A probabilistic approach to compare the risk associated with heavy metals and bromine in honey from Dominican Republic, Mexico, Mozambique and Spain.

This study aims to analyse the risk to consumers given the presence of heavy metals and bromine in honey from different countries. A probabilistic approach was applied to assess carcinogenic risk. Concerning exposure, Al in Spain (3.3E-04 mg/kgBw/day), B in Dominican Republic and Mexico (2E-04 mg/kgBw/day in both cases) and Fe in Mexico and Mozambique had the highest values (5E-05 and 4.8E-05 mg/kgBw/day). In risk characterisation, the values were less than 1 for hazard index (HI), meaning that the consumption of honey represents a low level of concern for non-genotoxic effects. A combination of margin of exposure and probability of exceedance results that exposure to Pb pose no threat. The probability of suffering cancer for Br, Cd, Ni and Pb was lower than 1.0E-06 and, therefore, considered safe. However, the risk at the 95th percentile of Br in Dominican Republic was 1.18E-04 in adults and 2.45E-04 in children, exceeding 1.0E-04, and therefore, considered intolerable. Finally, the sensitivity analysis indicated that the most influential factor in the HI was the consumption in adults and the concentration of Ni in children, whereas for cancer risk, were the concentrations of Ni, Cd, Br and Pb, in both cases.

Volatile markers as a reliable alternative for the correct classification of citrus monofloral honey.

The pollen analysis to classify monofloral honey is an unresolved challenge specially when the pollen is under-represented as the case of citrus honey. Thus, this study assesses the validity of the volatile fraction to differentiate types of honey, with special attention to markers compounds of citrus honey that could permit their distinction. Unsupervised analysis (PCA and HCA) showed that the volatile fraction of honey containing Citrus sp. pollen, undoubtedly differentiates it from other types of honey. An OPLS model focused on citrus honey selected 5 volatile compounds (of the 123 found in all samples by GC-MS) as significant predictors of the currently used value of methyl anthranilate obtained by HPLC. The joint detection of 4 lilac-aldehydes and the volatile methyl-anthranilate has the advantage of providing more precise information. Therefore, it could be proposed as a consistent marker to ensure the correct classification of citrus honey, fostering its labelling reliability.

High Fundamental Frequency (HFF) Monolithic Quartz Crystal Microbalance with Dissipation Array for the Simultaneous Detection of Pesticides and Antibiotics in Complex Food.

As in the case of the food industry in general, there is a global concern about safety and quality in complex food matrices, such as honey, which is driving the demand for fast, sensitive and affordable analytical techniques across the honey-packaging industry. Although excellent techniques such as liquid chromatography-tandem mass spectrometry (LC-MS/MS) are available, these are located in centralized laboratories and are still lacking in speed, simplicity and cost-effectiveness. Here, a new approach is presented where a competitive immunoassay is combined with a novel High Fundamental Frequency Quartz Crystal Microbalance with Dissipation (HFF-QCMD) array biosensor for the simultaneous detection of antibiotics and pesticides in honey. Concretely, thiabendazole and sulfathiazole residues were monitored in spiked honey samples. Results revealed that HFF-QCMD arrays provide a complementary and reliable tool to LC-MS/MS for the analysis of contaminants in these kinds of complex matrices, while avoiding elaborate sample pre-treatment. The good sensitivity achieved (I50 values in the 70-720 µg/kg range) and the short analysis time (60 min for 24 individual assays), together with the ability for multiple analyte detection (24 sensor array) and its cost-effectiveness, pave the way for the implementation of a fast on-line, in situ routine control of potentially hazardous chemical residues in honey.

Monofloral honey authentication by voltammetric electronic tongue: A comparison with 1H NMR spectroscopy.

Proton-nuclear-magnetic-resonance-spectroscopy (1H NMR) is the widely accepted reference method for monitoring honey adulteration; however, the need to find cheaper, faster, and more environmentally friendly methodologies makes the voltammetric-electronic-tongue (VET) a good alternative. The present study aims to demonstrate the ability of VET (in comparison with 1H NMR) to predict the adulteration of honey with syrups. Samples of monofloral honeys (citrus, sunflower and heather, assessed by pollen analysis) simulating different levels of adulteration by adding syrups (barley, rice and corn) from 2.5 to 40% (w/w) were analyzed using both techniques. According to the indicators (slope, intercept, regression coefficient-R2, root mean square error of prediction-RMSEP) of the partial-least-squares (PLS) regression models, in general terms, the performance of these models obtained by both techniques was good, with an average error lower than 5% in both cases. These results support the use of VET as a screening technique to easily detect honey adulteration with syrups.

