Assessment of Proximate Composition and Cyanide Content of Different Cassava Products (Fufu and Garri)
The Objective of the Study
Therefore, the aim and objective of this study were to assess the cyanide content and proximate composition of cassava products (garri and fufu).
Review on Cassava Roots (Manihot esculenta Crantz)
Cassava (Manihot esculenta Crantz), also referred to as yucca in Spanish, mandioca in Portuguese and tapioca in French, belongs to the Euphorbiaceae family (Opara,1999; Burrell, 2003). It has been reported that the crop originated from South America and was domesticated between 5,000 and 7,000 years B.C. (Olsen and Schaal, 2001). The first import of cassava to Africa was by the Portuguese from Brazil in the 18th century, but now cassava is cultivated and consumed in many countries across Africa, Asia and South America (Nhassico et al., 2008; FAOSTAT, 2013). The crop has drought resistant root which offers low cost vegetative propagation with flexibility in harvesting time and seasons (Haggblade et al., 2012). Cassava can be cultivated throughout the year between latitude 30º N and 30º S, in different soil types except hydromorphic soil with excess water (Iyer et al., 2010). The stem grows to about 5 m long with each plant producing between 5 to 8 long tubers with firm, homogenous fibrous flesh covered with rough and brownish outer layer of about 1 mm thick. The root can be stored in the ground for over 2 years, and this serves as a means of food security to the farmer in West African countries such as Nigeria (Nhassico et al., 2008; Falade and Akingbala, 2010).
Cassava is a subsistence crop in Africa, and supplies about 200 – 500 calories per day (836.8 – 2092J) for households in the developing countries (Sánchez et al., 2006; Omodamiro et al., 2007). In the early years, cassava was neglected as food crops because of its low protein content (< 2%) and high cyanide content (120-1945 mg HCN equivalent/ kg) (Iglesias et al., 2002; Charles et al., 2005), but it is considered the fourth most energy rich food source due to the high (>70 %) carbohydrate content (Falade and Akingbala, 2010). The leaf of cassava plant is higher in protein (3 – 5%) and some macro nutrients, and therefore consumed as vegetable in some countries (Salcedo et al., 2010; Burns et al., 2012). However, the tuberous root is the major edible part of the crop. The root serves as a source of food security against famine because of its long storage ability in the ground prior to harvest (El-Sharkawy, 2004). The root can be processed into different food forms for human consumption, animal feed and as industrial raw material for paper, textiles and alcoholic drinks (Falade and Akingbala, 2010; Haggblade et al., 2012). In Thailand, cassava dry chips and pellets are the major export commodity (Falade and Akingbala, 2010), while in Nigeria, it is processed mainly into gari and fufu.
Utilization of Cassava Root
Utilization of cassava root in food is numerous, however, the potential in food and other industrial applications is limited by the rapid postharvest physiological deterioration, which reduces the shelf-life and degrades quality attributes (Sánchez et al., 2006). This physiological deterioration is attributed to its high moisture level (60 to 75%), and respiration rate which continues even after harvest (Salcedo et al., 2010), resulting in softening and decay of the root and thus rendering it unwholesome for human consumption. Other factors that can cause deterioration of cassava root include pests, disease, and mechanical damage such as cuts and bruises which occur during postharvest handling and processing (Falade and Akingbala, 2010; Iyer et al., 2010). The cut area exposes the root to vascular streaking and microbial attack, thereby accelerating deterioration and decay (Opara, 1999; Opara, 2009; Buschmann et al., 2000). Studies have shown that physiological changes start within 24 h after harvest with a blue black discoloration commonly appearing on the root after 72 hours (Iyer et al., 2010; Zidenga et al., 2012). The colour change of the root is accompanied by fermentation and thereafter an offensive odour indicating complete rotting (Reilly et al., 2004). This rapid degradation of quality in fresh cassava roots is a major reason for the poor utilization, poor market quality, short root storage life and low processing yield (Reilly et al., 2004; Sánchez et al., 2006).
Converting cassava root to other food forms creates products with longer shelf-life, adds value to the root, and reduce postharvest loses (Falade and Akingbala, 2010). Furthermore, theapplication of novel postharvest handling, processing, packaging and storage techniques is of critical importance for successful large scale production and utilization of cassava roots and products. Successful application of these postharvest technologies will contribute towards maintaining product quality and safety as well as reducing incidence of postharvest losses, and thereby, improve food security (Opara, 2013). However, information on the postharvest handling, processing and storage of cassava roots and products are limited in comparison with other globally important food crops such as wheat (Butt et al., 2004; Kolmanič et al., 2010) and rice (Falade et al., 2014). Therefore, this study reviews the postharvest handling and spoilage mechanisms of cassava root, and the role of packaging and storage on quality of fresh cassava root and products.
MATERIALS AND METHODS
Collection of Materials
Matured cassava (Manihot esculanta crantz) was purchased from Oja Oba market in Owo, Ondo State and was processed to obtain cassava products in the food processing laboratory of department of food science and technology (FST) Rufus Giwa Polytechnic Owo, Ondo State.
RESULTS AND DISCUSSION
Table 4.1: Proximate Composition Garri and Fufu Produced from Cassava
CONCLUSION AND RECOMMENDATION
In conclusion, storage has been revealed to have great influence on nutritional (proximate), and cyanide of cassava products. According to results of this study, it is observed that GS (Garri Sample) has greater value in terms of crude proteinwhile FS (Fufu Sample) has higher value in other parameters (Moisture, ash, crude fiber, and carbohydrates). The cyanide content of each product is observed to be influence by period of fermentation and processing (dewatering) which remove a lot of cyanide from garri.
It can be recommended that cassava should be allowed to ferment for at least 3 days during the production of garri to help reduce the cyanide content and other methods should be adopted in order to preserve the nutritional composition of garri during processing.
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