Acid In Food Products Research Articles

Prenylated (iso)flavonoids as antifungal agents against the food spoiler Zygosaccharomyces parabailii

Species belonging to the Zygosaccharomyces bailii sensu lato clade are some of the most troublesome spoilage yeasts of acidic food products, primarily due to their resistance towards synthetic food preservatives, like weak organic acids. Therefore alternative, powerful and more natural antifungal agents are needed. Herein, prenylated isoflavonoids, present mainly in the Leguminosae family, were investigated for their antifungal properties (including potency and mode of action) against a Z. bailii food isolate, its interspecies hybrid, Z. parabailii. The mono-prenylated isoflavonoids, wighteone and glabridin were the most active, with minimum fungicidal concentrations (MFC) of 12.5 μg/mL (37 μM) and 25 μg/mL (77 μM), respectively, at pH 4.0, rendering them over 20 times (on weight basis) more potent than sorbic acid (MFC 550 μg/mL, 4.5 mM). The two active mono-prenylated isoflavonoids induced killing within 15 min, suggesting potential membrane activity. Membrane permeabilization by these molecules was confirmed by propidium iodide uptake and TEM imaging. Membrane permeabilization was accompanied with leakage of intracellular material. Molecular properties such as the electrostatic energy potential and the hydrophobic integy moment were correlated to activity through a binary classification quantitative structure-activity relationship (QSAR) model. Altogether, mono-prenylated isoflavonoids can serve as highly potent, novel and natural antifungal against Z. parabailii acting by severely compromising the membrane integrity.

Facile and sensitive photoelectrochemical detection of kojic acid in food products: a general strategy for immobilization-free analysis of enzyme inhibitors.

As one of the representative secondary metabolites in fermentation processes and common additives in modern industry, kojic acid (KA) has been mired in controversy in recent years due to its potential toxicity and carcinogenicity. Hence, it is of high importance to develop novel analysis strategies for KA to surveil its rational utilization and ensure public health. Based on enzyme modulated sensitization of TiO2 NPs and the inhibition effect of KA towards tyrosinase (Tyr), we report a facile and sensitive photoelectrochemical (PEC) sensor for KA in food samples. On an operational level, this protocol excluded the tedious immobilization process of traditional PEC enzyme sensors, allowing the crucial catalysis and sensitization process to take place in a small centrifuge tube, making the experimental process concise and fast. Under optimized conditions, a linear detection range of 10-7 M to 10-3 M was achieved, with a detection limit of 3.2 × 10-8 M. Furthermore, the feasibility of the strategy in food samples was validated in vinegar and wheat flour. This protocol would hold great promise for real application in diverse food products, and offer a general prototype for future immobilization-free and quick analysis of other enzyme inhibitors.

Studies of the content of optical isomers of amino acids in food

Food products undergo a wide range of chemical changes during their processing and storage. As a result of such reactions, both new chemical compounds and optical isomerization of compounds already present in the composition can be formed. The second case concerns the formation of D-enantiomers of amino acids from their L-forms. D-forms of amino acids not only have no biological value for the body, but also often have a negative effect on the human body due to the impossibility of metabolizing them and, as a consequence, their accumulation in the body. The aim of the work was to study the quantitative content of D-isomers of amino acids in milk that passed the ultra-pasteurization process and dairy products based on bacterial starter culture. The research results showed that in both cases of the considered technological methods, amino acid isomerization occurs. The highest degree of isomerization was observed in kefir samples relative to other samples. However, from the results obtained, it is not possible to estimate which amino acid is most susceptible to the racemization process, since different samples contained different D-isomers of amino acids. The smallest amount of D-isomers is found in milk that has not undergone any industrial processing. Studies have shown that technological processing of milk inevitably leads to the formation of D-isomers of amino acids, and this, in turn, at least reduces the nutritional and biological value of the product, which makes it necessary to conduct deeper studies in this direction to establish the most important factors in the process of racemization of amino acids in food products.

