We adult a simple microtechnique to measure lipids in milk by UV spectrophotometry. This technique is based upon the property of fatty acids to absorb UV light proportional to their concentration. Samples of powdered or fluid milk (30 or 60 muL) were added to 3 mL of analytic grade ethanol and stored at -20 degrees C for at least 1 h. This procedure precipitates proteins and hydrophobic peptides that interfere with UV measurement. Sample absorbances are so measured at 208 nm in an UV-Vis spectrophotometer. This technique correlated very well against Milko-Scan, a device that measures milk fat by IR spectroscopy, with an r(ii) >0.982. Accuracy and precision, evaluated past recovery and replicate assays, are also very acceptable. This method is suitable every bit a fast, cost-effective alternative screening method to approximate milk fat content in pocket-size samples without prior lipid extraction.

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Milk Fatty Content Measurement by a Simple UV Spectrophotometric

Method: An Culling Screening Method

D. O. Forcato,

1

M. P. Carmine,

2

Thou. E. Echeverrı

´

a,

3

R. P. Pe

´

cora,

2

and South. C. Kivatinitz

1

1

Departamento de Quı

´

mica Biolo

´

gica-CIQUIBIC, Facultad de Ciencias Quı

´

micas, Universidad Nacional de Co

´

rdoba, Argentina

two

Departamento de Quı

´

mica Industrial y Aplicada, Ca

´

tedra de Bromatologı

´

a y Toxicologı

´

a, Facultad de Ciencias Exactas,

Fı

´

sicas y Naturales, Universidad Nacional de Co

´

rdoba and Departamento de Proteccio

´

n de Alimentos,

Ministerio de la Produccio

´

n y Trabajo, Gobierno de Co

´

rdoba, Argentine republic

three

Fundacio

´

n Escuela Superior Integral de Lecherı

´

a (FUNESIL), Villa Marı

´

a, Co

´

rdoba, Argentine republic

ABSTRACT

We deve loped a simp le microtechnique to mensurate

lipids in milk by UV spectrophotometry. This tech-

nique is based upon the property of fatty air conditioning ids to ab-

sorb UV lite proportional to t heir concen tration.

Samples of powdere d or fluid milk (30 or threescore µ L) were

added to 3 mL of analytic grade e thanol and stored at

−twenty°C for at least 1 h. This procedure precipitates

proteins and hydrophobic peptides that interfere with

UV meas urement. Sample absorb ances are and so mea-

sured at 208 nm in an UV-Vis spectrophotometer. This

technique correla ted very well against Milko-Scan, a

device that measur es milk fat by IR spectroscopy, with

an r

2

> 0.98 2. Accurateness and precision, evaluated by

recovery and replicate assays , are also ve ry adequate.

This method is suitable as a fast, cost-eff ective alterna-

tive screening met hod to estimate milk fat content in

small samples without prior li pid excerpt ion.

(Fundamental words: milk fat, UV-spectrophotometry, lipid

measurement)

Abbreviation primal: %RSD = perce ntage of relative

standard departure.

INTRODUCTION

Milk fat measurement is a common job in the dairy

industry, because milk fat content is one factor that

determines milk toll and is necessary to know for

casein/fat ratio n ormalizati on. It is als o of import for

the dairyman to know milk fatty co ntent verbal ly: dis-

crepancies in the r esults of mi lk fat tests (normally per-

formed in the dairy industrial plant) have economic

relevance. In add-on, a low milk fatty content could

betoken the existence of fauna wellness deficiencies.

Received July 28, 2004.

Accepted October 4, 2004.

Corresponding author: S. C. Kivatinitz; e-mail: skivat@dqb.fcq.

unc.edu.ar.

This is all the more of import i due north Argentina, where

exact yard ilk fat contents for the different grand ind of milk

are established by Federal regulations for both fluid

and powdered milk.

