Worldwide stable carbon and nitrogen isotopes of Big Mac® patties: An example of a truly “glocal” food

The Big Mac®, McDonald’s® signature burger, is a global food served in over 100 countries. We measured carbon (δ¹³C) and nitrogen (δ¹⁵N) stable isotope ratios of Big Macs® from twenty-six countries. The δ¹³C values varied from −25.4‰ to −11.1‰, representing cattle-rearing systems based exclusively on C₃ plants, exclusively on C₄ plants, or both C₃ and C₄ plants. Median δ¹⁵N value was 6.6‰; the 25th and 75th percentile were 5.9‰ and 7.3‰, respectively. Calculated percentages of imported beef were consistent with the δ¹³C values of purchased Big Macs®. Japanese patties had higher δ¹³C values than expected based on that country’s C₃ agriculture, however Japan imports beef from Australia, where C₄ plants are prevalent. Lower latitude countries generally had higher δ¹³C values than higher latitude countries, reflecting the larger distribution of C₄ plants in warm regions. Although Big Macs® are a global food, we conclude they also contain local components.     

Verifying the geographical origin of beef: The application of multi-element isotope and trace element analysis

Beef samples originating from the major cattle producing regions of the world (Europe, USA, South America, Australia and New Zealand) have been analysed using IRMS and ICP-MS. C and N isotope composition of the beef defatted dry mass and H and O isotope composition of the corresponding lipid fractions were determined. It was observed that intensive maize and/or C₄ pasture feeding, during cattle production, gave rise to significant differences in the ¹³C content of beef produced in Brazil and the USA versus British beef fed predominantly on C₃ pasture and fodder. The mean δ²H‰ and δ¹⁸O‰ values of beef lipid correlated well with the latitude of production regions and the relationship between the H and O isotopic contents were found to parallel the Meteoric Water Line. These findings support the hypothesis that the systematic global variations in the ²H and ¹⁸O content of precipitation are transferred through drinking water and feed into beef lipid. Multi-element concentrations determined in the beef were combined with the stable isotope data and submitted to multivariate analysis. Six key variables (δ¹³C‰ (defatted dry mass), Sr, Fe, δ²H‰ (lipid), Rb and Se) were identified by canonical discriminant analysis as providing the maximum discrimination between beef samples on the basis of the broad geographical areas (Europe, South America and Australasia). It was concluded that the methodology in its current state can be used to provide reliable origin information, but this is dependent upon the countries under investigation.     

Geographical origin of polished rice based on multiple element and stable isotope analyses

We determined carbon and nitrogen contents (C and N contents) and stable carbon, nitrogen, and oxygen isotopic compositions (δ¹³C, δ¹⁵N, and δ¹⁸O) of polished rice in order to develop a simple method to discriminate its geographical origin. As a first attempt, we examined a single cultivar, Koshihikari rice, from 14 different cultivation areas including Australia (n = 1), Japan (n = 12), and USA (n = 1). For all rice samples, C and N contents and the isotopic compositions are consistent with those of general plant materials, being 37.2–40.0% (C content), 0.8–1.4% (N content), −27.1 to −25.4% (δ¹³C), +0.4 to +9.0% (δ¹⁵N), and +18.8 to +22.9% (δ¹⁸O). However, its cultivated area is clearly distinguished by a pentagonal radar plot based on the elemental and isotopic compositions. Thus, the comparison of C and N contents and δ¹³C, δ¹⁵N, and δ¹⁸O values would potentially be useful for rapid and routine discrimination of geographical origin of the polished rice.     

Isotopic composition of dissolved inorganic carbon in bottled waters on the Slovene market

This study investigates the stable isotopic composition of dissolved inorganic carbon (DIC), expressed as δ¹³C_DIC, in domestic and foreign bottled waters randomly collected on the Slovene market. All together 58 brands and 16 replicates were analysed. The δ¹³C_DIC values varied between −63.1‰ and +1.0‰ with an average of −12.3‰. Average δ¹³C_DIC values for naturally sparkling, artificially sparkling, still and flavoured waters were −3.3‰, −36.5‰, −10.0‰ and −11.0‰, respectively. The lowest values are characteristic of artificial sparkling waters (minimum −63.1‰) and can be attributed to injection of industrial CO₂ during bottled water production. Therefore, determination of the isotopic composition of DIC can represent a useful analytical tool to distinguish between natural and artificially sparkling waters. Furthermore, the method used enabled determination of the various origins of still waters. From the bottled waters sampled it was possible to discern waters that originate from deeper aquifers, from aquifers in equilibrium with soil CO₂, or from aquifers with their recharge in a mountainous area. Finally, δ¹³C_DIC values of flavoured waters illustrate that isotopic fractionation occurs during the production process and that δ¹³C_DIC values in products of some producers have a large variation.     

