Rodica Sima

Effects of Extraction Solvents on the Quantification of Free Amino Acids in Lyophilised Brewer’s Yeast

The aim of this work was to test some solvents in order to improve the free amino acids extraction from lyophilised brewer’s yeast. The brewer’ yeast was treated with four types of extraction solvents: Solvent I – acetonitrile 25%/HCl 0.01M (ACN); Solvent II – ethanol 80%; solvent III – HCl 0.05M/deionized water (1/1 volume); Solvent IV – HCl 0.05M/ethanol 80% (1/1 volume). The supernatants were analysed by HPLC-DADESI-MS method. Acetonitrile provided the less quantities and number of amino acids extracted due to its weaker polarity. Solvent II and IV (ethanol, respectively acidified ethanol), which have an increased polarity, extracted 15 amino acids due to the addition of HCl in solvent IV. Solvent III (acidified water) proved to be the best extraction solvent for the amino acids from brewer’s yeast providing the separation of 17 compounds: GLN, ASN, SER, GLY, ALA, ORN, PRO, HIS, LYS, GLU, TRP, LEU, PHE, ILE, AAA, HPHE, TYR.

The Test of some Annual and Perennial Fodder Cultures for Fresh Matter Production in Ecological Conditions of Cojocna

The rhythmic supply with quantitative and qualitative fresh matter forage during the summer represents for bovine breeders one of the most important problem that they confronted with. In order to give Transylvanian farmers some solutions for this problem, in the frame of Cojocna Didactic Station, in the spring of 2010 year, were settle down experiments with perennial fodder plants, sown in the last decade of March (alfalfa pure culture as control – M1 and eight mixtures of poaceous and fabaceous, from M2 to M9) and with annual fodder plants, sown in the last decade of April (oat and pea as control; triticale and pea; rape; millet; sorghum x sudangrass hybrid). By choosing of a varied assortment of species, as ecological requirements, it was tried to establish some structures of cultures which have to respond both to the actual climatic changes (Lorgeou et al., 2007; Pervanchon, 2007) and to the principles of sustainable agriculture concept.

Determination of apparent density and water absorbtion capacity of different cellulosic substrates used in Pleurotus mushrooms culture.

Pleurotus mushrooms are one of the most important cultivated mushrooms, after species of Agaricus and Lentinus. The increasing interest, for oyster mushrooms is due to their nutritional and medicinal value. The technology of culture is relatively simple and a lot of cellulosyc materials can be used as substrate. In plus, high benefits can be obtained with relatively low investments. Experiences have been organized in a greenhouse from Vegetable Growing Department, Horticultural Faculty, University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Biological material has been represented by Pleurotus hybrid HK35. One of the first phases in mushroom Pleurotus technological process is wetting materials. The purpose of this operation is to ensure optimum moisture for fungus development (68-75%). If the water content is too high this will lead to anaerobic conditions, unfavorable to spawn. Anaerobic conditions favors the development of harmful microorganisms that produce toxic metabolites. Their presence is signaled by the appearance of a very unpleasant smell. A low content of water prevents the mycellium growth (Oei, 1996; Tudor, 2001).

Ccontribution to Perfecting Technology of Early Savoy Cabbage Culture in Polyethylene Tunnels

In Europe, the major ways to obtain earlier yields are: plastic tunnels, low plastic tunnels, or directly temporally protection using different crops covers. In this way plants have better condition to grow and the yields are earlier. Pedoclimatic condition of our region (Transylvania, Romania) are less favorable for obtaining high and early yields than other region from Romania as South, or West parts. Do of this reason, vegetables farmers from Transylvania, are obliged to find technological arrangements that allowed them to obtain earlier and safety crops. Savoy cabbage in Romania is cultivated only in open field on the small surfaces around the towns of Transylvania region (Indrea et al., 2009). Savoy cabbage has a very big content in vitamins and mineral salts, and it is an excellent source of vitamin C. The cellulosic content of savoy cabbage is lower comparing with white cabbage or red cabbage (Ciofu et al., 2003).