Using an automatic pulse voltammetric electronic tongue to verify the origin of honey from Spain, Honduras, and Mozambique.

BACKGROUND: The growing need to classify the origin of honey in a simple way is leading to the development of affordable analytical equipment that is in-line and manageable, enabling rapid on-site screening. The aim of this work was therefore to evaluate whether an electronic tongue (made of four metallic electrodes: Ir, Rh, Pt, Au), based on potential multistep pulse voltammetry with electrochemical polishing, is able to differentiate between honey samples from Spain, Honduras, and Mozambique. RESULTS: It was demonstrated, for the first time, that automatic pulse voltammetry, in combination with principal component analysis (PCA) statistical analysis, was able to differentiate honey samples from these three countries. A partial least squares (PLS) analysis predicted the level of certain physicochemical parameters, the best results being for conductivity and moisture with correlation coefficients of 0.948 and 0.879, whereas the weakest correlation was for the sugars. CONCLUSION: The tool proposed in this study could be applied to identify the country origin of the three types of multifloral honey considered here. It also offers promising perspectives for expanding knowledge of the provenance of honey. All of this could be achieved when a comprehensive database with the information generated by this electronic tongue has been created. © 2019 Society of Chemical Industry.

Food Safety Margin Assessment of Antibiotics: Pasteurized Goat's Milk and Fresh Cheese.

Traces of antimicrobials in milk are of great concern for public health. The European Union has established maximum residue limits in milk; these, however, by themselves do not guarantee the absence of drug residues in milk and related products. Currently, very little information is available on the transfer of antibiotic residues from milk to other dairy products and their potential effect on food safety. This work evaluated the presence of antibiotic residues in pasteurized fluid milk and fresh cheeses from goat's milk containing these veterinary drugs at legal safety levels (maximum residue limits) and assessed the safety margin of these dairy products for consumers. Eight antibiotics (amoxicillin, benzylpenicillin, cloxacillin, neomycin, erythromycin, ciprofloxacin, enrofloxacin, and oxytetracycline) were selected, and three batches of fresh cheese were made from pasteurized goat's milk spiked with each of these drugs. Drug residues in milk and cheese samples were analyzed by liquid chromatography-tandem mass spectrometry. The safety margin of goat's milk products was calculated taking into account different age groups (children, teenagers, and adults). Results showed that most antibiotics present in raw milk remained in pasteurized milk and were transferred to cheese to a high extent; retention was above 50% in most cases. The minimum safety margin in pasteurized milk was obtained for enrofloxacin, ciprofloxacin, and erythromycin for the children's group. For fresh cheese, an elevated safety margin was obtained for all antibiotics and age groups considered. However, the large amounts of antibiotics retained in the cheese might contribute to the development and spread of antimicrobial resistance. Considering the differences in milk from different species and the great variety of cheeses, it would be advisable to continue the traceability study of antibiotics in order to increase the safety margin of dairy products.

Quality parameters, pollen and volatile profiles of honey from North and Central Mozambique.

Honey from different provinces of North and Central Mozambique was characterised considering their physicochemical quality parameters, colour, sugars, total antioxidants, pollen analysis and volatile profile. Flora that surrounds the hives, and the apicultural practices also influence in their characteristics. According to a similar pollen spectrum, eight types of honey were found. In these, the predominant pollens were: I-Astragalus type; II-Acanthus sp; III-Celastraceae; IV-Brassicaceae; V-Anacardiaceae and Astragalus type; VI-Astragalus type and Myrtaceae; VII-Asteraceae family and VIII-unknown. Group I (from Nampula), especially distanced itself from the others mainly due to the special abundance of certain compounds (alcohols, aldehydes, esters, acids and terpenes). The presence of furan compounds largely identified in Sofala and Manica honeys could be due to inadequate beekeeping practices or storage conditions. A discriminant analysis correctly classified 96.7% of the groups, being electrical conductivity and moisture followed by the volatile-compound 3-Methylbutan-1-ol and the free acidity, the variables that most contributed.

Standardizing the analysis of phenolic profile in propolis.