Tissue turnover in ovine muscles and lipids as recorded by multiple (H,C, O,S) stable isotope ratios

Multiple stable isotope ratios (δ²H, δ¹³C, δ¹⁸O and δ³⁴S) were measured in muscle, muscle lipids and lipid fractions collected from 28 lambs, subjected to a diet-switch and raised on two energy allowances (EAs), to determine tissue turnover and diet-tissue fractionation. The diet-muscle fractionations prior to the diet-switch were estimated to be −44.0‰, +1.9‰ and 0‰ for H, C and S, respectively, while the drinking water was demonstrated to be the main source of muscle O and thus δ¹⁸O variation. The diet-intra-muscular lipid fractionations prior to the diet-switch were estimated to be −172.7‰, −1.3‰ and −11.5‰ for H, C and O, respectively. The C half-lives of muscle were determined to be 75.7 and 91.6 days for animals receiving the high and low EA, respectively. Extracting temporally resolved pre-slaughter dietary information from meat by analysing bulk muscle, muscle lipids and muscle lipid fractions appeared to be not practicable due to possible incomplete turnover of lipids.     

Effects of ageing and low internal temperature of grilling on the formation of heterocyclic amines in beef Longissimus dorsi muscle

The mutagenic heterocyclic amines (HAs) originate in processed proteinaceous food. The effects of ageing (non-aged - i.e. 24 h post mortem vs. 14 and 28 days post mortem kept at 1 °C) and final internal temperature on cooking (T_i, 65 and 80 °C) on the content of HAs in grilled steaks (two-plated grill, temperature of 220 °C) were studied. HA precursors (creatine, creatinine, and free amino acids) and ageing indicators, such as instrumentally measured colour values, pH_ultimate values and length of myofibrilar fragments on raw and cutting values on grilled beef Longissimus dorsi muscles were determined. The muscles originated from eight commercially slaughtered Simmental bulls, 19-20 months old. The content of HAs was determined by a solid-phase extraction procedure. Meat ageing is accompanied by large changes in the chemical composition and structure of muscle tissues. In general, all the ageing indicators and precursors of HAs were influenced by ageing time at the 5% level or less. Creatine content declined significantly (non-aged: 6.00 mg g⁻¹, 14 days: 5.82 mg g⁻¹, and 28 days: 5.55 mg g⁻¹) and creatinine increased with days of ageing (non-aged: 0.19 mg g⁻¹, 14 days: 0.24 mg g⁻¹, and 28 days: 0.26 mg g⁻¹). Higher contents of total free amino acids were determined after 14 and 28 days of storage (28.18 μmol g⁻¹ and 37.59 μmol g⁻¹) than in non-aged beef (19.00 μmol g⁻¹). In this study, two HAs were determined: MeIQx (2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline) and PhIP (2—amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine). The content of HAs increases with ageing. At lower T_i, more MeIQx was formed; at higher T_i, more PhIP was formed. MeIQx was present in all samples while PhIP was found only in samples grilled to higher T_i. Samples treated to T_i = 80 °C generally contained less HAs (non-aged meat: 0.20 ng g⁻¹, 14 days: 0.26 ng g⁻¹, and 28 days: 0.28 ng g⁻¹) than samples treated to T_i = 65 °C (non-aged meat: 0.19 ng g⁻¹, 14 days: 0.36 ng g⁻¹, and 28 days: 0.39 ng g⁻¹) on account of MeIQx thermolability.     

Shellac and aloe-gel-based surface coatings for maintaining keeping quality of apple slices

Apple slices, ozonised in water (1:2 w/v; 200 mg O₃/h, for 5 min) and then soaked in a solution containing ascorbic acid (200 mg kg⁻¹), citric acid (200 mg kg⁻¹) and sodium benzoate (200 mg kg⁻¹) for 10 min, were coated with edible surface coatings made up of shellac and aloe gel (AG), separately and in combination. Application of coatings was found to significantly (p < 0.05) reduce the respiration and ethylene synthesis rates as well as electrolyte leakage. The AG-coated samples showed reduced polyphenol oxidase (96.1) and peroxidase activity (211.2) followed by the samples coated with combination of shellac + AG, and shellac alone; the uncoated samples being showing maximum values (122.8, 288.5) for these enzymes in terms of units/g/min, respectively. The L*, a* and b* values, firmness, microbiological and keeping quality of the coated slices also showed reduced changes during storage for 30 days at 6 ± 1 °C.     

