Voltammetric E-Tongue for Honey Adulteration Detection.

The aim of this study is to establish the usefulness of an electronic tongue based on cyclic voltammetry e-tongue using five working electrodes (gold, silver, copper, platinum and glass) in honey adulteration detection. Authentic honey samples of different botanical origin (acacia, tilia, sunflower, polyfloral and raspberry) were adulterated with agave, maple, inverted sugar, corn and rice syrups in percentages of 5%, 10%, 20% and 50%. The silver and copper electrodes provided the clearest voltammograms, the differences between authentic and adulterated honey samples being highlighted by the maximum current intensity. The electronic tongue results have been correlated with physicochemical parameters (pH, free acidity, hydroxymethylfurfural content-5 HMF and electrical conductivity-EC). Using statistical methods such as Linear discriminant analysis (LDA) and Support vector machines (SVM), an accuracy of 94.87% and 100% respectively was obtained in the calibration step and 89.65% and 100% respectively in the validation step. The PLS-R (Partial Least Squares Regression) model (constructed from the minimum and maximum current intensity obtained for all electrodes) was used in physicochemical parameters prediction; EC reached the highest regression coefficients (0.840 in the calibration step and 0.842 in the validation step, respectively), being followed by pH (0.704 in the calibration step and 0.516 in the validation step, respectively).

Raspberry, Rape, Thyme, Sunflower and Mint Honeys Authentication Using Voltammetric Tongue.

The aim of this study was to authenticate five types of Romanian honey (raspberry, rape, thyme, sunflower and mint) using a voltammetric tongue (VE tongue) technique. For the electronic tongue system, six electrodes (silver, gold, platinum, glass, zinc oxide and titanium dioxide) were used. The results of the melissopalynological analysis were supplemented by the data obtained with the electronic voltammetric tongue system. The results were interpreted by means of principal component analysis (PCA) and linear discriminant analysis (LDA). In this way, the usefulness of the working electrodes was compared for determining the botanical origin of the honey samples. The electrodes of titanium dioxide, zinc oxide, and silver were more useful, as the results obtained with these electrodes showed that it was achieved a better classification of honey according to its botanical origin. The comparison of the results of the electronic voltammetric tongue technique with those obtained by melissopalynological analysis showed that the technique was able to accurately classify 92.7% of the original grouped cases. The similarity of results confirmed the ability of the electronic voltammetric tongue technique to perform a rapid characterization of honey samples, which complements its advantages of being an easy-to-use and cheap method of analysis.

Comparative evaluation of maceration, microwave and ultrasonic-assisted extraction of phenolic compounds from propolis.

The aim of this study was to compare different techniques in order to achieve a high extraction of phenolic compounds from propolis. For this purpose, it was investigated the use of double maceration (24 h at room temperature with continuous agitation at 250 rpm), double microwave treatments (1 min at 140 W) and double ultrasound-assisted extraction (15 min at 20 kHz) using 70% ethanol. The extraction efficiency was measured based on extraction yield, total phenolic content, flavones and flavonol content, and flavanone and dihydroflavonol content. The ultrasonic extraction had an extraction yield higher than microwave extraction and maceration. The yield of the propolis ranged between samples and between the years of propolis harvesting. Of the twelve quantified phenolic compounds, p-coumaric acid was the most abundant (271.65 mg/g propolis).

Optimization of Pectin Enzymatic Extraction from Malus domestica 'Falticeni' Apple Pomace with Celluclast 1.5L.

: Pectin was extracted from apple (Malus domestica 'Falticeni') pomace with Celluclast 1.5L, at doses of 20, 40, and 60 µL/g of material. The temperature and time of extraction were varied on three levels-temperature-40, 50, and 60 °C; time-12, 18, and 24 h. For each experiment, the extraction yield (R2 = 0.8905), the galacturonic acid content (R2 = 0.9866), and the degree of esterification (R2 = 0.9520) of pectin was determined. Response surface methodology (RSM) was implemented via a Box-Behnken design, to optimize pectin extraction. In the optimum extraction conditions (temperature of 48.3 °C, extraction time of 18 h 14 min, and enzyme dose of 42.5 µL/g of pomace), the design predicted a 6.76% yield with a galacturonic acid content of 97.46 g/100 g of pectin and a degree of esterification of 96.02%. FT-IR analysis of the pectin sample obtained in these conditions showed a chemical structure similar to that of commercial apple and citrus pectin.