Several techniques that mensurate milk fat c ontent

have exist en used and improved over fourth dimension. The Ro

¨

se-

Gottlieb referenc eastward method and the Gerber b utyrome-

tric me thod are the near extended and traditional ones

(International Da iry Federation, 1987, 1991), but they

are lab or and time consuming, a nd utilise several

reactives (some of them dangerous) and spe cific equip-

ment. I n add-on, these metho ds are non su itable for

a big number of samples. Othe r methods involve

milk fa t extraction with organ ic solvents earlier mea-

surement, a time consuming procedure that involves

several manual operations and high intraassay and

interassay error. These metho ds ordinarily make utilise of

large amounts of chlorinated or nonchlorinated sol-

vents (Smedes, 1999; Application Note, Di onex 345,

1999), which are expensive and produce adverse ef-

fects on the environment. The dairy industry makes

apply of s everal automatic methods peculiarly developed

for it (Wu

¨

st and Rudzik, 2003). These proce dures have

proved to be precise and accura te, assuasive industries

to measure several other milk components i n addition

to fat, and are capa ble of multiple-sample assay, but

they nevertheless crave specific devices and are very expen-

sive for the budgets of not-ind ustrial lab oratories.

Nutrient la boratories , which seldom perform milk fat

measurements, need toll-effective methods de-

manding merely regular laborato ry equipment. Here we

nowadays a fast, cos t-effectiv due east, and reproducible met hod

for mil thousand fat measurement in fluid and powdere d milk,

which makes use of t he UV adsorption proper ties of

lipids, uses ethanol equally the sole solvent, and only re-

quires a UV spectrophotometer .

MATERIALS AND METHODS

Milk Samples

Whole milk (3% milk fat), skimmed milk (one.five% milk

fatty), defatted milk (0.01 and 0.04% milk fat), milk

Table i. Correlation assay between Milko-Browse and UV ab-

sorbance at 208-nm measurements performed in dissimilar labora-

tories.

r

two

n P

Laboratory ane

1

1

0.990 fourteen <0.001

2

one

0.982 14 <0.001

three

ii

0.982 14 <0.001

Laboratory two

1

1

0.983 12 <0.001

2

2

0.992 12 <0.001

ane

thirty-µL sample.

2

60-µ50 sample.

cream (44% milk fat), powdered milk (iii% mil k fat),

and azidiol (fifty µL/ x mL of milk; milk preservative on

the basis of sodium azide and ch lorampheni col kindly

provided by FUNESIL, Villa Marı

´

a, Co

´

rdoba, Argen-

tina) were provide d by a local dairy plant (La La

´

cteo

S.A., C o

´

rdoba, Argentina). Samples with unlike fat

content were prepared mixing proper volumes of

whole, skimmed, and defatted m ilk. Samples con-

taining >3% of fat were prepared by adding milk cream

to 3% fat milk. Samples were pre served with azidiol

until fat measurement. Samples were divided into 3

subsamples and measured with two unlike M ilko-Browse

equipments from different laboratories (kindly pro-

vided b y La La

´

cteo S RL and FUNESIL, Villa Marı

´

a,

Co

´

rdoba, Argentin a) and by the UV method. C alibra-

tion of both devices was performed bimonthly using

xi samp les certified past the Argentinean official body

INTI/CITIL (Buenos Aires, Argentina). Daily controls

were pe rformed using two samples of 3 and 4% of milk

fat measured by the Mojonnier 1000 ethod.

Procedure

Milk (xxx or threescore µL) was added to three mL of absolute

ethanol (Ciccarelli, Argentina) at −twenty°C . All vials were

hermetically capp ed and store d for i h at − 20° C. This

procedure allows the precipit ation of proteins and hy -

drophobic peptides that interfere with UV mensurate-

ment. Due south amples were centrifuge d at 13,000 rpm for 15

min and allowed to r each room temperature. Aliquots

of the s upernatant due south were direct transferred to a ane-c m

path, a nd samples w ere measured at UV wavelengths

(spectral range, 200 to 300 nm) .

RESULTS AND Give-and-take

Scale Curves at Different UV Wavelength

The spectral curves of several milk sample south were

analyzed. Effigy 1A shows that milk sample due south have a

broad absorption peak in the range of ∼ 220 to 240 nm

Figure 1. A) Ultraviolet spectrum of milk samples with unlike

milk fat content in absolute ethanol. Note the peak shift at higher

fat concentrations. B) Ultraviolet absorbance at various wavelengths

of milk samples with unlike fat contents. To assess the most suit-

able wavelength for milk fat measurement, several milk samples

with different fat contents were evaluated by the UV method, and

their absorbances at various wavelengths were plotted. AU = arbi-

trary unit.

that corresponds mainly to naturally occurring conju -

gated d ienes (Hamilton and Cas t, 1999) and a sharp

absorption acme in the range of ∼202 to 215 nm that

depends linearly on total lipi d concentration (Gun-

stone et al., 1994), equally previously reported for phosph a-

tidyl choline (Klein, 1970). As can exist observed from

Figure 1A, the absorption peak of lipids shifts toward

a higher wavelength (λ) when mi lk fat content in-

creases, so it was n ecessary to place a wavelength

that fo llowed the L ambert and B eer police inde pendently

of the amount of milk fatty presen t in the samp le.