Effect of flaxseed meal on the dynamic mechanical properties of starch-based films

Starch (S)–flaxseed meal (FM) biofilms were prepared from potato and maize starch by incorporating FM up to 15% (dry solid basis) and using glycerol as plasticizer. The dynamic mechanical properties, tensile properties and water vapor permeability (WVP) of these films were measured. The storage modulus of both the starch (control) and starch–FM films decreased as temperature increased. Tan δ increased initially in all the films with increase in temperature until a peak value was reached which allowed the determination of glass transition temperature (T_g). Both tensile strength and Young’s modulus of the starch–FM films increased with increase in the FM content. The WVP of the potato starch–FM films first increased to 2.261 (×10⁵ g m⁻² h⁻¹ Pa⁻¹) when FM content increased to 5% and decreased down to 1.832 (×10⁵ g m⁻² h⁻¹ Pa⁻¹) with further increase in the FM content to 15%. While the WVP values of the cornstarch and corn starch–FM films were not significantly (p > 0.05) different. The incorporation of FM increased the tensile strength, decreased the % elongation at break and increased the T_g.     

α-Tocopherol stereoisomers in beef as an indicator of vitamin E supplementation in cattle diets

These studies investigated the potential application of analysis of stereoisomers of α-tocopherol to discriminate between beef from animals raised at pasture or fed concentrates containing synthetic vitamin E. Muscle α-tocopherol levels were affected (P < 0.05) by diet with mean values of 2.63, 1.14, 2.43 and 1.77 μg g⁻¹ muscle for beef from animals receiving pasture only (P), a barley-based concentrate with synthetic vitamin E (C), winter silage followed by summer pasture (SiP) and winter silage followed by summer pasture with concentrate (SiPC), respectively. Stereoisomeric analysis of α-tocopherol permitted discrimination between beef from the P/SiP, C and SiPC animals. In a comparison of Irish and non-Irish beef, Brazilian beef had higher (P < 0.05) α-tocopherol (8.13 μg g⁻¹) than beef from Austria, England, France, Germany, the U.S. and Ireland (mean 2.51 μg g⁻¹). Stereoisomeric analysis of α-tocopherol in non-Irish beef revealed supplementation with synthetic vitamin E in all samples, including the samples marketed as pasture-fed beef.     

Effect of chemical and physical pretreatments on the convective drying of cape gooseberry fruits (Physalis peruviana)

Drying of cape gooseberry fruits is a slow process because of the low permeability to moisture of the fruit’s waxy skin. In this work, the effect of chemical pretreatments (sunflower oil/K₂CO₃ or olive oil/K₂CO₃ at 28 °C, and NaOH/olive oil at 96 °C) and physical pretreatments (blanching) to break down the waxy surface and accelerate moisture diffusion during drying, was assessed. Drying was carried out at 60 °C and 2 m/s air velocity for 10 h. The lowest moisture content (0.27 kg water/kg db), the highest vitamin C content (0.36 mg/g), and the greatest rehydration capacity (1.89) were obtained in fruits pretreated with olive oil (9.48%) and K₂CO₃ (4.74%). However, the greatest changes in color (ΔE^* = 15.05) and chroma (ΔC^* = 9.03) were also associated to fruits pretreated with olive oil and K₂CO₃. The effective diffusivity of water during drying was 7.37 × 10⁻¹¹ m²/s in pretreated samples compared with 6.61×10⁻¹¹ m²/s for untreated samples.     

Effects of water extract of Urtica dioica L. and modified atmosphere packaging on the shelf life of ground beef

Effects of lyophilized Urtica dioica L. water extract (LUWE) and modified atmosphere packaging (MAP) on the quality and shelf life of ground beef were investigated. Ground beef was stored as aerobic control, MAP (80%O₂ + 20% CO₂), MAP + 250 ppm LUWE and MAP and 500 ppm LUWE at 2 ± 0.5 °C for 14 days. MAP and LUWE had significant effects on mesophilic, psychrotrophic and lactic acid bacteria and Pseudomonas counts. Depending on the level of LUWE, Pseudomonas and psychrotrophic counts decreased. Treatment with 500 ppm LUWE + MAP showed the lowest TBARS values compared to other groups during storage. 80% O₂-MAP increased TBARS values. Treatment had no significant effect on L* and b* values of the exterior of the ground beef, but had significant effects on the color of interior sections.     

