Characteristics of amorphous matrices composed of different types of sugars in encapsulating emulsion oil droplets during freeze-drying

Koreyoshi Imamura, Yoshifumi Kimura, Shota Nakayama, Miki Sayuri, Seiji Ogawa, Tatsuya Hoshino, Jun Oshitani, Takashi Kobayashi, Shuji Adachi, Tsutashi Matsuura, Hiroyuki Imanaka, Naoyuki Ishida, Kazuhiro Nakanishi

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


The encapsulation of emulsion oil droplets by amorphous sugar matrices, formed by freeze-drying, was investigated, with a focus on the influence of the type of sugar. An oil-in-water emulsion, comprised of linoleic acid methyl ester (LME) and sucrose monolaurate (SML) as an oil phase and surfactant, respectively, were freeze-dried in the presence of different types of sugars. LME-droplet encapsulation during and after freeze-drying were evaluated by FTIR analysis. The loss of LME largely occurred in the early stage of freeze-drying. The size distribution of the encapsulated LME droplets remained unchanged before and after freeze-drying in most cases. The encapsulated fractions of LME droplets could be correlated with the glass transition temperature of the sugars in the fully hydrated state (Tg*), and the existence of an optimum Tg* value for the sugar matrix was predicted. The encapsulation ability of an amorphous sugar matrix was maximized when mono- and polysaccharide were combined so as to give a value for Tg* of approximately -50°C, although, individually, mono- and polysaccharides were quite poor for oil droplet encapsulation. These findings suggest that the structural flexibility of the amorphous sugar matrix is a major determinant in oil droplet encapsulation by an amorphous sugar matrix during freeze-drying.

Original languageEnglish
Pages (from-to)201-207
Number of pages7
JournalFood Research International
Issue number1
Publication statusPublished - 2013 Apr
Externally publishedYes


  • Amorphous sugar
  • Freeze-drying
  • Glass transition temperature
  • Micelles
  • Retention

ASJC Scopus subject areas

  • Food Science


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