The purpose of this study was to investigate the antioxidant capacity of different tea plant: mint, linden, chamomile, St. John’s wort, green and black tea in relation to total phenolic content. The antioxidant capacity of the tea infusions at different brewing times was determined using DPPH assay while the total phenolic content (TPC) was assessed using the modified Folin-Ciocalteu method. The results showed that there were significant statistical differences in antioxidant capacity depending on infusion time, according to one-way ANOVA analysis. Leaves used as components of tea infusions were analyzed by FAAS for their content of iron and copper in the dry product and in the infusion. The correlation between TPC and DPPH capacity of tea plant infusions was evaluated by Pearson correlation matrix. Total phenolics compounds content was positively and significantly correlated with DPPH capacity for all infusions time. Significant correlation was observed between TPC and the copper concentration (p < 0.05). Consequently, the correlations between the physicochemical parameters, TPC, DPPH capacity, Fe and Cu content suggested that the TPC may be a good indicator of the DPPH capacity in the tea infusions and also, suggested the influence of antioxidant compounds on mineral bioavailability.

The purpose of this paper was to evaluate the quality of bee honey from different sources: beekeeper, local market and organic honey. Sensory analysis was performed and the water content, pH, acidity, protein content and total metal content (Cu, Cr, Mn, Co, Ni, Pb, Cd, Fe) were determined. The sensory analysis was carried out by a group of untrained panelists for quality assessment of honey. The metal content was determined by graphite atomic absorption spectrometry (GTAAS). Mineralization was carried out in a microwave digestion system, in a high-pressure polytetrafluoroethylene (PTFE) vessel, using a standard acid-digestion protocol. The results regarding the physico-chemical parameters showed that the honey samples were in accordance with the quality regulations for honey as a commercial product. The concentration of metals in the investigated honey samples varied in the order Cu > Cr > Pb > Fe > Ni > Mn > Co > Cd, the values being within the limits established by the EU Commission (No. 1881/2006). The variations observed in the evaluated parameters can be caused by the difference in plant species from which the honey comes, the harvesting period and the level of environmental pollutants. The Pearson correlations between the physico-chemical parameters and the metals indicate that water content (w_c) is strongly negatively correlated with Cd and Ni, while pH is strongly positively correlated with Mn and Fe. Moreover, EC is strongly negatively correlated with Ni and Fe, and the Brix degrees are strongly positively correlated with Cd and Ni. Statistically significant positive correlation was found between Brix–Cd, Ni–Cd and Cu–Cr and a statistically significant negative correlation was detected between w_c and Cd.

Groundwater pollution is a very common problem worldwide, as it poses a serious threat to both the environment and the economic and social development and consequently generates several types of costs. The analysis of pollution control involves a permanent comparison between pollution costs and the costs associated with various methods of pollution reduction. An environmental policy based on economic instruments is more effective than an environmental policy focused on command and control tools. In this respect, the present paper provides a case study showing how anthropogenic factors such as wastewater, industrial, agricultural, and natural factors are able to change the physical and chemical parameters of groundwater in the study area, thus endangering their quality. In order to monitor the groundwater quality in the region of Dobrudja, an analysis of physico-chemical parameters was performed. The content of heavy metals was analyzed and the health risk index was taken into account and analyzed, in order to set a better correctness of the metal content from the underground waters. Studies on groundwater quality control have shown that, in many parts of the world, water has different degrees of quality depending on the natural and anthropogenic factors acting on the pertaining environment. This is why more attention should be paid to the prevention of groundwater pollution and the immediate remediation of accidents.

Vitamin C or ascorbic acid is a basic nutrient, a highly effective antioxidant, widely used as food additive. Therefore, quality control in food industry demands ascorbic acid determination methods. The purpose of this study was to determine vitamin C in natural orange juices by spectrometric and voltammetric methods. Another goal was to determine the kinetic and thermodynamics activation parameters for ascorbic acid degradation in orange juices over time and at different temperatures. It was observed that during storage, ascorbic acid concentrations in orange juices were gradually decreased with time at a rate depending on storage temperature and type of orange juice. The reaction order was determined through integrated graphical analysis where the dependences of ln c_t/c₀ as a function of time reveals the high values for R², indicating that the kinetics of the degradation of AA follows first order reaction at both studied temperatures. For studied samples the loss of ascorbic acid was varied between 4.33% and 9.13%. Enthalpy variation (ΔH) and entropy variation (ΔS) of activation process were obtained from the Eyring–Polany model based on transition state theory. The values of activation energy ranged between 7289.24 kJmol⁻¹ and 15689.54 kJmol⁻¹.