ATR-FTIR and Spectrometric Methods for the Assay of Crocin in Commercial Saffron Spices (Crocus savitus L.)

Attenuated total reflectance Fourier transform infrared spectrometric method for determination of crocin in commercial saffron samples was studied. Calibration models were built based on the peaks at spectral region of 1700–900 cm^?1 and spectral wavenumbers with correlation coefficient (r) greater than 0.99 were selected for quantification of crocin in the samples. The quantitative analysis of samples by attenuated total reflectance Fourier transform infrared was tested against reference UV-visible spectrophotometry method. Considerable correlation (r = 0.95) between both methods in prediction of crocin content among the saffron samples indicated that the proposed methodology has the potential application as a rapid screening tool.     

HPLC quantification of major active components from 11 different saffron (Crocus sativus L.) sources

Eleven certified saffron samples (Crocus sativus L.), one each from Azerbaijan, China, Greece, France, India, Iran, Italy, New Zealand, Spain, Turkey and the Sigma Chemical Company, were analyzed by using an HPLC photodiode array detection method. This analysis quantified the 10 major saffron compounds in each sample and their concentration was analyzed at three different wavelengths. Results indicated that the Greek, Indian, New Zealand, and Spanish saffron extracts possessed the highest concentrations of water-soluble glycosidic carotenoids (?8.0%) suggesting that they could be a good source of this type of metabolites for further biological evaluation.     

Geographical differentiation of saffron by GC–MS/FID and chemometrics

The volatile compounds of saffron of different origins were investigated to check their suitability as markers of geographic differentiation. A total of 247 saffron samples from Greece (40 samples), Iran (84 samples), Italy (60 samples) and Spain (63 samples) which were harvested in 2006 were analysed using ultrasound-assisted extraction, gas chromatography followed by mass spectrometry and flame ionisation. All regions were easily differentiated by canonical discriminant analysis. The percentages of correct classification and validation were 96.4 and 94.3%, respectively. These investigations showed the potential of saffron volatiles to discriminate saffron samples with different geographical origins.     

Geographical origin differentiation of saffron spice (Crocus sativus L. stigmas) – Preliminary investigation using chemical and multi-element (H,C, N) stable isotope analysis

A preliminary study of the bulk hydrogen, carbon and nitrogen stable isotope composition of 28 authentic saffron samples produced from Crocus sativus L. cultivated in the typical production areas of Western Macedonia in Greece (8), Khorasan Province in Iran (7), Sardinia in Italy (6) and Castilla-La Mancha in Spain (7) is described. A chemical characterisation of 16 key quality parameters was also completed on the same samples by UV–Vis, HPLC and GC analyses. Multivariate analysis of the data revealed that 60.7% of saffron samples could be correctly assigned to their respective production countries using the chemical parameters. However, the combined bio-element stable isotope data reliably classified 100% of the saffron samples according to their respective geographical origins using posterior cross validation. Further work is required to establish the long-term stability of these models with respect to different years of production and other major producers such as India and Morocco.     

Evaluation of Nano Zinc (ZnO) for Surface Enhancement of ATR–FTIR Spectra of Butter and Spread

The effect of nano zinc (ZnO) particles in surface enhancement of attenuated total reflection–Fourier transform mid-infrared spectroscopy (ATR–FTIR) has been studied in butter and spread. Due to the health implications associated with consumption of trans fats, the studies also included the determination of band corresponding to trans fats of butter/spread in the nano-zinc-treated samples. The FTIR spectra of nano-zinc-treated butter showed enhancement of bands related to (―C―O, ―CH₂―) at wave number 1,238 cm⁻¹ and (O―C―C) band of esters at wave number 1,100 cm⁻¹. Shifting in wave number to 1,150 cm⁻¹ and reduction in its peak intensity was observed with the band corresponding to 1,162 cm⁻¹ (―C―O stretch). Reduction in peak intensity of the bands at about 2,915 and 2,850 cm⁻¹ (C―H groups) was also observed. In the case of spread, nano zinc reduced the peak intensities of FTIR bands at 2,915 cm⁻¹, 2,850 cm⁻¹ (―C―H― (CH₂) stretches), 1,746 cm⁻¹ (―C═O ester), 1,465 cm⁻¹ (―C―H (CH₂, CH₃)), 1,375 cm⁻¹ (―C―H (CH₃)) and 1,156 cm⁻¹ (C―O, ―CH₂). Trans fats band corresponding to ═C―H stretch (trans bonds, 966 cm⁻¹), was observed in pure butter and spread. Trans fatty acids in butter and spread were quantified with the aid of calibration/validation standards using trielaidin and triolein and by using partial least squares regression analysis. However, the band at 966 cm⁻¹ was hindered in Zn-treated butter and reduced in Zn-treated spread.     