Honey adulteration detection: voltammetric e-tongue versus official methods for physicochemical parameter determination.

BACKGROUND: The aim of this study was to evaluate the usefulness of a voltammetric e-tongue (three electrodes: reference electrode (Ag/AgCl), counter electrode (glassy carbon electrode rod) and working electrode (Au, Ag, Pt and glass electrode)) for honey adulteration detection. For this purpose, 55 samples of authentic honey (acacia, honeydew, sunflower, Tilia and polyfloral) and 150 adulterated ones were analyzed. The adulteration was made using fructose, glucose, inverted sugar, hydrolyzed inulin syrup and malt wort at different percentages: 5%, 10%, 20%, 30%, 40% and 50%, respectively. The e-tongue has been compared with the physicochemical parameters (pH, free acidity, electrical conductivity (EC) and CIEL*a*b* parameters (L*, a* and b*)) in order to achieve a suitable method for the classification of authentic and adulterated honeys. RESULTS: The e-tongue and physicochemical parameters reached a 97.50% correct classification of the authentic and adulterated honeys. In the case of the adulterated honey samples, the e-tongue achieved 83.33% correct classifications whereas the physicochemical parameters only achieved 73.33%. CONCLUSION: The e-tongue is a fast, easy and accurate method for honey adulteration detection which can be used in situ by beekeepers and provide useful information on EC and free acidity. © 2018 Society of Chemical Industry.

Honey authentication using rheological and physicochemical properties.

The aim of this study was to evaluate the influence of honey botanical origins on rheological parameters. In order to achieve the correlation, fifty-one honey samples, of different botanical origins (acacia, polyfloral, sunflower, honeydew, and tilia), were investigated. The honey samples were analysed from physicochemical (moisture content, fructose, glucose and sucrose content) and rheological point of view (dynamic viscosity-loss modulus G″, elastic modulus G', complex viscosity η*, shear storage compliance-J' and shear loss compliance J″). The rheological properties were predicted using the Artificial Neural Networks based on moisture content, glucose, fructose and sucrose. The models which predict better the rheological parameters in function of fructose, glucose, sucrose and moisture content are: MLP-1 hidden layer is predicting the G″, η* and J″, respectively, MLP-2 hidden layers the J', while MLP-3 hidden layers the G', respectively. The physicochemical and rheological parameters were submitted to statistical analysis as follows: Principal component analysis (PCA), Linear discriminant analysis (LDA) and Artificial neural network (ANN) in order to evaluate the usefulness of the parameters studied for honey authentication. The LDA was found the suitable method for honey botanical authentication, reaching a correct cross validation of 94.12% of the samples.

Blue and Red LED Illumination Improves Growth and Bioactive Compounds Contents in Acyanic and Cyanic Ocimum basilicum L. Microgreens.

Microgreens are an excellent source of health-maintaining compounds, and the accumulation of these compounds in plant tissues may be stimulated by exogenous stimuli. While light quality effects on green basil microgreens are known, the present paper aims at improving the quality of acyanic (green) and cyanic (red) basil microgreens with different ratios of LED blue and red illumination. Growth, assimilatory and anthocyanin pigments, chlorophyll fluorescence, total phenolic, flavonoids, selected phenolic acid contents and antioxidant activity were assessed in microgreens grown for 17 days. Growth of microgreens was enhanced with predominantly blue illumination, larger cotyledon area and higher fresh mass. The same treatment elevated chlorophyll a and anthocyanin pigments contents. Colored light treatments decreased chlorophyll fluorescence ΦPSII values significantly in the green cultivar. Stimulation of phenolic synthesis and free radical scavenging activity were improved by predominantly red light in the green cultivar (up to 1.87 fold) and by predominantly blue light in the red cultivar (up to 1.73 fold). Rosmarinic and gallic acid synthesis was higher (up to 15- and 4-fold, respectively, compared to white treatment) in predominantly blue illumination. Red and blue LED ratios can be tailored to induce superior growth and phenolic contents in both red and green basil microgreens, as a convenient tool for producing higher quality foods.

