Effect of elevation of total solids by ultra-filtration and reverse osmosis on thiol groups in milk

Ozer B., Robinson R., Grandison A.

MILCHWISSENSCHAFT-MILK SCIENCE INTERNATIONAL, cilt.57, sa.11-12, ss.609-611, 2002 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 57 Sayı: 11-12
  • Basım Tarihi: 2002
  • Dergi Adı: MILCHWISSENSCHAFT-MILK SCIENCE INTERNATIONAL
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.609-611
  • Ankara Üniversitesi Adresli: Hayır

Özet

Batches of pasteurised whole milk (120 g l(-1) total solids) were concentrated to (160 gl(-1) total solids) by ultrafiltration (UF) or reverse osmosis (RO). After heat treatment at 85 degreesC for 20 min to simulate the treatment of milk for yoghurt making, the total and reactive thiol groups (SH) in the milks were measured. Results showed that the control sample (120 gl(-1) total solids) had a lower level of total SH groups than the concentrated milks, but that the percentage of active SH groups was higher (85%) than in the membrane treated samples (74% for the UF milk and 66% for the RO milk). It is suggested that, as the gel properties of yoghurt are dependent on the level of protein-protein interactions, it might be desirable if the level of reactive SH groups in UF milk could be increased by, perhaps, a modification of the time/temperature applied during the heat treatment stage.