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. 51 44 48 Fleming, H. P. & Mcfeeters (1981): Use of microbial cultures: vegetable products. Fd. Technol. , 35 , 88

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Pigments, such as carotenes, xanthophylls and chlorophylls, were extracted from both vegetables and their industrial products by using a 2:1 (v/v) dichloromethane/methanol solution. To separate and quantify the components in the extraction mixture, a HPLC analysis on reversed phase C30 column and binary gradient, made of methanol/water solution and dichloromethane, was employed. This gradient appears to have some advantages over other reported methods, which utilize reversed phase C30 column, in terms of resolution and analysis time. The linearity range of the detection response, the chromatographic resolution of a standard mixture constituted of lutein, zeaxanthin, trans-ß-apo-8?-carotenal, ß-cryptoxanthin, chlorophyll-b, ?-carotene, chlorophyll-a, ?-carotene, lycopene and the conditions for the complete extraction of those substances from the vegetable matrix were investigated. Both retention time and peak area reproducibility showed an average variation coefficient of about 2% for all the analyzed compounds. As a consequence of the good chromatographic separation of chlorophylls from carotenoids, sample saponification was found unnecessary when analyzing green vegetable products. Finally, to illustrate the applicability of the method, the presence of carotenoid esters in tomato and orange products was examined.

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A capillary isotachophoretic (cITP) method to determine the concentration of nitrates and nitrites in vegetables and lactic acid fermented tomato, cucumber and cucumber-onion juices is described. Method characteristics (selectivity, response function, linearity, precision, accuracy and limit of quantification) were determined. The minimal sample pretreatment and relatively low running make isotachophoresis a good alternative to existing methods.

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Összefoglalás

A tápanyag-gazdálkodás továbbfejlesztéséhez szükséges a növények tápláltsági állapotát jól jellemző, valamint a várható terméssel minél megbízhatóbb kapcsolatot mutató tápelem-koncentrációk megállapítása. Ismert, hogy a kálium számos életfolyamat nélkülözhetetlen eleme a növény életében.

Dolgozatunk célja, hogy összefüggést keressünk a kijuttatott kezelések és a növény tápláltsági állapota között.

Tenyészedényes kísérletünket 2006 tavaszán üvegházi körülmények között állítottuk be agyagbemosódásos barna erdőtalajon. Tesztnövénynek a tavaszi árpa (Hordeum vulgare L.) Scarlett fajtáját választottuk. A trágyázatlan kontrollon kívül nyolc NPK kezelést alkalmaztunk két NP szinten növekvő K-adagokkal. Különböző fejlettségi stádiumokban, fő növényi részenként folytattunk vizsgálatokat.

A legmagasabb K-koncentráció a bokrosodáskori növényekben mutatható ki, az általunk kijuttatott kezelések hatására mért legmagasabb K-koncentráció 6,6% volt, melyet az N2P2K3 kezelésnél kaptunk. A virágzó kalász K-tartalma a trágyázástól függetlenül közel azonosnak bizonyult, 0,81–0,90% közé esik. A K0 kezelések kivételével az általunk mért K-koncentrációk a kielégítő, ill. magas kategóriába esnek. Az összefüggés-vizsgálatok eredményei igazolják, hogy szoros kapcsolat van a növény K-tartalma és száraztömeg gyarapodása között. A különböző adagú és arányú kezelések erősen befolyásolják, hogy az egyes növényi részek különböző fejlettségi stádiumokban mekkora mennyiségben és milyen eloszlásban tartalmazzák a felvett K-ot, hogyan alakul száraztömegük, víztartalmuk.

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): Fermented vegetable products.-in: Microbiology of food fermentation . AVI Publ. Co., Westport, CT, pp. 108–152. Pederson C.S. Microbiology of food

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and quality control for fruit and vegetable products. 2 nd ed. Tata McGraw Hill , New Delhi, India . p. 597 . S inija , V.R. & M ishra , H.N. ( 2011 ): Fuzzy analysis of sensory data for

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There is a clear need for application of proper methods for measuring food quality and safety in the globalized food-webs. Numerous instrumental methods have been established in the course of the 20th century and are developing further, together with data analysis techniques, for such purposes. Among them, near-infrared and fluorescence spectroscopic methods and chemical sensor arrays called electronic noses show particular promise for rapid, non-destructive, non-invasive and cost-effective ways for assessing changes and enhancing control during processing and storage of foods. Their key advantages as analytical tools are 1) their relatively high speed of analysis, 2) the lack of a need to carry out complex sample preparation or processing, 3) their relatively low cost, and 4) their suitability for on-line monitoring or quality control. The present survey attempts to demonstrate examples from the above areas, limiting itself mainly to monitoring some quality indices which contribute to the functionality or acceptability of foods as affected by alternative processing technologies, or loss of freshness/microbial safety, or developing spoilage during storage and marketing. These instrumental methods are correlative techniques: they must be calibrated first against (traditional) reference properties, and the instrumental data are evaluated with the help of chemometric methods. Near-infrared (NIR) spectroscopy can be used in either the reflectance or the transmittance mode. NIR spectra transformed to mathematical derivatives allows subtle spectrum changes to be resolved. Selected examples from the extensive NIRS literature relate to assessment of the quality of frozen fish, predicting cooking loss of chicken patties, detecting complex physico-chemical changes of minced meat as a function of the intensity of high hydrostatic pressure treatment, comparing changes of NIR spectrometric “fingerprints” caused by gamma radiation or high pressure pasteurization of liquid egg white. Changes of NIR spectra reflect several parameters which suit the evaluation of loss of freshness, and onset of spoilage of various foods. NIR spectroscopy shows an application potential for rapid detection of bacterial or mould contamination. It may serve as a tool for detecting initial stages of mobilization processes during germination of cereal grains, or even for GMO screening. Spectrofluorometic measurements have shown potential, e.g. to monitor lipid oxidation and development of meat rancidity, to differentiate between raw and processed milks, and to monitor fish and egg freshness. Electronic noses containing chemical sensor arrays offer a rapid method for evaluation of head-space volatiles of food samples, important for characterizing quality and safety. Such gas sensors may be able to classify storage time, and determine spoilage, either earlier or at the same time as the human senses, or “sniffing out” bacterial pathogens or (toxigenic) fungal growth on certain foods. Electronic nose sensing is also a promising method for detecting quality changes of fruit- and vegetable products non-destructively. In relation to some examples to be presented in the paper, certain software developments as qualitative classification tools made by Hungarian scientists will be pointed out.

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373 Ranganna, S. (1997): Handbook of analysis and quality control for fruit and vegetable products . Tata McGraw Hill Publishers, New Delhi, India, 1112 pages

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Anon. (1972): Fruits and vegetables products. TSE 1129. The standard of total dry matter. Turkish Standards Institute Publications, Ankara. Fruits and vegetables products

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. Food Sci., 58 , 204 – 205 . Ranganna , S. ( 1986 ): Handbook of analysis and quality control for fruit and vegetable products . Tata

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