Authentication of Romanian honeys based on physicochemical properties, texture and chemometric.

The purpose of this study was to investigate the physico-chemical properties (free acidity, pH, aw, ash content, moisture content, color (L*, a*, b*, hue-angle, chroma and yellow index), fructose, glucose and sucrose content) and textural parameters (viscosity, hardness, adhesion, springiness, cohesiveness, chewiness and gumminess) of 50 samples of honey of different botanical origin (acacia, polyfloral, honeydew, sunflower and tilia). In order to achieve the authentication of the honey samples analyzed, their data have been subjected to linear discriminant analysis (LDA) and principal component analysis (PCA).The PCA and LDA have proved the possibility of honey authentication using the physico-chemical and textural properties. LDA classified correctly 92.0% of the honeys based on their botanical origin, using the cross validation. In the LDA projection, the textural parameters (chewiness, hardness, cohesiveness, springiness) dominated the two functions.

Chemical composition and temperature influence on honey texture properties.

The aim of this study is to evaluate the chemical composition and temperatures (20, 30, 40, 50 and 60 °C) influence on the honey texture parameters (hardness, viscosity, adhesion, cohesiveness, springiness, gumminess and chewiness). The honeys analyzed respect the European regulation in terms of moisture content and inverted sugar concentration. The texture parameters are influenced negatively by the moisture content, and positively by the °Brix concentration. The texture parameters modelling have been made using the artificial neural network and the polynomial model. The polynomial model predicted better the texture parameters than the artificial neural network.

Honey microbiota, methods for determining the microbiological composition and the antimicrobial effect of honey - A review.

Honey is a natural product used since ancient times due to its taste, aroma, and therapeutic properties (antibacterial, antiviral, anti-inflammatory, and antioxidant activity). The purpose of this review is to present the species of microorganisms that can survive in honey and the effect they can have on bees and consumers. The techniques for identifying the microorganisms present in honey are also described in this study. Honey contains bacteria, yeasts, molds, and viruses, and some of them may present beneficial properties for humans. The antimicrobial effect of honey is due to its acidity and high viscosity, high sugar concentration, low water content, the presence of hydrogen peroxide and non-peroxidase components, particularly methylglyoxal (MGO), phenolic acids, flavonoids, proteins, peptides, and non-peroxidase glycopeptides. Honey has antibacterial action (it has effectiveness against bacteria, e.g. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Acinetobacter, etc.), antifungal (effectiveness against Candida spp., Aspergillus spp., Fusarium spp., Rhizopus spp., and Penicillium spp.), antiviral (effectiveness against SARS-CoV-2, Herpes simplex virus type 1, Influenza virus A and B, Varicella zoster virus), and antiparasitic action (effectiveness against Plasmodium berghei, Giardia and Trichomonas, Toxoplasma gondii) demonstrated by numerous studies that are comprised and discussed in this review.

Characterization of Beeswax and Rice Bran Wax Oleogels Based on Different Types of Vegetable Oils and Their Impact on Wheat Flour Dough Technological Behavior during Bun Making.