Figure 2. Correlation curves between Milko-Scan equipment and

the UV method. Information from experiment 1 from laboratory 1 and experi-

ment 1 from laboratory two were performed using 30 µL of sample (〫).

Experiment iii (laboratory 1) and experiment 2 (laboratory 2) were

performed with threescore µFifty of sample (䊐) and were analyzed together.

AU = arbitrary unit.

In Effigy 1B, absorbance vs. fluid milk fat co ntent

is plot ted for several wavelen gths. Even though linea r-

ity is observed for a wide range of waveleng ths (from

208 to 2 15 nm), sensitivity decays at higher wave-

length every bit a consequence of lower molar absorptivity

(ε ). Another drawback of using a wavelength > 215 nm

is the overlapping of oxidized lipid (conjugated dienes)

absorption, which could influence lipid mea surement

(Recknagel and Gle nde, 1984; Forcato et al., 2002).

Thus, 208 nm was called as the measurement wave-

length, although ii 10-, 212-, and 215-nm wavelengths

are roughly equally suitable f or milk fatty determina-

tions. A scale curve using powdered milk was

also performed, showing the sa me overall functioning

every bit the fluid milk calibration bend (r

2

= 0.986; data

not shown).

Correlation Betwixt Milko-Scan Assay

and UV Measurements

A correlation stud y was performed betwixt data

from the Milko-Scan assay and the UV method from

5 separate experiments from ii laboratories. Linear

regression analysis showed a significant understanding

between these methods (Table 1; Effigy ii) in both

laboratories using 30 and lx µ L of milk samp le equally an

assay fraction, although a better sensitivity (linear

regression gradient closer to i) was achieved with an

assay fraction of 60 µ 50 (Figure ii).

Milk Fat Recovery Analysis

To asse ss the accur acy of the UV method, a mi lk fat

recovery assay was performed. Ten sets of t riplicate

Tabular array 2. Milk fat recovery assay.

% Milk fatty recovery

Milk fat content

one

Milko-Scan ± SD UV method ± SD

0.threescore g/100 mL 80.9 ± 0.9 92.1 ± 0.ix

1.00 g/100 mL 89.1 ± 0.3 110.4 ± ane.2

1.fifty g/100 mL 87.0 ± 0.3 102.8 ± 0.eight

1.80 thou/100 mL 88.iv ± 0.4 116.8 ± 1.5

two.20 k/100 mL 88.2 ± 0.5 103.5 ± 0.v

2.lx g/100 mL 87.i ± 0.6 97.ii ± 0.four

3.00 grand/100 mL 86.v ± 0.8 111.4 ± 0.9

3.50 thou/100 mL 102.1 ± 1.1 98.3 ± 0.4

3.90 one thousand/100 mL 98.4 ± 0.2 101.0 ± 0.iv

iv.30 yard/100 mL 98.1 ± 0.ii 97.8 ± 0.4

Mean ninety.6 ± 6.seven 103.one ± 7.6

i

Milk fatty was added to skimmed milk (0.01% milk fat) and whole

milk (3% milk fat) to obtain different milk fat values. Percentages

of recoveries are averages of iii samples.

samples were increased up to di fferent concentration s

by adding milk fatty directly to defatted and whole milk

samples and were measured with Milko-Browse equip-

ment and past the UV method. Every bit can exist observed in

Tabular array ii, Milko-Sca n showed poo r recovery (between

11 and two 0% less fat than bodily content) at low fat

concentrations, p robably because of calibration in the

range of 3% fat. The UV method showed a signi ficant

agreement with low fat samples , with only 3 recoveries

exceeding ten%. Recoveries for both methods were very

good for normal and high fatty con tent samples, simply,

because of the lack of accurateness of Milko-Browse for depression

fat content samples, mean recovery was better for the

UV method.