Influence of Transglutaminase on Glucono-δ-lactone-Induced Soy Protein Gels

Enzymatic cross-linking of proteins can be used to create a variety of foods with appealing textures and facilitate further processing such as slicing or packaging. Transglutaminase (TG), a protein-glutamine-γ-glutamyltransferase, has been used in the production of processed meat and fish products. However, it has a reaction optimum at pH 7 and is therefore typically unsuitable for application in up-and-coming acidic food products such as fermented vegan meat product alternatives. To determine whether a simultaneous addition of slowly acidifying glucono-δ-lactone (GDL) and TG can facilitate protein cross-linking prior to the pH becoming too low, TG and GDL were added separately or in combination to soy protein suspensions composed of 10–15% soy protein concentrates or isolates (SPI). Texture analysis showed that SPI gels at pH 5–6, induced by GDL and TG combined, were harder than only GDL-induced gels and as hard as TG-induced gels at the optimum pH of 7. Decreased tan δ values and confocal laser scanning microscopy images indicated that protein cross-linking had taken place in combined gels. The results suggest an initial network formation induced by TG, which later in the acidification is being supplemented by an agglomeration of proteins due to weakened electrostatic repulsion. Taken together, the combination of slow acidification by GDL and TG addition leads to acidic gels with enhanced textural properties and shelf life.

Determination of quinoxalines veterinary drug residues in food products of animal origin by high performance liquid chromatography-tandem mass spectrometry

To establish a high performance liquid chromatography-tandem mass spectrometry(HPLC-MS/MS)method for simultaneous determination of olaquindox, quinoxaline-2-carboxylic acid, 3-methyl-quinoxaline-2-carboxylic acid in food products of animal origin. Samples were extracted with ethyl acetate-0.1 mol/L sodium dihydrogen phosphate(1∶9, V/V) solution in water bath at 40 ℃, purified by solid phase extraction column(olaquindox uses HLB SPE cartridge, quinoxaline-2-carboxylic acid and 3-methyl-quinoxaline-2-carboxylic acid use MAX SPE cartridge), evaporated by concentrator, and dissolved by mobile phase. The supernatant was separated on Agilent ZORBAX SB-C_(18) column(2.1 mm×50 mm, 1.8 m), using 0.2% formic acid solution methanol solution as mobile phase, and then detected by HPLC-MS/MS using multiple reaction monitoring(MRM) in positive ionization mode. The linear range for olaquindox、quinoxaline-2-carboxylic acid and 3-methyl-quinoxaline-2-carboxylic acid were 2.5-100 μg/L, r & gt; 0.9990.The average recoveries were 72.6%-90.5% and the precisions were 3.2%-13.1%(n=6). The detection limits for olaquindox、quinoxaline-2-carboxylic acid and 3-methyl-quinoxaline-2-carboxylic acid were 0.08 μg/kg. The method is specific, sensitive, easy, fast and suitable for the confirmation and quantification of olaquindox、quinoxaline-2-carboxylic acid、3-methyl-quinoxaline-2-carboxylic acid in food products of animal origin.

Approaches to study the oxidative stability of oleogels

Research is currently underway on structured edible oils (oleogels) as an alternative to traditional fats in healthy food technologies. The main function of oleogels is to replace trans-isomer and saturated fatty acids in food products. In this regard, most studies are focused on the structural and mechanical properties of oleogels and the factors influencing structural formation. However, insufficient attention is paid to the study of oxidative processes in such systems. This work aimed to study the oxidative stability of oleogels based on sunflower oil and beeswax during storage. Oxidative stability studies were carried out using standard (ISO 3960: 2007, Cd-12c-16 AOCS) and original (by measuring the rate of dye penetration into the oleogel volume) methods. Oleogels were stored at 35 °C for 144 hours. It was found that 3% and 6% of beeswax in the composition of oleogel express the prooxidant properties relative initial oil.

Quantification of ω-fatty acids through GC-MS analysis in flaxseed (Linum Usitatisium L.)

The current research is focused on the evaluation of ω-unsaturated fats on dry basis in flaxseed to enhance the implementation of Polyunsaturated fatty acids (PUFA) in the prepared nourishment to get the total eating regimen for customers. These have significant result on infection anticipation like cardiovascular disorder, coronary ailment, sickness possibility, (for instance, prostate lung, and colon, chest, etc.), immune disarray, menopause, and diabetics. The extraction of flaxseed performed with (solvent ratio1:5v/v) utilizing hexane, methanol, dichloromethane, and acetonitrile. The portrayal and evaluation of ω-unsaturated fats was by the GC-MS interpretation with utilizing the popularity of standard fatty acid methyl ester (FAME) solution. The Linolenic acid (ω-3), Linoleic acid (ω-6), and Oleic acid (ω-9) unsaturated fats amount in flaxseed concentrate was found to be 21.36 µg/g, 5.6 µg/g and 2.9 µg/g (dry matter basis) respectively. This would be beneficial to the improvement of practical and nutraceutical nourishment for destitute buyers and investigate the usage of PUFA acids in food products.

