Qualitative tests for the determination of fraud in raw milk: evaluation of the influence of analytical parameters of the tests and the stability of the samples as a function of time and preservation form

The present work aimed to evaluate the robustness of qualitative tests of frauds of addition of chlorine/hypochlorite, hydrogen peroxide and starch in raw milk, which parameters have the greatest influence on these analytical methods, and to evaluate the influence of time and mode of preservation of intentionally adulterated samples. The effects of the variation of some parameters of the analytical procedures were evaluated, making combinations between the different factors, determining the degree of influence of these variations on the tests. The stability time of the frauds in the samples was evaluated, keeping them under refrigeration (3±2 °C) and carrying out the tests on the same day, and under freezing (≤ -18 °C) for 5, 9 and 15 days, later analyzed, verifying if the frauds were detected. According to the results, it could be observed that the chlorine/hypochlorite detection method was adequate, detecting the addition of the adulterant in all combinations of variables and in all forms of conservation of the samples. The method for detecting the addition of hydrogen peroxide proved to be adequate for the samples analyzed immediately (< 24 h), detecting the presence of the substance in all combinations. However, the method did not detect the presence of peroxide in the combinations for the frozen samples, indicating that the method can generate false negatives in samples that are not fresh. The starch detection method did not detect the presence of this contaminant in all combinations of variables. The combinations that used only a drop of the Lugol’s iodine solution showed false negatives, so the amount of added solution is a critical variable for the method. However, for the other combinations, the method proved to be adequate for both fresh and frozen samples, detecting the addition of starch, regardless of storage time.

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Choline Salicylate Analysis: Chemical Stability and Degradation Product Identification

Molecules ◽

10.3390/molecules25010051 ◽

2019 ◽

Vol 25 (1) ◽

pp. 51

Author(s):

Katarzyna B. Wróblewska ◽

Szymon Plewa ◽

Paweł Dereziński ◽

Izabela Muszalska-Kolos

Keyword(s):

Hydrogen Peroxide ◽

Hplc Analysis ◽

Degradation Products ◽

Hydrolytic Degradation ◽

Acid Media ◽

Product Identification ◽

The Stability ◽

Degradation Degree ◽

Effect Of Light

Choline salicylate (CS) as a derivative of acetylsalicylic acid is commonly used in different drug forms. In medicine, it is applied topically to inflammation of the oral cavity mucosa and in laryngology. However, this substance in the form of an ionic liquid has not been investigated enough. There are no literature studies on stability tests constituting a stage of pre-formulation research. HPLC (Nucleosil C18, 4.6 × 150 mm, 5 μm; methanol-water-acetic acid 60:40:1, 230 nm or 270 nm) and UV (276 nm) methods for the determination of CS in 2% (g/mL) aqueous solutions were developed. Under stress conditions, CS susceptibility to hydrolytic degradation in aqueous medium, hydrochloric acid, sodium hydroxide, and hydrogen peroxide, and the effect of light on the stability of CS solutions were studied with HPLC analysis. The degradation degree of CS and the purity of the solutions were also tested. Choline salicylate has been qualified as practically stable in neutral and acid media, stable in an alkaline medium, very stable in an oxidizing environment, and photolabile in solution. The HPLC-MS/MS method was used to identify 2,3- and 2,5-dihydroxybenzoic acids as degradation products of CS under the tested conditions.

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The Study of Raw Milk Quality Control

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.411-414.2417 ◽

2013 ◽

Vol 411-414 ◽

pp. 2417-2422

Author(s):

Yao Li Zhang ◽

Jing Chen ◽

Xin Zhong

Keyword(s):

Dairy Products ◽

Detection Method ◽

Microbiological Quality ◽

Raw Milk ◽

Test Methods ◽

Milk Quality ◽

Living Standard ◽

Practical Consideration ◽

Key Points

Now, along with the improvement of people's living standard, more and more people quality safety problems of dairy products by the attention. Milk quality index basically has sensory indexes and physiochemical index, microbiological quality and harmful material residues and pollutants quantity four aspects. Regarding the enterprise, it wants to produce milk, besides should assured teaches defend in production of various indexes; outside the control of raw also cannot be ignored. The key points to control of raw comparison of raw index are to ensure effective method.In recent years, as environmental pollution increasingly heavier, antibiotics, making the wrong use already slowly pollution to harmful material variety of dairy products, in the milk antibiotic and heavy metal content has become the focus of people are indexes. First, in this paper introduces dairy products can exist of antibiotic types and the detection method, then to mercury as example, the paper introduces the current national state currently can several methods of determination of mercury, through the practical consideration, find a relatively simple, efficient, feasibility big test methods.

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Evaluation of the caseinomacropeptide (CMP) content in raw and uht milk during storage time.

