MIDDLE EAST TECHNICAL
UNIVERSITY
DEPARTMENT OF FOOD ENGINEERING
Assoc. Prof. Dr. Serpil Sahin
1
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Founded in 1982
„
ABET 2000 accreditated
„
Get only the top high school graduates (~
(~4 %) of the
students passing the Central University Entrance exam
„
~300 undergraduate and ~50 graduate students
„
8 Professors, 5 Associated Professors, 1 Assistant Professor
RESEARCH ACTIVITIES
„
Number of articles published in International
Journals in 2005: 25
„
In 2006 one book published by SpringerSpringer-Verlag.
Sahin,
Sahin, S. and Sumnu,
Sumnu, S.G. Physical Properties of
Foods,
oods, Food Science Text Series, Springer: New York, USA,
2006 (ISBN: 00-387387-3078030780-X)
2
RESEARCH ACTIVITIES
¾
INDUSTRIAL BIOTECHNOLOGY
FUNGAL MOLECULAR BIOLOGY & ENZYMOLOGY
FOOD MICROBIOLOGY
FOOD SCIENCE
¾
FOOD PROCESS ENGINEERING
¾
¾
¾
„
Pervaporation
„
NonNon-thermal Processing
„
Supercritical Fluid Extraction
„
Microwave Processing
INDUSTRIAL BIOTECHNOLOGY
Prof. Dr. Haluk Hamamcı
Hamamcı
3
„The physiology of the
filamentous fungus
Rhizopus oryzae is being
investigated by focusing on
different parts of the
metabolism,
metabolism, mainly
a. pyruvate branch point and its
regulation
b. glycolytic pathway and its
regulation
c. trehalose metabolism
„
Fermentation
Kinetic and stochiometric
modeling of glycolytic
pathway with particular
interest on the biomass
yield in Baker's yeast
propagation
Fructose-1,6-phosphate
d [ F16 P ]
= V PF 1 K − V ALD
dt
Phophofructo kinase:
VPFK = Vm PFK
gr ⋅ λ1 ⋅ λ2 ⋅ R
R2 + L ⋅T 2
Aldolase:
V ALD = (0.35)Vm ALD
F 16bP
(1 − Teq )
K F 16 bP
F 16bP DHAP GAP F16bP ⋅ GAP DHAP ⋅ GAP
+
+
+
+
(1 +
)
K F 16 bP K DHAP K GAP K F 16 bP ⋅ KiGAP K DHAP ⋅ K GAP
Metabolic modelling
4
„
„
Production and purification of β-galactosidase
from Kluyveromyces lactis, Rhizomucor species
and Aspergillus niger.
niger. The scope of the research
is to find traditional and novel solutions for the
lactose intolerance problem
Application of foam
separation technique in
recovery proteins from
industrial wastes,
wastes, enzyme
recovery from fermentation
medium with retention of
activity and partial
purification of fermentation
products
5
„
Growth of
agriculturally
important Bacillus,
Pseudomonas and
Azotobacter spp. on
food wastes
FUNGAL MOLECULAR BIOLOGY
AND ENZYMOLOGY LABORATORY
Genetic Engineering Applications
Prof. Dr. Zumrut Ogel
6
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„
„
„
„
„
„
Heterologous Expression
of Industrially Important
Enzymes
„ Mannanase
„ AlphaAlpha-galctosidase
„ Laccase
Analysis of Autocatalytic
Processing Mechanism of
GalactoseGalactose-Oxidase
Mycotoxin Genetics
Adaptation to Stress and
Memory in Fungi
Production of bioactive
compounds by fungal organic
biotransformations with
emphasis on the utilization of
phenol oxidases and
monooxyganases
Extracellular hydrolytic enzymes
produced by fungi associated
with the southern pine beetle
Production of thermostable
β -galactosidase from
thermophilic fungi
Microscopic view of
Ophiostoma minus
7
MICROBIOLOGY LABORATORY
Assoc. Prof. Dr. Candan Gultekin
„
Isolation and identification of Streptococcus
thermophilus and Lactobacillus delbrueckii
ssp. bulgaricus from traditionally prepared
Turkish yogurts
„
Pathogens:
Salmonella and Listeria
8
FOOD SCIENCE LABORATORY
Prof. Dr. Fatih Yı
Yıldı
ldız
„
„
Minimally Processed Foods
Food Safety and Security: Risk Assessment
Models
RESEARCH ACTIVITIES
¾
FOOD PROCESS ENGINEERING
„
Pervaporation
„
Non-thermal Processing
„
Supercritical Fluid Extraction
„
Microwave Processing
9
PERVAPORATION
Assoc.Prof.Dr.Serpil Sahin -Assoc.Prof.Dr.Gulum
Sumnu
Pervaporation is a selective
selective membrane technique
in which a liquid feed mixture is separated by
means of partial vaporisation through a nonnonporous permselective membrane
Advantages over conventional aroma revovery
processes:
„ High selectivity
„ Low energy consumption
„ Moderate operating temperatures
temperatures
Ö quality improvement
„
10
NON-THERMAL PROCESSING
LABORATORY
Assoc. Prof.Dr.Hami Alpas, Prof.Dr. Faruk Bozoglu,
Prof.Dr. Alev Bayı
Bayındı
ndırlı
rlı
¾
Effect of high hydrostatic
pressure and ultrasound on;
on;
„ some quality parameters,
parameters,
enzymes, microorganisms
microorganisms
and shelfshelf-life of fruit and
vegetable juices
„ drying rate of fruits and
vegetables
„ extraction of polyphenols
from fruit pomace
11
Ilkay Sensoy, Ph.D. (New faculty member)
Research Areas:
NonNon-thermal processing (Pulsed electric
field, High hydrostatic pressure)
Moderate electrical field treatment, Ohmic
heating
Functional foods
Numerical simulation of processes
Research Objectives:
Develop new processing technologies and,
and,
safe and high quality food products for well
being, disease prevention and recovery from
diseases
Non Thermal Processing (PEF and HHP) :
Advantages:
Advantages: fresher, more nutritious foods
Challenges:
Challenges: safety and quality is not
optimal yet for many product types (spores and
some enzymes are still a challenge).
