A study of some sudanese edible forest fruits and their nectars

Non-wood forest products (NWFPs) have received high attention since they have important usages throughout the world during the last years. Forest fruits are one of these NWFPs. Sudanese forest fruits are used traditionally as foods as well as medicines. However, only little information is available about its manufacture. Doum (Hyphaene thebaica L), kirkir (Randia geipaeflora), karmadoda (Naucleae latifolia) and godeim (Grewia tenax) are some of the indigenous fruits in Sudan. The objectives of this work were directed towards the study of characterization and the suitability of these Sudanese forest fruits for the production of nectars and to establish the effect of different storage temperatures on the products stability. The physical properties of forest fruits indicated that there were significant differences in diameters (P 0. 05) of forest fruits after sorting into three sizes. As well as the fruits have different figures and colours. The chemical composition of the fruits showed that they have good quantities of extractable matter and protein. As well as, they are containing high percentages of soluble carbohydrates and excellent quantities of ascorbic acid of 156.25, 153.9, 76.33 and 63.64 mg/100g for kirkir, karmadoda, godeim and doum, respectively. The karmadoda and kirkir contain adequate amounts of beta-carotene of 178.45 and 115.61 IU vitamin A/100 g, respectively. Doum and kirkir are rich in P and K, karmadoda is rich in P, K, Mg and Ca; while godeim is rich in Mg, K, Ca and Fe. Moreover, these forest fruits are rich in several essential amino acids such as leucine, isoleucine, valine and arginine. They are also rich in some non-essential amino acids alanine, aspartic acid, glutamic acid, glycine, serine and proline. The processing operation included preparation, choice of the best extraction and processing methods of three nectars from doum, kirkir and mixture of karmadoda and godeim (karmadoda: high acid, low sugars with bitterness and godeim: low acid, high sugars). Godeim was mixed with karmadoda to mask its bitter taste. Different extraction conditions were considered and the extraction with high total and total soluble solids has been chosen. In addition, the effect of storage temperatures; ambient (30 ± 5 deg C) and refrigerator (4 - 6 deg C); were investigated for forest fruits nectars packaged in can containers. The results showed that soaking of doum and kirkir fruits at ratios 1: 4 / 2 hr and 1: 4 / 8 hr, respectively, were the most appropriate methods for extraction, with total solids of 10.61 and 10.32 %, respectively. The total soluble solids were 10.50 and 9.50 %, respectively. While, blanching karmadoda fruit in water at the ratio of 1: 2 / 10 minutes gave total solids of 5.63 % and total soluble solids of 5.00 %. The nectars have reported significant differences (P 0.05) in physico-chemical composition during storage period; six months; and at different storage temperatures; ambient and refrigeration. The results indicated that TSS, pH, total acidity and total sugars were almost stable neither due to storage period, nor to temperature (insignificantly different). The reducing sugars content, viscosity and absorbance at 420 nm in nectars increased, while the non-reducing sugars and total tannins decreased during storage time and under both temperatures. The vitamin C showed noticeable decrease during storage. The nectars stored at ambient temperature decrease more than those stored at refrigeration temperature. On the other hand, the qualities of the nectars during the six months of at the two temperatures of storage were evaluated microbiologically for total bacterial count, lactic acid bacteria, Salmonella spp, Staphylococcus aurous, spore former bacteria and mould and yeasts, have shown that they were free of microbial or fungal contamination throughout the period of storage. This complies with the standards being conducted by the Sudanese Standards and Metrological Organization (SSMO) for foods. Sensory evaluation reflected that doum nectar was the most acceptable for the panelists followed by kirkir and then karmadoda nectars. The conclusion of this study shows that these forest fruits are very rich in minerals, amino acids and vitamins (C and A). Karmadoda have the highest amino acids chemical score. The proteins of kirkir and karmadoda are rich in nutritionally essential amino acids. Doum has higher sulphur amino acid (methionine). Blending karmadoda (bitterness) with godeim (high sugars) gave a good taste of nectar. The nectars were stored up to six months without deterioration in the quality, either at ambient temperature or refrigeration