Chapters 8.27

8.27-Cassava Value Addition

Neha Moodley, University of Guelph, Canada

Related video(s): Making cassava snacks, Quality cassava planting material (Source: Access Agriculture)

https://www.accessagriculture.org/making-cassava-snacks?cat_id=1499

https://www.accessagriculture.org/quality-cassava-planting-material

Suggested citation for this chapter.

Moodley,N. (2022) Cassava Value Addition,In Farmpedia, The Encyclopedia for Small Scale Farmers. Editor, M.N. Raizada, University of Guelph, Canada. http://www.farmpedia.org

What is Cassava

Cassava (also known as yucca) is a perennial woody shrub that produces starchy root tubers, and is an important carbohydrate source for more than 500 million people in Africa, Latin America and the Caribbean, and Asia (Plucknett, Phillips & Kagbo, 2000). Cassava is consumed by cooking the root and leaves or as dried products. It is commonly consumed as garri (also known as eba, rale, farinha) and fufu (foufou, amala lafun) in African countries (Bokanga, 1994).

A Note on Safety

Bitter cassava varieties contain cyanogens which can cause illness, paralysis (konzo) and death if high amounts are consumed. Traditional detoxification methods (sun-drying, heap fermentation and soaking in water for 3-4 days) often do not reduce the toxin content to a level that is deemed safe by the World Health Organization (WHO). The wetting method can be done after the traditional methods are used to help eliminate residual toxins (Bradbury, Cliff & Banea, 2015). The wetting method involves placing cassava flour in a bowl, adding water and mixing until the level of flour drops and rises again to initial level. The flour is then thinly spread on mats to dry for 2-5 hours (Bradbury et al., 2015, p. 6). To remove cyanogens from cassava leaves they should be pounded, sundried for 2-5 hours then washed 3 times (Bradbury & Denton, 2013). Sweet cassava can be boiled and eaten without safety concerns (Bradbury et al., 2015).

Commercialization

Cassava and cassava products can be sold at village centres, town markets or along roadsides. These products have a higher value than selling the fresh root due to the convenience of being ready for direct consumption or ready to cook with. Selling is more feasible when the farm is close to the point of retail (Plucknett et al., 2000). Storing dry cassava products like flour and garri for sale in the dry season when food availability is low may provide the farmer with higher returns (Parmar et al. 2018). Use of animal-drawn carts may be useful for transporting cassava efficiently from the field to household or roadside. It is likely that farmers will have to connect with local traders to get their product to the market, especially if they are located far from the point of sale (Sewando, 2012). To process cassava into cassava into garri, high quality cassava flour, or starch, farmers will need:

• Basins, clean water and sponge or cloth for washing roots

o Spring water should be used to process flour, if only river water is available it should be properly sanitized (Grace, 1977)

• Clean knives

• Clean, tightly woven bags (such as rice or cocoa sacks) (Grace, 1977)

• Sieve or sifter

• Fuel for roasting garri

• Packaging materials for final products (polythene bags)

• Grater (ideally mechanized or semi-mechanized for efficiency)

• Pressing machinery (not necessary)

• Scale for weighing

• Sealing/ stitching machine (not necessary) (Emmanuel et al., 2010).

Step-by-Step Post-Harvest Processing of Value Added Products

Note: Roots are peeled and washed before processing – cleaning must be done carefully to ensure quality (change water for each batch) (Taiwo, 2006).

Packaged garri (roasted flour):

1. Chop roots (into chunks then in halves) and remove central fibres

2. Reduce size by grinding with pestle & mortar or milling machine

3. Pack in bags and ferment for 2-3 days

4. Dewater by placing weights such as heavy stones on top of bags (or use hydraulic press), press until water stops being released (bags should not be in contact with sand, and water should be allowed to seep out)

5. Sieve and remove large fibres using a mesh or bamboo sieve

6. Roast on pan over fire or on hot plate

7. Sieve again to remove large pieces then bag once cooled (Emmanuel et al., 2010; Kouakou et al. 2016)

Packaged cassava flour:

1. Grate by hand or mechanically

2. Press (dewater)

3. Sun-dry on cloth or black plastic sheet on a slight incline

4. Grind/ mill dried paste in mortar (labour intensive) or in mechanized mill

5. Sift then bag (Technology, 2006)

High quality cassava flour (HQCF): grate, dewater, pound/mill, dry, fine mill, sieve, package (Technology, 2006)

Fufu flour (cassava and plantain flour mix):

Suitable in region where plantain is also grown. Mix cassava flour with plantain flour and package.

Chips:

For human consumption, animal feed or to mill into HQCF (Sewando, 2012)

1. Soak roots for 3-6 days

2. Remove fibres and cut into small pieces (can use mechanical slicer for this)

3. Sun-dry, store in bags (Kouakou et al. 2016)

Cassava starch

1. Chop/ grate

2. Mill with water

3. Sieve

4. Mill again

5. Allow to settle (1 hour)

6. Slowly decanter water, remove top layers of fibre

7. Ferment (to make sour starch)

8. Break and dry starch in sun (24-120 hours)

9. Grind, sift and package into bags (Kouakou et al. 2016)

Bagged dried & ground cassava leaves:

The leaves can be washed, pounded, then sundried and packaged (Technology, 2006).

