Nitrogen Metabolism Components as a Tool To Discriminate between Organic and Conventional Citrus Fruits

Abstract

The aim of this work was to develop a method for authenticity control of organically grown orange fruits. Due to the different kinds of nitrogen fertilization of the soil in organically and conventionally managed farms, the study tried to verify the possibility to differentiate Navelina and Tarocco orange fruits obtained by these production systems through the detection of markers linked to nitrogen metabolism. In addition to the classic quality parameters, total nitrogen (N) and synephrine contents in juice and (15)N/(14)N isotope ratio (expressed as delta(15)N per thousand) in proteins of pulp and amino acids of juice were determined. The results obtained indicated that total N and synephrine contents were significantly higher in conventional fruits, whereas the delta(15)N per thousand values were higher in the organic ones. The new markers identified in this research by linear discriminant analysis of the data may constitute a useful tool to differentiate organic citrus fruits or juices from conventional ones.

Multivariate Analysis of Tronchuda Cabbage (Brassica oleracea L. var. costata DC) Phenolics: Influence of Fertilizers

“…It has been shown that nitrogen can become a growth-limiting nutrient in organic production, affecting negatively yield (12). This problem is overcome by conventional farmers, who obtain roughly the same nutrient supply across a variety of soil types and farming systems, because fertilization is adjusted to the level that gives the highest yield.…”

Applying Determined Ratios of Stable Isotopes Ratios in Selected Elements to Evaluate Authenticity of Organically Grown Products

“…Produkcja żywności ekologicznej wyklucza moż-liwość stosowania pestycydów i nawozów mineralnych, a dopuszcza stosowanie nawozów organicznych [20]. Poszukuje się więc bardziej nowoczesnych metod umożliwiających sprawdzanie autentyczności produktów żywnościowych deklarowanych jako ekologiczne.…”

“…Skupili się oni na oznaczeniu wartości δ We Włoszech podjęto badania mające na celu charakterystykę składu izotopowego azotu owoców z produkcji organicznych [7,20]. Prace te dotyczyły pomarańczy [7,20] oraz truskawek, mandarynek i brzoskwiń [7]. Wartości δ 15 N oznaczono w białku z miąższu owoców i w aminokwasach w soku [20].…”

“…Prace te dotyczyły pomarańczy [7,20] oraz truskawek, mandarynek i brzoskwiń [7]. Wartości δ 15 N oznaczono w białku z miąższu owoców i w aminokwasach w soku [20]. Prace prowadzono przez 3 lata.…”

Influence of N doses and form on 15N natural abundance of pepper plants: considerations for using δ15N values as indicator of N source

“…1,2 In particular, several studies have used δ 15 N values as a potential tool to detect fraudulent applications of synthetic nitrogen fertilizers to organic crops. 3,4 This is in part due to the expectations of this agricultural management with regard to health and environment. On a global level, the organic land area increased in 2008 by almost 1.8 million hectares compared to 2005.…”