The Application of NIR FT-Raman Spectroscopy to Monitor Starch Retrogradation and Crumb Firmness in Semolina Bread

In this study, the potential application of near-infrared (NIR) Fourier-transform (FT)-Raman spectroscopy to monitor starch retrogradation in stored bread crumb was investigated. Semolina-based bread was made and cut into slices, which were stored under controlled conditions in sealed plastic bags. The aging of the bread crumb was monitored by both NIR FT-Raman spectroscopy and a texture analysis over a period of 20 days. Two-dimensional correlation analysis in the spectral range of 390–975 cm⁻¹ revealed characteristic differences among the spectra collected over time for bands that peaked at 480, 765, and 850 cm⁻¹. The band at 480 cm⁻¹ is studied here in detail. During the storage, the peak frequency of this band shifted towards lower wavenumbers, and its full width at half height decreased. Both of these parameters are highly correlated (R ² = 0.921 and R ² = 0.949, respectively) to crumb hardness measured by the texture analyzer.     

Fourier transform infrared spectroscopy (FTIR) as a tool for discriminating <Emphasis Type="Italic">Salmonella typhimurium</Emphasis> contaminated beef

Detection of beef contamination from harmful pathogens will be helpful in protecting the consumer safety and controlling the outbreaks. In this paper, the potential of Fourier transform infrared spectroscopy (FTIR) was investigated to discriminate the Salmonella contaminated packed beef. A suitable headspace sampling system was designed and used to collect the headspace volatiles from the packed meat to the FTIR gas cell. Spectral signatures of headspace volatiles of meat packages were used to classify the packed meat samples as contaminated or not. FTIR spectrum was divided into several regions in order to reduce the dimensionality as well as to select the regions based on the absorbance properties of various volatiles present in headspace of meat package. Principal component analysis was performed on the entire spectrum (4000–500 cm⁻¹) as well as on the selected sub-regions of entire spectrum. Two statistical classification techniques (linear and quadratic discriminate analysis) were used to develop classification models. The statistical models were validated using bootstrap cross validation technique. The total average classification accuracies were evaluated in terms of coefficient of variance (% CV). Based on the mean of total average classification accuracies and its % CV calculated from five similarly conducted experiments, it was found that the statistical models developed on a part of the spectra (500–850 cm⁻¹) and full spectra (4000–500 cm⁻¹) can be used as potential classification models for non-destructive discrimination of Salmonella contaminated packed beef samples from uncontaminated ones. These results need to be further validated on dataset with larger sample size.     

FTNIR Spectroscopic Method for Determination of Moisture Content in Green Tea Granules

The feasibility of measuring moisture content in green tea by Fourier transform near infrared (FTNIR) spectroscopic technique was investigated. Green tea granules samples with different moisture contents were scanned using FTNIR spectroscopy. The spectra were measured in diffused reflectance mode by keeping 4–5 g samples in small sample bottle. A partial least-square regression model was developed with vector normalization method in the near-infrared region (4,000–12,000 cm⁻¹ or 800–2,500 nm). The developed model was validated using cross-validation technique. Maximum coefficient of determination (r ²) value of 0.997 was obtained for the calibration model developed. The developed method was used further for quantification of moisture content in fresh green tea samples, and the results were compared with other methods like gravimetric method and moisture analyzer. Results indicated that FTNIR spectroscopy could be used for rapid detection of moisture content in green tea granules without destruction of samples. The measurement will take only 5–10 s.     

Determination and Evaluation of the Mineral Composition of Chinese Cabbage (Beta vulgaris)

Inductively coupled plasma optical emission spectrometry was used to determine the elements present in Chinese cabbage (Beta vulgaris). The accuracy of the method was confirmed by analysis of a certified reference material of spinach leaves. The study involved 57 samples that were collected in 13 Brazilian cities. Average concentrations of elements found per gram of Chinese cabbage were as follows: 3.44 mg g⁻¹ sodium, 5.09 mg g⁻¹ potassium, 1.25 mg g⁻¹ phosphorous, 0.85 mg g⁻¹ calcium, 0.49 mg g⁻¹ magnesium, 2.79 μg g⁻¹ manganese, 9.50 μg g⁻¹ iron, 0.74 μg g⁻¹ copper, 14.28 μg g⁻¹ zinc, and 6.44 μg g⁻¹ strontium. Principal component analysis and hierarchical cluster analysis demonstrated that there is no systematic difference in the mineral composition between the cabbage samples that were analyzed.     