Modeling the buffer capacity of ingredients in salad dressing products.

The pH of most acid food products depends on undefined and complex buffering of ingredients but is critically important for regulatory purposes and food safety. Our objective was to define the buffer capacity (BC) of ingredients in salad dressing products. Ingredients of salad dressings were titrated individually and in combination using concentrations typical of dressing products. Titration curves from pH 2 to 12 were generated with sodium hydroxide and hydrochloric acid, which were then used to generate BC curves. A matrix of concentration and pK values for a series of monoprotic buffers approximated the pH of each ingredient. Some buffer series required anion or cation corrections for accurate pH prediction, possibly due to the presence of salts of acid or bases. Most buffers had BC values less than 10-fold the BC of acetic acid (0.25 β) typically in dressing formulations and had little influence on the final product pH of the dressings tested. Unexpectedly, we found that sugars in dressing formulations, including sucrose or corn syrup, exhibited buffering at pH values greater than 11 (0.035 β and 0.059 β, respectively), which was likely due to weakly acidic hydroxyl groups on the sugar molecules. However, the concentration and pK for buffers above pH 11 or below pH 2 were difficult to quantify due to the BC of water. The BC data may help to quantify the effects of salad dressing ingredients on the final product pH and benefit regulatory agencies and manufacturers in assessing product pH and safety. PRACTICAL APPLICATION: Buffer capacity data for salad dressing ingredients may help determine the influence ingredient addition will have on the final pH of a salad dressing product. The addition of low acid ingredients with little or no buffering may not significantly alter pH. The modeling method may be useful for regulatory purposes to estimate the effects of low acid ingredients on pH changes for food safety and may also be useful for product development of acid and acidified foods.

MnFe2O4/1-Butyl-3-methylimidazolium hexafluorophosphate modified carbon paste electrode: an amplified food sensor for determination of gallic acid in the presence of ferulic acid as two phenolic antioxidants

A MnFe2O4 nanoparticle/1-Butyl-3-methylimidazolium hexafluorophosphate (BMIM-PF6) was incorporated into carbon paste electrode (MnFe2O4/BMIM-PF6/CPE) and used as food electrochemical sensor for the study of the electrochemical determination of gallic acid in the presence of ferulic acid for the first time. The structure and morphology of MnFe2O4 nanoparticle was investigated by TEM methods. Meanwhile, the electrochemical performance of the MnFe2O4/BMIM-PF6/CPE towards gallic acid and ferulic acid determination was demonstrated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The MnFe2O4/BMIM-PF6/CPE exhibited a wide linearity of 0.005–220.0 µM for gallic acid and 0.3–250 µM for ferulic acid with detection limits of 1.0 nM and 0.1 µM, respectively. Furthermore, the ability of MnFe2O4/BMIM-PF6/CPE was tested for the determination of gallic acid and ferulic acid in food products.

Improving emulsion stability based on ovalbumin-carboxymethyl cellulose complexes with thermal treatment near ovalbumin isoelectric point

Ovalbumin (OVA) is an important protein emulsifier. However, it is unstable near the isoelectric point pH, which limits its applications in the food industry. Polysaccharides may be explored to tackle this challenge by improving its pH-dependent instability. In this work, carboxymethyl cellulose (CMC) was used as a model polysaccharide to mix with OVA near its isoelectric point (pH 4.7) with subsequent mild heating at 60 °C for 30 min. The molecular interactions between OVA and CMC were comprehensively studied via a series of characterizations, including turbidity, zeta potential, intrinsic fluorescence, surface hydrophobicity, circular dichroism (CD) spectra and Fourier transform infrared spectroscopy (FTIR). The droplet sizes of the emulsions prepared by OVA-CMC were measured to analyze emulsifying property and stability. The results indicated that free OVA was easily aggregated due to loss of surface charges, while complexing with CMC significantly inhibited OVA aggregation before and after heating owing to the strong electrostatic repulsion. In addition, OVA exposed more hydrophobic clusters after heating, which resulted in the growth of surface hydrophobicity. Altogether, the heated OVA-CMC complexes presented the best emulsifying property and stability. Our study demonstrated that complexing OVA with CMC not only greatly improved its physicochemical properties but also significantly enhanced its functionality as a food-grade emulsifying agent, expanding its applications in the food industry, as development of emulsion-based acidic food products.