Cassava beer:

1. Soak tubers in water for 7 days

2. Peel and grind

3. Add 20 litres of water and mix, let stand for 3 days

4. Filter juice and store in jars or suitable container (Kouakou et al. 2016)

Food Vendor Products

If the farmer is in close proximity to an urban or semi-urban area or has access to a market or roadside, selling ready-made foods may be an option to increase income. The foods that are sold will depend on demand and what is culturally appropriate. For example, women may cook fufu and sell directly to consumers (this can be done at the household level). However, the fufu flour mix (above) is a more appealing product to consumers (Westby, 2002). Other cassava foods or baked goods that could be sold at vendors include fritters, chips, tapioca flatbread (pancake known as salgados or doces), cakes (bammy) and bread (by replacing a portion of wheat flour with cassava flour), cassava beer and dried leaves (Henry et al., 2004). See Helpful Tips for how to make some of these simple cassava snack foods for retail. When marketing cassava products in urban markets, it is important to have attractive and appropriate packaging (Plucknett et al., 2000). Food packaging can be fairly inexpensive and simple such as polythene/ polypropylene packaging with a well-designed sticker. See foodpackaginglabels.net, rebsons.co.za and Alibaba.com for labeling and packaging options.

Equipment & machinery

To achieve value addition on a small scale, farmers could form communal cooperatives to investment in small scale mechanized cassava processing technologies (i.e. grating, chipping and pressing machinery), to increase efficiency, product quality and reduce high labour requirements of traditional processing methods (Abass et al., 2017). Processing machinery is costly so to make it more accessible, it is recommended that a community collectively invests in processing capital (Taiwo, 2006). Processing does not need to be entirely mechanized, however farmers should invest in, or have access to a grating/rasping machine and pressing machine (hydraulic press)

Peelers:

Peeling is the most laborious step of processing (Westby, 2002). A mechanized cassava peeler, such as the one from Capsfeed, can save several hours of labor but are costly. Lower-cost pedal operated peelers are also available. However, machinery is expensive and results in higher losses than manual peeling. If done manually, peeling should be done using sharp knives with strong handles (Taiwo, 2006).

• Pedal operated peeler US $490: https://www.indiamart.com/proddetail/cassava-skin-peeler-pedal-operated-12493530491.html

• Capsfeed peeler: http://www.capsfeed.com/catalog/product/peeling-machine-7-5-kw/

Graters:

Taiwo (2006) suggests that grating is done with a hammer mill made of galvanized sheet metal or Wooden hopper, wooden hollow drum, galvanized metal discharge chute, short metal stand, or rasper made of galvanized metal. A simple grater can be made by “perforating a sheet of galvanized iron with a nail and then clamping it around a wheel with the sharp protruding rims of the nail openings turned outward” (Grace, 1977). This wheel can be driven by hand or pedal. The roots are pressed onto the grater or the grater is attached to a side of the rotating disk with a crank (Grace, 1997). Grating and milling can also be done using machines that run on diesel fuel (possibly in a communal facility) (Davies et al., 2008).

• Manually cranked cassava chipper $US 70-300: https://www.alibaba.com/product-detail/manual-machine-cassava-chipper-for-sale_60778076657.html?spm=a2700.7724857.normalList.37.3a1b1007cbvhU1

• Slicing machine US $100-200: https://www.alibaba.com/product-detail/Cassava-Duble-Slicing-Machine_122537653.html?spm=a2700.7724838.2017115.180.3cfb16eeLKNUYV

• Grating machine US $300-900: https://www.alibaba.com/product-detail/Fresh-cassava-grating-machine-008618237112106_60624141308.html?spm=a2700.7724857.normalList.38.1fb42948IeNApp

Pressers:

Pressing can be done using rocks to compress the sacks of fermented paste or using parallel press boards screwed together (Technology, 2006). Investing in a hydraulic jack press is highly efficient and does not necessarily require fuel or manpower (Davies et al., 2008). A centrifuge or vacuum filter may be used for dewatering (Taiwo, 2006) but the former would be expensive.

Drying:

Drying can be done on bamboo mats, concrete floors, black plastic sheets, etc. Drying of starch can be in fluid-bed driers, tray driers and flash driers (Taiwo, 2006), but the latter would be expensive.

• Solar dryer US $500-1500: https://www.alibaba.com/product-detail/industrial-commercial-tomato-dates-cassava-chip_60677584495.html?spm=a2700.7724838.2017115.12.579f3debYX1waA

Helpful Tips

• Low-cost storage methods:

o Pile roots on layers of straw in conical heaps, cover with straw and soil but leave some openings.

o Trench storage – place palm and raffia leaves at the bottom of a trench, place a layer of roots on top, keep layering leaves and roots until the trench is filled, cover in soil and construct a roof over-top (Technology, 2006)

.

• Higher cost methods:

o Dip roots in paraffin or wax and/or fungicide & store in airtight polythene bags.

• To minimize losses from post-harvest physiological disorder (PPD), only harvest what can be processed in a day (Parmar, Fikre, Sturm, & Hensel, 2018).

• Remove leaves two weeks prior to root harvest to extend shelf life (Plucknett et al., 2000).

• Dry cassava products can be packed into 50 or 100kg polypropylene sacks (Parmar et al. 2018).

• Low-cost vacuum sealer bags available here: https://www.alibaba.com/product-detail/embossed-vacuum-sealer-bags-PA-PE_60027033264.html?spm=a2700.7724838.2017115.123.6bb71db3eAgvIP

• High quality cassava flour should be packaged in polypropylene sacs lined with polythene for bulk sale (Emmanuel et al., 2010).

• See Nans.in and Cassavaprocessingmachine.com for more machinery

How-to Videos & Links:

How to make Gari with processing machinery: https://www.youtube.com/watch?v=ejPuV1NFxgg&t=90s

How to make Cassava chips snack: https://www.youtube.com/watch?v=6zbxZHN-BR8

How to make Tapioca Flatbread (Brazilian pancake): http://ediblehouston.ediblecommunities.com/recipes/tapioca-brazilian-snack

How to make Bammy cakes: https://tastetheislandstv.com/bammy/

References

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