Antioxidant and antiacetylcholinesterase activities of five plants used as Portuguese food spices

In the present work, we report the results of a study aimed at evaluating the antiradical activity, the antioxidant activity and the acetylcholinesterase (E.C. 3.1.1.7.) inhibitory capacity of essential oils, ethanol and boiling water extracts from five aromatic herbs growing wild in Portugal and used in traditional food preparations: fennel (Foeniculum vulgare), mint (Mentha spicata), pennyroyal (Mentha pulegium), rosemary (Rosmarinus officinalis) and wild thyme (Thymus serpyllum). The water extracts of M. spicata and M. pulegium showed the highest radical-scavenging activity (DPPH test) values (IC₅₀ = 5.7 ± 0.4 and 8.9 ± 0.2 μg ml⁻¹ respectively). This activity was higher than that found with the standard antioxidant BHT. The ethanol extracts of M. spicata, T. serpyllum and F. vulgare showed the highest antioxidant activities measured by the β-carotene/linoleic acid assay, IC₅₀ = 36.9 ± 0.1, 41.2 ± 0.1 and 68.7 ± 0.1 μg ml⁻¹, respectively. The inhibition of AChE was higher in the essential oil fraction. The highest activity was found for R. officinalis with an IC₅₀ = 69.8 ± 0.1 μg ml⁻¹.     

C/C pattern of honey from Turkey and determination of adulteration in commercially available honey samples using EA-IRMS

Honey adulteration particularly by adding cheap sugars such as High Fructose Corn Syrup (HFCS) and cane sugar syrup into natural honey is widespread. This study reports (¹³C/¹²C, ‰) patterns of 31 authentic honey samples obtained from different sources and regions of Turkey as well as 43 commercial honey samples to determine the adulteration using mass spectrometer coupled to elemental analyzer (EA-IRMS). The analyses indicated that the ranges of (¹³C/¹²C, ‰) values of honey and protein fractions of Turkish honey are from −23.30 to −27.58‰ and −24.13 to −26.76‰, respectively. These values for commercial honey samples were determined to range from −11.28 to −25.54‰ and −19.35 to −25.61‰, respectively. The numbers of adulterated commercial honey samples were found to be 10, which corresponds to 23% of the total number of the samples. Diastase activity, HMF content, electrical conductivity and moisture content of honey samples were also determined. Method validation and uncertainty budget calculations were also reported.     

Contents of biologically active polyamines in chicken meat,liver, heart and skin after slaughter and their changes during meat storage and cooking

Dietary polyamines, putrescine, spermidine (SPD) and spermine (SPM), participate in an array of important physiological roles, including tumour growth. Thus, reliable information on polyamine content in foods has been needed. We therefore determined polyamine contents in chilled chicken meat and giblets (n = 20) and skin (n = 10) 24 h after slaughter. The polyamines were determined, after extraction with perchloric acid, as dansyl derivatives, using an HPLC method. Mean SPD values were 4.8, 10.2, 11.4, 48.7 and 12.1 mg kg⁻¹ and SPM values were 36.8, 38.0, 24.3, 133 and 82.7 mg kg⁻¹ in breast, thigh, skin, liver and heart, respectively. Significant statistical correlations between SPD and SPM contents were observed in breast, thigh, skin and liver, whereas correlations were insignificant in heart. An increase of SPD and SPM was apparent in breasts and thighs stored at −18 °C for 6 months; however, it was significant only for SPM in thighs. The losses of both SPD and SPM were statistically insignificant during storage of aerobically packaged breasts up to 9 days at +2 °C. A significant decrease of SPM to about 60% of the initial contents was observed in both vacuum-packaged and in modified atmosphere (20% CO₂ and 80% O₂)-stored breasts on day 21 at +2 °C. For both SPD and SPM, roasting, grilling and frying of fresh breasts caused losses of about 40–60% of the initial contents (higher than boiling and stewing). Similarly, losses of SPM, due to roasting of breasts frozen for 3 or 6 months, were higher than those caused by stewing. Putrescine was detected only sporadically and at levels close to the detection limit of 1.0 mg kg⁻¹ (fresh matter).     

