By Joel Waramboi and Raghunath Ghodake
Post-harvest activities include processing, preservation, storage, packaging, handling and transportation of agricultural commodities after crop harvest. These activities help preserve the commodities and add value to the end product. The areas of post-harvest agricultural research for development are crucial in PNG because of the nature and type of agricultural commodities produced in the country.
These commodities include root and tuber crops, vegetables, fruits and nuts, tree crops, sago, livestock products and feeds. Most of these are to a large extent seasonally produced, perishable and bulky in nature, characterised by low values to weight or volume, consumed domestically or exported in unprocessed forms, or have low and variable marked demand. It is essential to protect and raise the economic values of these commodities if the status of farming communities producing these commodities is to be improved.
Improved and new post-harvest technologies offer a huge untapped potential for most agricultural commodities produced in PNG. Post-harvest processing reduces bulkiness and transportation costs; improves storage life, taste, preference and nutritional value; increases market appeal; reduces the adverse effects of seasonality; and increases the value of the product.
Post-harvest activities like product handling, cool chain arrangement, storage, packaging, quality management, food hygiene and safety are equally important for preserving and enhancing the quality and value. For example, consumption of peanuts poses health risks from aflatoxin contamination, which predominantly a post-harvest problem. Furthermore, processed and preserved products can provide adequate sources of well-balanced food of high nutritional value for people.
Annually, PNG produces about 2.9 million tonnes of sweet potato, 700,000 tonnes of banana, 300,000 tonnes of yams, 350,000 tonnes of taro and 80,000 tonnes of cassava. However, very little or no processing is done for these crops.
Options for processing root and tuber crops include fries, chips, whole nutrition and instant flour, composite bread, biscuits, cakes, fried balls and livestock feed through fermentation or reconstitution with fishmeal, copra meal and other ingredients.
Fruits and vegetables produced in PNG are highly perishable and suffer huge loses during transportation. These losses can be avoided by processing into fruit juices, concentrated, jams, pickles, chutneys, sweet candies and other products. Novel techniques such as application of wax coatings and controlled atmosphere storage need to be investigated to avoid losses caused by enzymatic browning, chilling injury, oxidation and other factors. Such technologies will slow down ripening, and enhance self-defence and wound healing in products.
Rice and other cereal grains can be stored for longer periods. However, processing options can add value and create products such as snack and breakfast foods like crisps, flour and canned or frozen goods. Peanuts and soybeans are good for spreads (peanut butter), imitation milk and vegetable oil. Other post-harvest issues include grain drying, pest management, storage methods, bulk handling, milling, cooking, eating quality, food safety (eg aflatoxins in peanuts) and improved post-harvest tools and equipment.
Recently some emerging food and cash crops have gained popularity in PNG. Good examples include vanilla, kava, turmeric, galip nut, nutmeg, pyrethrum and cashew nut. Vanilla could be easily processed into extracts, oleoresins and powder for use in the food, perfumery and medical industries. Similar options could also be investigated for kava, turmeric (curry powder) and other crops.
PNG has more than one million hectares of land under sago and it is the staple diet in many areas of the country. It is currently an under-utilised crop for food, feed or industrial use. The starch can be used in composite flour to make pancakes. It can be processed into noodles, biscuits, glucose and caramels. The pith can be used as livestock feed and the fronds for pulp and paper-making.
Of the huge quantity of roots and tubers produced in PNG, only less that 1% is sold in domestic markets and hardly any quantity is exported. These commodities need to be improved in terms of quality and form to increase their marketability and competitiveness through enhanced consumer demand.
NARI recognises the need for and value of post-harvest agricultural research for development in PNG and has developed a programme on post-harvest technology development and evaluation. PNG Government, through its public investment programme, has initiated development grant for post-harvest research to NARI beginning next year for the period of next five years. Post-harvest R&D has emerged as a national programme in NARI.
Processed and preserved products have the potential to increase the market demand for these crops as a wider spectrum of consumers with different tastes, preferences and geographical locations (domestic and international) can be attracted.
Such efforts will also help generate productive employment, raise incomes, assure food security and improved nutrition, and contribute to broad-based economic growth and improved living standards of the people of PNG.
Current activities in NARI include the evaluation of milling, cooking and eating qualities of rice varieties; and developing products like chips, crisps, peanut butter, jam, flour, ground spices, fruit juices and candies. NARI had already addressed issues of vanilla curing and quality management in several provinces. Besides developing new products, important activities include assessing consumer acceptability, doing market studies and promoting and facilitating the growth of small and cottage industries.
Likewise, NARI will be engaged in developing and adapting techniques for avoiding losses, quality deterioration and wastage during handling, transportation, storage and marketing, as well as ensuring product safety and improving health and nutrition.
The institute is collaborating with R&D organisations, acquiring additional expertise in the area and soliciting technical assistance on sweet potato processing from the Crops Research Institute in China. A yam-based eco-tourism project, focusing on yam processing, was signed early this year with the South Korean government on a pilot basis and is presently being implemented in Morobe province.
To have effective development impact from post-harvest R&D activities, it is important to have active participation and support from the private sector, credit institutions, entrepreneurs, policy bodies, extension and training institutions, traders and farmers.
Next week’s article will focus on ‘Potential for biotechnology in research and development in PNG’.