Cashew apple in Tanzania: status of utilization, challenges, and opportunities for sustainable development

Benefits of cashew apples

There are several feasible usages of the cashew apple (Table 1), which if sufficiently exploited could help in part achieve the goals of the FYDP III and TDV 2025. For instance, in the arena of food and nutrition security, the FYDP III looks to reduce the prevalence of vitamin A deficiency among children aged 6-59 months to less than 20 percent, the proportion of women aged 15-49 years with anaemia from 44 to 22 percent, and reduction of acute malnutrition by year 2025, among others (URT, 2021). The same micronutrient challenges were addressed by the Tanzania Demographic Health Survey 2010 (URT, 2011). Increasing public awareness on the health benefits of cashew apple could increase their consumption (raw or processed form) and hence reduce a prevailing health burden. With regard to industrialization, the FYDP III emphasizes on value addition in agriculture through the use of science, technology and innovation as well as research and development (URT, 2021). Since huge postharvest losses impact nutrition (especially on micronutrient deficiencies), the NPHMS outlines strategic interventions including facilitation of awareness on postharvest management, value addition, and improving agricultural marketing infrastructure to reduce losses particularly on perishable crops such as fruits and vegetables (URT, 2019). For these reasons, cashew apple provides a diversified quality of products for domestic and export market, and hence stimulates socio-economic development.

Equally important, according to Country Development Cooperation Strategy October 19, 2020 – October 19, 2025 (USAID/Tanzania, 2023), there is an increasing unemployment burden in Tanzania, particularly among young people in rural areas. In addition, a large segment (75 percent) of Tanzania’s workforce population is under the age of 35 years. This young generation faces a great challenge to land employment immediately after finishing their qualifications as they lack sufficient basic and technical knowledge and soft skills needed to succeed in today’s competitive workforce (USAID/Tanzania, 2023; Mgaiwa, 2021). Statistically, out of one million young people, less than 20 percent get employed immediately (Mgaiwa, 2021). In line with the FYDP III and TDV 2025, an entrepreneurship approach is the feasible option to solve youths’ unemployment burden. Establishing and strengthening the Small and Medium Enterprises (SMEs) is critical due to the fact that, SMEs utilize locally available materials and have the potential to engage many people especially youth, women, and people with disabilities. There are many SMEs processing cashew nuts in cashew producing regions such as Mtwara, Lindi, Tanga, and Pwani, while not the same can be said about cashew apples. With the aforementioned benefits, cashew apple presents greater opportunities for researchers, politicians, investors and farmers to exploit its potentials, and ultimately drive forward national economy.

Quality and utilization of raw cashew apples in Tanzania

Based on a recent study by Msoka et al. (2017), Tanzania’s cashew apple varieties are of considerable good quality. The aforementioned study revealed a good quantity of valuable components such as vitamin C, carotenoid (provitamin A), sugars, polyphenols, dietary fibers, and minerals such as calcium, magnesium, sodium, potassium as well as low quantities of phosphorus, iron, and zinc. These ingredients make cashew apple a perfect raw material in food, energy, agriculture, pharmaceutical, and biochemical processing industries. From a health perspective, vitamin C, carotenoids, and polyphenols have antioxidant and anti-inflammatory activities, thus provide cashew apple an ability to reduce, prevent, or treat a number of chronic diseases such as scurvy, cancer, and neurodegenerative diseases. Since this fruit has a vitamin C content almost five times that of orange or mango, it can be used in food fortification and formulation. Furthermore, presence of sugars, dietary fibers, and minerals make cashew apple a perfect microbial substrate in different fermentation processes to produce value added products such as ethanol (as food drink or energy), organic acids, and bio-surfactant.

A field survey was conducted in major cashew producing regions i.e. Mtwara and Lindi to obtain insightful information regarding the utilization aspects of cashew apple (Dimoso et al., 2021). The study revealed that the majority (98 percent) of cashew farmers consume raw cashew apples, with 62 percent consuming more than five fruits a day and about 56 percent consuming almost every day during the fruit season. However, farmers’ knowledge on the importance of eating cashew apple seemed limited. As a matter of fact, the majority of consumers (53 percent) claimed to eat cashew apple just because it is a fruit. In addition, few respondents seemed to acknowledge the contribution of fruits such as cashew apple to human health. Moreover, nearly 44 percent of farmers traditionally process cashew apple into porridge (traditionally called Mkongohu) and alcoholic drinks namely wine (traditionally called Uraka) and distilled liquor (traditionally called Nipa). With respect to challenges, lack of knowledge on postharvest handling (86 percent), and inadequate processing technologies (83 percent), among others were mostly claimed to hamper the utilization.