Effect of phosphorus on the fruit yield and food value of two landraces of Trichosanthes cucumerina L.- Cucurbitaceae

Studies were conducted in the early season of 2002 and 2003 at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife, Nigeria to evaluate the effect of phosphorus (P) on fruit yield and chemical composition of two landraces of Trichosanthes cucumerina L. For the purpose of the study, two landraces of T. cucumerina named Landrace I and Landrace II were used. The five levels of phosphorus evaluated were 0, 30, 60, 90 and 120 kg P₂O₅ ha⁻¹ using single super phosphate fertilizer (8% P). Statistical analysis showed that 90 kg P₂O₅ ha⁻¹ gave statistically significant higher fruit yield (16.4 tons ha⁻¹) compared to other P levels. The fruit yield of the two Landraces did not differ significantly. Except for crude protein content, the 90 kg P₂O₅ ha⁻¹ produced significantly higher ether extract (1.22 g 100 g⁻¹), crude fibre (1.93 g 100 g⁻¹), moisture content (90.5 g 100 g⁻¹), ash (0.90 g 100 g⁻¹), total sugars (0.81 g 100 g⁻¹) and ascorbic acid (28.7 mg 100 g⁻¹) than other P levels. The essential amino acids compositions were also significantly higher at 90 g 100 g⁻¹ compared to other lower P levels. Landrace I had significantly higher ether extract (0.90 g 100 g⁻¹) content than Landrace II (0.62 g 100 g⁻¹) while Landrace II in turn had significantly higher total sugar (0.76 g 100 g⁻¹) compared to Landrace I (0.61 g 100 g⁻¹). The essential amino acids composition is high and the oxalate composition is low. The high ascorbic acid and amino acid content together with a low oxalate composition suggested a strong basis for encouraging the cultivation of this indigenous fruit vegetable to augment nutrient requirement, improve diet and consequently alleviate poverty, preserve the biodiversity and increase the gene bank of neglected wild species of high quality nutrient sources.     

Seasonal variation in the C,N and S stable isotope composition of retail organic and conventional Irish beef

The objective of this study was to investigate seasonal variation in the C, N and S stable isotope composition of retail organic and conventional Irish beef. A total of 242 beef samples (127 organic, 115 conventional) was collected in a one-year survey and analysed by isotope ratio mass spectrometry. The δ¹³C time series in conventional beef was significantly non-random, with a pronounced seasonal positive shift of >2‰ between December and June, whilst δ¹³C in organic beef was less variable and significantly more negative. In conventional beef, δ¹⁵N was remarkably invariant (remaining close to 7‰) throughout the year, while organic beef was more variable and also significantly lower in δ¹⁵N. The S isotope composition (δ³⁴S) exhibited a complex seasonal pattern in both types of beef. These results show that seasonal patterns can occur in the isotopic composition of beef, probably reflecting seasonality in animal feeding practices modulated by tissue turnover rates. Such seasonal variation needs to be considered in the isotopic authentication of beef and other animal-derived products.     

Antioxidant potential of solvent extracts of Kappaphycus alvarezii (Doty) Doty – An edible seaweed

Various solvent extracts of Kappaphycus alvarezii, an edible red seaweed (family Solieriaceae) were screened for total phenol content and antioxidant activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferrous ion chelating activity, reducing power and antioxidant activity assays in a linoleic acid system with ferrothiocyanate reagent (FTC). The total phenol content of different extracts of K. alvarezii varied from 0.683 ± 0.040% to 2.05 ± 0.038%. The radical-scavenging activity of ethanol extract was, as IC₅₀ 3.03 mg ml⁻¹, whereas that of the water extract was IC₅₀ 4.76 mg ml⁻¹. Good chelating activity was recorded for methanol extract (IC₅₀ 3.08 mg ml⁻¹) wherein 67.0 ± 0.924% chelation was obtained using 5.0 mg ml⁻¹ of extract. The reducing power of the samples was in the following order: BHT > methanol > ethanol > ethyl acetate > water > hexane. But, in the linoleic acid system, the ethanol extract proved superior to the synthetic antioxidants butylated hydroxytoluene (BHT). Hence, these extracts could be considered as natural antioxidants and may be useful for curing diseases arising from oxidative deterioration.     

Discrimination of Korean beef from beef of other origin by stable isotope measurements

Beef samples from Korea and from some of the main beef exporting countries (USA, Mexico, Australia, New Zealand) were analysed for carbon, nitrogen and hydrogen isotope ratios of the defatted dried matter. Results showed that the samples from each country investigated could be assigned to a typical isotope signature and can be separated from each other. The main discriminating factors were δ¹³C and δ²H, which mainly reflect feeding of C₃ and C₄-plants and the isotopic composition of the water, respectively, consumed by the cattle. Australian beef showed the largest variation in its isotopic signature, suggesting heterogeneous rearing conditions. By contrast, for beef from New Zealand, Mexico, USA and Korea, each batch had typical signatures with a smaller variability.