Dairy products are worldwide spread and have great commercial importance within the food industry. Rapid and reliable analysis of these products would be highly desirable for both the manufacturers and consumers. This work aimed to investigate the feasibility of Near-infrared spectroscopy and Aquaphotomics for discrimination between natural and imitation cheese and yogurt. Several experiments with white brine cheese and yogurt were performed. The first experiment was carried out with yogurt from cow milk (natural or mixed with 5, 10, 15, and 20% dry skim milk), prepared in laboratory conditions. The milk was pasteurized (95°C/30 min), cooled to 45°C, and inoculated with a 1.5% yogurt culture consisting of Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophiles. The second experiment was with Bulgarian white brine cheese - natural from cow milk or produced from a mixture of cow milk and reconstructed dry skim milk. Spectra of all tested samples were obtained with a scanning NIRQuest 512 (Ocean Optics, Inc.) instrument in the range 900-1700 nm using a reflection fiber-optics probe. A Pirouette 4.5 (Infometrix, Inc.) was used for performing spectral data processing. Partial least square (PLS) models were developed for quantitative determination and Soft Independent Modeling of Class Analogy (SIMCA) for classification. Aquagrams were calculated using transformed by multiple scatter correction spectral data. Comparison of near-infrared spectra of yogurt and imitation products, produced with added reconstructed dry skim milk showed significant differences, especially in the range of first overtone water region. Reconstructed dry skim milk caused changes in water functionally structure in yogurt, which is confirmed by aquagram charts of analysed yogurt samples. Differences in near-infrared spectra of natural cheese and cheese produced with added dry milk also existed. PLS model for determination of added dry skim milk in yogurt samples and SIMCA model for discrimination of natural cheese and cheese produced with added dry skim milk showed good accuracy. Near-infrared spectroscopy and aquaphotomics approaches have the potential as a rapid screening tool for detecting the adulteration of dairy products.

1.
H. G.
Yakubu
,
Z.
Kovacs
,
T.
Toth
and
G.
Bazar
,
The recent advances of near-infrared spectroscopy in dairy production—a review
,
Critical Reviews in Food Sci. and Nutr.
62
(
3
),
810
831
(
2022
).
2.
M.
De Marchi
,
M.
Penasa
,
A.
Zidi
and
C. L.
Manuelian
,
Invited review: Use of infrared technologies for the assessment of dairy products - applications and perspectives
,
J. Dairy Sci.
101
,
10589
10604
(
2018
).
3.
R.
Tsenkova
,
Aquaphotomics: Dynamic spectroscopy of aqueous and biological systems describes peculiarities of water
,
J. Near Infrared Spectrosc.
17
,
303
313
(
2009
).
4.
Y.
He
,
S.
Feng
,
X.
Deng
and
X.
Li
,
Study on lossless discrimination of varieties of yogurt using the visible/NIR-spectroscopy
,
Food Research International
39
(
6
),
645
650
(
2006
).
5.
L.
Xu
,
S. M.
Yan
,
C. B.
Cai
,
Z. J.
Wang
and
X. P.
Yu
,
The feasibility of using near-infrared spectroscopy and chemometrics for untargeted detection of protein adulteration in yogurt: Removing unwanted variations in pure yogurt
,
J. of Analytical Methods in Chemistry
9
,
201873
(
2013
).
6.
Y.
Shao
and
Y.
He
,
Measurement of soluble solids content and pH of yogurt using visible/near infrared spectroscopy and chemometric
,
Food and Bioprocess Technology
2
,
229
233
(
2009
).
7.
C.
Jarén
,
M.
Gago
,
S.
Arazuri
,
A.
López
,
N.
Arias
,
A. C.
Agulheiro-Santos
and
P. C.
Correa
, “
The potential of near infrared spectroscopy as a method of determination of the fat content in yogurt
,” in
Ag. Eng. Int. Conf. of Agricultural Engineering
(Federacion de Gremios de Editores de España,
2012
) pp.
2
3
.
8.
S. S.
Fluvia
, “
NIR techniques and chemometric data analysis applied to food adulteration
,”
Màster universitari en Tecnologies Facilitadores per a la Indústria Alimentària i de Bioprocessos
,
2015
.
9.
J.
Muncan
,
K.
Tei
and
R.
Tsenkova
,
Real-time monitoring of yogurt fermentation process by aquaphotomics near-infrared spectroscopy
,
Sensors
21
,
177
(
2021
).
10.
M.
Kamal
and
R.
Karoui
,
Analytical methods coupled with chemometric tools for determining the authenticity and detecting the adulteration of dairy products: A review
,
Trends in Food Science & Technology
46
,
27
48
, (
2015
).
11.
H.
Singh
and
A.
Waungana
,
Influence of heat treatment of milk on cheesemaking properties
,
Int. Dairy J.
11
(
4-7
),
543
551
, (
2001
).
12.
N. M.
Rynne
,
T. P.
Beresford
,
A. L.
Kelly
and
T. P.
Guinee
,
Effect of milk pasteurization temperature and in situ whey protein denaturation on the composition, texture and heat-induced functionality of half-fat Cheddar cheese
,
International Dairy Journal
14
(
11
),
989
1001
, (
2004
).
13.
A.
Gulati
,
D.
Hennessy
,
M.
O’Donovan
,
J. J.
McManus
,
M. A.
Fenelon
and
T. P.
Guinee
,
Dairy cow feeding system alters the characteristics of low-heat skim milk powder and processability of reconstituted skim milk
,
Journal of Dairy Science
102
(
10
),
8630
8647
, (
2019
).
14.
J.
Workman
and
L.
Weyer
,
Practical guide of interpretative near-infrared spectroscopy
(
Taylor and Francis Group
:
CRC Press
,
2008
) pp.
344
.
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