Current modern processing and opportunities of cashew apple in Tanzania

Recently, Nelson Mandela African Institution of Science and Technology (NM-AIST) has formulated dried fruit slices and juice products from cashew apple (Dimoso et al., 2020). The formulated cashew apple products were deemed acceptable with respect to nutrient retention, shelf-life stability and sensory properties. Similarly, Tanzania Agricultural Research Institute (TARI) - Naliendele and Ndanda Mission have also been developing cashew apple juice, jam and wine (UNIDO, 2011). However, a commercialization stage of the aforementioned prototypes is yet to be attained.

It is apparent that, while few food products have been already developed, other value-added products for sectors such as bio-chemical, energy, and pharmaceutical industries remain unexplored. The current situation provides an opportunity for stakeholders to venture in cashew apple value chain. Therefore, the initiatives for product development and commercialization of cashew apple value-added products need to be formulated and implemented. This will foster the sustainable existence of cashew apple products in the market.

Value addition through agro-processing of highly perishable crops such as fruits and vegetables should be emphasized. According to the Ministry of Industry and Trade survey 2013, there were only 17 fruit processing units in a country, of which none is for cashew apples (URT, 2019). Shortage of fruit processing industries account largely for the reported huge postharvest losses of such commodity. In this regard, the NPHMS has the following strategic objectives, among others that could benefit the cashew apple value chain: (1) promote availability, accessibility, affordability and adoption of tested technologies and processes to reduce post-harvest losses; (2) promote research and innovations of new and appropriate technologies and methods to reduce crop losses; (3) facilitate agricultural marketing systems to improve market access and minimize post-harvest losses. Likewise, value addition, food fortification and formulation, technology development and transfer, and commercialization of local agro-products are among the top research priorities outlined by the National Research Priorities 2021/22-2025/26 (URT, 2022) to facilitate human capital development and building of strong and competitive industrial economy.

International evidence on cashew apple processing

The most successful country in cashew apple processing is Brazil. This country has about 12 different cashew apple juice processing industries alone, while others sell fresh fruits, dried fruits, jam, wine, confectionaries, and animal feeds. Equally important, the Brazilian Agricultural Promotion Agency (EMBRAPA) is the leading actor in cashew apple value chain. For instance, it developed a cashew apple variety that can remain on the ground for 1 day without being damaged or beginning to ferment. On the contrary, Tanzanian varieties are very soft and get damaged once they fall on the ground, hence they require immediate processing and/or a cold chain facility for distant transportation or long-term storage. In addition, limited access to a sustainable cold chain for perishable crops (fruits and vegetables) is a dominant challenge not only in Tanzania but the whole region of Sub-Saharan Africa (Makule et al., 2022). India has also progressed in developing cashew apple products, however, their commercialization is still a challenge.

However, in West African countries such as Ghana, Benin, Senegal, Nigeria, and Guinea-Bissau, there is little effort regarding cashew apple usage (Monteiro et al., 2017), in spite of a large number of research publications and several stakeholders’ training sessions on cashew apple valorization. For instance, Benin and Ghana have started producing and marketing cashew apple juice, such as the brand Sweet Benin juice, through the BeninCaju project, although the sector is still in its infancy (TechnoServe, 2017). Agbara-Oluwa Cooperative is a fruit processing company that recently began to produce cashew apple juice and sell it in Benin and nearby countries, including Niger, Burkina-Faso, and Togo (USAID/Catholic Relief Services, 2023). In Senegal, a well-established fruit processing company known as Zena Exotic Fruit has started to commercially produce cashew apple juice, butter, and jam, which are sold at the physical and online markets (Zena Exotic Fruits, 2024). Likewise, along with other fruits in Senegal, a Casadeliz company produces and sells cashew apple juice (Casadeliz, 2021). According to Yantannou (2017), no country in Africa is processing more than 1% of its cashew apple production. Despite the fact that Africa is home to very few small-scale enterprises, their important role as forerunners in the commercial processing of cashew apples deserves recognition. With the available publications and ongoing research, it is feasible to upscale the processing in order to efficiently and effectively benefit from the untapped health and economic potential of cashew apples. Therefore, there are greater business opportunities in the cashew apple value chain in African cashew-producing countries.