Effects of Lactic and Acetic Acid on Survival of Salmonella enteritidis During Refrigerated and Frozen Storage of Chicken Meats

Chicken leg and breast meat samples inoculated with Salmonella enteritidis [4–5 log most probable number (MPN)/cm²] were dipped into lactic acid (LA; 1% and 3%) and acetic acid (AA; 1% and 2%) solutions for 10 min. After packaging, samples were stored at 4 °C (10 days) or −18 °C (6 months). Immediately after dipping into 1% LA, 3% LA, 1% AA, and 2% AA solutions, S. enteritidis counts on leg meat samples were reduced by 0.75, 1.21, 0.85, and 0.95 log MPN/cm², while the reductions were 0.97, 1.72, 0.92, and 1.58 log MPN/cm² on breast meat samples, respectively. The differences between the water-washed control and the acid-treated groups for Salmonella counts were statistically significant (P < 0.05). Salmonella counts on leg meat samples treated with 1% LA, 1% AA, and 2% AA were reduced by 0.54–1.52 log MPN/cm² (P < 0.05) during storage at 4 °C. However, for the breast meat samples, only Salmonella counts of water-washed controls were significantly reduced during refrigerated storage (P < 0.05). S. enteritidis counts on organic acid-treated samples were reduced by 0.13–0.55 log MPN/cm² during storage at −18 °C for 6 months, while the reduction on the water-washed controls was 0.64 log MPN/cm². It can be concluded that lactic or acetic acid treatment could be useful especially for reducing the initial Salmonella contamination. On the other hand, this pathogen could survive on poultry meats during refrigerated and frozen storage even following lactic or acetic acid decontamination.     

Occurrence of aflatoxin M1 in raw, pasteurized and UHT milk commercialized in Esfahan and Shahr-e Kord, Iran

Between September 2006 and September 2007, 236 samples of raw (n = 140), pasteurized (n = 48) and UHT (n = 48) milk were collected from supermarkets and from bulk milk tanks of eight dairy plants in the cities of Esfahan and Shahr-e Kord, Iran. All samples were analyzed for aflatoxin M₁ (AFM₁) contamination by ELISA and 213 (90.3%) were positive with mean concentrations 65 ng.l⁻¹. These concentrations are lower than the standards of Codex Alimentarius and FDA (500 ng.l⁻¹), but 119 samples (55.9%) had higher concentrations than the maximum tolerance accepted by some European countries (50 ng.l⁻¹). Mean concentrations of AFM₁ in raw, pasteurized and UHT milk were 68, 56, and 65 ng.l⁻¹, respectively. Mean concentrations of AFM₁ in autumn and winter samples were significantly higher (P < 0.05) than those of spring and summer but differences between AFM₁ concentrations of spring and summer samples were not significantly different. Concentrations of AFM₁ in milk from Shahr-e Kord were significantly lower (P ≤ 0.05) than those from Esfahan.     

Benzyloxybenzaldehydethiosemicarbazone: Extractive Spectrophotometric Reagent for the Determination of Cu(II) in Food and Water Samples

Benzyloxybenzaldehydethiosemicarbazone (BBTSC) was prepared and developed a new method for the simple, highly selective, and extractive spectrophotometric determination of copper(II) with BBTSC at wavelength 370 nm. The metal ion formed a bluish green colored complex with BBTSC in acetate buffer of pH 5.0, which was easily extractable into n-butanol with 1:1(metal/ligand) composition. The method obeys Beer’s law in the range of 0.5–5.2 ppm. The molar absorptivity and Sandell’s sensitivity were found to be 1.5 × 10⁴ l mol⁻¹ cm⁻¹ and 0.00412 g cm⁻², respectively. The correlation coefficient of the Cu(II)–BBTSC complex was 0.998, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD; n = 10), which was 0.377% and its detection limit 0.0204 μg ml⁻¹. The interfering effect of various cations and anions were also studied. The proposed method was successfully applied to the determination of copper(II) in food and water samples. Comparing the results with those obtained using an atomic absorption spectrophotometer tested the validity of the method.     

