Adding Value to Tropical Fruits – The Case of the Jamaican Ackee Industry: Lessons for Policy and Practice.

Toxic Principle

 The toxicity of ackee fruit has been associated with the consumption of unripe fruits (Scott, 1916). Hassel and Reyle (1954) first isolated the two toxic constituents (hypoglycin A and B) from the arils and seeds of unripe ackee (Figure 2). In 1976, Tanaka et al. (1976) confirmed the ingestion of hypoglycin A from unripe ackee fruits as a cause of illness.

Figure 2. Structures of hypoglycin A (1) and B (2).

Biochemical and Nutritional Profile

 Despite its importance and frequency of consumption in the local diet, there is little data reporting the biochemical composition of ackee fruit. As shown in Table 1, ackee fruit contains high proportions of fatty acids, carbohydrates, proteins and is quite rich in fibres, other vitamins and minerals. Mitchikpe (2007) reported close values and found that ackee arils contain 12.1, 46.2, 20.0 and 17.4 g/100 g of dry matter of proteins, fats, carbohydrates and fibres, respectively.

Recently, some physiological and biochemical studies have been conducted on ackee fruits. It was reported that total sugars increased during the maturation and ripening but decreased when the fruit was ripe. However, reducing sugars increased progressively during maturation and ripening (Emanuel et al., 2011). The level of total phenolic compounds is somewhat high in the arils of green ackee fruits, but decreases by 30% during maturation and ripening. The levels of anthocyanins in arils also showed a similar pattern, decreasing by 95% during maturation and ripening (Emanuel, 2011).

Table 1. Nutritional value of raw edible arils of ackee fruits.

 (from Food Reference website: http://www.foodreference.com/html/artackee.html)

Oladiji et al. (2009) analyzed the physicochemical properties of the oil from ackee fruit. They found that the fruit oil yield was 20.02%, and consisted of 22.22% saturated, 56.43% monounsaturated, and 21.35% polyunsaturated fatty acids. They also noted that the oil is rich in behenic, palmitoleic, oleic, gadoleic, erucic, and 9,12-eicosanoic acids. Odutuga et al. (1992) analyzed the fatty acid composition of arils at four different stages and found that lipids content was higher in arils of fruit opened in sun, and palmitic (16:0), stearic (18:0) and linoleic (18:1) acids were the predominant fatty acids. They also analyzed the content of total proteins and noted that a high content (31.8 g/100 g dry weight) was measured in arils of fruits opened on the tree.

Food and Other Uses

The ackee fruit is freshly sold in the local markets and on the roadsides of the island of Jamaica. Most Jamaicans eat the fruit cooked, while others consume it raw. In order to be consumed, the fruit must be ‘yawned’ (the seed sand internal median pink tissue removed) (Figure 3). When seeds are discarded, the fresh and firm arils are parboiled in salt water, and then lightly fried in butter. The arils are also cooked with codfish, onions and tomatoes. The parboiled ackee arils are also added to stew beef and salt pork with a range of herbs and spices. In addition, they are sometimes curried and eaten with rice. Beside the culinary uses mentioned above, ackee fruits are also used for making soap, perfumes and medicines, for fishing, for construction and several other purposes.

Figure 3. Ripe ackee fruits showing seed, arils and internal median pink tissue.

Processing

Ackee fruit is often processed at different stages of maturity. When the ackee fruit is harvested for canning, the agroprocessors receive mature fruit from the suppliers. The fruit can be received as mature unopened pods or mature open pods that were open while on the tree. The open pods are used immediately but the unopened mature pods are rack-ripened. Only the fruit that is opened within three days of picking can be used. Therefore, a large amount of ackee pods have to be discarded at such canning facilities. This ripening process has to be documented and controlled as part of the entire production process and monitored by the Bureau of Standards as stipulated in the Processed Food Act of 1959 and as part of the Hazard Analysis and Critical Control Point (HACCP) system of production set by the Jamaican Standard Specification for canned ackee in brine (Mitchell et al., 2008).

