GROUP OF FOOD AND BIOENGINEERING
Hidefumi Yoshii, Professor (Dr. of Engineering)
Department of Applied Biological Science, Kagawa University
RESEARCH SUBJECTS
1. Microencapsulation of food and pharmaceutical related ingredients by spray drying
and the storage stability
The incorporation of hydrophobic flavors into powders
by encapsulation is great importance in the food and
flavors industries. Microencapsulation of flavors is a
technology of enclosing flavor compounds in a carrier
matrix to provide dry and free-flowing powders, which
Sectional view of a
are easy to handle. Furthermore, it also provides Spray dried powder
spray-dried
particle
protection against the degradative reaction and prevents
the loss of flavors during food processing and storage. Among various microencapsulation methods, spray
drying is the most common technique to produce flavor powders, since it has many merits such as low
process cost, wide choice of carrier solids, good retention of flavors, and good stability of the finished
flavors. In this research, the main emphasis of the microencapsulation of flavors has concentrated on
preventing the flavor losses during spray drying and extending the shelf life of the products. The focus is on
the effect of emulsion droplet size, powder size as well as the type of the model flavors. More specifically
the aim is to understand the mechanism loss and oxidation of encapsulated flavor from the droplet which
directly relate to the shelf life of product. The work is focused on the effect of water activity as well as the
change of the capsule structure on the stability of encapsulated flavor. Furthermore, in order to understand
the morphology of spray dried powder and encapsulated flavor powder, CLSM was using to view the cross
sectional of the spray dried powder and the arrangement of encapsulated flavor in powder without the
destruction of the powders.
2. Encapsulation of flavors by molecular inclusion in cyclodextrins
Cyclodextrin (CD) is a family of cyclic oligosaceharides with truncated
d-Limonene
molecular structure. The relatively hydrophobic cavity of CD provides a
less polar microenvironment in CD solution for the appropriately-sized
hydrophobic molecules to reside in. T heir applications are mainly intended
for the entrapment of smaller molecules, stabilization of reactive
intermediates and drug delivery device as potential molecular transport. In
food related applications, flavor compounds are being encapsulated into
CDs for better retention and protection from various possible means of
deterioration, as well as for controlled delivery. However, the inclusion and
-Cyclodextrin
release characteristics of the guest molecules have not been fully
d-Limonene included
in -cyclodextrin
understood. The aim of this study was to examine the effects of inclusion
methods on the properties of inclusion complex powders especially with
respect to flavor retention and release of the guest flavor compounds under various temperatures and
relative humidities.
3. Crystal transformation of sugars by ethanol dehydration technique
α,α-Trehalose(α-D-glucopyranosyl α-D-glucopyranoside) is a non-reducing disaccharide found in many
organisms as an energy source and protection of living cells from the damage caused by dryness. Since
trehalose is also present at low concentration in various food we continually ingest this sugar as part of a
daily diet. The main purposes for using trehalose are lowering of
sweetness, moisture retention and prevention of starch
retrogradation. Trehalose crystal exists in the dihydrate and
polymorphic anhydrous crystalline forms, which exhibit
complicated polymorphism depending on the given thermodynamic
conditions. In this study, an innovative process to produce
anhydrous crystal of trehalose with fine porosity using ethanol as
the dehydration medium was explored. Using this method, a new
type of porous crystal particle with a three-dimensional fine
Porous structures of
network structure could be obtained. The specific surface area of
anhydrous trehalose
2
the anhydrous crystal transformed at 50 C was 3.3 m /g, with a
median pore diameter of 0.21 μm, and void volume of 0.22 mL/g. The crystal transformation was
monitored by measuring the crystal moisture content. The crystal transformation rates could be correlated
with the Avrami equation, using the mechanism parameter n = 11.5, suggesting that the change of surface
area occurred during crystal transformation from dehydrate to anhydrous trehalose. The activation energy
of the crystal transformation rate was 132 k J/mol.
