The Effect of Different Indigenous Processing Methods on the Chemical Composition of Cassava Products

摘要

Effective processing and knowledge of the food composition of indigenous staples are imperative for optimal benefit from the nutritive value of food products. This study investigates the effect of different processing methods on the chemical composition of cassava productsBitter variety of cassava was harvested from a farm in Akpabuyo Local Government Area of Cross River state, Nigeria. The raw bitter cassava roots were peeled and divided into five equal parts of about 500g each. They were processed into garri, “fufu”, dry “abacha” wet “abacha”, and cassava starch. The “garri” was produced by grating, fermenting (72hrs), sieving and toasting the raw cassava. Cassava starch was produced by fermenting the raw cassava at room temperature (31 o C) in a root water ratio of about 1:3w/v for 5 days. The “Fufu” was prepared by boiling moulded cassava starch in water for 15 min. After which it was pounded. Wet “abacha” was produced by cutting (10cm) and boiling the cassava roots for about 25mins. After which it was sliced into jardinière shape of about 3 x 3 x 18mm batons and soaked for 8 hours. Dry “abacha” was produced by shredding the boiled (25mins) raw cassava and sun drying it for 5 days. The products were dried using a food dehydrator (40 o C ) and stored in an airtight container for chemical analysis. The products were analyzed using standard AOAC laboratory methods. Data were analyzed using Statistical Package for the Social Sciences. Mean and standard deviations were calculated and significance accepted at p0.05.The results of the proximate composition of the products were as follows; moisture (13.2 -65.1%), Ash (0.2 -0.5%), Fat (0.3-0.9%), Dietary fibre (1.2 - 4.3%), protein (0.6-1.6%) and available carbohydrate (32.1- 81%). The Energy contents of the samples ranged from 688 KJ in dry “fufu” to 1451 KJ in dry “abacha”. “Garri” had the highest calcium (20mg/100g), phosphorus (56mg/100g), potassium (222mg/100g) and sodium (7mg/100g) contents. The raw starch had the highest magnesium content of 10mg/100g. The percentage contributions of the products to the recommended nutrient intake (RNI) of adults were as follows: “fufu” had the highest contribution of phosphorus (10%). Sodium (0.1- 0.4%), potassium (1-6mg %) and magnesium (1-4%) contributions were generally low in all the products. The Protein (1-3%) and fat (0.5%-1%) contributions to the RNI were low but that of carbohydrate was high and ranged from 30% in “fufu” to 62% in “dry “abacha”. “Garri” had the highest contribution of dietary fibre (17%). Dry “abacha” and “garri” had the highest energy contributions of 17% to the RNI of adults. All the cassava products had low levels of hydrogen cyanide which ranged from 3.42mg/100g in “garri” to 7.57mg/100g in “fufu”. The traditional processing used for processing raw bitter cassava into dry “abacha” is shown to be insufficient in reducing the HCN to a safe level of 50mg/kg so further processing is recommended. Knowledge of the chemical composition of cassava products will enable consumers to make informed food choices for better nutrition and health outcome.