Recently, increased public attention has been paid to the geographical authentication of food, including vegetables, which are considered to be one of the major health-promoting components in a ...balanced diet. The purpose of the present study was to investigate the suitability of the use of isotopic compositions of light elements (δ13C, δ15N, δ18O, δ34S) in combination with multi-elemental fingerprinting (P, S, Cl, K, Ca, Mn, Fe, Zn, Br, Rb, Sr) to provide rapid, robust and inexpensive screening methods for distinguishing lettuce, sweet pepper, and tomato samples according to their given country of origin (i.e., Slovenia, Austria, Spain, Morocco, Italy, Greece), and thus ensuring their traceability in terms of their authenticity. The classification efficiency of the proposed multivariate statistical models using supervised pattern-recognition analysis, namely multivariate discriminant analysis, was sufficient for rapid and robust screening purpose. The predictions of the suggested discriminant analysis models per kind using cross-validation leave-one-out were 86.2%, 71.1% and 74.4% for lettuce, sweet pepper and tomato, respectively. The first use of the proposed methodology on vegetable samples on European and Mediterranean scales provides a valuable and necessary contribution to the development and implementation of a new national surveillance system that can be used to trace the geographical origins of vegetables.
•Acceptable discrimination of vegetable products according to the country of origin was achieved.•Combination of stable isotope and elemental composition was used.•The classification efficiency of the proposed multivariate statistical models was 71–86%.•Methodology could be used for establishment of databanks and creation of traceability models.•Methodology could be used for rapid food screening purposes.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The influence of different storage conditions on the storability of packaged shredded cabbage has been studied. The cabbage cultivar Fieldrocket was cut and packaged in glass jars and in polyethylene ...(PE) or polypropylene (PP) film. Several initial atmospheres were established within the packaged cut cabbage: 100% N.sub.2, 5% O.sub.2/95% N.sub.2, 10% O.sub.2/90% NZ, normal atmosphere (NA), 70% O.sub.2/30% N.sub.2 and 100% O.sub.2. Samples were stored at two different temperatures of 0 and 10 °C for 7 days. Variation in CO.sub.2 and O.sub.2 concentrations was higher at 10 °C compared to 0 °C and the highest at the atmosphere consisting of 70 % O.sub.2/30% N.sub.2. A decrease of O.sub.2 below 3-5% and an increase of CO.sub.2 above 2-5% in the packed product resulted in the appearance of anaerobic metabolism. An initial atmosphere consisting of 100% O.sub.2, and a storage temperature of 0 °C resulted in delayed anaerobic metabolism compared to other atmospheric conditions and storage temperature of 10 °C. Rinsing of fresh cut cabbage also resulted in lower accumulation of acetaldehyde and ethanol. A higher variation in CO.sub.2 and O.sub.2 concentrations, and consequent accumulation of anaerobic metabolites had a negative influence on the sensorial properties of the cut cabbage. The higher permeability of PE film compared to PP and glass enabled faster exchange of CO.sub.2 and O.sub.2, which resulted in lower accumulation of anaerobic metabolites. However, a higher O.sub.2 concentration had a negative influence on the colour of fresh-cut cabbage. The best results were achieved by packing the fresh-cut cabbage in PE film with an initial atmosphere of 100% O.sub.2 and stored at 0 °C. Key words: cabbage, modified atmosphere, packaging, polyethylene, polypropylene, respiration, anaerobic metabolism
•SI can help to determine the right maturity stage of Conference and Alexander Lucas pears destined for 1-MCP application.•Harvest fruits at more mature stage cancel the 1-MCP inhibitory effect on ...the Conference and Alexander Lucas pear ripening.•ULO decreases the production of aromatic compounds less severely than 1-MCP.•Maturity stage at harvest has no clear effect in Conference and Alexander Lucas pears under ULO.•CA storage has no effect on the ripening in terms of aroma compounds production as compared to CS.