HPLC Analysis of Citric and Tartaric Acids in Fruit Nectars and Juices

The aim of this study was to estimate a level of citric and tartaric acids in fruit nectars (n = 17) and juices (n = 13) available on the Croatian market. For analysis reverse-phase HPLC with UV/Vis detector set at 214 nm was used. Mobile phase was phosphate buffer (50 mM, pH = 2.80) at flow rate 0.5 mL min–1. The method was linear (r2 = 0.9999). LoD was 0.01 g L–1, LoQ was 0.03 g L–1 and the intra-day along with the inter-day variability were up to 3 %. The level of citric and tartaric acids in fruit nectars ranged from 1.26 to 4.42 g L–1 and 0.68 to 0.86 g L–1, respectively, and in fruit juices ranged from 3.03 to 7.67 g L–1 and 3.09 to 4.68 g L–1, respectively. A higher level of citric acid in fruit juices than in fruit nectars was detected (p < 0.05; MannWhitney U test). Six fruit juices contained a higher level of citric acid allowed by EU regulation implying the importance of monitoring concentrations of both acids in food products. This work is licensed under a Creative Commons Attribution 4.0 International License .

Norbixin binding to whey protein isolate - alginate electrostatic complexes increases its solubility and stability

Norbixin is a carotenoid extracted from the Annatto plant (Bixa orellana) and widely used as a natural colorant in pharmaceuticals, cosmetics and food. It is water-soluble at neutral and alkaline pH, but below neutral pH, norbixin starts to precipitate limiting the use in acidic food products. As a new approach to enhance the solubility and stability of norbixin in aqueous solution under acidic conditions, the colorant was applied in the presence of whey protein isolate (WPI) and alginate (ALG). Addition of WPI prevented norbixin precipitation between pH 2 and pH 7 except at the pI of WPI, pH 5. The visual appearance, colorimetric measurements and a blue shift in the absorbance spectrum indicated that norbixin formed H-aggregates at pH < 7, but the aggregates were stabilized by WPI addition. Fluorescence spectroscopy measurements indicated interactions between both soluble norbixin and WPI at pH 7 and aggregated norbixin and WPI at pH 3. Particle size measurements indicated formation of complexes between norbixin aggregates and WPI. Additionally to preventing the precipitation of norbixin, the WPI-norbixin interaction also increased the color stability of norbixin during storage at both neutral and acidic pH. At pH 5, isoelectric precipitation of WPI was prevented by the inclusion of ALG, likely due to electrostatic interactions between WPI and ALG leading to the formation of norbixin, WPI and ALG complexes. The use of WPI and ALG complexation of norbixin can therefore be a new way to expand the usage of norbixin coloring of foods at acidic pH conditions.

Estimation of prospects of the production from domestic vegetable raw materials balanced on polyunsaturated fatty acids

There was made an evaluation of the possibility of the solution of the problem of imbalance of polyunsaturated fatty acids in the diet ration of the population by means of engagement of vegetable sources. There were both analyzed the composition and properties of products of the processing of unoiled domestic plant raw material containing w-3 unsaturated acids and established prospects of their use in technologies of the balancing of polyunsaturated fatty acids in food products.

Characteristic of Protein Hydrolyzate Starch of Snakehead Fish (Channa Striata) Head

The making of protein hydrolyzate of snakehead fish head by using spray drying method and it is encapsulated with maltodextrin in which a final product in the form of starch is expected to ease the process of storage and extend the shelf-life of the product. This research was aimed to determine the quality of protein hydrolyzate starch of snakehead fish head with inlet temperature treatment of spray drying 1200C and outlet temperature of 800C and the addition of maltodextrin. The design used is independent t-test. It was conducted to compare the average value of sample composition. Experimental data were processed using Statistical Package for Social Science (SPSS) 21.0 for Windows. The best treatment from the research is a comparison of snakehead fish starch and maltodextrin 95%:5%. The characteristic of physicochemical of snakehead fish starch as produced in the form of white starch with a yield of 21.35%, white degree L 97.73, water content 4.52%, ash 7.92%, protein 75.25%, fat 0.60%. Based on this, the protein hydrolyzate of snakehead fish head has the potential to be applied as a flavoring or flavor enhancer and it can be developed as a source of essential amino acids in food products because they contain almost complete essential amino acids.

