ABSTRACT
Raphia hookeripalms, planted in the same ecological areas of the Nigerian Institute for Oil Palm Research, Benin City, were selected, using the appearances of three spear leaves or inflorescences on the palms, as indicators of their state of maturity. The palms were tapped and the sap was collected throughout the life span of the palms. The effects of thermal treatment and chemical preservatives on the stability of the sap were examined. Nutrients such as carbohydrates (sucrose), protein, water-soluble vitamins and mineral elements were assayed for in the sap. The shelf-life of the sap was determined. By using reduced pressure dehydration technique, two multi-nutrient products were derived from the sap. The activation energies for thiamine and riboflavin extracted from the sap of Raphia hookeri palm were also determined. The UV-visible absorption spectrum of Raphia hookeri sap was developed with a computerised spectrophotometer.
The results obtained from the analyses of the sap indicated that eleven mineral elements, three water -soluble vitamins and other nutrients such as sucrose, proteins and water were present in various concentrations. A minimum of twenty-four months was established as the shelf life of the sap. The maximum yield of sucrose and sap occurred in the 4th week. Two multi-nutrient products with 2% and 3% moisture contents were developed.
The activation energies determined for thiamine and riboflavin in the sap were 4.0kJmol-1 and 32.0kJmol-1, respectively. Statistical analyses revealed that there were no significant differences between the Raphia hookeripalms investigated with respect to their levels of mineral elements assayed for. In contrast, significant differences were observed between the multi-nutrient products and the fresh sap, with respect to their nutrient concentration.
The sap can also be useful precursors of products such as sugar syrups and dehydrated derivatives. Sharp absorption peaks by the palm sap were observed at 196 and 336 nanometers. The UV-visible scan of the sap could be used as a quality control parameter.