Polycyclic aromatic hydrocarbons (PAHs) in traditional and industrial smoked beef and pork ham from Serbia

Smoked beef and pork ham samples were analysed during process of smoking (after packing and storing) for the presence of the 16 EU priority PAHs via Fast GC/HRMS method. This study showed that there are differences in PAH contents between final smoked beef ham samples from traditional smokehouse (TS) (3.9 μg kg⁻¹) and industrial smokehouse (IS), (1.9 μg kg⁻¹). Also there is a difference in PAH contents in final smoked pork ham samples (4.9 μg kg⁻¹, TS; 4.2 μg kg⁻¹, IS). In beef and pork ham samples from the same smokehouse different PAH contents were observed during smoking. The highest content of examined PAHs in all beef and pork ham samples during smoking showed benzo[c]fluorene (BcL) (beef ham: from 0.3 μg kg⁻¹ to 1.5 μg kg⁻¹; pork ham: from 0.2 μg kg⁻¹ to 2.1 μg kg⁻¹).The maximum level for benzo[a]pyrene (BaP) of 5 μg kg⁻¹ in smoked meat products was not exceeded in any samples. Correlation statistic analysis (P < 0.05) of obtained contents from samples both from TS and IS showed that BaP is a good marker both for 16 EU priority PAHs and 12 IARC probably and possibly carcinogenic PAHs (IS: R _BaP/Σ16PAHs = 0.95, R _BaP/Σ12PAHs = 0.96; TS: R _BaP/Σ16PAHs = 0.71, R _BaP/Σ12PAHs = 0.88).     

Selenium Content of Raw and Cooked Marine Species Consumed in Portugal

The present study evaluates the effects of different cooking methods (grilling, frying and boiling) on selenium contents of six marine species commonly consumed in Portugal. Forty-two composite samples of sardine, horse mackerel, gilthead seabream, silver scabbardfish, hake and octopus were digested in a microwave system and analysed by electrothermal atomic absorption spectrometry. The described method is adequate for the analysis of selenium in marine species and meets the requirements of validation and quality control. Mean selenium contents in raw species ranged from 0.35 mg kg⁻¹ to 1.24 mg kg⁻¹. Cooked samples presented mean selenium contents from 0.38 mg kg⁻¹ to 1.85 mg kg⁻¹ in grilled fish, from 1.22 mg kg⁻¹ to 1.28 mg kg⁻¹ in fried fish and from 0.84 mg kg⁻¹ to 0.87 mg kg⁻¹ in boiled fish. No statistically significant differences were determined for selenium levels in raw and cooked samples and in different marine species. Estimated selenium intake agrees well with recommendations and is far below the Upper Tolerable Nutrient Level. This is the first study concerning the evaluation of the effects of cooking methods on selenium contents of marine species consumed in Portugal.     

A Rapid Spectrophotometric Method for Trace Determination of Zinc

A simple, sensitive, and highly selective method is proposed for the determination of zinc(II) using a bis-azo dye, 2,6-bis(1-hydroxy-2-naphthylazo)pyridine as spectrophotometric reagent. At pH 7.8, in 50% (v/v) ethanol–water medium, the complex is found to obey Beer’s law up to 1.3 mg/L with an optimum concentration range between 0.19 and 1.0 mg/L. Sandell’s sensitivity of the color reaction was calculated to be 0.0011 μg cm⁻² with molar absorptivity of 6.0 × 10⁴ L mol⁻¹ cm⁻¹ at 560 nm. The optimum conditions for the determination of Zn(II) with the reagent were ascertained. The complexation at different pH was studied in water–ethanol medium. The composition of the complex is 1:2. The action of some interfering ions was verified, and the developed method applied successfully for the estimation of zinc levels in food and milk samples, and the results were then compared with those obtained by using AAS.     

Use of Metals and Anion Species with Chemometrics Tools for Classification of Unprocessed and Processed Coconut Waters

Coconut water is a natural isotonic, nutritive, and low-caloric drink. Preservation process is necessary to increase its shelf life outside the fruit and to improve commercialization. However, the influence of the conservation processes, antioxidant addition, maturation time, and soil where coconut is cultivated on the chemical composition of coconut water has had few arguments and studies. For these reasons, an evaluation of coconut waters (unprocessed and processed) was carried out using Ca, Cu, Fe, K, Mg, Mn, Na, Zn, chloride, sulfate, phosphate, malate, and ascorbate concentrations and chemometric tools. The quantitative determinations were performed by electrothermal atomic absorption spectrometry, inductively coupled plasma optical emission spectrometry, and capillary electrophoresis. The results showed that Ca, K, and Zn concentrations did not present significant alterations between the samples. The ranges of Cu, Fe, Mg, Mn, PO₄³⁻, and SO₄²⁻ concentrations were as follows: Cu (3.1–120 μg L⁻¹), Fe (60–330 μg L⁻¹), Mg (48–123 mg L⁻¹), Mn (0.4–4.0 mg L⁻¹), PO₄³⁻ (55–212 mg L⁻¹), and SO₄²⁻ (19–136 mg L⁻¹). The principal component analysis (PCA) and hierarchical cluster analysis (HCA) were applied to differentiate unprocessed and processed samples. Multivariated analysis (PCA and HCA) were compared through one-way analysis of variance with Tukey–Kramer multiple comparisons test, and p values less than 0.05 were considered to be significant.     

