Peaches are one of the most preferred seasonal fruits, and a reliable source of nutrients. They possess biologically active substances that largely differ among varieties. Hence, revealing the potential of several late season peaches is of present interest. Three commonly consumed varieties (“Flat Queen”; “Evmolpiya”; “Morsiani 90”) were studied in terms of nutritive and phytochemical content, as well as antioxidant activity with the use of reliable spectrophotometric and High Performance Liquid Chromatographic (HPLC) methods. An analysis of the soil was also made. The phytochemical data were subjected to principal component analysis in order to evaluate their relationship. The “Morsiani 90” variety had the highest minerals concentration (2349.03 mg/kg fw), total carbohydrates (16.21 g/100 g fw), and α-tocopherol (395.75 µg/100 g fresh weight (fw)). Similar amounts of TDF (approx. 3 g/100 g fw) were reported for all three varieties. “Flat Queen’s” peel extract was the richest in monomeric anthocyanins (2279.33 µg cyanidin-3-glucoside (C3GE)/100 g fw). The “Morsiani 90” variety extracts had the highest antioxidant potential, defined by 2,2-diphenil-1-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP) and cupric ion-reducing antioxidant capacity (CUPRAC) assays.

No abstract

The objective of this study was to investigate the impact of foliar zinc application in the form of zinc hydroxy nitrate suspensions on maize grain yield and quality and on zinc distribution in the plant organs. The preparation of the zinc hydroxide nitrate (Zn5(OH)8(NO3)2·2H2O) was performed by pouring a NaOH solution into Zn(NO3)2·6H2O under vigorous stirring. All samples were characterized in detail by X-ray diffraction, scanning electron microscopy, thermal analysis, and inductively coupled plasma (ICP) mass spectrometry to determine their content, morphology and physicochemical properties. The field experiment was conducted at the Research Farm, Agricultural University, Bulgaria, via a randomized block design with eight variants in 3 replications. A significant (p < 0.05) effect on Zn accumulation in the maize stems and leaves by foliar zinc application during the first growth stage was found. The accumulation of zinc was followed by its remobilization from the stems to other plant organs during the second growth stage. It was concluded that the synthesized zinc hydroxy nitrate has potential as a long-term foliar fertilizer. Ensuring the optimal concentration of Zn at different times during the vegetative period lead to a substantial increase in the grain yield along with an improvement in the quality of the corn grain for all variants compared to those of the control.

The solid state interactions of CaO and MgO with synthetic and industrial ZnFe,O^ (in zinc cake) have been studied using chemical, XRD analysis and Mossbauer spectroscopy. The exchange reactions in the systems ZnFe,O^ -CaO and ZnFe,0 -MgO have been investigated in the range of 850-1200 "C and duration up to 180 min. It has been established that Ca-* and Mg" ions exchange Zn-* in ferrite partially and the solubility of zinc in a 7% sulfuric acid solution increases. The possibilities for utilization of the obtained results in zinc hydrometallurgy have been discussed.

Bulgaria is a major producer of zinc in the Balkans (about 100,000 tons per year). The two zinc plants (KCM S.A., Plovdiv, and LZC S.A., Kardzhali) deliver the necessary raw materials from Bulgaria and abroad. But the zinc production at LZC Kardzhali for nearly a year has stopped. Turkey is a main producer of zinc sulfide concentrates from the Balkan countries. In this connection, an analysis of the delivered Turkish sulfide zinc concentrates is made through statistical processing of data about their chemical content. For the aim of processing them according to the classic hydrometallurgical scheme, studies are carried out using X-ray phase analysis as well as DTA and TGA. Providing optimal charge for roasting in fluid bed furnace (FBF) can be successfully done by using the WEBbased information system we have written, which calculates mixtures of different raw materials. The program system developed is illustrated by calculations of charges of 5 zinc concentrates from Turkey. The accomplishment of optimal mixing of concentrates and providing a stable mix composition for a long period of time is a task of primary importance in the technological process control in zinc hydrometallurgy.