Stable isotope ratios of H, C, N and O in Italian citrus juices

Abstract

Stable isotope ratios (SIRs) of C, N, H and O have been exensively used in fruit juices quality control (ENV and AOAC methods) to detect added sugar and the watering down of concentrated juice, practices prohibited by European legislation (EU Directive 2012/12). The European Fruit Juice Association (AIJN) set some reference guidelines in order to allow the judging of the genuiness of a juice. Moreover, various studies have been carried out to determine the natural variability of SIRs in fruit juices, but none of these has investigated SIRs extensively in authentic citrus juices from Italy. In this work, about 500 citrus juice samples were officially collected in Italy by the Italian Ministry of Agricultural and Forestry Policies from 1998 onwards. (D/H)(I) and (D/H)(II) in ethanol and δ(13) C(ethanol), δ(13) C(pulp), δ(13) C(sugars), δ(18) O(vegetalwater), δ(15) N(pulp), and δ(18) O(pulp) were determined using Site-Specific Natural Isotope Fractionation-Nuclear Magnetic Resonance and Isotope Ratio Mass Spectrometry, respectively. The characteristic ranges of variability in SIRs in genuine Italian citrus juice samples are here presented as well as their relationships and compliance with the limits indicated by the AIJN and others proposed in the literature. In particular, the Italian range of values was found to be not completely in agreement with AIJN guidelines, with the risk that genuine juices could be judged as not genuine. Variety seems not to influence SIRs, whereas harvest year and region of origin have some influence on the different ratios, although their data distribution shows overlapping when principal component analysis is applied.

Stable isotope composition of cocoa beans of different geographical origin

“…As reported for other plant products, such as olive oil, or orange juice, in cocoa beans δ 2 H is correlated with δ 18 O (Fig. ).…”

“…More recently, 1 H NMR spectra of traded cocoa beans were used to characterise fermented cocoa beans on the basis of the variety and geographical origin. [15,16] H, C, N, O and S stable isotope ratios measured using Isotope Ratio Mass Spectrometry (IRMS) have been shown to be a reliable tool for establishing the authenticity of a wide variety of food products, such as wine, [17] olive [18] and sesame oils, [19] orange juice, [20] honey, [21] beef, [22] fish, [23,24] shrimps [25] and prawns, [26] ham, [27] milk, [28] rice, [29] lentils. [30] This is due to particular isotopic fractionation processes, which reflect both climatic phenomena (e.g.…”

“…H, C, N, O and S stable isotope ratios measured using Isotope Ratio Mass Spectrometry (IRMS) have been shown to be a reliable tool for establishing the authenticity of a wide variety of food products, such as wine, olive and sesame oils, orange juice, honey, beef, fish, shrimps and prawns, ham, milk, rice, lentils . This is due to particular isotopic fractionation processes, which reflect both climatic phenomena (e.g.…”

Volatile Organic Compounds Profiles to Determine Authenticity of Sweet Orange Juice Using Head Space Gas Chromatography Coupled with Multivariate Analysis

“…Volatile organic compounds (VOCs) in citrus juice are a class of secondary metabolites produced. It has been found that sweet orange juice and mandarin juice have different VOCs [25][26][27], and the difference between them can be used to identify whether orange juice contains excessive mandarin juice. Given this, we have collected a full range of varieties of citrus that can be used for juicing and prepared them into NFC citrus juice.…”

Exploratory Analysis of Sparkling Wines Based in the Combined Data of Stable Isotope Analysis with Physicochemical Variables and Volatile Profile

“…9 These isotopic ratio techniques have been widely applied to identification of geographical origin as well as to authentication/ traceability of sparkling and non-sparkling beverages such as ciders, [10][11][12] beer, 13 juice 14 and wine. 15,16 According to the Brazilian legislation 17 (decree No.…”