The objective of this investigation was to evaluate the quality parameters and aroma profiles of Conference and Alexander Lucas pears after 7 months of storage. Fruits of both cultivars were harvested at two different maturity stages and stored under cold (CS) (20.9 kPa O2 + <0.04 kPa CO2), controlled atmosphere (CA) (2 kPa O2 + <0.7 kPa CO2) and ultra-low oxygen condition (ULO) (0.7 kPa O2 + <0.7 kPa CO2). CS and CA storage also included treatment with 1-methylcyclopropene (1-MCP) at 300 nL L−1. After seven months of storage at 0 ± 0.1 °C and 94 ± 2% RH plus seven days at 20 ± 2 °C and 60 ± 5% RH, fruits were evaluated for flesh firmness, peel color ('hue' angle = h°), soluble solids content (SSC), titratable acidity (TA), respiratory rate, ethylene production rate, and production of aromatic compounds. Fruits of both cultivars from the first maturity stage treated with 1-MCP did not develop a buttery texture or yellow color and produced significantly less alcohols and esters. A combination treatment (1-MCP + CA) most severely suppressed aroma development, particularly in the Conference cultivar. ULO storage also reduced yellowing, ethylene production and the development of aromatic compounds in both cultivars from the first maturity stage, but this reduction was less pronounced than that observed for 1-MCP treatments. The production of aromatic compounds was lower in fruits from ULO, regardless of their maturity stage. Fruits from the second harvest treated with 1-MCP had significantly more aromatic compounds than did those from the first harvest. In general, the CA condition has no effect on the ripening and production of aromatic compounds in both cultivars compared to CS.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
In recent years, the geographical authentication of different agro-products, including vegetables, has gained an increasing amount of attention. This study investigated different approaches, both ...independently and in combination, to assign the country of origin to commercial tomato samples from Slovenia, Italy, Spain and Morocco. To create a model for their traceability, three sets of parameters were used: stable isotopes of the major bioelements (δ13C, δ15N, δ18O, δ34S), macro and micro elements (P, K, Ca, S, Cl, Zn, Br, Rb, Sr), and chemical markers (total antioxidant potential, total phenolic compounds, ascorbic acid, lutein, nitrates and nitrites, ammonium). The data obtained were analysed using the supervised pattern-recognition technique of multivariate discriminant analysis. The statistical analysis based on leave-one-out cross-validation revealed that the best overall success rate was achieved when using either the combination of all three sets of parameters, or only the elemental content data. In both cases, correct classification was obtained for 80% of the samples. Moreover, the present study highlights the first characterisation and classification of commercial tomato samples using the combination of the methodologies proposed.
•Different approaches to assign the country of origin to commercial tomato samples.•Three sets of parameters were used: stable isotopes, elements, and chemical markers.•The first use of the combination of proposed parameters.•The elemental data provides the same predictive power as the combined data from all three approaches.•In both cases, correct classification was obtained for 80% of samples.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Fatty acid composition of different cultivars of blackcurrant (Ribes nigrum L.), redcurrant (Ribes rubrum L.), gooseberry (Ribes uva-crispa L.) and jostaberry (Ribes nidrigolaria Bauer) was studied. ...These seeds contained from 17.8% to 22.4% of oil. The major fatty acid (FA) determined in these Ribes species was linoleic acid and significant differences were determined between the seeds of these Ribes species for all fatty acids analysed, except for stearic acid. Jostaberries had the lowest n-6/n-3 ratio, Index of Atherogenicity, Index of Thrombogenicity and the highest α-linolenic and stearidonic acid contents. Blackcurrants had the highest γ-linolenic acid content, followed by gooseberries. With their favourable FA composition, seeds of these Ribes species represent an interesting new source of essential FA that can be used as a supplement in everyday nutrition.
