Microwave irradiation of hazelnuts for the control of a
flatoxin producing
Aspergillus parasiticus
Pervin Basaran
1
, Ümran Akhan
Department of Food Engineering, Suleyman Demirel University, Isparta, Turkey
a b s t r a c t
a r t i c l e i n f o
Article history:
Received 13 May 2009
Accepted 18 August 2009
Editor Proof Receive Date 3 September 2009
Keywords:
Aspergillus
MW
A
flatoxin
In this study, the effects of microwave treatment on hazelnuts arti
ficially contaminated with aflatoxigenic
fungi were evaluated qualitatively and quantitatively. The physical quality attributes (color, moisture loss,
and sensory attributes) of microwave treated hazelnuts were also evaluated. A signi
ficant 3-log reduction in
Aspergillus parasiticus contamination was observed after 120 s treatment, no or similar changes were
observed during the storage of microwave treated hazelnuts under the storage conditions. While taste and
odour of microwaved in shell hazelnuts were unaffected during treatment and subsequent storage,
microwave treatment duration of 120 s was found to be capable of reducing fungal count of A. parasiticus on
in-shell hazelnut without any noticeable change in nutritional and organoleptic properties of nuts. Based on
this and the earlier study, a hybrid process is proposed, where UV-C surface treatment and vacuum assisted
microwave are combined with air drying to increase the shelf life and control the quality.
Industrial relevance: A hybrid industrial process is proposed, where UV-C surface treatment and vacuum
assisted microwave treatment are combined to increase the shelf life and control the quality of hazelnuts.
© 2009 Elsevier Ltd. All rights reserved.
1. Introduction
Drying and roasting are the most important practices for
processing and preserving hazelnut as they also cause signi
ficant
chemical, physical, structural and sensorial changes in the produce.
Conventional roasting of hazelnut is carried out by commercial
electrical processors at 120
–160 °C for 10–20 min depending on the
temperature. Roasting reduces moisture content from 4
–6% to 1–3%;
lower surface microbial load and inactivates enzymes that cause lipid
oxidations (
Demir, Baucour, Cronin, & Abodayeh, 2003
). Furthermore,
roasting removes pellicle of hazelnut kernels and signi
ficantly
improves organoleptic properties (crisp texture, rich
flavor and a
light golden color) (
Ozdemir & Devres, 2000; Demir, Celayeta, Cronin
Contamination by a
flatoxin producing fungi is the major problem
encountered during production, storage and marketing of hazelnuts
(Corylus avellana L.) (
). A
flatoxins are among the
most genotoxic and carcinogenic substances known, and therefore the
contamination levels are rigorously controlled by the national and
international regulations. Various physical (e.g., mechanical sorting, heat
treatment, and irradiation) and chemical (e.g., surfactants, benzalkonium
chloride, and SF
6
plasma) approaches have been reported for the control
of a
flatoxigenic fungi, however, these treatments may have their own
disadvantages such as cost and lack of ef
ficiency, and undesirable
organoleptic and nutritional changes (
Basaran, Akgul, & Oksuz, 2008;
Basaran, 2009-a,b; Das & Mishra, 2000
). There is, therefore, increasing
interest in developing economically feasible and environmentally safe
non-chemical processes to control a
flatoxigenic fungi in hazelnuts while
retaining product quality.
Dielectric processes of Radiofrequency (RF) and Microwave (MW)
are among the fastest growing food processing applications (
). The frequency range of MW (300 MHz
–
300 GHz) corresponds to quantum energies that can be absorbed by the
polar materials and as a result the food gets warmer. There has been a
great deal of research on the application of MW to food for a variety of
purposes e.g., drying, cooking, blanching of fruits and vegetables,
pasteurization, and disinfection, (
Akgul et al., 2008; Brody, 1992
). Here
in this study, 2.45 GHz MW was applied directly to hazelnuts
contaminated with Aspergillus parasiticus and the MW effects on post
harvest safety and quality of hazelnuts were determined.
2. Materials and methods
2.1. Water content
To evaluate the drying effect of MW, moisture content (dry basis)
of the kernel in relation to different MW durations was determined by
placing hazelnut kernels in a hot air oven at 40 °C and weighing until
constant weight.
Innovative Food Science and Emerging Technologies 11 (2010) 113-117
⁎ Corresponding author. University of Heidelberg, Institute for Physical Chemistry,
D69120 Heidelberg, Germany. Tel.: +90 542 431 0413.
E-mail addresses:
,
(P. Basaran).
1
On Sabbatical Leave.
