Determination of Technology for Processing Indigenous Spices to Enhance Quality and Flavour Retention

ABSTRACT

In this study, the appropriate technology for processing three indigenous spices for enhancement of their quality and flavour retention was investigated. Some freshly harvested fruits of Tetrapleura tetraptera (oshorisho), Xylopia aethiopica (uda) and Piper nigrum (uziza) were processed in ground and liquid forms, and packaged and stored in plastic cans, high density polyethylene and metal cans for six months. The samples were analysed for some non – sensory quality attributes. Piper nigrum had a moisture content of 11.00%, starch 52.18%, crude fibre 3.81%, total ash 4.50%, ash soluble in water 1.30%, ash insoluble in water 3.20%, ash soluble in Hcl 0.18%, alcohol extract 6.50% and volatile oil 1.76% . The major flavour compounds identified in Piper nigrum were Piperine - (1.09%), alpha-pipene - (4.22%), beta-pipene - (3.60%) and flavonoids - (91.09%). A breakdown of the flavonoid composition gave flavonoid A - (9.73%), B - (7.71%), C - (44.81%), D - (13.07%), E - (6.72%), F - (3.89%) and G - (5.16%). Tetrapleura tetraptera had a moisture content of 10.11%, starch 21.50%, crude fibre 10.11%, total ash 13.50%, ash soluble in water 9.20%, ash insoluble in water 4.30%, ash insoluble in Hcl 0.43%, alcohol extract 15.50% and volatile oil 2.54%. Also the major compounds identified in the fruit of Tetrapleura tetraptera were scopoletin - (8.56%), glucose - (10.82%), fructose - (6.71%), sucrose - (44.10%), alkanoid - (14.53%), saponin - (3.03%), tannin - (4.93% and flavonoid - (7.31%).Xylopia aethiopica had a moisture content of 12.00%, starch 21.80%, crude fibre 34.00%, total ash 5.50%, ash soluble in water 0.50%, ash insoluble in water 5.00%, ash insoluble in Hcl 0.53%, alcohol extract 9.00% and volatile oil 1.03% . The major flavour compounds identified in fruits of Xylopia aethiopica were Piperine - (14.12%), alpha-pipene - (4.15%), beta- pipene - (15.44%), Xylopic acid - (46.80%), Myrcene -(3.92%), Linalool - (10.99%) and Limonene - (4.58%). There were reductions in the moisture contents and volatile

oils of these spices after three and six month’s storage respectively, which was traceable to the loss of volatiles during storage. Plastic cans with airtight covers were found most suitable for storage of ground spice powders. Metal cans appeared to be attacked by components of volatile oils in spices, the cans rusted thereby creating pinholes for escape of flavours and a reduction in spice product quality. Ambient temperatures appear suitable for the storage of dried spice product forms as long as the containers are airtight. The microbiological analysis showed that spices do not support the growth of most microorganisms likely due to their chemical constituents. The sensory evaluation showed that the mixed spice ethanol extract was preferred in jollof rice dish and there was no significant difference with imported curry products, while the ground spice mix was preferred in fresh fish peppersoup.