Cassava processing involves steps to remove toxicity and turn the raw root and plant into products, including flour, starch, chips, pellets, and biofuel.
The cassava value chain which starts from cassava farming, is one of the key stages to getting quality cassava byproducts, an essential aspect of food production in many countries, especially in Africa, South America, and Asia.
This introduction will explain the various methods of processing cassava, including traditional or local and modern methods which include harvesting, peeling, grating, fermenting, drying, and milling.
Key Takeaway
- Traditional Processing: Cassava processing methods have been refined over time, with techniques like peeling, grating, and fermentation used to create various manioca products.
- Modern Processing: Modern methods incorporate advanced technologies like mechanical peeling, extrusion, and drying to enhance efficiency and product quality.
- Key Benefits: Modern processing methods offer improved food safety, reduced labor costs, and increased product shelf life.
What is cassava processing?
Cassava processing involves various methods to transform fresh cassava roots into different products, such as fried chips, flour, and starch. Traditional methods include peeling, grating, and fermentation, while modern methods incorporate advanced technologies like mechanical peeling and extrusion to improve efficiency and product quality.
Related: Basics of Cassava Research
The Reasons Why Cassava is Processed
Removal or Reduction of Toxic Compounds: Processing cassava removes or reduces the potentially toxic cyanogenic glucosides present in fresh cassava, making it safe for consumption.
Preservation: Processing helps preserve cassava by extending its shelf life and preventing spoilage, which is critical for storage and transportation purposes.
Product Variety: Processing yields products with different characteristics, creating variety in cassava diets and enhancing its nutritional value.
Recommended: Different Names for Cassava around the World
Traditional Methods of Cassava Processing
Traditional cassava processing techniques have been used for centuries to prepare cassava for consumption, and these methods continue to be used, especially in Africa to keep the value chain active.
Traditional processing of cassava requires intensive manual labour that has been passed down through generations.
A typical traditional processing of cassava is through one of these methods depending of the final product desired:
- Harvesting
- Peeling
- Fermentation
- Grating
- Drying: Sun-drying and oven-drying
- Cooking: Boiling and frying
- Packaging
There is however a semi-mechanized cassava processing technique by Noal Farm.
They used make-shift equipment to wash/clean, grate, drain, ferment, remove excessive moisture and package the desired product.
Traditional Cassava Harvesting
Traditional methods of cassava harvesting have deep historical roots and are tied to the cultural practices of various communities where it is cultivated.
Traditional harvesting methods, often manual, are labor-intensive and time-consuming, which can limit production capacity and lead to post-harvest losses.
Cassava has no harvesting period after maturity as it is safer in the ground. It can be harvested root by root or plant by plant within six months and two years.
The cassava plant top can also be harvested for several uses, including for cooking, animal feeds and for medicinal purposes.
But our focus in this post is the harvesting of the cassava roots.
One of the traditional methods of harvesting cassava is by hand, a labor-intensive process that has been practiced for generations.
While this slows down the value chain of cassava, people in developing countries have no choice.
In many communities, cassava is grown in small family farms, where it is tended to until maturity and ready to be harvested.
The local method relies solely on manual labor and basic farm tools. Farmers use hands to pull up the stems, or simple implements such as hoes and cutlasses to carefully remove the cassava tubers from the soil.
This hands-on approach not only requires physical effort but also demands substantial knowledge of the land and the crop.
The process begins with clearing the foliage, which allows better access to the stems above the ground.
After clearing, the soil around the cassava plant is loosened using hoe-like tools. These tools are preferred for their ability to perform precise cuts, minimizing damage to the tubers.
The next step in harvesting cassava is to carefully dig up the roots from the ground.
Farmers then manually extract the tubers, ensuring each one is intact. This method provides an intimate connection between the farmer and the crop, allowing for immediate inspection and selection of quality produce.
This is typically done using tools like a hoe or a shovel, to gently loosen the soil around the base of the plant. The roots are then pulled up by hand with care not to damage them in the process.
Advantages of Traditional Harvesting
- Simplicity: Traditional methods rely on basic tools like hoes and machetes that are readily available and easy to use.
- Flexibility: Harvesting can be done gradually as needed, allowing farmers to leave cassava in the ground for longer periods.
- Minimal investment: No costly machinery is required, making traditional harvesting accessible to small-scale farmers.
