Benefits of preserving sweet potato for food security

Display of dried sweepotato slices and flour at Teptep in Raikos district, Madang


Communities in Papua New Guinea have traditional ways of coping with shortages of fresh food (taim hangere) based on local seasonal calendars. However, extreme climatic pattern changes and events such as the 2015-2016 droughts have shown that food processing and preservation is an area that needs to be improved to enhance food security and livelihoods of rural communities. To build the resilience of these communities, the National Agricultural Institute (NARI) has been delivering climate-smart agricultural trainings under the European Union funded Climate Change Resilience (EUCCR) project. Part of this programme focuses on up-skilling vulnerable communities with food processing methods to improve the length of time for storing and using important staple food crops. One of these methods looks at how flour can be made out of tuber crops like sweetpotato.

Communities located along the Madang-Morobe provincial boarders have benefited from these trainings. One of these places is Teptep. Teptep is situated some 2100 metres above sea level in the Naiyudo local level government (LLG) of Raikos district of Madang province. It shares a common border with Yus LLG of Kabwum district, Morobe. Teptep was placed under Categroy 4 of disaster impact during the 2015-2016 droughts. Sweetpotato flour processing skill was introduced to farmers in Teptep in trainers of trainers workshops between October and December, last year. In total, over 150 farmers representing 10 parishes from both Naiyudo and Yus were trained.

Sweetpotato was introduced here over 300 years ago but has now become one of the most commonly cultivated staple food crops in the Highlands and parts of the Momase and New Guinea Islands regions. Teptep is no different. Its cool, highlands like climate makes it ideal for sweetpotato farming. In fact, the area was once known for supplying fresh produce into Madang town and Lae city, by air.

Apart from its socio-cultural significances, sweetpotato also has great economic potential for the livelihoods of rural farmers. Annually, about 520,000 metric tonnes of sweetpotato is produced around the country. However, sweetpotato tubers are best consumed fresh within two to three weeks. They are highly perishable because they contain large amounts of carbohydrate and moisture. But as flour, sweetpotato can be stored and used for six to 12 months since about 87 % of moisture is removed.

Sweetpotato flour offers many other useful benefits besides extended shelf life and use, over long periods. Sweetpotato flour can be used best when mixed with conventional wheat based flours.  In this way, sweetpotato flour can be made into bread and muffins, for household consumption. This can diversify the range of food and diet of rural families.

Furthermore, blending sweetpotato flour with wheat flour can also boost the nutritional value of bakery products. It has been established that sweetpotato varieties are rich in nutrients like beta-carotene and vitamins A, C and E. So bakery products made with sweetpotato flours do contain high amounts of vitamins with many health benefits. For example, sweet potatoes contain essential fibers and magnesium that can help to prevent or manage many health conditions such as diabetes; depression, heart diseases, arthritis and cancers. Vitamins in sweetpotato can also help improve hair, skin, vision and digestion

There is also opportunity for rural farmers to process and sell sweetpotato flour as well as home baked buns and scones made with it. Income earned from these could help families to purchase store foods like rice to sustain them during times of stress such as the current Covid-19 pandemic lockdown.

Sweetpotato is made into flour using cleaned tubers that have been peeled and stripped into very thin pieces using knives, peelers or graters. The thin slices of sweetpotato are soaked in a solution of lemon and water for five minutes to prevent browning. They are then removed and dried in the sun, on a safe raised bed, for a minimum of 8 hours to become completely dried. This depends on the weather and the amount of the sunlight.

The final step is where dried pieces of sweetpotato are grounded into flour using pestles and mortars or hand mills. The flour is then packed into containers and stored away in used bags of rice or pots for up to a year in cool, dry places.

EUCCR project trainings promote active participation of young people. This can be seen in the success of Yangen Etara, a youth from Kaweng parish. He started training farmers in his own area and a local school has expressed interest in engaging his services. Women are also engaged prominently. Yamoi Mussa, a mother from Teptep, said such trainings help to complement existing local church programmes for women. These would enable women to generate income their families need to afford basic goods and services, like education and health.

NARI has been undertaken sweetpotato flour making training with inclusive farmer groups under different projects over the last few years. We believe this would help to increase the resilience of rural farming communities now and long into the future.