EFFECT OF STORAGE CONTAINERS ON THE NUTRITIONAL QUALITY OF STORED KOLANUT, COLA NITIDA (VENT) SCHOTT ENDLICHNER.

Abstract

This study involved investigations into the effect of four packaging materials namely, CP (cement paper), CP + BL (cement paper plus dry banana leaves), PG5μm (5μm gauge polythene) and PG10μm (10μm gauge polythene) on the keeping quality of stored nuts, Cola nitida between months of July, 2010 and January, 2011. Seventy five clean, disinfested kolanuts were packed separately in each container and replicated three times for each container. The stored nuts were sampled monthly and analyzed for proximate composition, mineral profile, organoleptic properties and microbes. In addition to the nutritional qualities of the kolanuts, organoleptic tests on appearance, odour and taste were carried out after each month of storage for six consecutive months, with the aid of ten panels each month using Nine – Point Hedonic scale. Prior storage in July, 2010 the proximate composition was ( moisture, 60.40 ± 0.01; crude fat, 5.71± 0.02; crude protein, 2.63 ± 0.01; crude fibre, 7.13 ± 0.00; ash content, 1.46 ± 0.01; dry matter, 33.60 ± 0.01; total carbohydrate, 16.67 ± 0.03), the caffeine in milligram per 100gram was 1.46 ± 0.00, the mineral profile in parts per million was (Sodium, 202.33 ± 0.02; Potassium, 183.89 ± 0.02; Calcium, 245.09 ± 0.02; Magnesium, 169.98 ± 0.02; Zinc, 3.29 ± 0.04; Iron, 12.27 ± 0.02; Copper, 0.86 ± 0.01; Manganese, 0.73 ± 0.02; Selenium, 0.90 ± 0.03), and the total spore count in spores per gram was zero. An organoleptic test was not carried out in July, 2010 because the kolanuts were yet to be stored. However, from the month of August, 2010, to January, 2011, organoleptic tests revealed that nuts stored in 5μm and 10μm were preferred to nuts stored in CP and CP + BL by panels. Moreover, the nutritional quality was higher and the total spores count was low in kola nuts rated high by the panels. These variations show that the packaging materials significantly affected the stored kolanuts, placed under the same environmental condition (relative humidity and temperature). The packaging materials with the kolanuts of the highest ratings, on appearance, odour and taste were PG5μm followed by PG10μm.The factors that could have attributed to these high ratings by the panels could be as a result of the high spores count on the kolanuts stored in the other two packaging materials (CP and CP + BL). Moreover, the changes in the nutritional content of the kolanuts affected the taste of the kolanuts over the months of storage. The caffeine content of the kolanuts stored in CP and CP + BL reduced drastically in the months of November, 2010, December, 2010 and January, 2011 while kolanuts in PG5μm and PG10μm increased considerably over the initial result. This study has thus revealed that polythene bags could be used to store kolanuts meant to be chewed for months, without the use of preservatives. The fact that panels preferred kolanuts stored in PG5μm to those in PG10μm shows that higher grade of polythene is unnecessary to achieve the best result. Moreover, nuts with low moisture content had lost its freshness, appeal and market value hence storage in PG5μm and PG10μm is recommended for traders. The overall nutritional composition also shows that kolanuts are best stored in the polythene to retain quality. Also, storage in polythene is cheap and less laborious because it does not require changing of the packaging materials itself and wetting of the nuts during the dry hot seasons of storage.