ARECANUT

Storage of nuts

In stored nuts, there was a significant decrease in all the constituents studied as compared to fresh nuts. The total protein content decreased by 22.19 and 30.27 per cent in stored nuts with and without husk respectively. A reduction of 10.38 per cent in protein content occurred when the nuts were dehusked as compared to whole nuts. Phenol content decreased significantly by 23.20 and 34.34 per cent in stored nuts with and without husk respectively. Comparing nuts with and without husk, a decrease of 14.5 per cent in phenols was observed in the latter during storage. Though ortho dihydorxy phenols registered a significant decrease of 44.34 per cent and 32.94 per cent in de husked nuts as compared to whole dried nuts.

The total sugars showed a reduction of 24.01 per cent and 50.7 per cent respectively in nuts with and without husk, during storage. A reduction of 32.42 per cent more was observed in de husked nuts. Storage of nuts caused a decrease of 16.32 per cent and 35.32 per cent respectively in nuts with and without husk with regard to reducing sugars. Here a reduction of 23.44 per cent was observed in dehusked nuts as compared to whole dried nuts. Even though there was a reduction in the arecoline content to the extent of 47.86 per cent and 39.91 per cent was observed in de husked nuts as compared to whole nuts during storage. Total fat also registered a significant decrease of 25.02 per cent and 46.74 per cent during storage. However, the fat content was more in nuts stored with husk as compared to de husked ones, the decrease in latter being 28.96 per cent.

Deterioration of quality of arecanut:

1. Microbial and pathological aspects:

Lack of proper drying yards, improper spreading and turning of nuts and exposure to unexpected rains during the drying period lead to microbial infection of the husk as well as kernel. These infections affect the quality of the nuts rendering them unsuitable for consumption and thus lowering their market value. The invading fungi first attack the embryo and then spread to the central white core. In the advanced stage of infection the kernel would present a hollow cavity due to the complete disintegration of the tissue by the invading fungi. The extent of damage due to fungi and other biological agents aiding deterioration depends upon the nature and season of drying.

Elimination of soil contact by the harvested nuts is beneficial in reducing nut infection since it is the prime source of infection. Harvested nuts treated with copper oxychloride showed less infection. Steeping the nuts in Bordeaux mixture followed by drying on cement floor reduced the percentage of infection significantly. Polythene lined gunny bags can be used with advantage over plain gunny bags for storing nuts. Storage of arecanut in air tight bins also minimizes the fungal infection.

2. Stored product pests aspects:

The husked arecanut known, as chali is stored in godowns, sometimes even upto one year in gunny bags before marketing. Insect damages by feeding on the inner central core and due to this, holes appear on the surface of the nuts. More than 21 species of insects and mites are recorded infesting stored arecanut in the country. The insect damage is maximum during the rainy months when the humidity is high and minimum during winter and summer months.

Arecanut beetle (Cocotrypes carpophagus Horn) is the most important storage pest of arecanut. The damage is mainly caused by adult beetles, which bore into the nuts and feed on the inner contents. The infested nuts show holes of 0.6-1.0 mm diameter. Both adults and grubs of coffee bean weevil (Araecerus fasciculatus D.) have been reported to damage stored arecanut. Infested nuts have holes 1.5-2.5 mm in diameter. Unhusked nuts with intact perianth are not infested by this insect even after one year of storage. Cigarette beetle (Lasioderma sp.) is a widely distributed storage pest infesting stored arecanuts throughout the year. Both the adult and grubs damage the nuts and make them as powder. The caterpillars of Rice moth (Corcyra cephalonica) construct galleries of silk and frass over stored nuts, remain within and feed on them.

 

Last updated: 22-05-2008