Analysis of trans‐Fatty Acids in Food Products Using Various GC Columns

Analysis of <i>trans</i>‐Fatty Acids in Food Products Using Various GC Columns

Purification and characterization of dextran produced by Leuconostoc pseudomesenteroides PC as a potential exopolysaccharide suitable for food applications

Abstract An exopolysaccharide (EPS)-producing bacterial strain, PC, was isolated from pickled Chinese cabbage and identified as Leuconostoc pseudomesenteroides. EPS yield was up to 30.5 g/L when bacteria were cultivated in Man-Rogosa-Sharpe (MRS) medium containing 5% sucrose at 30°C for 48 h. Further analysis by gas chromatography, high performance size exclusion chromatography, and nuclear magnetic resonance revealed that the EPS consisted of glucose with α-(1→6) linkages and had a molecular weight of 3.13 × 106 Da. Scanning-electron microscopy demonstrated an irregular sheet structure and porous surface, and lumps with an average height of 77.803 nm were observed by atomic force microscopy. Physical-chemical analysis showed that the EPS exhibited excellent thermal stability and possessed high viscosity at high concentration, low temperature and acidic pH, making it promising to be used in thermal processed foods and fermentation of acidic food products. Milk solidification test also suggested the promising potential for application as a dairy and food additive since the EPS could activate the solidification of sucrose-supplemented milk. Taken together, this study provides a commercial guidance for the practical application of PC EPS in food industry and other areas.

The bioavailability of iron picolinate is comparable to iron sulfate when fortified into a complementary fruit yogurt: a stable iron isotope study in young women

PurposeA technological gap exists for the iron (Fe) fortification of difficult-to-fortify products, such as wet and acid food products containing polyphenols, with stable and bioavailable Fe. Fe picolinate, a novel food ingredient, was found to be stable over time in this type of matrix. The objective of this study was to measure the Fe bioavailability of Fe picolinate in a complementary fruit yogurt.MethodsThe bioavailability of Fe picolinate was determined using stable iron isotopes in a double blind, randomized cross-over design in non-anemic Swiss women (n = 19; 25.1 ± 4.6 years). Fractional Fe absorption was measured from Fe picolinate (2.5 mg 57Fe per serving in two servings given morning and afternoon) and from Fe sulfate (2.5 mg 54Fe per serving in two servings given morning and afternoon) in a fortified dairy complementary food (i.e. yogurt containing fruits). Fe absorption was determined based on erythrocyte incorporation of isotopic labels 14 days after consumption of the last test meal.ResultsGeometric mean (95% CI) fractional iron absorption from Fe picolinate and Fe sulfate were not significantly different: 5.2% (3.8–7.2%) and 5.3% (3.8–7.3%) (N.S.), respectively. Relative bioavailability of Fe picolinate versus Fe sulfate was 0.99 (0.85–1.15).ConclusionTherefore, Fe picolinate is a promising compound for the fortification of difficult-to-fortify foods, to help meet Fe requirements of infants, young children and women of childbearing age.

PREREQUISITES FOR THE FORMATION OF D - ENANTIOMERS OF AMINO ACIDS OF ANIMAL PROTEINS IN THE MANUFACTURING PROCESS OF MEAT PRODUCTS

The paper presents studies on the presence or formation of d - enantiomers of amino acids in animal tissues or organs, in meat products during its production processes. It is shown that the process of epimerization of L - amino acid residues with the formation of D-enantiomers affect the reduction of the properties of food products, including the formation of oncoassociated subsequent effects on the human body.Modern control of the quantitative and qualitative composition of d-enantiomers of amino acids in food products, monitoring for stratification of the increased risk of toxic compounds in food are becoming an urgent medical and social problem. The studies planned in this paper are aimed at developing approaches to the creation of food products that reduce the oncogenic alimentary load on human health by solving the problem of technological modification of production, eliminating or minimizing post - translational modifications in proteins that contribute to the formation of d-enantiomers of amino acids. These studies will create a scientific and technological database associated with the risk assessment of carcinogenesis in protein matrices of animal origin. Based on the presented analysis, the task of developing and testing a method to control the accumulation of D-isomers in the course of various technological processes of meat production is extremely popular.

Release kinetics of rosemary (Rosmarinus officinalis) polyphenols from polyvinyl alcohol (PVA) electrospun nanofibers in several food simulants

Abstract Polyvinyl alcohol (PVA) electrospun mats with antioxidant activity (PVA/Ros) were obtained by incorporating rosemary extract (RE) into the electrospinning precursor solution. RE compounds interact with PVA, favoring the retention of polyphenols (88 ± 2%), and improving its thermal stability. The components extracted from PVA/Ros mat were the same as those of the RE. PVA/Ros mats showed a polyphenol content of (15.4 ± 0.5) mg gallic acid equivalent/g of mat (mg GAE/g) and achieved an antioxidant activity of (120 ± 8) μmoles Trolox equivalent/g of mat (μmol TE/g), as measured by Folin-Ciocalteu method and DPPH assay. The release rate of rosemary polyphenols to several food simulants was measured and kinetic data was adjusted by Fick’s diffusion law, Power Law, and Weibull model. The resulting parameters suggested that polymer chain relaxation is the leading mechanism in hydrophilic simulant, while an anomalous release occurred in acid medium. A burst release was observed in lipophilic food simulant, limiting its effectiveness over time. This work shows the potential application of PVA/Ros mats as active food packaging, particularly for hydrophilic and acid food products.

