Accumulation of proteose peptones (PP) deriving from β-casein degra-dation by plasmin was studied du-ring storage of pasteurized and extended shelf-life (ESL) milk, with the aim of identifying the optimum conditions to preserve milk freshness. Two lots of pasteurized milk were obtained from the same raw milk, heat treated 3h or 48h af-ter milking and stored at 6 and 8°C. Initial PP content was higher in sam-ples pasteurized after 48h and the difference remained during storage. Plasmin activity persisted until the end of observations and was more intense in samples stored at 8oC. Af-ter 12 days, in all but one of the samples stored at 8oC, PP exceeded 900 mg/L, suggested threshold limit for pasteurized milk, never reached in samples stored at 6oC. Two lots of ESL milk were produced as well and stored at 8oC: PP content did not in-crease during storage. Besides the storage at 6oC rather than at 8oC, an early heat treatment is a crucial con-dition to maintain pasteurized milk freshness.
Scientific papers / Original article24 Dicembre/2020Scienza e Tecnica Lattiero-Casearia / Vol 70, n.6, 24 - 28, 2020DOI: 10.36138/STLC.06.2020.012020; (6)70: 24 - 28© 2020 QUINERiassuntoL’accumulo di proteoso peptoni (PP), prodotti di degradazione della β-caseina da parte della plasmina, è stato studiato per identificare le condizioni ottimali per preservare la freschezza del latte. Due lotti di latte crudo sono stati pastorizzati dopo 3 e 48 ore dalla mungitura e conservati a 6 e 8°C. L’attività del-la plasmina si è mantenuta in tutti i campioni, ma il contenuto in PP è risultato più alto nei campioni trat-tati dopo 48 ore e in quelli conser-vati a 8°C. Dopo 12 giorni, in tutti i campioni tenuti a 8°C, eccetto in uno, i PP hanno superato i 900 mg/l, considerato il valore soglia per valutare la freschezza del latte, mai raggiunto nei campioni con-servati a 6°C. In aggiunta, dallo stesso latte crudo sono stati pro-dotti due lotti di latte ELS, stoccati a 8°C: il contenuto in PP non è au-mentato durante la conservazione. Quindi, oltre alla conservazione a 6°C piuttosto che a 8°C, un tratta-mento termico precoce si dimostra determinante per mantenere la freschezza del latte pastorizzato.
Effect of processing and storage conditions on the evolution of the proteose peptone content in pasteurized and extended shelf-life milk / J.A. Hogenboom, V. Rosi, L. Monti. - In: SCIENZA E TECNICA LATTIERO-CASEARIA. - ISSN 0390-6361. - 70:6(2020 Dec), pp. 24-28. [10.36138/STLC.06.2020.01]
Effect of processing and storage conditions on the evolution of the proteose peptone content in pasteurized and extended shelf-life milk
J.A. Hogenboom
Primo
;V. RosiSecondo
;L. MontiUltimo
2020
Abstract
Accumulation of proteose peptones (PP) deriving from β-casein degra-dation by plasmin was studied du-ring storage of pasteurized and extended shelf-life (ESL) milk, with the aim of identifying the optimum conditions to preserve milk freshness. Two lots of pasteurized milk were obtained from the same raw milk, heat treated 3h or 48h af-ter milking and stored at 6 and 8°C. Initial PP content was higher in sam-ples pasteurized after 48h and the difference remained during storage. Plasmin activity persisted until the end of observations and was more intense in samples stored at 8oC. Af-ter 12 days, in all but one of the samples stored at 8oC, PP exceeded 900 mg/L, suggested threshold limit for pasteurized milk, never reached in samples stored at 6oC. Two lots of ESL milk were produced as well and stored at 8oC: PP content did not in-crease during storage. Besides the storage at 6oC rather than at 8oC, an early heat treatment is a crucial con-dition to maintain pasteurized milk freshness.File | Dimensione | Formato | |
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