Precision of the UV Method

To evaluate the precision of this method, 2 sets of

nine replicates of whole milk and due south kimmed milk were

analyzed at 208, 21 0, 212, and 215 nm. Raw da ta was

subjected to ANOVA assay (T able iii). The percent-

age of relative standard devia tion (%RSD) was take-

able for all wavelengths in both sets, with an overall

%RSD of 3.79 ± 0.12 for the samples with college fat

content and an overall %RSD of four.88 ± 0.xvi for lower

fatty sam ples. Average values of both sets of replicates

at 208, 210, and 212 nm were non s ignificantly different

from reference values, although boilerplate values ob-

tained at 215 nm differed significantly from reference

values (Table 3).

CONCLUSIONS

Here we present a simple, economic metho d to

mensurate fatty content in fluid and powdered milk sam-

ples without prior extraction. This method makes use

of the U V absorption properties of lipids t hat is propor-

Table iii. Precision information for UV method.

Sample milk fat UV wavelength of measurement

(reference

value) 208 nm 210 nm 212 nm 215 nm

Replicates

1.80 mg/sixty µL

Mean ane.79 ± 0.06 ane.75 ± 0.07 1.84 ± 0.07 1.67 ± 0.06

% RSD

1

3.62 3.87 3.87 3.eighty

P NS

a

NS

b

NS

c

SD

2

1.15 mg/lx µL

Mean 1.sixteen ± 0.05 1.13 ± 0.05 1.17 ± 0.06 one.03 ± 0.05

% RSD four.70 4.79 5.02 v.02

P NS

a

NS

a

NS

a

SD

1

% RSD = Per centum of relative standard difference.

ii

SD = Media obtained is significantly different from reference value.

a

Media obtained is non significantly different from reference value (P > 0.0010).

b

Media obtained is not significantly different from reference value (P > 0.1).

c

Media obtained is non significantly different from reference value (P > 0.2).

tional to its concentration in the range of 208 to 215

nm. The UV method correlated ve ry well with Milko-

Scan fa t measures ( r

2

> 0.982; P < 0. 001), which uses

equipment standard in the industry. Accuracy and

precision were also acceptable, with a mea n recovery

percentage of 103. one ± 7.six SD (n = 30) and %RSD ≤ 5

for the replicate assays.

ACKNOWLEDGMENTS

This research was s upported by grants from Agencia

Co

´

rdoba Ciencia, Agencia Nacional de Promocio

´

n

Cientı

´

fica y Tecnolo

´

gica (FONCYT), and Secretarı

´

advertisinge

Ciencia y Te

´

cnica-Universidad Nacional de Co

´

rdoba.

The authors give thanks L a La

´

cteo Southward.A for the use o f Milko-

Scan equipment and Ing. Sergio Fernandez a nd Bioq.

Claudio Gottero for their assi stance. The authors also

thank A. Mangeaud for his stati stical supp ort.

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cora, and S. C. Kivatinitz. 2002. Conjugated

diene generation in thermically processed milk. BIOCELL Sup-

plement 3 26:76.

Gunstone, F. D., J. L. Hardwood, and F. B. Padley. 1994. The Lipid

Handbook. 2nd ed. Chapman & Hall, London, Great britain.

Hamilton, R. J., and J. Cast. 1999. Chemistry and Technology of

Oils and Fats. 15th ed. Sheffield Academic Press, Sheffield, UK.

International Dairy Federation. 1987. Milk. Determination of fat

content—Ro

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se Gottlieb gravimetric method (referenceastward method).

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content. General guidance on the useastward of butyrometric methods.

IDF (FIL-IDF standard 52), Brussels, Kingdom of belgium.

Klein, R. A. 1970. The detection of oxidation in liposome prepara-

tions. Biochim. Biophys. Acta 210:486–489.

Recknagel, R. O., and E. A. Glende, Jr. 1984. Spectrophotometric

detection of lipid conjugated dienes. Met. Enzimology

105:331–337.

Smedes, F. 1999. Determination of full lipid using not-chlorinated

solvents. Analyst 124:1711–1718.

Wu

¨

st, E., and L. Rudzik. 2003. The apply of infrared spectroscopy in

the dairy manufacture. J. Mol. Struct. 661:291–298.