Technical challenges in cashew apple processing

Unlike other tropical fruits in Tanzania, such as avocado, mango, pineapple, passion, and orange, cashew apples present several underlying constraints that limit their wider utilization on both an individual and industrial scale. Firstly, its astringent nature due to tannins provides an unpleasant taste in extracted juice. The presence of tannins increases the turbidity of the juice, hence the unpleasant appearance of the formulated products. Thus, several studies are dedicated to applying different techniques to reduce tannin concentration or its influence on final products by using clarifying agents (Talasila et al., 2012; Aluko et al., 2023), tangential microfiltration (Soro et al., 2017), blending with other fruit juices (Adou et al., 2017), and the production of tannin-free products such as distilled ethanol and organic acids (Betiku et al., 2016). Also, the level of tannins often varies with respect to cashew variety and geographical location. Hence, each country or processing entity should find a standardized formulation to reduce tannin concentrations depending on their location or the cashew variety used in their processing.

Another challenge relates to its high perishability due to the thin and soft outer skin of the cashew apple. This property affects its harvesting, transportation, and storage as it makes the fruit more susceptible to physical damage or bruises, high temperatures, and insects or microbial infestations. Cashew apples should not fall to the ground when being harvested, hence specialized harvesting hooks are frequently employed to gather the fruits from the tree.. It is noteworthy that the Brazilian agency EMBRAPA has developed a variety that can fall and remain on the ground without being damaged for more than a day. Unfortunately, this type of variety is not present in Tanzania or other African cashew-producing countries. Other studies suggested the use of cold storage (Makule et al., 2022) and chemical pretreatment by using sodium chloride, calcium chloride, and potassium metabisulphite solutions (Ghag et al., 2024) to extend the shelf life of cashew apples. However, more widely applicable, reasonably priced techniques are required. If not, primary processing facilities ought to be set up close to the cashew orchards.

Although cashew apple skin colors range from yellow to red, its juice after extraction is not as colorful as the skin due to the fact that most pigmented compounds, such as carotenoids and polyphenols, are present on the fruit skin. However, after thermal processing, the color of a juice ranges from yellow to brown, depending on the processing temperature and time. This is due to the fruit-reducing sugars, which undergo the Maillard reaction, thus affecting the flavor and color of the product. Also, other heat-sensitive bioactive compounds, such as vitamin C and polyphenols, are reduced during thermal processing. Therefore, temperature control is a critical parameter in cashew apple processing in order to produce an acceptable, nutritious product.

Future perspectives on cashew apple processing

In Tanzania, as in many African countries, the agriculture sector is the foundation of the economy. The cashew subsector has already proved its huge contribution to the economy among the agricultural products in the country. Its counterpart, the cashew apple subsector, also offers huge economic potential for its utilization to produce value-added products in the food, biochemical, energy, and feed industries (Table 1), among others. Although there are several research publications on cashew apple processing worldwide, the establishment of processing factories in many African countries remains a challenge. Inherent cashew apple properties, such as its astringent taste and high perishability nature, are the most limiting factors in its valorization; thereby, further innovative research will need more attention on this topic. Considering its abundance, cashew apple offers an inexpensive biomaterial for integrated upstream and downstream processes based on many products. For instance, cashew apple by-products after juice production by the food industry can be used by the feed, biochemical, and energy industries to produce animal feeds, oligosaccharides, and bioethanol, respectively, among others. And by-products from later industries can be used to produce fertilizer, which is applied to cashew plantations. This approach is viable if bioprocesses and engineering techniques are successfully combined. To create sustainable processes that can promote economic growth, engineering parameters should be studied in conjunction with process integration and scale-up, as well as research on life-cycle analysis and system analysis. Furthermore, the non-climacteric nature and seasonal availability of cashew apples should be taken into account for overall industrial production and processing.

Underlying data

The raw data for the survey conducted by Dimoso et al. (2021) is restricted. Only members of the Fruits and Vegetables for all Season (FruVaSe) project can access the data directly. However, data can be accessed upon request by non-members. Please consult Dr Edna Makule via email (edna.makule@nm-aist.ac.tz) to obtain the data file.

These data are under open access and can be accessed at their respective links/DOI.