Future needs:
Validation and comparison with
conventional technologies
Combine processes, use synergy and
optimization
12
Functional Foods:
People are in demand for high value foods:
Foods that improve performance, reduce
health risks,
risks, increase quality of life,
life, reduce aging
and help recovering from diseases.
diseases.
Future needs:
needs:
Collaboration with health professionals.
SUPERCRITICAL FLUID
EXTRACTION LABORATORY
Assoc. Prof. Dr. Esra Yener
ƒ Environmentally friendly technology
ƒ Heat sensitive compounds are not degraded
ƒ Higher yield is obtained
13
Pressure
The combined liquidliquid-like solvating capabilities and gasgas-like
transport properties of supercritical fluids make them particularly
suitable for the extraction of diffusiondiffusion-controlled matrices such as
plant tissues
Solid
Liquid
Supercritical
Fluid
Critical Point
Triple Point
Temperature
¾
¾
Supercritical carbon dioxide extraction of
biomaterials
„ Extraction of specialty oils
„ Extraction of essential oils from herbs
„ Recovery of antioxidants from industrial bybyproducts
Modelling phase equilibria and extraction process
14
MICROWAVE PROCESSING
LABORATORY
Assoc.Prof.Dr. Gulum Sumnu-Assoc.Prof.Dr.Serpil Sahin
„
„
„
„
„
Microwave Extraction
Microwave Baking
Microwave Frying
Microwave Drying
Microwave Thawing
15
Microwave Extraction
Oreganum vulgare
Extraction of essential oils from herbs
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„
„
9
9
Saves time and energy
Green technology, no solvent is required
Provides valuable essential oils
SolventSolvent-free Microwave Extraction (SFME):
Combination of microwave heating and dry
distillation (soaked dry spices)
MicrowaveMicrowave-assisted Hydrodistillation(MAHD)
Combination of microwave heating and
hydrodistillation
16
Microwave Baking
Optimization of microwave
baked bread formulations
„ Retardation of staling of
microwave baked products
„ Design of gluten free cake
formulations for
MicrowaveMicrowave-IR combination
oven
„
„
„
Modelling of physical
properties (rh
(rheological,
eological,
thermal, dielectric
properties, colour) of
different cake and bread
formulations during baking
with Microwave and
MicrowaveMicrowave-IR combination
ovens
Image analysis and porous
media characterization
17
Physical properties of breads baked by
different heating methods
Oven types:
„ Jet impingement (JET),
„ Microwave -Jet impingement (MJET)
„ Microwave - Infrared (MIR) oven
Physical properties measured during baking:
ƒ Moisture content
ƒ Porosity
ƒ Dielectric
ielectric properties
ƒ Thermal conductivity
110
100
Temperature (°C )
90
MJET
80
MIR
70
60
JET
50
40
30
20
10
0
0
1
2
3
4
5
6
7
8
Time (min)
18
Moisture content (%)
42
39
JET
36
MIR
MJET
33
30
0
2
4
6
8
Time (min)
1.05
JET
1
MJET
0.95
Porosity
0.9
0.85
0.8
0.75
MIR
0.7
0.65
0.6
0
2
4
6
8
Time (min)
19
Dielectric constant
.
25
20
15
MIR
10
MJET
5
0
0
2
4
6
8
Time (min)
12
L o ss fa cto r
10
8
6
MJET
4
MIR
2
0
0
2
4
6
8
Baking time (min)
20
Thermal conductivity (W /m°C )
0.35
0.30
0.25
0.20
MIR
JET
0.15
0.10
MJET
0.05
0.00
0
2
4
6
8
Time (min)
Microwave Frying
„
Optimization of
microwave frying of
potato slices
„
Acrylamide formation
during microwave frying
21
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Functionality of batters having
different formulations for deepdeep-fat
frying
Effects of batter consistency on frying
performance
Effects of microwave frying on
acrylamide content of potatoes
Acrylamide;
ƒ It is probably carcinogenic to human
ƒ It is mainly formed through the Maillard reaction
ƒ f (T , t, pH, food composition (reducing sugars
such as glu and fru, and amino acids such as
asparagine))
22
.
600
M ois ture Content (% db)
500
400
400 W
550 W
300
Conventional
200
100
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Frying Time (min)
70
65
.
60
400 W
55
E
550 W
Conventional
50
45
40
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0
Frying Time (min)
23
.
4000
2.0 min
A c ry lam ide Content (ppb)
3500
3000
2500
2000
1500
400W
5.5 min
1.5 min
550W
4.5 min
Conv.
2.0 min
1000
1.0 min
500
0
1.5 min
1.0 min
80 100 120 140 160 180 200 220 240 260 280
Moisture Content (% db)
24