BackgroundFresh coconut (Cocos nucifera L) water is a clear, sterile, colourless, slightly acidic and naturally flavoured drink, mostly consumed in tropical areas. It is a rich source of nutrients and has been used for medical purposes. This study was designed to investigate changes in selected characteristics of coconut water after autoclaving, gamma irradiation and storage. Also, the study was designed for assessing the possibility of measuring the growth of bacterial in fresh, stored or sterilised coconut water using turbidity measurements (at wavelengths between 600 nm and 800 nm) or by dry biomass determinations.ResultsPortions of coconut water aseptically extracted from the matured fruit, (average pH of 6.33 ± 0.17) were either stored at 4°C, autoclaved at 121°C for 20 min., or irradiated with gamma rays at 5 kGy. Subsequent changes in selected characteristics were determined. Autoclaving, gamma irradiation and long term storage of coconut water at 4°C resulted both in the development of a pale to intense yellow colour and changes in turbidity. After storage, the dry matter content of fresh, autoclaved and irradiated coconut water by 52.0%, 23.5% and 5.0% respectively. There were also significant differences in the UV spectra before and after sterilisation and during the storage of the coconut water. Although changes in total carbohydrates were observed, they were not significant (p > 0.05).ConclusionsThe enormous differences in the characteristics before and after storage suggests that the use of turbidity and dry biomass measurements for measuring the growth of bacteria in fresh, autoclaved and gamma irradiated coconut water before storage is practicable without any possibility of interference by the innate turbidity, colour and dry matter of the coconut water. However, this is not practicable after storing the coconut waters at 4°C, since there were increases in the turbidity and dry matter of the coconut water to levels that will mask the turbidity of a growing bacteria culture.

Coconut (<i>Cocos nucifera</i> L.) water is a refreshing drink consumed mostly directly from the fruit. However, in recent times, consumers in Accra prefer to have it transferred into plastic bags for later consumption; this favours a high risk of bacterial contamination. Since it is rich in nutrient, it may become unwholesome with possible high bacteria loads. However, its use for managing and preventing diarrhoeal diseases and the report that coconut water contains anti-bacterial proteins, suggests a bacteria growth inhibition potential for it. Therefore, the propensity of fresh coconut water to support the growth of two pathogenic bacteria was studied. Using mostly optical density measurement, and where possible, growth parameters and bacteria loads were estimated for the growth of two gram negative bacteria in fresh, stored and sterilized coconut water, and also in Luria-Bertani (LB) broth as a control. The study revealed that fresh coconut water is a drink favourable for the survival and growth of <i>Escherichia coli</i>, and <i>Klebsiella pneumoniae</i>. It supported the growth of these bacteria recording lag times of 101.4 ± 1.00 minutes for E. <i>coli</i> and 154.8 ± 0.45 minutes for K. <i>pneumoniae</i>, and high loads of viable cells of ~ 2.27 × 10⁸ cfu/mL and > 2.83 × 10⁸ cfu/mL at the stationary phase for E. <i>coli</i> and K. <i>pneumoniae</i> respectively. These and other growth parameters in coconut water were comparable to those in Luria-Bertani (LB) broth medium. However, when autoclaved, gamma irradiated or stored at 4℃ for two weeks or more, the growth of these bacteria becomes extremely limited. Fresh coconut water will support the growth of these bacteria to high and infective load of viable cell if it becomes contaminated with and is kept at ambient temperatures for two or more hours. Thus, it will be safer to consume coconut water directly from the fruit, since there is a high risk for bacteria contamination associated with the transfer and storage in other containers

Seed extraction and drying methods are important procedures employed after harvesting fruits of African eggplant as these methods affect the seed quality. This study sought to evaluate the seed physiological quality of two cultivars of African eggplant subjected to various durations of natural fermentation and different drying methods. In the first study, fruits were fermented for 0, 6, 12, 24 and 48 h before seed extraction. In the second experiment, seeds were extracted and subjected to sun/24 h; shade/24 h; shade/48 h; desiccant (silica gel)/24 h; shade/24 h + 30 °C oven (24 h); 30°C/24 h; 35 °C/24 h; 45 °C/24 h; 50°C/24 h and 60°C/24 h for drying. The seed quality evaluation were seed moisture content, seed dry weight, first count, seed germination and accelerated aging. The results suggest that African eggplant seeds do not require natural fermentation during extraction for enhanced seed germination. All drying methods were able to reduce seed moisture content to an ideal level for storage and maintained seed physiological quality. The latent effect of these methods on seed physiological quality needs to be studied.