Exploring the influence of sterilisation and storage on some physicochemical properties of coconut (Cocos nucifera L.) water

Abstract

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.

Application of ultraviolet-C radiation to inactivate acid-and-desiccation stressed Salmonella enterica in young and mature coconut liquid endosperm mix beverage

“…A significant increase in the L* value (toward lighter sample), and non-significant decrease and increase in a* (toward redder sample) and b* (toward yellower sample) values, respectively of the beverage were observed immediately after pasteurization of 120 s (storage day 0). Awua et al (2011) reported significant color changes, particularly yellowing, results from exposing coconut liquid endosperm to sterilization processes such as severe heating and gamma radiation.…”

“…The endosperm becomes prone to microbial contaminations and degradation when exposed to external environment (Awua, Doe, & Agyare, 2011;Rolle, 2007). Spoilage microorganisms that cause coconut water quality degradation ferment sugars and break down fats, resulting in sensory quality alteration (Rolle, 2007).…”

Decimal reduction times of acid-adapted and non-adapted Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes in young Cocos nucifera Linn. liquid endosperm

“…The liquid endosperm remains sterile and stable while in an undamaged fruit (Awua, Doe, & Agyare, 2011) but easily gets contaminated with microorganisms when taken out in an unhygienic manner (Paguirigan, Molina, Lorenzana, Valencia, & Masa, 2000). Its physicochemical and nutritional properties make the liquid endosperm an ideal growth medium for microorganisms; and in fact commonly used in the cultivation of microbial and plant cells (Banzon & Velasco, 1982;Campos, Souza, Coelho, & Gloria, 1996).…”

Preliminary study of coconut water for graft tissues preservation in transplantation

“…The modified coconut electrolytic solution had a composition similar to the Belzer solution and was subjected to a physico-chemical process of sterilization and pH change, which may have altered the natural properties of the coconut water 17 , justifying the inadequate preservation of ovarian tissue, as well as by Belzer solution. The highest levels of FSH may suggest a lower effectiveness of the Belzer solution for preservation of ovarian function.…”