Revista Brasileira de Pesquisa em Alimentos ◽

10.14685/rebrapa.v2i2.54 ◽

2013 ◽

Vol 2 (2) ◽

Author(s):

Elaine Closs ◽

Claucia Fernanda Volken de Souza

Keyword(s):

Storage Time ◽

Chromatographic Method ◽

Correlation Coefficients ◽

Storage Period ◽

Raw Milk ◽

Bacteria Growth ◽

Uht Milk ◽

Psychrotrophic Bacteria ◽

Spectrophotometric Methods

Coolers are used in raw milk storage in order to inhibit the growth of lactic acid producer mesophilic microorganisms. However, refrigerated milk is a favorable environment to psychrotrophic aerobic bacteria growth. These psychrotrophic bacteria promote proteolysis which is of concern to the dairy industry since it may indicate a false positive of fraudulent addition of whey to raw milk. This study evaluated the influence of storage time on the presence of caseinmacropeptide (CMP) in raw milk during storage as well as in ultra-high temperature milk (UHT) throughout its shelf life. Three different determination methods were compared each other, namely the standard chromatographic method and two spectroscopy methods for the quantitative determination of sialic acid. One is based on the determination of ninhydrin acid and the other one is an adapted method using the Ehrlich reagent. An increase of CMP content throughout the storage period for the cooled raw milk and UHT milk was detected despite the fact that none had cheese whey. The spectrophotometric methods showed correlation coefficients greater than 0.97 with the chromatographic method established by Brazilian legislation. The results indicate that the spectrophotometric method using the ninhydrin acid can be used as an alternative method for the determination of CMP in milk samples. DOI: http://dx.doi.org/10.14685/rebrapa.v2i2.54

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A Modified Fluorimetric Method for Determination of Hydrogen Peroxide Using Homovanillic Acid Oxidation Principle

BioMed Research International ◽

10.1155/2014/342958 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 14

Author(s):

Biswaranjan Paital

Keyword(s):

Hydrogen Peroxide ◽

Biological Samples ◽

Homovanillic Acid ◽

Low Cost ◽

Internal Standard ◽

Acid Oxidation ◽

Tissue Samples ◽

The Stability ◽

Multiple Samples

Hydrogen peroxide (H2O2) level in biological samples is used as an important index in various studies. Quantification of H2O2level in tissue fractions in presence of H2O2metabolizing enzymes may always provide an incorrect result. A modification is proposed for the spectrofluorimetric determination of H2O2in homovanillic acid (HVA) oxidation method. The modification was included to precipitate biological samples with cold trichloroacetic acid (TCA, 5% w/v) followed by its neutralization with K2HPO4before the fluorimetric estimation of H2O2is performed. TCA was used to precipitate the protein portions contained in the tissue fractions. After employing the above modification, it was observed that H2O2content in tissue samples was ≥2 fold higher than the content observed in unmodified method. Minimum 2 h incubation of samples in reaction mixture was required for completion of the reaction. The stability of the HVA dimer as reaction product was found to be >12 h. The method was validated by using known concentrations of H2O2and catalase enzyme that quenches H2O2as substrate. This method can be used efficiently to determine more accurate tissue H2O2level without using internal standard and multiple samples can be processed at a time with additional low cost reagents such as TCA and K2HPO4.

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Synthesis and properties of dehydroabietyl glycidyl ether grafted hydroxypropyl chitosan

BioResources ◽

10.15376/biores.15.2.4110-4123 ◽

2020 ◽

Vol 15 (2) ◽

pp. 4110-4123

Author(s):

Wei Guo ◽

Zhaosheng Cai ◽

Qi Xu ◽

Kaiyong Sun ◽

Xujuan Huang ◽

...

Keyword(s):

Molecular Weight ◽

Nonionic Surfactant ◽

Foam Stability ◽

Glycidyl Ether ◽

Surface Activities ◽

The Stability ◽

Stability Time ◽

First Time ◽

Emulsifying Ability

A nonionic surfactant based on chitosan and rosin, i.e. dehydroabietyl glycidyl ether grafted hydroxypropyl chitosan (DAGE-g-HPCS), was synthesized for the first time through reaction between hydroxypropyl chitosan (HPCS) and dehydroabietyl glycidyl ether (DAGE). The surface activities of DAGE-g-HPCS in aqueous solution were investigated via determination of surface tension, and its emulsifying ability was evaluated according to the stability time of emulsion composed of benzene-water with DAGE-g-HPCS as emulsifier; the foam stability was evaluated using the oscillation method. Through modulating the molecular weight of HPCS and the grafting degree (DG) of DAGE-g-HPCS, the emulsion stability and foam stability were surprisingly controllable. Compared to HPCS and specific emulsifier, the stability time of emulsion composed of benzene-water with DAGE-g-HPCS showed a remarkable performance with DG of 16.5% as the emulsifier was 7320 s, and the foam retention of DAGE-g-HPCS with 2.0 g·L-1 was 91.5%. Simultaneously, the critical micelle concentration (CMC) of DAGE-g-HPCS decreased with increased DG, while the emulsifying ability and foam stability exhibited opposite trend. The CMC, emulsifying ability, and foam stability of DAGE-g-HPCS increased with decreased HPCS molecular weight. These results demonstrated that the DAGE-g-HPCS was an excellent surfactant that should be considered as a promising substitute for petrochemical nonionic surfactant.

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Cu-MOFs/Hemin：A bionic enzyme with excellent dispersity for the determination of hydrogen peroxide released from living cells

The Analyst ◽

10.1039/d1an01323h ◽

2021 ◽

Author(s):

Hong Cui ◽

Shuaishuai Cui ◽

Siyuan Zhang ◽

Qiuju Tian ◽

Yunfeng Liu ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Aqueous Medium ◽

Electrochemical Biosensor ◽

Metal Organic Frameworks ◽

Living Cells ◽

Metal Organic ◽

The Stability

The stability, repeatability and sensitivity of an electrochemical biosensor material are closely connected with the dispersibility of metal organic frameworks (MOFs) in aqueous medium. Herein, a nanocomposite based on Cu-MOFs/Hemin,...

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