Disadvantages of Traditional Harvesting
- Labor-intensive: Manually digging, pulling, and separating roots is very time and energy-consuming.
- Low efficiency: Traditional methods result in lower yields and productivity compared to mechanized harvesting.
- Drudgery: Repetitive motions and strenuous work can lead to health issues like blisters, fatigue, and respiratory problems from dust exposure
- Losses: Irregular root shapes and sizes, as well as damage during harvesting, lead to significant losses of usable root material.
- Hygiene: Manually processed cassava products may be contaminated with undesirable organisms and extraneous matter, reducing quality and safety.
- Deforestation: Reliance on fuelwood for processing contributes to deforestation and environmental degradation.
Peeling
Peeling is one of the processes in cassava processing and can be achieved both in the traditional and mechanized way.
In the traditional way of peeling cassava, the process typically involves using a sharp knife to carefully remove the topmost layer of the root vegetable.
The cassava is thoroughly washed and then cut into smaller, manageable pieces to make the peeling process easier.
The rough exterior is peeled away in long, downward strokes, revealing the white, fibrous flesh underneath.
Related: Cassava for Animal Feed
Fermentation
The traditional fermentation of cassava comes in two ways – solid-state fermentation and submerged fermentation
Solid-State Fermentation
In the traditional Southern Nigerian setting, the cassava for garri is processed by the solid-state fermentation method.
This is achieved by peeling the cassava tubers a day after harvesting after which it is washed clean and grated to form a paste before bagging in a mesh to remove excess water.
The bagging takes two or three days for it to be properly rid of moisture and toxic cyanogenic glucosides. The cassava is fried to remove more moisture to get the garri byproduct. See production of garri.
Submerged Fermentation
The submerged fermentation method is mostly used to produce fufu – a popular food and byproduct of cassava in Nigeria.
The submerged fermentation involves cutting the cassava into 3-5 inches chunks either peeled or unpeeled and soaked in water for 4 or five days.
The now fermented cassava, which is almost decomposed and the toxicity broken down to form a soft mass is sieved in water and the water drained to leave fairly foul-smelling pasty consistency which is cooked to form fufu.
This is the most effective traditional way to ferment cassava to remove the toxicity, but it produces a somewhat foul smell that follows the fufu to the dining table.
Grating
The traditional method of grating cassava involves using a manual grater made of a perforated metal sheet or flattened tin fastened onto a wooden board.
The peeled cassava roots are rubbed against the rough perforated surface, which tears off the flesh into a mesh that falls into a container below.
This method is very laborious and time-consuming, with a skilled person able to produce only about 20 kg/hour. It also poses risks of injury to the fingers.
Another traditional grating method that is prevalent in my community of Southern Nigeria is a diesel-powered lister generator constructed with a perforated roller-grater within a feeder bucket made of wood.
The cassava is fed into the bucket which guides it to the perforated rolling grater which crushes and grates the cassava into a paste.
Drying Method
Another common traditional method of processing cassava is by drying.
Drying cassava helps to preserve it for longer periods and also makes it easier to transport and store.
This is achieved by spreading the cassava under the sun on a mat to dry.
The drying process can take several days, depending on the weather conditions.
The cassava slices are frequently turned over to ensure even drying.
Once the cassava is fully dried, it is typically roasted over an open flame to further enhance its flavor and create a crispy texture.
Fire Drying
Fire drying is another traditional method of drying cassava. In this method, cassava is dried over an open fire or in a smokehouse.
The heat from the fire helps to remove the moisture from the cassava, resulting in a dried product.
However, fire drying can sometimes impart a smoky flavor to the cassava, which may not be desirable for all uses.
Oven Drying
Oven drying is a more controlled method of drying cassava compared to sun drying and fire drying.
In this method, cassava slices are placed in an oven set at a low temperature to gently dry them.
This method allows for more consistent and uniform drying of the cassava slices.
However, oven drying may not be as commonly used in traditional processing due to the lack of access to ovens in some regions.
Grinding
In the grinding processing method, the peeled cassava roots are dried in the sun or over a fire to reduce moisture content.
Once dried, the roots are then ground using a large mortar and pestle or a mechanical grinder to create a fine powder.
This powder can be used directly in cooking or further processed into different cassava products such as tapioca flour or starch.
This method has been passed down through generations and is still commonly practiced in many regions where cassava is a staple food.