Five varieties of vegetable oil underwent oleogelation with two types of wax as follows: beeswax (BW) and rice bran wax (RW). The oleogels were analyzed for their physicochemical, thermal, and textural characteristics. The oleogels were used in the bun dough recipe at a percentage level of 5%, and the textural and rheological properties of the oleogel doughs were analyzed using dynamic and empirical rheology devices such as the Haake rheometer, the Rheofermentometer, and Mixolab. The thermal properties of beeswax oleogels showed a melting peak at a lower temperature for all the oils used compared with that of the oleogels containing rice bran wax. Texturally, for both waxes, as the percentage of wax increased, the firmness of the oleogels increased proportionally, which indicates better technological characteristics for the food industry. The effect of the addition of oleogels on the viscoelastic properties of the dough was measured as a function of temperature. All dough samples showed higher values for G' (storage modulus) than those of G″ (loss modulus) in the temperature range of 20-90 °C, suggesting a solid, elastic-like behavior of all dough samples with the addition of oleogels. The influence of the beeswax and rice bran oleogels based on different types of vegetable oils on the thermo-mechanical properties of wheat flour dough indicated that the addition of oleogels in dough recipes generally led to higher dough stability and lower values for the dough development time and those related to the dough's starch characteristics. Therefore, the addition of oleogels in dough recipes inhibits the starch gelatinization process and increases the shelf life of bakery products.

Development and Characterization of New Plant-Based Ice Cream Assortments Using Oleogels as Fat Source.

The objective of this study was to develop candelilla wax oleogels with hemp seed oil and olive oil and use them as a fat source in the development of new plant-based ice cream assortments. Oleogels were structured with 3 and 9% candelilla wax and characterized by oil-binding capacity, peroxide value and color parameters. The oil-binding capacities of 9% wax oleogels were significantly higher than those of 3% wax oleogels, while peroxide values of oleogels decrease with increasing wax dosage. All oleogel samples are yellow-green due to the pigments present in the oils and candelilla wax. Physicochemical (pH, titratable acidity, soluble solids, fat, protein) and rheological (viscosity and viscoelastic modulus) parameters of plant-based ice cream mixes with oleogels were determined. Also, sensory attributes and texture parameters were investigated. The results showed that titratable acidity and fat content of plant-based ice cream samples increased with increasing wax percentage, while pH, soluble solids and protein values are more influenced by the type of plant milk used. The plant-based ice cream sample with spelt milk, hemp oil and 9% candelilla wax received the highest overall acceptability score. The hardness of the plant-based ice cream samples increased as the percentage of candelilla wax added increased.

Structural, functional and physicochemical properties of pectin from grape pomace as affected by different extraction techniques.

Pectin from grape pomace (Vitis vinifera var. Feteasca Neagra and Vitis vinifera var. Rara Neagra) was extracted by using different extraction techniques (conventional, microwave-assisted and pulsed ultrasound-assisted extraction). Microwave-assisted extraction showed highest yield (11.2 %) for Rara Neagra pectin, while conventional extraction presented highest yield (9.9 %) for Feteasca Neagra pectin. The yield was directly correlated with the galacturonic acid content, degree of esterification, molecular weight and functional features (water-holding, oil-holding and water-swelling capacity, emulsifying properties and rheological behavior of pectin emulsions). In addition, the FT-IR, morphological structure, thermal analysis and emulsion properties of obtained pectin samples from different extraction techniques revealed dissimilar results by comparing with commercial pectin.

Characterization of Babeasca Neagra Grape Pomace and Incorporation into Jelly Candy: Evaluation of Phytochemical, Sensory, and Textural Properties.

The influence of particle size intervals (<125 µm, ≥125-<200 µm, and ≥200-<300 µm) of grape pomace (Vitis vinifera var. Babeasca Neagra) was analyzed in terms of the proximate composition, functional properties, and physicochemical parameters. The aim was to study the effect of the formulation variables (extract from grape pomace with different particle size intervals and gelatin doses-7, 8.5, and 10 g) on the mechanical properties (hardness, cohesiveness, adhesiveness, springiness, and gumminess), color, and sensorial, microbiological, and phytochemical parameters. The jelly candy formulated with grape pomace extract (<125 µm) and 7 g of gelatin showed the highest total phenolic content (156 mg GAE/g) and antioxidant activity (65.8% inhibition), while grape pomace jellies with a particle size of ≥125-<200 µm and different concentration of gelatin presented the greatest sensory acceptance in terms of sweetness, taste, odor, elasticity, color, and overall acceptability of the resulting jelly. The concluding observation was supported by the microbiological analysis, which also showed that there is no growth in jelly samples except the jelly candies prepared with a ≥200-<300 µm particle size interval of grape pomace extract.

