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The Impact of Beta-Casein Genetic Variant on the Physicochemical Properties of Various Fermented Milk Types Cover

The Impact of Beta-Casein Genetic Variant on the Physicochemical Properties of Various Fermented Milk Types

Open Access
|Feb 2026

Figures & Tables

Diagram 1.

Fermented milk types with the most popular examples (Tamime et al., 2007)
Fermented milk types with the most popular examples (Tamime et al., 2007)

Diagram 2.

Production of fermented milks
Production of fermented milks

Figure 1.

Colour profiles of fresh (-0w) and stored (-3w) fermented milks, i.e. A1 and A2 ABT-yoghurts (Y_A1, Y_A2, respectively), kefirs (K_A1, K_A2, respectively) and cultured milks (CM_A1, CM_A2, respectively); a, b – different letters denote significant differences between results for a specific colour attribute (P≤0.05)
Colour profiles of fresh (-0w) and stored (-3w) fermented milks, i.e. A1 and A2 ABT-yoghurts (Y_A1, Y_A2, respectively), kefirs (K_A1, K_A2, respectively) and cultured milks (CM_A1, CM_A2, respectively); a, b – different letters denote significant differences between results for a specific colour attribute (P≤0.05)

Basic chemical composition of A1 and A2 fermented milks (g/100 g; x ±SD, n=4)

Componentβ-CN variant in milk
A1A2
TS11.00a ± 0.2811.12a ± 0.26
MSNF9.13a ± 0.209.23a ± 0.19
Protein3.63a ± 0.283.66a ± 0.20
Fat1.87a ± 0.131.89a ± 0.16
Ash0.8002a ± 0.00810.7910a ± 0.0233
Carbohydrates4.68a ± 0.25*4.80a ± 0.23*

Microbiological characteristics of the analysed fermented milks (x ±SD, n=4)

Count of starter microorganism [log CFU/g]Storage time [week]Genetic variant of β-CN
A1A1A2A2
ABT-yoghurt
Lb. acidophilus LA-508.47a ± 0.048.39a ± 0.07
38.20a ± 0.018.42a ± 0.15
Bifidobacterium BB-1206.42a ± 0.666.65a ± 0.95
35.48a ± 0.545.45a ± 0.85
Str. thermophilus09.16a ± 0.749.13a ± 0.81
38.51a ± 0.148.52a ± 0.02
Kefir
Lactobacillus spp.09.16a ± 0.698.93a ± 0.88
36.76b ± 0.316.73b ± 1.03
Lactococcus spp.09.16a ± 0.049.19a ± 0.05
38.20b ± 0.408.01b ± 0.30
Yeasts02.99a ± 0.653.13a ± 0.57
34.33a ± 0.223.59a ± 1.28
Cultured milk
Lactococcus spp.08.98a ± 0.378.92a ± 0.19
37.45b ± 0.057.44b ± 0.16

Textural and rheological characteristics of the analysed fresh (0w) and stored (3w) fermented milks (x ±SD, n=4)

AttributeABT-yoghurtKefirCultured milk
0w3w0w3w0w3w
Hardness (N)A10.85a ± 0.091.13b ± 0.160.39a ± 0.010.49bc ± 0.040.45a ± 0.020.50ab ± 0.01
A20.97a ± 0.071.28b ± 0.040.46b ± 0.040.54c ± 0.070.51b ± 0.020.59c ± 0.06
Adhesiveness (|N×s|)A11.52a ± 0.192.41a ± 0.370.63a ± 0.050.89a ± 0.170.74a ± 0.141.08b ± 0.09
A22.25a ± 0.621.63a ± 0.930.92a ± 0.291.39b ± 0.381.12b ± 0.241.21b ± 0.31
Cohesiveness (−)A10.44c ± 0.010.38a ± 0.010.48a ± 0.010.46a ± 0.040.50a ± 0.000.48a ± 0.01
A20.41b ± 0.010.37a ± 0.030.50a ± 0.020.47a ± 0.020.43a ± 0.120.51a ± 0.01
Gumminess (N)A10.37a ± 0.040.43ab ± 0.050.19a ± 0.000.22ab ± 0.010.22ab ± 0.010.22a ± 0.01
A20.40a ± 0.030.47b ± 0.020.23b ± 0.010.26c ± 0.040.26b ± 0.020.29c ± 0.02
Hysteresis loop area (kPa · s−1)A14.63a ± 0.254.73a ± 0.311.46a ± 0.101.50a ± 0.091.70a ± 0.071.71a ± 0.06
A28.54b ± 0.098.61b ± 0.351.93b ± 0.091.78b ± 0.161.91b ± 0.042.10c ± 0.17
k (Pa sn)A12.89a ± 0.264.17b ± 0.401.55a ± 0.405.19b ± 0.746.73a ± 0.246.58a ± 0.35
A27.90c ± 0.6512.23d ± 0.904.42b ± 0.354.92b± 0.737.29a ± 0.717.27a ± 0.67
nA10.40c ± 0.010.24b ± 0.010.37c ± 0.020.29b ± 0.050.25a ± 0.010.27a ± 0.01
A20.26b ± 0.030.16a ± 0.020.23a ± 0.010.32b ± 0.010.24a ± 0.030.26a ± 0.04
Initial η (Pas)A14.90a ± 0.284.79a ± 0.061.71a ± 0.112.32b ± 0.382.48a ± 0.112.71a ± 0.22
A26.07b ± 0.216.88c ± 0.462.17ab± 0.182.57b ± 0.252.82a ± 0.142.87a ± 0.26
Final η (Pas)A10.21b ± 0.010.15a ± 0.000.14a ± 0.010.16a ± 0.030.16a ± 0.000.19b ± 0.01
A20.24c ± 0.020.18ab ± 0.010.16a ± 0.010.17a ± 0.010.18b ± 0.010.21c ± 0.00
τ0 (Pa)A123.13a ± 1.1125.74b ± 1.0012.68a ± 1.3112.81a ± 1.5511.26a ± 1.7513.29a ± 0.97
A229.67c ± 1.1629.28c ± 1.0110.96a ± 1.3011.92a± 0.9918.03b± 1.0317.11b ± 0.59

