Lactose Crystallization in Skim Milk Powder Observed by Hydrodynamic Equilibria, Scanning Electron Microscopy and 2H Nuclear Magnetic Resonance

HSI‐MEI ‐M LAI, SHELLY J. SCHMIDT

Research output: Contribution to journalArticle

Abstract

Lactose crystallization in medium heat nonfat dry milk as a function of water activity (0.01 to 0.94 aw) and time (2 wk) at constant temperature (20°C) was investigated by changes in moisture during the equilibration period and scanning electron microscopy. Discontinuous sorption behavior observed at aw 0.54 and above was ascribed to lactose undergoing a transition from the amorphous to the crystalline state. Scanning electron micrographs taken throughout the equilibration period revealed increasing lactose crystallization with time at and above aw 0.54. Deuterium(2H) Nuclear Magnetic Resonance (NMR) spectroscopy was used to monitor the water mobility during the amorphous to crystalline state transition. Changes in water mobility were found to be directly related to the observed moisture changes and the transition of lactose from the amorphous to crystalline state.

Original languageEnglish (US)
Pages (from-to)994-999
Number of pages6
JournalJournal of food science
Volume55
Issue number4
DOIs
StatePublished - Jul 1990

ASJC Scopus subject areas

  • Food Science

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