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Proteolytic degradation of ewe milk proteins during fermentation of yoghurts and storage.
Nahrung. 2003 Jun; 47(3):199-206.N

Abstract

Yoghurts are mostly produced from cow milk and to a very limited extent from ewe milk. The evolution of caseins and whey proteins in ovine milk submitted to different thermal treatments (63 degrees C/30 min; 73 degrees C/15 min; 85 degrees C/10 min or 96 degrees C/5 min) was followed during fermentation of yoghurts and during their storage up to 14 days, using two different sets of starters. One set of starter LAB was a "ropy" culture (YC-191), which is a well-defined mixed strain culture containing Streptococcus thermophilus ST-143 and Lactobacillus delbrueckii subsp. bulgaricus (LB-18 and LB-CH2). The other set of starter bacteria (YC-460) was a standard yoghurt culture("non-ropy") containing mixed strain culture of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Contents of free amino groups in produced yoghurts increased gradually during the fermentation, up to a maximal value obtained after 4 h fermentation, then they did not change significantly during storage of yoghurt produced with YC-191 starter. In contrary, a large drop in the amount of free amino groups was observed in the first 24 h of storage in the case of yoghurt made with YC-460 indicating that microorganisms continue still to grow in low temperatures. During fermentation and storage of both yoghurt types, alpha-lactalbumin was hydrolyzed to a slightly bigger extent than beta-lactoglobulin. During fermentation, beta-casein was slightly more degraded than alpha(s)-caseins; however, the opposite was observed during storage up to 14 days. Generally, a more intense heat pretreatment led to a higher degradation of whey proteins and caseins during fermentation and storage. Differences in proteolytic activity between the two starters used (whey proteins more degraded by YC-191; caseins more degraded by YC-460) may lead to improvement in production and formulation of yoghurts differing in their physicochemical and rheological properties.

Authors+Show Affiliations

El-Zahar K
Institut National de la Recherche Agronomique, Laboratoire d'Etude des Interactions des Molécules Alimentaires, BP 71627, F-44316 Nantes Cedex 3, France.
Chobert JM
No affiliation info available
Sitohy M
No affiliation info available
Dalgalarrondo M
No affiliation info available
Haertlé T
No affiliation info available

MeSH

Amino AcidsAnimalsFermentationFood HandlingFood MicrobiologyHot TemperatureHydrogen-Ion ConcentrationLactobacillusMilkMilk ProteinsRefrigerationRheologySheepStreptococcusTime FactorsYogurt

Pub Type(s)

Journal Article

Language

eng

PubMed ID

12866624

Citation

El-Zahar, Khaled, et al. "Proteolytic Degradation of Ewe Milk Proteins During Fermentation of Yoghurts and Storage." Die Nahrung, vol. 47, no. 3, 2003, pp. 199-206.
El-Zahar K, Chobert JM, Sitohy M, et al. Proteolytic degradation of ewe milk proteins during fermentation of yoghurts and storage. Nahrung. 2003;47(3):199-206.
El-Zahar, K., Chobert, J. M., Sitohy, M., Dalgalarrondo, M., & Haertlé, T. (2003). Proteolytic degradation of ewe milk proteins during fermentation of yoghurts and storage. Die Nahrung, 47(3), 199-206.
El-Zahar K, et al. Proteolytic Degradation of Ewe Milk Proteins During Fermentation of Yoghurts and Storage. Nahrung. 2003;47(3):199-206. PubMed PMID: 12866624.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Proteolytic degradation of ewe milk proteins during fermentation of yoghurts and storage. AU - El-Zahar,Khaled, AU - Chobert,Jean-Marc, AU - Sitohy,Mahmoud, AU - Dalgalarrondo,Michèle, AU - Haertlé,Thomas, PY - 2003/7/18/pubmed PY - 2003/11/8/medline PY - 2003/7/18/entrez SP - 199 EP - 206 JF - Die Nahrung JO - Nahrung VL - 47 IS - 3 N2 - Yoghurts are mostly produced from cow milk and to a very limited extent from ewe milk. The evolution of caseins and whey proteins in ovine milk submitted to different thermal treatments (63 degrees C/30 min; 73 degrees C/15 min; 85 degrees C/10 min or 96 degrees C/5 min) was followed during fermentation of yoghurts and during their storage up to 14 days, using two different sets of starters. One set of starter LAB was a "ropy" culture (YC-191), which is a well-defined mixed strain culture containing Streptococcus thermophilus ST-143 and Lactobacillus delbrueckii subsp. bulgaricus (LB-18 and LB-CH2). The other set of starter bacteria (YC-460) was a standard yoghurt culture("non-ropy") containing mixed strain culture of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Contents of free amino groups in produced yoghurts increased gradually during the fermentation, up to a maximal value obtained after 4 h fermentation, then they did not change significantly during storage of yoghurt produced with YC-191 starter. In contrary, a large drop in the amount of free amino groups was observed in the first 24 h of storage in the case of yoghurt made with YC-460 indicating that microorganisms continue still to grow in low temperatures. During fermentation and storage of both yoghurt types, alpha-lactalbumin was hydrolyzed to a slightly bigger extent than beta-lactoglobulin. During fermentation, beta-casein was slightly more degraded than alpha(s)-caseins; however, the opposite was observed during storage up to 14 days. Generally, a more intense heat pretreatment led to a higher degradation of whey proteins and caseins during fermentation and storage. Differences in proteolytic activity between the two starters used (whey proteins more degraded by YC-191; caseins more degraded by YC-460) may lead to improvement in production and formulation of yoghurts differing in their physicochemical and rheological properties. SN - 0027-769X UR - https://www.unboundmedicine.com/medline/citation/12866624/Proteolytic_degradation_of_ewe_milk_proteins_during_fermentation_of_yoghurts_and_storage_ DB - PRIME DP - Unbound Medicine ER -