•Seed oil content and fatty acids were analysed across Ribes species and cultivars.•Seeds showed similar oil contents across species, but varied fatty acid compositions.•The main fatty acids in these seeds were linoleic, α-linolenic and γ-linolenic.•γ-Linolenic acid prevails in blackcurrant, stearidonic acid prevails in jostaberry.•Good nutritional quality of these Ribes seeds supports their use as food supplements.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Namen raziskave je bil preučiti in s prehranskega vidika ovrednotiti maščobnokislinsko sestavo 12 kultivarjev zelja (Brassica oleraceae L.). Vzorce smo homogenizirali in jim z liofilizacijo ...odstranili vodo. Maščobnokislinsko sestavo smo določili z izolacijo metilnih estrov in z analizo na plinskem kromatografu. Iz rezultatov je razvidno, da zelje vsebuje malo nasičenih maščobnih kislin. Analiza nenasičenih maščobnih kislin kaže na to, da zelje v povprečju vsebuje 18,8 mg/100 g SS ?-linolenske, 17,1 mg/100 g SS linolne in 14,8 mg/100 g SS oleinske kisline. Zeljne glave vsebujejo v največji meri ravno obe najpomembnejši esencialni maščobni kislini (n-6 in n-3), kar zelju daje visoko prehransko vrednost. Vsebnost posameznih nenasičenih maščobnih kislin se med kultivarji zelja značilno razlikuje. Največji delež ?-linolenske kisline ima cv. 'Maestro' (29,9 mg/100 g SS), linolna kislina je najbolj zastopana v cv. 'Holandsko pozno zelje' (30,6 mg/100 g SS) in oleinska v cv. 'Galaxy' (29,9 mg/100 g SS) in cv. 'Vestri' (26,1 mg/100 g SS).
The intake of foods containing trans fatty acids (TFAs) can have deleterious effects on human health, mainly on the cardiovascular system. Thus, it is important to consider the processes that form ...TFAs in foods, and the alternatives to minimise their formation. The influence of two added natural antioxidants on TFA formation during heat treatment (120 h at 180°C) of sunflower vegetable oil were examined: rosemary extract (Rosmarinus officinalis L.) (1 g per kg oil) and lutein (0.1 g per kg oil). Changes in FA composition were determined using Ag-ion SPE and gas-liquid chromatography, with total polar compounds determined using dielectric constant measurements and the index of atherogenicity was calculated. Total TFAs with ≥1 trans double bond increased from 0.91 to 1.71% in control samples; this increase was significantly less with both rosemary extract (1.55%) and lutein (1.43%) additions. Among the individual TFAs, significant increases were seen for C18:1,t-9, C18:2,t-9,t-12 and C18:2,c-9,t-12/9-t,12-c. Polar compounds also increased, with the highest concentrations in control samples, and significantly less with both rosemary extract and lutein additions. According to results of our study, we can summarize that addition of lutein have greater effect on reduction of TFA formation than rosemary extract. Practical applications: Antioxidants, particularly from plants, are widely used in the food industry. They can provide benefits in food preparation, including improving colour, odour and stability, acting as acid regulators and natural preservatives. They have also become accepted by customers and consumers, and so indirectly they have had effects on consumer perception. Addition of natural antioxidants such as rosemary extract is usually limited by the sensory characteristics of the food, with one study showing that addition of rosemary extract at 1-3 g per kg vegetable oil is recommended. The effects of antioxidants on the formation of TFAs in vegetable oils has not been well studied in the literature. Among the already known benefits, the use of such antioxidants as functional ingredients in lipid technologies might reduce the formation of TFAs during thermal treatment.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Organic crop production has become a highly attractive way of production over the world and thus the need for robust analytical techniques for their authentication. The main aim of this study is to ...identify appropriate biomarkers to discriminate between organic and conventionally grown chicory. Chicory is an appreciated leafy vegetable among producers and consumers, especially due to its undemanding cultivation and content of bioactive substances. Six different fertility management practices (control, two organic, two mineral, and a combination of organic and mineral fertilizers) were used to produce five chicory cultivars in a glasshouse pot experiment. Analysis of bioactive compounds, nitrogen assimilation, multi-elemental profiling and stable isotope ratio determination of carbon (C), nitrogen (N) and sulphur (S) were performed to differentiate between organic and conventional production. In this study, nitrogen isotopes are found to be an excellent way of identifying organically produced chicory of a different variety with the highest δ15N values. Conversely, the same samples had the lowest δ34S values indicating that also stable isotopes of S could be used as a marker for the authentication of organic production.
•Five chicory cultivars were grown in a pot experiment.•Six different fertility management practices were applied.•Differences in bioactive compounds content and nitrogen assimilation were evaluated.•Multi-elemental profiling and stable isotope ratios of light elements were studied.•Parameters to discriminate organic and conventionally grown chicory were identified.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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