... FT-Raman was used to quantify fat and micronutrients in commercial bovine milk (Mazurek, Szostak, Czaja, & Zachwieja, 2015) and IR reflectance spectroscopy has been used in fat studies of ewe and caprine animal milk (Albanell, Caja, Such, & Rovai, 2003;Revilla, Escuredo, Gonz alez-Martín, & Palacios, 2017). Ultraviolet (Bogomolov & Melenteva, 2013;Forcato, Carmine, Echeverrıa, Pecora, & Kivatinitz, 2005;Xiong, Adhikari, Chen, & Che, 2016) and FT-IR spectroscopy (Cirak, Icyer, & Durak, 2018;Nicolaou, Xu, & Goodacre, 2010) have been applied in studies of milk fat content, either in precise measurements of fat in milk samples or in grouping milk samples and mixtures by fatty content. Fluorescence (Genis, Sezer, Bilge, Durna, & Boyaci, 2019;Velioglu, Ercioglu, & Boyaci, 2017) and FT-IR spectroscopy (Eskildsen et al., 2014;Ferrand-Calmels et al., 2014) have also been utilised in the analysis of milk in terms of its biological origin, distinguishing between milk samples of different animals. ...

... The peaks observed at 220e240 nm and at 260e300 nm stand for to the aromatic amino acids of the poly peptide content of milk: phenylalanine, tyrosine and tryptophan (Fletouris, Botsoglou, Papageorgiou, & Mantis, 1993;Hansen, 1998). Conjugated dienes and trienes of the unsaturated fatty acids in milk besides absorb in the same wavelength region (Forcato et al., 2005). Information technology is noticeable that sample absorption drops with fat content in the 300e400 nm region: sample S1 (6% fatty) absorbs the maximum, followed by S3 (5.5% fat) and then two groups can be distinguished: full fat (C1eC5, G2eG6) samples and low-cal (C6eC11, G7eG9) samples. ...

... Overall, discrimination forth LV1 seems to have two factors: fat globule scattering at 300e400 nm and fatty acid/protein assimilation at 260e300 nm. LV2 contribution contains these 2 regions but also includes pregnant signal from the 220e240 nm range, which is also due to fatty acid/protein absorption (Forcato et al., 2005;Hansen, 1998). ...

Distinguishing milk products past fat content and animal origin is of import every bit it can address issues in quality command in the dairy manufacture and in adulteration testing for regulatory bodies. Optical spectroscopy, combined with statistical analysis methods, can exist useful in such analyses, beingness fast, non-destructive and cheaper compared with conventional analytical methods. In this study nosotros discriminate commercial (supermarket) moo-cow, goat and sheep milk based on their fat content and creature origin, by applying three spectroscopic techniques: ultraviolet assimilation, Fourier-transform infrared reflectance (FTIR) and fluorescence. Orthogonal partial least-squares discriminant assay (OPLS-DA) of the information grouped the samples past animate being origin and fat content. All techniques exhibit at to the lowest degree seventy% success rates in grouping the samples. UV absorption works best in fat-based discrimination (96% success), while fluorescence and UV are the almost successful in animal-based discrimination (both 91% success).

... The sharp and small absorption peaks in 202− 215 nm are dependent on total lipid concentration. The broad and significant absorption peaks in 220− 240 nm mainly correspond to naturally occurring conjugated dienes (Forcato et al., 2005). The gentle absorption peaks effectually 280 nm are associated with Tyr and Trp in the protein of milk samples (Aitken and Learmonth, 2009). ...

... There were two apparent peaks effectually 240 nm and 280 nm. The showtime peak might exist influenced by conjugated dienes, and the 2d 1 might be correlated with Tyr and Trp in the protein of milk (Forcato et al., 2005). Fig. 6 illustrated the loading weights of the starting time 3 factors of built PLSR models utilizing the all-time spectral preprocessing methods for four main components concentrations in HPH milk. ...

