ABSTRACT
The leakage of sewage and agricultural drains has led to the contamination of freshwater branches with toxic heavy elements. This raises concerns about their toxic effects on aquatic ecosystems, especially on fish. Tilapia is regarded as an important protein source in Egypt and many other countries. The biophysical, nutritional, and histological aspects of water pollution in the El-Rahawy and Al-Qatta locations of the Nile on Nilotic tilapia muscle were evaluated by assessing the level of contamination of Nilotic tilapia fish. The current study showed that water of the Rosetta branch water was polluted with a very high level at El-Rahawy Drain discharge (RD) location, and with a high level at Al-Qatta (Q) location, while El-Rahawy (R) location was polluted with a lower level. The study traced the pollution effects on Tilapia (Nilotic) muscles in the previous locations. Bioaccumulation factor (BAF) showed a high value of all heavy metals in Tilapia muscle at the Q and R locations. Contrary to what was expected, discharge (RD) location contamination caused BAF increment of heavy metals in Tilapia muscles at upstream R location. All these results were compared with measured dielectric parameters of Tilapia muscle samples in the frequency range (0.02-1000) kHz. There was an increase in conductivity (σac), dielectric constant (ε'), dielectric loss (εâ³), penetration depth (dp), and dissipated power (PD) values of Tilapia muscle, with increasing pollution level. The values of permittivity at low and high frequencies (ε's & ε'∞) for Tilapia muscle decreased by increasing pollution. Finally, the variation of these parameters, based on that proportionality relationship, can be considered as a physical indicator for fish contamination affected by their environment pollution, although these parameters need further studies in a controlled (qualitatively and quantitatively) polluted media.
ABSTRACT
Artificial sweeteners have become increasingly popular worldwide owing to their lower calorie content in addition to the claims of health benefits such as weight control, blood glucose level regulation in diabetics, and protection against dental caries. Nevertheless, there is still controversy regarding their safety, especially when administered over the long term, taking into account that most of the safety studies are based on animal models and only a few human studies. This review focuses on low-calorie protein/peptide sweeteners. These include artificial sweeteners, i.e. aspartame, advantame, neotame, and alitame which are synthetic, versus those of natural origin such as thaumatin, monellin, brazzein, pentadin, mabinlin, curculin, and egg white lysozyme. We conducted a systematic literature survey to ensure the accuracy of the data regarding the chemical properties, synthesis, and industrial applications. The health benefits and safety of these sweeteners in humans are presented for the first time in context to their metabolic profiles and gut interaction.