Packaging
The final step in the traditional processing of cassava is grinding the dried and roasted roots into a fine powder.
This powder can be used in a variety of dishes, such as bread, porridge, and cassava fufu.
The ground cassava powder is then typically packaged in bags or containers for storage and transportation.
Related: Cassava Cuisines Around the World
Modern Processing of Cassava
There have been breakthroughs in the manufacture of tailored equipment for the processing of cassava for efficiency and cost-effectiveness, strengthening and commercializing the cassava value chain, and the economic value of the crop.
The modern processing of cassava follows the same steps as described in the traditional methods above. The only difference is that in modern methods, it is mechanized.
Let’s take a look:
Modern Methods of Cassava Harvesting
The modern way of harvesting cassava involves the use of machinery and technology to streamline the process.
Farmers use mechanical harvesters that efficiently remove the cassava tubers from the ground, reducing the need for manual labor.
These machines are equipped with blades that cut the tubers from the roots, making the process quicker and more efficient.
Unlike traditional methods that primarily rely on manual labor, these machines can harvest large areas of cassava fields in a fraction of the time.
This leads to a substantial reduction in labor requirements and the associated costs. Additionally, mechanical harvesters often minimize crop damage, thereby enhancing the overall yield.
Beyond machinery, modern tools such as improved cutting devices and handling equipment contribute to more efficient harvesting processes.
These tools are designed to reduce physical strain on workers and increase the speed of operations. As a result, farmers can manage larger fields and potentially boost their productivity.
Advantages of Modern Cassava Harvesting
- Increased Efficiency: Mechanization reduces time and labor, boosting productivity and enabling larger cultivation areas.
- Higher Yields: Minimizing tuber damage during harvesting improves yield and profitability.
- Reduced Labor Costs: Machinery lowers labor expenses, benefiting regions with rising labor costs or worker shortages.
- Improved Quality: Modern techniques reduce bruising, enhancing market prices and decreasing post-harvest losses.
- Consistency in Harvesting: Mechanized methods ensure uniform quality and size of cassava roots, important for processing.
Disadvantages of Modern Cassava Harvesting
- High Initial Investment: Machinery costs can be prohibitive for smallholders, favoring larger enterprises.
- Technical Knowledge Required: Operating equipment demands skills that may not be widely available among farmers.
- Dependence on External Resources: Access to fuel and maintenance can be limited in rural areas, hindering effectiveness.
- Environmental Impact: Heavy machinery can cause soil compaction and degradation, affecting soil health and crop yields.
- Displacement of Traditional Practices: Modern methods may erode traditional farming practices and cultural knowledge.
Cleaning
The cassava after being harvested have sand, mud or debris all over it. To get these off, the cassava must be washed thoroughly.
The modern way of washing cassava involves using machines to ensure efficient and effective cleaning.
Two methods are commonly used:
- The dry sieve and paddle washing machine, and
- The cassava washing and peeling machine.
The dry sieve uses friction and collision to remove debris, followed by a paddle washing machine that uses countercurrent washing to remove silt.
The cassava washing and peeling machine uses a brush roller to generate friction and achieve peeling.
These machines are designed to minimize water usage and ensure high-quality cassava products.
Peeling
The modern way of peeling cassava involves using machines to ensure efficient and effective peeling.
There are several types of peeling machines available, including
- Stainless steel brush roller
- Plastic brush roller
- Nail roller, and
- Sand roller type machines
The sand roller type is considered the most reliable, with a peeling rate of up to 96%.
These machines use friction and abrasion to remove the peel from the cassava, reducing labor costs and increasing production efficiency compared to traditional manual peeling methods.
Grating
The modern way of grating cassava involves using machines designed for efficient and effective processing.
These machines typically consist of a hopper, grating unit, and delivery unit.
The hopper unit holds the cassava roots, which are then forced into the grating unit where they are rubbed against a perforated metal sheet or drum to tear off the peel and create a mesh.
The grated cassava is then collected in a container. Modern grating machines are designed to be compact, convenient, and durable, with features such as stainless-steel construction and electric or diesel power options.
Drying
Drying cassava with modern machinery involves using advanced machines to ensure efficient and high-quality drying.
There are two primary methods:
- Continuous multi-layer mesh belt drying and
- Hot air drying.
The continuous multi-layer mesh belt dryer spreads cassava evenly and uses hot air to draw out moisture.