The analysis of propolis is controversial, hampering the comparison of its biological properties and estimation of its commercial value. This work evaluates the effectiveness of combining maceration and ultrasonication extraction techniques on the yield, total phenol content (Folin-Ciocalteau) and the specific phenolic compounds (HPLC-UV), on propolis from different origins. The extraction method was not significant in any case; therefore ultrasonication is recommended (time-saving) but only when a double extraction is performed. Propolis yield varies significantly between samples, as it includes impurities, consequently the results should be expressed considering the yield (as balsam) instead of raw propolis. Of the 13 quantified phenolic compounds, CAPE and pinocembrin (803 and 701 mg/g balsam) stand out. The phenolic profile of a propolis must be fixed using both total phenol content (with a consensus reference compound) and the specific phenolic compounds, since the latter provides information about compounds that can play a significant antioxidant role.

Volatile profile in the accurate labelling of monofloral honey. The case of lavender and thyme honey.

The proliferation of hybrid plant varieties without pollen, such as lavender, has complicated the classification of specific types of honey. This study evaluated the correlation between the proclaimed type of monofloral honey (lavender or thyme) as appears on the label with the actual percentage of pollen. In addition, physicochemical parameters, colour, olfacto-gustatory profile, and volatile compounds were tested. All of the samples labelled as lavender were wrongly classified according to the usual commercial criteria (minimum 10% of pollen Lavandula spp.). In the case of lavender honey, there was significant agreement between commercial labelling and classification through organoleptic perception (81.8%), and above all between the commercial labelling and the volatile compounds (90.9%). For thyme honey, agreement for both parameters was 90.0%. These results offer compelling evidence that the volatile compounds are useful for the classification of lavender honey with low levels of pollen since this technique agrees well with the organoleptic analysis.

Antioxidant activity and physico-chemical parameters for the differentiation of honey using a potentiometric electronic tongue.

BACKGROUND: This work evaluates the capacity of a potentiometric electronic tongue to differentiate between types of honey (orange blossom, rosemary, thyme, sunflower, winter savory and honeydew honey) according to their antioxidant level. The classical procedures used to evaluate the antioxidant potential of honey are inappropriate for in situ monitoring on reception of batches of raw honey in the packaging industry. They are also destructive, time-consuming and very tedious, requiring highly expert analysts and specialised equipment. RESULTS: The electronic tongue system made with Ag, Ni, Co, Cu and Au was able to not only differentiate between types of honey but also to predict their total antioxidant capacity. The discrimination ability of the system was proved by means of a fuzzy ARTMAP type ANN, with 100% classification success. A prediction multiple linear regression model showed that the best correlation coefficient was for antioxidant activity (0.9666), then for electrical conductivity (0.8959) and to a lesser extent for aw , moisture and colour. CONCLUSION: The proposed measurement system could be a quick, easy option for the honey packaging sector to provide continuous in-line information about a characteristic as important as the antioxidant level. © 2016 Society of Chemical Industry.

Effect of chitosan-lemon essential oil coatings on volatile profile of strawberries during storage.

Chitosan coatings containing lemon essential oils were described as effective at controlling fruit fungal decay at 20°C during 7 days. In this work, GC-MS was used to characterise the volatile compounds of strawberries during cold storage in order to analyse the influence of fruit coatings with chitosan, containing or not containing lemon essential oil, on the volatile profile of the fruits. The coatings affected the metabolic pathways and volatile profile of the fruits. Pure chitosan promoted the formation of esters and dimethyl furfural in very short time after coating, while coatings containing lemon essential oil incorporated terpenes (limonene, γ-terpinene, p-cymene and α-citral) to the fruit volatiles and enhanced the fermentative process, modifying the typical fruit aroma composition. No effect of chitosan coatings was sensorially perceived, the changes induced by lemon essential oil were notably appreciated.

Influence of Extraction Methods on the Yield of Steviol Glycosides and Antioxidants in Stevia rebaudiana Extracts.