A miniature milk quality detection organization based on ultraviolet/visible (UV/Vis) spectroscopy was designed. One hundred and eighty milk samples were obtained, and each sample was divided into two parts. I function was utilized every bit fresh raw (FR) milk, and another part was processed using a high-pressure homogenizer. The UV/Vis absorption spectra of milk samples were collected, preprocessed, and analyzed. The models for predicting fat, protein, lactose, and total solids concentrations of FR and loftier-pressure homogenized (HPH) milk were established by using partial least squares regression algorithm. The accurateness of the system was evaluated with some other 60 milk samples. The validation experiment showed that the root-mean-squares errors of the developed system were 0.35%, 0.xix% 0.13%, and 0.46% for fat, poly peptide, lactose, and total solids concentrations of FR milk, and were 0.17%, 0.14%, 0.09%, and 0.27 % for HPH milk. Homogenization can significantly improve the accuracy of the milk quality detection system.

... Enquiry methods based on lite propagation are convenient and non-intrusive as the methods do not bear upon or destroy the samples [11]. Previous analysis of milk employed spectroscopy [12], motorcar learning [13] and chemical reactions [14]. Abohassan et al. [15] designed a photonic crystal sensor to detect the fat volume in milk, and Frizzarin et al. [13] used statistical machine learning methods to predict the cow'south milk quality. ...

Milk is a valuable correspondent to a salubrious diet as it contains nutritional components such equally fats, proteins, carbohydrates, calcium, phosphorous and vitamins. This research aimed to differentiate milk from animal, found and human sources based on light propagation and random-laser properties. Experimental, statistical and theoretical analyses were used. Light propagation in different types of milk such equally almond milk, oat milk, soy milk, fresh milk, goat milk and man breast milk was measured using the spectrometry method. Nigh-IR and visible light transmission through the diluted milk samples were compared. Soy milk and fresh milk have the highest absorbance and fluorescence of light, respectively, due to a loftier content of fat, protein and carbohydrates. Principal component analysis was used to make up one's mind the accuracy of the experimental results. The enquiry method is comprehensive equally it covers light propagation from 350 nm to 1650 nm of wavelength range and non-intrusive every bit it does not affect the sample. Meanwhile, analysis of milk was also conducted based on random-laser properties such every bit multiple emission peaks and lasing threshold. College fat content in milk produces a lower random lasing threshold. Thus, we found that milk from animals, plants and humans can be analyzed using lite absorption, fluorescence and random lasers. The enquiry method might be useful for time to come report of milk contaminants that change the properties of milk.

... The test samples were mixed with CH at a west/w ratio of 150:1. The samples were stored in the fridge at 4°C for 4 months and the emulsion stability alphabetize was estimated on a weekly basis post-obit the protocol given by Forcato et al. (2005) with required modifications. For surface action assay, the samples designated for that week were thawed for 20min. ...

This study was conducted to decipher the mechanism of emulsion-based food stabilization past fish-derived collagen hydrolysate. Collagen type I was isolated from 7 fish processing past-products with yields ranging from 9.15 to 92.38%. The isolated samples had a mass of 110–120kDa and eluted at 30.44% NaCl in ion-exchange chromatography. The collagen samples were enzymatically digested to obtain collagen hydrolysate (CH) with mass <6kDa. The vii CH samples were afterwards screened for surface activeness. CH obtained from Pacu skin and Tilapia bones exhibited more than 80% solubility over a wide pH range, zeta potential greater than +50mV, wet retentivity upwardly to 92–96%, emulsification activity of 53–70 m²grand⁻¹, and emulsion stability of 62–85min, and successfully increased the emulsion stability of a drug past 14 times. Both CH samples were able to retain the emulsion backdrop of butter and chocolate sauce for 25 weeks and did not show whatever cytotoxic event on leukocytes and Vero cells. Structural studies revealed that the CH peptides existed in polyproline-Ii conformation that assembled to form a vast quasifibrillar network. Sequence analysis through tandem mass spectroscopy revealed that the peptides could be classified into multiple groups depending on the distribution of hydrophilic/lipophilic residues (H/L). The surface action of the CH was institute to be dependent on (1) small size and a wide array of H/Fifty ratio, (2) affluence of hydroxyproline, and (3) associates of the peptides in the emulsion interface to form a mimic-helix–based quasifibrillar network which ensured optimal orientation and subsequent interaction with multiple phases.