Honey authentication and adulteration detection using emission - excitation spectra combined with chemometrics.

The aim of this study was to evaluate the usefulness of emission-excitation matrices for honey authentication and adulteration detection. For this purpose, 4 types of authentic honeys (tilia, sunflower, acacia and rape) and samples adulterated with different adulteration agents (agave, maple, inverted sugar, corn and rice in different percentages - 5%, 10% and 20%) were analysed. Each honey type and each adulteration agent exhibit unique emission-excitation spectra that can be used for the classification according to the botanical origin and for the detection of adulteration. The principal component analysis clearly separated the rape, sunflower and acacia honeys. The partial least squares - discriminant analysis (PLS-DA) and support vector machines (SVM) were used in a binary mode to separate the authentic honeys from the adulterated ones, and the SVM proved to separate much better than PLS-DA.

A comparative study regarding the adulteration detection of honey: Physicochemical parameters vs. impedimetric data.

Honey adulteration is a major issue for European Union and its members because of an unfair practice of different producers and beekeepers, many adulterations involve the addition of sweet, concentrated syrups which may appear like honey. In our study we analysed the influence of adulteration of tilia honey with different syrups (such as corn, rice, inverted sugar, agave, maple syrups) in different percentages (5%, 10%, and 20% respectively) on physicochemical parameters (moisture content, L*, hab,cab, pH, free acidity, electrical conductivity (EC), 5-hydroxymetilfurfural (HMF), fructose, glucose, sucrose, turanose, trehalose, melesitose and raffinose) and impedimetric properties using electrochemical impedance spectroscopy. The impedimetric sensing was made using an electrochemical cell composed of two gold electrodes, and the frequency ranged between 0.1 kHz and 100 kHz. The impedimetric parameters (Z', Z″ and phase) and Randal circuit parameters can distinguish the authentic honeys from the adulterated ones (based on the adulteration agent and adulteration percentage, respectively). The partial least squares - discriminant analysis (PLS-DA) and support vector machines (SVM) were used in a binary mode to separate the authentic honeys from the adulterated ones, and the SVM proved to separate much better than PLS-DA.

Structuring of Cold Pressed Oils: Evaluation of the Physicochemical Characteristics and Microstructure of White Beeswax Oleogels.

The aim of the study was to characterize the gelling effect of beeswax (BW) using different types of cold pressed oil. The organogels were produced by hot mixing sunflower oil, olive oil, walnut oil, grape seed oil and hemp seed oil with 3%, 7% and 11% beeswax. Characterization of the oleogels was done using Fourier transform infrared spectroscopy (FTIR), the chemical and physical properties of the oleogels were determined, the oil binding capacity was estimated and the SEM morphology was studied. The color differences were highlighted by the CIE Lab color scale for evaluating the psychometric index of brightness (L*), components a and b. Beeswax showed excellent gelling capacity at 3% (w/w) of 99.73% for grape seed oil and a minimum capacity of 64.34%for hemp seed oil. The value of the peroxide index is strongly correlated with the oleogelator concentration. Scanning electron microscopy described the morphology of the oleogels in the form of overlapping structures of platelets similar in structure, but dependent on the percentage of oleogelator added. The use in the food industry of oleogels from cold-pressed vegetable oils with white beeswax is conditioned by the ability to imitate the properties of conventional fats.

Oat Yogurts Enriched with Synbiotic Microcapsules: Physicochemical, Microbiological, Textural and Rheological Properties during Storage.