PUBLICATIONS
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H. Yoshii, F. Buche, N. Takeuchi, C. Terrol, M. Ohgawara, T. Furuta; Effects of protein on retention of
ADH enzyme activity encapsulated in trehalose matrices by spray drying, J. Food Eng,. 87, 34-39 (2008).
T. Ohashi, T. Shibuya, K. Oku, H. Yoshii, T. Furuta; Encapsulation of flax seed oil in anhydrous crystalline
maltose and trehalose with porous structure, (in Japanese) Nippon Shokuhin Kagaku Kogaku Kaishi, 55(1),
13 – 17 (2008).
T. L. Neoh, K. Yamauchi, H. Yoshii and T. Furuta; Kinetics of Molecular encapsulation of
1-methylcyclopropene into -cyclodextrin, J. Agric. Food Sci., 55, 26, 11020-11026 (2007).
A. Soottitantawat, Y. Ikuta, H. Yoshii, T. Furuta, M. Päivi, F. Pirkko and P. Kaisa; Visual observation of
hydrolyzed potato starch granules by -amylase with confocal laser scanning microscopy, Starch/Stärke, 59,
543-548 (2007).
H. Yoshii, A. Sakane, D. Kawamura, T-L. Neoh, H. Kajiwara and T. Furuta; Release kinetics of (−)-menthol
from chewing gum, J. Incl. Phenom. Macrocyclic Chem., 57, 591-596 (2007).
A. Soottitantawat, D. Muranaka, H. Yoshii and T. Furuta; Structural analysis of spray-dried powders by
confocal laser scanning microscopy, Asia-Pac. J. Chem. Eng., 2(1), 41-46 (2007).
T. Ohashi, H. Yoshii, and T. Furuta; Innovative crystal transformation of dihydrate trehalose to anhydrous
trehalose using ethanol, Carbohydrate Research, 342, 819–825 (2007).
T. Ohashi, H. Yoshii, T. Furuta; Effect of drying methods on crystal transformation of trehalose, Drying
Technology, 25, 1305-1311 (2007).
T-L. Neoh, H. Yoshii and T. Furuta; Encapsulation and release characteristics of carbon dioxide in
-cyclodextrin, J. Incl. Phenom. Macrocyclic Chem., 56, 125-133 (2006).
H. Yoshii, T. Ohhashi, T. Furuta and P. Linko; Enzyme encapsulation with crystal transformation of
anhydrous maltose or ahhydrous trehalose, J. Appl. Glycosci., 53, 99-103 (2006).
T. Furuta, Y. Kusuya, T-L. Neoh, L. Rehmann, S-H. Beak and H. Yoshii; Inclusion and release of hinokitiol
into/from MCT--CD fixed on Japanese washi paper, J. Incl. Phenom. Macrocyclic Chem., 56, 107-111 (2006).
A. Soottitantawat, F. Bigeard, H. Yoshii, T. Furuta, M. Ohkawara and P. Linko; Influence of emulsion and
powder size on the stability of encapsulated d-limonene by spray drying, Inn. Food Sci. and Emerg. Technol.,
6, 107-114 (2005).
M. Ishikawa, H. Yoshii, T. Furuta; Interaction of modified cyclodextrins with cytochrime P-450, Biosci.
Biotechnol. Biochem., 69, 246-248 (2005).
A. Soottitantawat, K. Takayama, K. Okamura, D. Muranaka, H. Yoshii, T. Furuta, M. Ohkawara and P.
Linko; Microencapsulation of l-menthol by spray drying and its release characteristics, Inn. Food Sci. and
Emerg. Technol., 6, 163-170 (2005).
H. Yoshii, M. Yasuda, T. Furuta, H. Kuwahara, M. Ohkawara and Pekka Linko; Retention of cyclodextrin
complex shiitake (Lentinus edodes) flavors with spray drying, J. Drying Technology, 23, 1205-1215 (2005).