Identification and differentiation of goat and sheep milk based on diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) using cluster analysis

A new methodology for identification and differentiation of goat and sheep milk was developed based on FT-IR spectroscopy using hierarchical and discriminant analysis. Forty-nine goat and 38 sheep defatted and freeze-dried Greek milk samples were analyzed. FT-IR spectra were obtained in the diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) mode. The spectral region 1840–950 cm⁻¹ was used to ‘fingerprint’ milk types. Main peak used for differentiation of goat/sheep milk is located at 1745 cm⁻¹, which is correlated to the degree of sugars carboxyl methyl esterification. Hierarchical and discriminant analyses were based on the absorptions of the above spectral region. These analyses showed that the samples of goat milk can be differentiated from the samples of sheep’s.     

Determination of free amino acids and ammonium ion in saffron (Crocus sativus L.) from different geographical origins

Amino acids are important in human nutrition and also influence the sensory traits of products. Up to now, no report has been available on the free amino acid content of saffron spice. This study developed a rapid method for the extraction of free amino acids and ammonium ion from saffron, thus permitting the differentiation of saffron samples by origin. The first step tested the extraction time (15, 30, 60, 120 and 240 min) and extractive solvent (water, 0.1 N HCl, 0.5 N HCl and 1 N HCl). The best results for the free amino acids and ammonium ion extraction were obtained using 0.1 N HCl during 60 min. Subsequently, these compounds were derivatised using diethyl ethoxymethylenemalonate (DEEMM) and analysed by HPLC. Using this method, 20 saffron samples from different countries (Spain, Italy, Greece and Iran) were analysed. Alanine, proline and aspartic acid were the major amino acids in all the samples. Alanine presented the maximum value in Iranian samples with 0.17 ± 0.02 mg/100 mg of saffron. The highest concentration of proline (0.087 ± 0.01 mg/100 mg) appeared in Greek samples and the maximum value of aspartic acid was 0.04 ± 0.01 mg/100 mg in Spanish samples. Greek and Iranian saffron presented the highest total free amino acid content, 0.50 ± 0.08 mg/100 mg and 0.55 ± 0.07 mg/100 mg, respectively. Furthermore, the free amino acid profile enabled us to differentiate the Iranian samples from the European samples (p < 0.05).     

Determination of Nitrite and Nitrate in Brazilian Meats Using High Shear Homogenization

Nitrate and nitrite are usually added to processed meat products to protect against the growth of microorganisms. Two sample preparation methodologies using either manual grinding (with a mortar and pestle) or mechanical high shear homogenization were investigated and compared. The results showed that high shear homogenization was the most suitable for the extraction of nitrite and nitrate from ham, salami, and bacon samples, achieving high extraction recoveries (>98%) together with low relative standard deviations (RSDs) for the samples analyzed. Analyses were performed using capillary electrophoresis. A running buffer consisting of 60 mmol L⁻¹ tetraborate and 0.2 mmol L⁻¹ cetyltrimethylammonium bromide enabled separation of the analytes in <5 min. In validation experiments, good repeatability was obtained for both migration times (<0.8% RSD) and peak areas (<1.1% RSD). Analytical curves for nitrite and nitrate were linear (r > 0.998) in the 0.2- to 2.5-mg L⁻¹ and 0.5- to 5-mg L⁻¹ concentration ranges, respectively. The limits of detection were 0.15 mg L⁻¹ for nitrite and 0.17 mg L⁻¹ for nitrate. The method developed was applied to the analysis of different kinds of meats (sausage, ham, salami, bacon, and others) produced in Brazil. The ranges of concentration found were 17.3–46.4 mg kg⁻¹ (nitrite) and 69.9–198.1 mg kg⁻¹ (nitrate). The contents of nitrate and nitrite in the samples were below the Brazilian legislation limit values (150 and 300 mg kg⁻¹ for nitrite and nitrate, respectively).