... In club to isolate the proteins and fat of milk, xxx μl of milk sample was mixed with iii ml of ethanol. The mixture was centrifuged at 4500 thou for 15 minutes, the transparent liquid was direct transferred into cuvette in the spectrophotometer and the absorbance was measured at 450 nm 18 . The final value of dye release into the milk sample containing complete label was obtained by comparing it with the absorption values for the negative command (milk sample without freshness label on the package, i.east., 0% dye release into milk) and positive command (milk sample with freshness label lacking polystyrene layers and white alum, i.due east., 100% dye release) 19 . ...

ORIGINAL ARTICLE Introduction: Applying of a new indicator in food packaging tin be effective to inform consumers well-nigh the freshness and quality of the products. Materials and Methods: In the current study, a new milk freshness label was investigated containing beetroot color and multi layers of polystyrene. The characterization characteristics were investigated past estimating colour number, release exam, and scanning electron microscopy (SEM). The total bacterial count, pH, lactic acid concentration in milk, and label color number were measured using standard plate count, pH meter, titration of acidity, color analysis software, and UV spectrophotometry on days 0, 3, 4, 5, vi, and 7 at refrigerator temperature (4 ± 0.2°C). Results: The label reacted to total bacterial count and pH changes with a visible color during milk spoilage. A positive correlation was constitute betwixt the characterization colour changes, total bacterial count, and pH. The color of label turned from nighttime cerise to light chocolate-brown, which was related to the chemical changes and bacterial count of milk. Conclusion: According to this simple, visible, and affordable characterization, the shelf life of pasteurized milk was estimated every bit five days.

Electronic cigarettes (eastward-cigarettes) have been marketed as a less lethal substitute for smoking traditional cigarettes. This study aims to investigate the impact of e-cigarettes aerosol exposure on lactating dams and pups, whose dams were exposed. Lactating dams received fresh air (control) or due east-cigarettes aerosol during lactation (twenty-four hour period 4-21). Maternal exposure to e-cigarettes aerosol during lactation induced significant reduction (P<0.0001) in the fatty content of the milk and serum Leptin level (P<0.005) compared to command dams. Furthermore, pups whose dams were exposed to e-cigarettes during lactation showed an increased level of glucose, thyroxine and decreased level of insulin. The exposure to e-cigarettes aerosol during lactation altered the composition of milk too as the hormonal and biochemical profile in dams and pups. This event, if observed in women using e-cigarettes, suggests that e-cigarettes' employ during lactation may have consequences on the milk production and hormonal and biochemical contour in breastfeeding mothers and nursing babies.

  • Sergej V. Medvedevskikh
  • V. B. Baranovskaya V. B. Baranovskaya
  • M. Yu. Medvedevskikh
  • A. South. Sergeeva

This article develops the reference measurement process (RMP), including acrid hydrolysis, Randall extraction, evaporation of solvent, and weighing of dry out residue in the determination of mass fraction of fat content. This paper'southward RMP applies to dairy, meat, and egg products, and to baby food. In order to develop this RMP, choice and optimization of hydrolysis and extraction parameters were carried out. The paper takes into consideration the components of measurement doubtfulness arising from the contributions of equipment and reagents. It also evaluates measurement equations and methodological factors. This article also presents the results of an inter-laboratory comparison of the conclusion of mass fraction of fat in Russian enterprises' dairy products. These results demonstrate that the RMP developed past this research had the highest level of accuracy and the absence of bias in the measurement results as compared to other routine methods. Experiments carried out during the participation of UNIIM in an inter-laboratory comparison organized past MUVA Kempten GmbH (Germany) confirmed the equivalence of the RMP developed by this inquiry with similar foreign measurement methods. The results of the piece of work will ensure coherence of the results of determining the fat content in food products and food raw materials in the Russian Federation, and their conformity with the results obtained in other countries.

Milk fat is a complex material that exists in the class of discrete lipid globules within the milk serum. The composition of milk fatty can vary because of physiological and environmental factors, and these variations contribute to the lipid'due south functional and flavor properties. Sensitive and discriminating analytical tools are required to quantify accurately both the major (fat acids in the course of triacylglycerols) and minor (diacylglycerols, monoacylglycerols, free fatty acids, phospholipids, membranous proteins, cholesterol, etc.) components. This chapter provides an overview of the unlike chromatographic and spectroscopic methods used in industry and research to examine the polar and non-polar components of milk fat. Topics include lipid extraction, the proximate determination of fat content, and the analysis of fat acids, lipid class, lipid species, milk fat globule membranous material, and headspace volatile flavour components. Advances in column specificity, instrumentation, and methodology for optimum separation and resolution are presented and limitations discussed.