The aim of this study was to evaluate the influence of synbiotic microcapsules on oat yogurt's properties. For this study, four different microcapsules were added into the oat yogurt and the modifications were studied for 28 days. Microbiological analysis was used to analyze the effect of different factors on the microencapsulated probiotic population in the product. Those factors are: the technological process of obtaining microcapsules; the type of prebiotic chicory inulin (INU), oligofructose (OLI) and soluble potato starch (STH); the prebiotic concentrations in the encapsulation matrix; the technological process of obtaining yogurt; and the yogurt storage period, gastric juice action and intestinal juice action. The experimental data show that oat yogurt containing synbiotic microcapsules has similar properties to yogurt without microcapsules, which illustrates that the addition of synbiotic microcapsules does not change the quality, texture or rheological parameters of the product. Oat yogurt with the addition of synbiotic microcapsules can be promoted as a functional food product, which, in addition to other beneficial components (bioactive compounds), has in its composition four essential amino acids (glycine, valine, leucine and glutamine acids) and eight non-essential amino acids (alanine, serine, proline, asparagine, thioproline, aspartic acid, glutamic acid and α-aminopimelic acid). After 28 days of storage in refrigerated conditions, the cell viability of the microcapsules after the action of the simulated intestinal juice were: 9.26 ± 0.01 log10 cfu/g, I STH (oat yogurt with synbiotic microcapsules-soluble potato starch); 9.33 ± 0.01 log10 cfu/g, I INU, 9.18 ± 0.01 log10 cfu/g, I OIL and 8.26 ± 0.04 log10 cfu/g, IG (oat yogurt with microcapsules with glucose). The new functional food product provides consumers with an optimal number of probiotic cells which have a beneficial effect on intestinal health.

Microwave-assisted extraction of pectin from grape pomace.

The utilization of microwave technique for the pectin extraction from grape pomace (Feteasca Neagra and Rara Neagra), its influence on yield, galacturonic acid content, degree of esterification and molecular weight of pectin were analyzed. The optimal conditions of the extraction process were microwave power of 560 W, pH of 1.8 for 120 s. The pectin samples extracted by MAE in optimal conditions were analyzed by comparing with commercial apple and citrus pectin based on FT-IR analysis, thermal behavior, rheological characteristics and microstructure. The FT-IR analysis established the presence of different functional groups which are attributed to the finger print region of extracted pectin, while the rheological behavior presented a good viscoelasticity of pectin solutions. The obtained data assumes that grape pomace has a great potential to be a valuable source of pectin which can be extracted by simple and quick techniques, while maintaining analogous quality to conventional sources of pectin.

The Influence of Extraction Conditions on the Yield and Physico-Chemical Parameters of Pectin from Grape Pomace.

Grape pomace is one of the most abundant by-products generated from the wine industry. This by-product is a complex substrate consisted of polysaccharides, proanthocyanidins, acid pectic substances, structural proteins, lignin, and polyphenols. In an effort to valorize this material, the present study focused on the influence of extraction conditions on the yield and physico-chemical parameters of pectin. The following conditions, such as grape pomace variety (Feteasca Neagra and Rara Neagra), acid type (citric, sulfuric, and nitric), particle size intervals (<125 µm, ≥125−<200 µm and ≥200−<300 µm), temperature (70, 80 and 90 °C), pH (1, 2 and 3), and extraction time (1, 2, and 3 h) were established in order to optimize the extraction of pectin. The results showed that acid type, particle size intervals, temperature, time, and pH had a significant influence on the yield and physico-chemical parameters of pectin extracted from grape pomace. According to the obtained results, the highest yield, galacturonic acid content, degree of esterification, methoxyl content, molecular, and equivalent weight of pectin were acquired for the extraction with citric acid at pH 2, particle size interval of ≥125−<200 µm, and temperature of 90 °C for 3 h. FT-IR analysis confirmed the presence of functional groups in the fingerprint region of identification for polysaccharide in the extracted pectin.