumption.
The top producing provinces are Southern Highlands (620,000), Eastern Highlands (470,000), Western Highlands (425,000), Enga (340,000) and Chimbu (294,000) tonnes respectively.
Smaller volumes are produced in Morobe (195,000), East Sepik, Bougainville and other places.
As a staple food, it provides about 64% of the energy needs for people.
At the current population of 6.5 million, per capita consumption is about 2.2 kg/person/year.
Its production is predominantly semi-subsistence.
Almost all of the sweetpotato is consumed at home as food, while a small amount is used for pig feed.
An increasing amount is being sold locally and or traded in distant markets of Lae, Port Moresby, Rabaul, and some mine sites.
Sweet potato has become a cash crop in PNG in recent years.
One major factor that has contributed to this trend is the rapid increase in urbanisation and population in major towns and cities.
Also, by value to weight, sweet potato is relatively cheaper and is affordable by low-income earners and families compared to imports like rice.
The farm-gate value of the sweetpotato industry in PNG is unknown.
By comparison, although Australia’s annual production is only 34,000 tonnes, their industry is worth A$40 million.
During transportation to markets, huge post-harvest losses occur because of improper handling, packaging, rotting and bruises.
The crop has high moisture, and is voluminous, and often fetches low market prices. Some studies have shown that, about 30% of the crop is already rotten on arrival in Port Moresby.
In monetary terms, this is K30 lost for every K100 that was supposed to be earned by the farmer.
There is no processing of the crop in PNG, unlike in China, where 10% of it is processed into foods like chips, crisps, snacks, bakes, breakfast food, candy and canned roots.
As livestock feed, it is fermented and reconstituted with either fish, copra or soybean meals for poultry and pigs.
Industrially, it is processed into starch, ethanol, bio-fuel, pigments, cosmetics, pharmaceuticals, plastics and modified starches.
In the 1990s, the food processing and preservation unit at University of Technology in Lae did some product development work looking at flour, fries, chips, crisps, composite flour bread and other foods.
At around the same time, National Agriculture Research Institute (NARI) scientists working on the Pacific regional agricultural programme in Keravat, East New Britain did similar work on lowland varieties.
Currently at the University of Queensland in Australia, a major research project is looking at the processing and utilisation options of PNG sweet potato.
Of the 25 varieties studied, the research has generated information on the flour-yielding ability, nutritional content (minerals, protein), starch pasting and gelatinisation properties, as well as determining starch granule morphology and particle sizes, all of which are very important traits required to optimise processing and utilisation options of the crop.
The study has also addressed the issue of identifying suitable varieties for end-use qualities by determining the starch, amylose and sugar contents.
This is critical to recommend suitable varieties for different products.
Food is the cause of many lifestyle diseases in the world like diabetes, obesity and hipolipdermia, and PNG is no exception.
This study using an in-vitro (test tube) technique has also found some beneficial starch fractions called resistant starches (RS) in the PNG sweet potato varieties.
The RS basically escapes digestion in the small intestine and is beneficial to human health because it do not increase the level of blood sugar leading to some of the diseases mentioned above.
The sweet potato varieties with very high RS fractions were L3 and L135, and these varieties are available in NARI.
Another exciting component of the research is on extrusion processing, using sweet potato flour to make snack foods from white and orange fleshed sweet potato varieties.
The results are promising and have the potential to be introduced in PNG, especially for small to medium scale cottage industries which may be interested to make snack foods from sweet potato.
The same technology can be used to process other foods like potato, taro, cassava, banana and sago.
A lot has been said about agriculture as being the backbone of PNG.
In 2005, the PNG Government put in place the green revolution and export-driven economic recovery strategy.
For the agriculture sector, this strategy was aimed at improving production and creating market demands for our crops to meet the growing domestic demands and also to seek export market opportunities.
However, to date, no substantial investments through possible avenues such as the public investment programme (PIP) or the national agriculture development plan (NADP) have been made to boost production, as well as to develop and upscale processing technologies to realise the full potential and contribution of the sector to PNG economy.
Downstream processing and value addition has the potential to benefit en masse, raise the economic value, and create market demand for local crops.
|Scientist Joel Waramboi doing research into kaukau|
• Joel G.Waramboi is a senior scientist with the National Agricultural Research Institute, and is currently doing his PhD at the University of Queensland, Australia. Copies of publications on this research are available and interested persons can contact him on firstname.lastname@example.org