There are two main varieties of ackee found locally in Jamaica: the butter (called also butta) or soft ackee with a soft yellow aril and the cheese or hard ackee with a cream coloured aril. However, free crossing of these two main varieties has produced a number of varieties, resulting in a wide variation in the quality of fruit (Royes et al., 1988). When cooking fresh ackee or opening the canned product, there is unevenness within the produce (Davidson, 1975). This is largely because of the wide variation that occurs with the various varieties in the island that produces different quality of fruits. However, for canning purposes, the hard or cheese ackee is preferred, because the shape and firmness of the arils in the can should be preserved for better quality attributes.

On the other hand, attempts have been made in the past to select certain ackee trees and fruits with excellent canning properties. In the 1960s, forty-five trees from stands at Vernamfield, Orange River, and Hopefield Agricultural Stations were selected as producing fruit with good canning properties, and were then vegetatively propagated. The selected varieties were planted at the Lawrence Field Research Station in 1969 and root cuttings were made available from the chosen varieties. However, in 1975, the main source of the cultivars at Vernamfield Research Station was destroyed. Therefore, the cultivars lost their research value and the project was abandoned (Ministry of Agriculture and Mining, 1995). Recently, for further expansion in the ackee sector, the Ministry of Agriculture, through the National Tree Crop Project, has sought to address the problem of good-quality raw material by establishing 62 hectares of ackee orchards throughout the island (Ministry of Agriculture, 2005).

Initially, ackee arils were subjected to marketing and export restrictions because of the toxic compound hypoglycin A. However, following recent toxicological and biochemical studies, which demonstrated that toxicity of ripe ackee is extremely low and the arils could be consumed, a technological process for aril canning was developed (US Patent 1982967B1). The process consists of mixing whole or diced arils with brine and then canning and sealing the product. The cans are sterilized at 210°C for 15 min. The temperature should be strictly below the boiling point so that the canned arils remain firm and retain good flavour (Figure 4).

Figure 4. Technological process of canning and sterilization of ackee arils.

The Ackee Industry   

The first exports of processed ackee began in 1954 when Da Costa Brothers Ltd exported 100 cases to Canada. Later, the trade was extended to Britain that proved an even more lucrative market (Davidson, 1971). The primary consumers of this product are predominantly Jamaicans who migrated to and settled down in these countries. In 1972, the US Food and Drug Administration (FDA) imposed an import alert on canned ackee, effectively banning the direct export of ackee from Jamaica into the US markets. The ban was imposed against the background of toxicological concentrations of hypoglycin A. The FDA placed an upper limit of 100 mg/kg of hypoglycin A in the canned arils of the fruit. A reproducible analytical procedure capable of detecting hypoglycin A in the arils and brine of the canned and unprocessed ackee to a detection limit of 0.1 mg/100g fresh weight was developed (Ashman, 1990). This analytical technique provided the basis for the successful defence for conditional re-entry of direct ackee export into the US market in 2000, thus lifting a 27-year ban, and ackee exports to the USA resumed. This canned product earned Jamaica US$4.3 million (for 1,507,635 kg of ackee exported) in 1999 and US$8.5 million in 2002 (Statistical Institute of Jamaica, 2002). However, in 2005, the exportation of ackee to the US market was suspended for almost one year for technical reasons. Presently, only certified agro-processors with food safety controls in place can export ackee that will not be automatically detained (Shakespeare-Blackmore, 2007). The Central Division of the Bureau of Standards of Jamaica (BSJ) stated that “the ackee industry is worth approximately J$ 400 million in the year 2005 [US$4.5 million approximately] with potential for further growth”. However, the markets are very fragile because of the fact that the industry is export-oriented and heavily dependent on the confidence of the overseas consumers (Ministry of Agriculture and Land, 2006).

Conclusion

Jamaica is the only place where the ackee fruit is extensively consumed. The cultivation and processing of ackee on the island gives it the potential to be a valuable crop and generate a consistent income for small farmers and the rural population at large. Given its high yield and multiple fruiting seasons, the development of the ackee value chain would be beneficial to the Jamaican economy. However, much research and development work still needs be undertaken to (i) understand the physiology and the biochemistry of ackee fruits, (ii) improve varietal selection and propagation, (iii) meet international food safety requirements for export, (iv) develop the knowledge base to respond adequately to food safety challenges in international markets and (v) preserve quality and flavour after processing.

References