Acidity and antioxidant characteristics of the fresh (0w) and stored (3w) A1 and A2 fermented milks (x ±SD, n=4)

CharacteristicABT-yoghurtKefirCultured milk
0w3w0w3w0w3w
pHA14.75b ± 0.154.41a ± 0.094.58a ± 0.034.54a ± 0.034.49a ± 0.014.47a ± 0.04
A24.72b ± 0.084.40a ± 0.084.58a ± 0.034.54a ± 0.044.50a ± 0.024.45a ± 0.03
acidity (% lactic acid)A10.70a ± 0.060.83b ± 0.030.92a ± 0.030.89a ± 0.020.98a ± 0.030.95a ± 0.03
A20.70a ± 0.030.81b ± 0.050.90a ± 0.020.90a ± 0.010.94a ± 0.030.96a ± 0.02
FRAP (mMFe2+/kg)A10.97a± 0.360.83a ± 0.110.72a ± 0.010.74a ± 0.030.92a ± 0.100.88a ± 0.22
A20.96a ± 0.280.76a ± 0.050.67a ± 0.090.66a ± 0.080.87a ± 0.120.81a ± 0.10
ARP (mMTE/kg)A10.32a ± 0.270.25a ± 0.090.23a ± 0.190.26a ± 0.130.29a ± 0.250.29a ± 0.14
A20.29a ± 0.160.30a ± 0.150.23a ± 0.160.27a ± 0.110.31a ± 0.260.31a ± 0.17

Sensory properties of A1 and A2 fermented milks (x ±SD, n=14)

Sensory characteristicABT-yoghurtKefirCultured milk

A1A2A1A2A1A2
Colour4.82a ± 0.374.82a ± 0.544.93a ± 0.274.93a ± 0.274.86a ± 0.365.00a ± 0.00
Appearance3.64a ± 0.663.29a ± 0.754.32a ± 0.424.29a ± 0.804.00a ± 0.554.61b ± 0.59
Consistency4.43a ± 0.584.29a ± 0.674.89b ± 0.294.39a ± 0.714.32a ± 0.644.86b ± 0.53
Odour4.57a ± 0.424.54a ± 0.374.89a ± 0.294.61a ± 0.494.54a ± 0.664.57a ± 0.51
Taste4.46a ± 0.574.29a ± 0.584.50a ± 0.484.64a ± 0.574.50a ± 0.734.71a ± 0.38
Total score4.38a ± 0.354.23a ± 0.414.67a ± 0.264.55a ± 0.434.42a ± 0.504.74b ± 0.21
DOI: https://doi.org/10.2478/aoas-2025-0113 | Journal eISSN: 2300-8733 | Journal ISSN: 1642-3402
Language: English
Submitted on: Jun 9, 2025
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Accepted on: Oct 2, 2025
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Published on: Feb 18, 2026
In partnership with: Paradigm Publishing Services
Publication frequency: Volume open

© 2026 Dorota Najgebauer-Lejko, Iwona Radkowska, Magda Filipczak-Fiutak, published by National Research Institute of Animal Production
This work is licensed under the Creative Commons Attribution 3.0 License.

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