This study evaluated the application of ultrasound techniques and microwave energy, compared to conventional extraction methods (high temperatures at atmospheric pressure), for the solid-liquid extraction of steviol glycosides (sweeteners) and antioxidants (total phenols, flavonoids and antioxidant capacity) from dehydrated Stevia leaves. Different temperatures (from 50 to 100 °C), times (from 1 to 40 min) and microwave powers (1.98 and 3.30 W/g extract) were used. There was a great difference in the resulting yields according to the treatments applied. Steviol glycosides and antioxidants were negatively correlated; therefore, there is no single treatment suitable for obtaining the highest yield in both groups of compounds simultaneously. The greatest yield of steviol glycosides was obtained with microwave energy (3.30 W/g extract, 2 min), whereas, the conventional method (90 °C, 1 min) was the most suitable for antioxidant extraction. Consequently, the best process depends on the subsequent use (sweetener or antioxidant) of the aqueous extract of Stevia leaves.

Antioxidants: Characterization, natural sources, extraction and analysis.

Recently many review papers regarding antioxidants from different sources and different extraction and quantification procedures have been published. However none of them has all the information regarding antioxidants (chemistry, sources, extraction and quantification). This article tries to take a different perspective on antioxidants for the new researcher involved in this field. Antioxidants from fruit, vegetables and beverages play an important role in human health, for example preventing cancer and cardiovascular diseases, and lowering the incidence of different diseases. In this paper the main classes of antioxidants are presented: vitamins, carotenoids and polyphenols. Recently, many analytical methodologies involving diverse instrumental techniques have been developed for the extraction, separation, identification and quantification of these compounds. Antioxidants have been quantified by different researchers using one or more of these methods: in vivo, in vitro, electrochemical, chemiluminescent, electron spin resonance, chromatography, capillary electrophoresis, nuclear magnetic resonance, near infrared spectroscopy and mass spectrometry methods.

Influence of drying method on steviol glycosides and antioxidants in Stevia rebaudiana leaves.

The application of different drying conditions (hot air drying at 100 °C and 180 °C, freeze drying and shade drying) on steviol glycosides (stevioside, dulcoside A, rebaudioside A and rebaudioside C) and antioxidants in Stevia leaves was evaluated. Stevioside, the major glycoside found in fresh leaves (81.2mg/g), suffered an important reduction in all cases, although shade drying was the least aggressive treatment. Considering the antioxidant parameters (total phenols, flavonoids and total antioxidants), the most suitable drying method was hot air at 180 °C, since it substantially increased all of them (76.8 mg gallic acid, 45.1mg catechin and 126 mg Trolox, all equivalent/g Stevia, respectively), with respect to those present in fresh leaves (44.4, 2.5 and 52.9 mg equivalent/g). Therefore, the ideal method for drying Stevia leaves depends on their final use (sweetener or antioxidant), although, hot air at 180 °C is the most recommendable if only one treatment has to be chosen.

Suitability of antioxidant capacity, flavonoids and phenolic acids for floral authentication of honey. Impact of industrial thermal treatment.

Total antioxidant activity, physicochemical parameters, and the profile of flavonoids and phenolic acid compounds were evaluated for: their ability to distinguish between the botanical origins of four types of Spanish honey, the impact of industrial thermal treatment, and the effect of the year of collection. Citrus honey had the lowest levels of all the analysed variables, then rosemary and polyfloral, and honeydew the highest ones. Botanical origin affects the profile of flavonoids and phenolic compounds sufficiently to permit discrimination thanks to the predominance of particular compounds such as: hesperetin (in citrus honey); kaempferol, chrysin, pinocembrin, caffeic acid and naringenin (in rosemary honey) and myricetin, quercetin, galangin and particularly p-coumaric acid (in honeydew honey). The impact of industrial thermal treatments is lower than the expected variability as a consequence of the year of collection, though neither factor has enough influence to alter these constituent compounds to the point of affecting the discrimination of honey by botanical origin.

Composition of antioxidants and amino acids in Stevia leaf infusions.

Stevia, a non-caloric natural sweetener with beneficial properties and considerable antioxidants and amino acids, is increasingly consumed as an infusion. This work evaluates the influence of the conditions (temperature: 50, 70 or 90 °C and time: 1, 5, 20 or 40 min) applied to obtain Stevia infusions, on antioxidants (total phenols, flavonoids and antioxidant activity) and amino acids. The total concentration of the eleven amino acids found was 11.70 mg/g in dried leaves and from 6.84 to 9.11 mg/g per gram of Stevia in infusions. However, infusions showed higher levels of certain amino acids (alanine, asparagine, leucine and proline), and greater values of the three antioxidant parameters in comparison with dry leaves. Temperature had more influence (minimum values at 50 °C and maximum at 90 °C) than time in the case of antioxidants. At 90 °C there were no important increases in the extraction of antioxidant compounds after 5 min; each gram of Stevia had 117 mg trolox (total antioxidant activity), 90 mg gallic acid (total phenols) and 56 mg catechin equivalents (flavonoids). Varying the temperature and time conditions no notable differences were observed in the concentrations of the majority of amino acids. However, the infusion treatment at 90 °C for 5 min was the best, as it gave the highest yield of 8 of the 11 amino acids. Therefore, with respect to the compounds analyzed in this study, the best way to obtain Stevia leaf infusions is the same as the domestic process, almost boiling water for a short time.