Electrochemical Determination of Tyrosine and Tryptophan Using Ultraviolet Irradiated Tungsten Trioxide Nanoparticles

Amino acids are derived by the human body through the breakdown of proteins that enters in the form of diet in foods. Among 22 standard amino acids, L-Tyrosine (Tyr) and L-Tryptophan (Trp) play important roles in the biochemical, nutritional and clinical significance in mammalian systems. Tyrosine (4- hydroxyphenylalanine) is a non-essential amino acid because, under normal conditions, the body synthesizes sufficient quantities from phenylalanine. It acts as a precursor for catecholamine neurotransmitters and hormones such as L-dopa, dopamine, norepinephrine and epinephrine, melanin and thyroid hormones. Tryptophan (2S-2-amino-3-(1H-indol-3-yl) propanoic acid) is one of the essential amino acids which is commonly synthesized in plants and microorganism from shikimic acid. Trp acts as precursor for the indolamine neurotransmitters such as serotonin, melatonin and vitamin B6 niacin. Improper metabolism of both the aromatic amino acids leads to depression, Parkinson’s disease, sister chromatid exchange, hallucinations, schizophrenia, drowsiness and appetite suppression [1]. Therefore, the development of a simple and sensitive tool for the determination of amino acids in food products and pharmaceuticals is necessary to have great importance in life science research. Here, we report a simple method for the electrochemical determination of Tyr and Trp based on ultraviolet (UV) irradiated tungsten trioxide (WO3) nanoparticles modified glassy carbon electrode (GCE) without using surface mediators or promotors. Irradiation with appropriate sources such as gamma rays, swift heavy ion and low energy ion beam have been used as an efficient tool to improve its physic-chemical properties [2-5]. In addition to these fairly sophisticated tools, UV light irradiation can be considered as an alternative method due to its advantageous features like room temperature processes, creating defects in a controlled manner, easy to operate and long service life. Li et al., reported that the exposure of WO3 photoanodes to UV irradiation leads to improvements in photoelectrochemical activity towards the oxygen evolution reaction [6]. In the current work, WO3 nanoparticles were synthesized via UV irradiation with variant exposure time (2, 4, 6 and 8 hr) and characterized by powder XRD, FESEM, Raman, UV-Vis absorption and photoluminescence spectra. Optimally irradiated (4 hr) WO3 NPs exhibited reduced crystallite size with fragmented spherical particles and increased band gap energy due to induced oxygen defects and vacancies. Cyclic Voltammetry (CV) studies of UV-4 hr WO3/GCE showed an excellent electrocatalytic activity towards the oxidation of Tyr and Trp in phosphate buffer solution (PBS, pH 6.0) in the presence of several potentially interfering compounds. Differential pulse voltammetry (DPV) studies of the modified GCE exhibited linear response over a wide concentration range of 0.1 to 1100 µM (Tyr) and 0.1 to 1000 µM (Trp) with the lowest detection limit of 41 nM and 55 nM respectively for Tyr and Trp. Under optimum experimental conditions, influence of various interfering compounds was investigated by DPV method. A series of foreign species were added into 0.1 M PBS (pH 6.0) containing 2 µM Tyr and 5 µM Trp and the tolerance limit was found to be approximately ±2% relative error in the determination of Tyr and Trp. It was noted that 500-fold excess of ascorbic acid, uric acid, cysteine, Na+ and K+ ions and 50-fold excess of dopamine, serotonin, melatonin, epinephrine and norepinephrine had no significant effect on the response of the two analytes. These results indicate that the proposed electrode can act as a highly selective sensor for recognition of Tyr and Trp in aqueous solutions. The fabricated sensor was successfully applied to determine Tyr and Trp concentration in milk, curd and egg samples with satisfactory recoveries. Keywords: WO3 nanoparticles; Ultraviolet irradiation; Electrochemical sensor; Tyrosine; Tryptophan; Dairy products.