  • Foppe Smedes Foppe Smedes

The restrictions on the use of chlorinated solvents under the Montreal Protocol makes it necessary to develop an alternative method to the Bligh and Dyer lipid extraction as currently applied to marine tissues. Several different solvent mixtures were systematically tested as a replacement for chloroform. The presence of a polar solvent is a prerequisite in order to obtain phase separation between the aqueous and organic phases, but likewise high a concentration of solvent in the aqueous stage prevents the more polar lipids from being extracted. A high content of water in the organic phase can consequence in co-extraction of non-lipids. Several combinations of solvents may be able to extract lipids, simply for reasons of safety and toxicity, a propan-two-ol–cyclohexane–water (8 + 10 + 11 v/five/v) mixture has been proposed. The method is not sensitive to a broad range of sample-phase book ratios provided that the solvent compositions remain constant. Awarding to plaice, mussel and herring samples showed results that were in understanding with the extraction following Bligh and Dyer using chloroform and methanol.

  • Eberhard Wüst Eberhard Wüst
  • L. Rudzik

An overview of infrared spectroscopic applications—incoming production command, process control and final product control—shows the importance of this technique in the dairy industry. To ensure proper operation of the infrared techniques a monitoring organisation has to be introduced. These tasks can efficiently exist performed within a network. Dissimilar kinds of networks will be discussed. The trend to movement the infrared techniques into the production line is exemplary shown.

  • Richard O. Recknagel
  • Eric A. Glende

Publisher Summary Similar many other substances, naturally occurring lipids exhibit uncomplicated terminate absorption in ultraviolet light equally the wavelength is lowered toward 200 nm. The spectra of a variety of organic molecules containing conjugated dienes, even so, are characterized by intense absorption, the then-chosen Chiliad band, which may range, with respect to height absorption, from 215 to 250 nm, depending on nearby substituent groups. Ultraviolet spectrophometric detection of conjugated dienes has been used for many years in the food manufacture for the detection of autoxidized lipids. The method appears to have been applied for the starting time time to the problem of liver prison cell lipid peroxidation of toxigenic origin in 1966 and has been widely used since. For a variety of pathological processes, the question has been raised whether peroxidative decomposition of membrane lipids has occurred in vivo . A second principle of the method recognizes that for whole-animal studies involving possible lipid peroxidation, the fraction of endogenous lipids actually peroxidized may not only be low, but the procedure of lipid peroxidation may be confined to a particular subcellular structure.

The detection of oxidation in liposome prepara-tions Spectrophotometric detection oflipidconjugated 105 Determination of full lipid using not-chlorinated solvents The utilize of infrared spectroscopy in the dairy manufacture

  • R A Klein
  • R O Recknagel
  • Eastward A Glende
  • Jr Smedes

Klein, R. A. 1970. The detection of oxidation in liposome prepara-tions. Biochim. Biophys. Acta 210:486–489. Recknagel, R. O., and E. A. Glende, Jr. 1984. Spectrophotometric detection oflipidconjugated 105:331–337. Smedes, F. 1999. Conclusion of full lipid using non-chlorinated solvents. Analyst 124:1711–1718. Wu ¨st, Eastward., and 50. Rudzik. 2003. The use of infrared spectroscopy in the dairy industry. J. Mol. Struct. 661:291–298. dienes.Met.Enzimology

Chemistry and Technology of Oils and Fats International Dairy Federation. 1987. Milk. Determination of fat content-Röse Gottlieb gravimetric method (reference method)

  • R J Hamilton
  • J Cast

Hamilton, R. J., and J. Cast. 1999. Chemistry and Technology of Oils and Fats. 15th ed. Sheffield Academic Printing, Sheffield, UK. International Dairy Federation. 1987. Milk. Determination of fat content-Röse Gottlieb gravimetric method (reference method).

Conjugated diene generation in thermically processed milk

  • D O Forcato
  • R P Pécora
  • Due south C Kivatinitz

Forcato, D. O., R. P. Pécora, and S. C. Kivatinitz. 2002. Conjugated diene generation in thermically processed milk. BIOCELL Supplement III 26:76.