Effectiveness of prerequisites and the HACCP plan in the control of microbial contamination in ice cream and cheese companies.

In food safety, implementation of prerequisites and application of Hazard Analysis and Critical Control Points (HACCP) guarantee the control of processes, and microbiological criteria permit validation of their effectiveness. With these aims in mind, this article presents the results obtained by the official control carried out by the Valencian administration in ice cream and cheese companies, located in the Xativa/Ontinyente area (Valencian region, Spain) in the period between 2005 and 2010. The audits of Good Hygienic Practices (GHP) and HACCP show that "Structure & Design" followed by "Hygiene & Cleaning" and "Traceability" were the evaluated items with most nonconformities. Pathogenic microorganisms were not found in any of the final products analyzed. Microorganism indicators of unhygienic conditions were present in 100% of the analyses; however, 87.98% of them had low levels, which did not exceed the microbiological criteria. These results highlight the general good effectiveness of the safety management systems implemented and emphasize that companies and official control must continue working in order to guarantee the consumers' welfare.

Volatile fraction composition and physicochemical parameters as tools for the differentiation of lemon blossom honey and orange blossom honey.

BACKGROUND: Volatile fraction profile and physicochemical parameters were studied with the aim of evaluating their effectiveness for the differentiation between lemon blossom honey (Citrus limon L.) and orange blossom honey (Citrus spp.). They would be useful complementary tools to the traditional analysis based on the percentage of pollen. RESULTS: A stepwise discriminant analysis constructed using 37 volatile compounds (extracted by purge and trap and analysed by gas chromatography-mass spectrometry), and physicochemical and colour parameters (diastase, conductivity, Pfund colour and CIE L a b) together provided a model that permitted the correct classification of 98.3% of the original and 96.6% of the cross-validated cases, indicating its efficiency and robustness. This model proved its effectiveness in the differentiation of both types of honey with another set of batches from the following year. CONCLUSION: This model, developed from the volatile compounds, physicochemical and colour parameters, has been useful for the differentiation of lemon and orange blossom honeys. Furthermore, it may be of particular interest for the attainment of a suitable classification of orange honey in which the pollen count is very low. These capabilities imply an evident marketing advantage for the beekeeping sector, since lemon blossom honey could be commercialized as unifloral honey and not as generic citrus honey and orange blossom honey could be correctly characterized.

Significance of osmotic temperature treatment and storage time on physical and chemical properties of a strawberry-gel product.

BACKGROUND: The development of fruit-based foods that maintain the nutritional and sensory properties of fresh fruit may help to stimulate fruit consumption by consumers. The possibility of formulating a fruit-gel product with osmodehydrated fruit and the reused osmotic solution (OS) obtained from the dehydration step has been demonstrated. However, the conditions of the osmotic process can significantly affect the properties of the obtained product. In this work an osmotic process at 22 °C for 6 h and at 30 °C for 3 h was employed to formulate a strawberry-gel product. RESULTS: Significant losses of ascorbic and citric acids and anthocyanins were observed and some relevant volatile compounds of the strawberry aroma profile were developed during the osmotic process. Changes in all analysed parameters occurred mainly during the first 2 days of storage. The flux of anthocyanins from the fruit to the gel gave an attractive appearance to the formulated product. These changes were more marked for samples obtained at 30 °C. CONCLUSION: Osmotic treatment at 30 °C was more suitable for formulation of the product, because the presence of nutritional/functional compounds in the OS, and consequently in the gel matrix, was higher and the aroma and colour were more stable and homogeneous during storage.

Sensory hybrid host materials for the selective chromo-fluorogenic detection of biogenic amines.

Pyrylium-containing mesoporous materials have been used for the chromo-fluorogenic sensing of biogenic amines in an aqueous environment.