The hot air-drying oven uses a reverse Carnot principle to circulate hot air and dry the material.
Both methods are designed for high production capacity and can be customized according to specific requirements.
These machines offer advantages such as high efficiency, uniform drying, and reduced labor costs compared to traditional natural drying methods.
Milling and Sifting
The cassava milling process begins with crushed the peeled cassava into a pulp using a file mill.
The pulp is dewatered using a plate and frame filter press and then dried using an air dryer as described above.
The dried cassava flour is sifted through a vibrating screen to remove coarse particles and ensure the desired fine quality.
This modern process eliminates the need for manual sieving and ensures consistent product quality.
Some key machines used include the dry sieve, paddle washer, cutter, file mill, plate and frame filter press, air dryer, and vibrating screen
Related: Some Investment Opportunities in the Cassava Industry
Starch Extraction
The modern way of extracting starch from cassava involves a physical separation process.
The process begins with cleaning and crushing the cassava roots to break down the cell walls and release the starch.
The crushed cassava is then separated from fibers and other impurities using centrifugal sieves and cyclones.
The starch is then concentrated and refined using hydrocyclones and vacuum washing.
Finally, the starch is dried using airflow dryers to achieve a moisture content of 12-14%.
This modern process ensures high starch extraction rates, typically above 94%, and produces high-quality cassava starch suitable for various industrial applications.
Packaging and Distribution
Packaging is crucial to protect the product from contamination and ensure its quality during transportation and storage.
Modern cassava packaging focuses on using eco-friendly and plant-based plastics and paper for sustainable packaging solutions.
The modern methods used to package processed cassava include:
- Biodegradable Materials: Plant-based plastics and paper are used to create sustainable packaging solutions that minimize waste and pollution.
- Vacuum Sealing: This technology removes air from packaging, extending the shelf life of cassava products and preserving freshness.
- Cold Storage Facilities: Investing in cold storage facilities ensures optimal temperature control, preventing mold growth and spoilage.
- Smart Packaging Solutions: Technologies like sensors and RFID tags provide real-time monitoring of product conditions, ensuring freshness and quality.
- Collaborative Supply Chain Management: Building partnerships between farmers, manufacturers, and distributors optimizes cassava packaging processes and reduces inefficiencies.
- Modern Packaging Facilities: Improving packaging infrastructure and access to modern facilities is critical for the growth of the Cassava Packaging Market.
These modern methods ensure that processed cassava products are packaged efficiently, effectively, and sustainably, meeting consumer demands for eco-friendly products and maintaining product quality.
Frequently Asked Questions
What is the processing of cassava?
Cassava processing is the various stages that helps to produce the various byproducts of cassava such as flour, garri, starch, fufu, biofuel, chips and pellets.
How to start cassava processing?
Start cassava processing by selecting high-quality raw materials, washing and cleaning the tubers, peeling, grating, and fermenting to produce garri or other products.
What are the key steps in cassava processing?
Key steps include harvesting, peeling, washing, grating, pressing and draining, drying, milling, screening/sieving, packaging, and storage.
What are the benefits of modern cassava processing techniques?
Modern techniques allow for safe storage of cassava chips over long periods without loss of nutritional value and buildup of aflatoxins, optimizing costs of packaging, storage, and transportation.
What are the common products derived from cassava processing?
Common products include cassava flour, starch, chips, and animal feed, with potential applications in food, pharmaceuticals, and biofuels
Final Word from Cassava Pathway
Cassava processing is an important step in the cassava value chain and production of various cassava-based products.
From traditional methods to modern technologies, the processing of cassava involves several stages, including peeling, grating, drying, sieving and milling.
Each stage requires careful attention to ensure the quality and safety of the final product throughout the cassava value chain.
The choice of processing method depends on the specific application, scale of production, and available resources.
Understanding the different stages and methods involved in cassava processing is essential for producing high-quality products that meet market demands and consumer expectations.
Citations:
https://www.ncbi.nlm.nih.gov/books/NBK234676
https://www.juanmagsasaka.com/2020/12/cassava-production-harvest-and-post.html
https://www.fao.org/fileadmin/user_upload/inpho/docs/Post_Harvest_Compendium_-_Cassava.pdf
https://www.fao.org/4/y5548e/y5548e0d.htm
https://www.arc.agric.za/arc-iic/Pages/Cassava.aspx
