Volume 14 July 2009

Use of Dried Papaya Milk in Chitosan Manufacture

2022-02-24T05:35:33Z

Use of Dried Papaya Milk in Chitosan Manufacture Yapa, P.A.J.; Silva, A.; Senarath, W.T.P.S.K. A new method for the production of chitosan from shrimp waste using dried papaya milk (OPM) has been developed. It involves the treatment of demineralized (with 4% HCI) shrimp waste with OPM followed by deproteinization with 3% NaOH and deacetylation with 50% NaOH. The use ofOPM brings about considerable reductions in the amount ofHCI (20%) and NaOH (40%), which are known to cause env.ironmental pollution problems. Typically, the degree of deacetylation (~O) of resulting chitosan was (67%) comparable to DO of conventional methods. Moisture content (9.12%) and ash content (0.09%) of resulting chitosan were significantly low compared to chitosan obtained by 100% chemical methods.

Studies on a Hyper-haemolytic Compound of Palmyrah Flour (Odiyal)

2022-02-24T05:35:32Z

Studies on a Hyper-haemolytic Compound of Palmyrah Flour (Odiyal) Keerthi, A.A.P.; Jansz, E.R.; Ekanayake, S. Palmyrah (Borassus flabellifer L.) flour (Odiyal) is well known to contain toxins. A new saponin was isolated from the medium pressure liquid chromatography (MPLC) fraction between 90% - 100% MeOH:EtOAc extract and crystallized. On subjecting to Micro-Time of Flight (Micro- TOF) mass spectrometry it was found to have a molecular weight of 1534, containing the common steroidal aglycone of odiyal of molecular weight 414, 5 ramhnosyl and Iglucosyl residues. The first fragment corresponding to MW 228 may be an uncommon fatty acid derivative. Testing for haemolysis on human red blood cells (RBC) showed the compound to be hyper-haemolytic with a haemolytic index 37 fold that of the flabelliferin B (F B) which had been the previously reported steroidal saponin RBC haemolyser with highest activity from palmyrah.

Spoilage after Cooking of Some Rice Varieties Commonly Consumed in Sri Lanka

2022-02-24T05:35:32Z

Spoilage after Cooking of Some Rice Varieties Commonly Consumed in Sri Lanka Waduwawara, S.; Manage, P.M. Rice once cooked is perishable. In the present study we investigated cooked rice spoilage of common rice varieties in Sri Lanka. The study was further extended to compare the effect of clay and aluminium pots on the cooked rice spoilage and to study the potential to put off cooked rice spoilage in the traditionally used botanicals rampe (Pandans latifolia), curry leaves (Murraya koenigii) and turmeric (Curcuma domestica). One Gram positive bacteria was isolated and identified as Bacillus cereus. In cooked rice, the total count of Gram positive bacteria increased with time while the total count of Gram negative bacteria decreased. When inoculated separately to sterilized rice, the Gram positive bacteria multiplied to a significantly greater number (p < 0.05) than did Gram negative bacteria. The total bacteria count of different rice varieties was not significantly different from each other. Rumpe and curry leaves reduced the total Gram positive bacteria count of rice significantly (p < 0.05) while turmeric did not. The total Gram positive bacteria count of rice cooked in aluminium pots was significantly lower (p < 0.05) compared to rice cooked in clay pots.

Species Richness and Ecological Characterization of Wood Inhabiting Agaric Fungi on Home-garden Logs in Semiurbanized Areas in Colombo Suburbs

2022-02-24T05:36:43Z

Species Richness and Ecological Characterization of Wood Inhabiting Agaric Fungi on Home-garden Logs in Semiurbanized Areas in Colombo Suburbs Fernando, K.M.E.P. Agaric fungi found on fallen logs of different wood species in home gardens were studied. Species richness and their substrate preferences were determined by examining the fruit body formation, habit and frequency of their appearance on the different wood. The effects of temperature, rain and moisture on fruit body formation were also correlated. During the study period 36 fungal species were identified as wood-inhabiting agaric fungi on 25 homegarden wood species. Frequency of appearance of fruit bodies was directly related to the rainfall pattern, but amount of rainfall, temperature and relative humidity did not show any relationship. The highest species richness was found on Cocos nusifera, recording 16 agaric species. Artocarpus heterophyllus, Tectonia grandis, Swietenia. macrophylla and Vitex altisima showed resistance to macro fungal attack. Schizophyllum commune was observed on 16 wood species as the commonest agaric species while 17 agaric species recorded their preference to one particular wood species. Since there was a high diversity of wood decaying agaric species inhabiting most of the wood species in this semi-urbanized area, it is possible to cause considerable damage to valuable wood and wood products in service resulting in economic loss.