1466-8564/$
– see front matter © 2009 Elsevier Ltd. All rights reserved.
doi:
Contents lists available at
Innovative Food Science and Emerging Technologies
j o u r n a l h o m e p a g e : w w w. e l s ev i e r. c o m / l o c a t e / i fs e t
2.2. Sensory analysis
Sensory evaluation was carried out following the triangle test
procedure by a trained sensory panel (
Basaran et al., 2008; Basaran,
).
2.3. Microbial preparation and MW treatment of hazelnuts
Fungi culturing and hazelnut contamination are performed as
described in
. MW heating was carried out using an
atmospheric MW oven model NN-H965BF (2.450 GHz, 1250 W)
(Panasonic, Secaucus, NJ, USA). To reduce temperature effect during
the holding period and to improve the surface heating of in-shell
hazelnuts, the system was adopted with a pulsing delivery MW power
which kept food temperature at a constant level. Samples were placed
in the center of the tray, and a fan and forced air were used to
maintain the air
flow speed (0.2 m/s).
A. parasiticus spore suspension, in-shell and unshelled hazelnuts
were prepared as follow and irradiated with MW. Inoculated hazelnuts
were prepared fresh each time to give an initial microbial concentration
of 10
6
–10
7
CFU/g and then incubated at 70% ERH for about four days
prior to MW treatment. For each MW treatment, 5 g of in shell and
unshelled hazelnuts were arranged in a single layer in Pyrex petri dishes
(9-cm diameter), and dishes were placed on the center of the turntable
plate and exposed to MW for various duration (0
–150s). For a separate
MW treatment, the MW duration of 120 s was divided in periods of 30 s,
and each 30-s treatment period was followed by an interval in which the
samples were cooled to the initial temperature.
Following MW exposure, the samples were homogenized in peptone
water (Oxoid, Hamshire, UK), and viable counts by surface plating on
potato dextrose agar (PDA, Merck, Darmstadt, Germany) were used to
determine the numbers of surviving A. parasiticus after incubation at
20 °C for 48 h (
Basaran et al., 2008; Basaran, 2009-a,b
).
2.4. A
flatoxin analysis by HPLC
A
flatoxin analysis was carried out by the HPLC method reported by
Basaran et al., 2008 and Basaran, 2009-a
2.5. GC
–MS analysis
Fatty acid composition in the hazelnut oil samples was determined by
gas chromatography (GC) using a QP 5050 GC/MS (Shimatzu, Shimadzu
Corporation, Kyoto, Japan), with a Cp WAX 52 CB (10 m×0.32 mm×
1.2
μm, Varian Inc., Palo Alto, CA, USA). Temperature was programmed
between 250 and 270 °C, with helium as gas carrier at a column
flow of
10.0 psi, and Wiley, Nist and Tutor Libraries were used for identi
fication.
2.6. Colorimetic analysis
Hazelnut color was determined using a Minolta colorimeter
CR200TM model (Minolta Camera Co., Osaka, Japan). The individual
lightness L
⁎, a⁎ and b⁎ parameters were recorded and results were
reported as the mean ± S.D. (n = 4) for each MW treatment duration.
2.7. Scanning electron microscopy
Control and 120 s MW-treated hazelnut samples were mounted on
bronze stub with double-sided adhesive tape allowing surface
visualization and examined in a Tescan Vega II (Tescan USA Inc., PA,
USA) scanning electron microscope at the operating voltage of 15 kV
(Suleyman Demirel University, Isparta, Turkey) (
).
2.8. Statistical analysis
All data were statistically analyzed according to
, mean values (±S.D) were calculated from at least three
replicates for each treatment, and least signi
ficant difference (LSD)
was used for comparing treatment means.
3. Results and discussion
3.1. Effect of MW on A. parasiticus contamination on Hazelnut
Results in terms of MW inactivation curves of A. parasiticus for various
durations are shown in
. Two-log CFU reduction of A. parasiticus
was observed after 60 s exposure time, when the surface temperature
was increased to nearly 50
–55 °C. For a total residence time of 120 s in the
applicator, up to 2.5-log reduction was found for A. parasiticus
contaminated on hazelnuts. The calculated D-value (using a regression
of all data points) was 45 s for A. parasiticus contaminated on hazelnut.
Treatment duration longer than 120 s, the nuts showed undesirable
burning signs; therefore, a maximum duration of 120 s was tested.
MW treatment is an emerging sterilization technique.
) observed nearly 6-log inactivation in CFU of coliform
bacteria in sludge after 120 s MW treatment at 2.45 GHz. The use of
MW at 650 W for 6 min achieved sterilization of dentures contami-
nated with Candida albicans (
). High
frequency electromagnetic MWs are not direct sources of heat, rather
with a frequency of 2.45 GHz; the waves agitate the water molecules,
which in turn raise the temperature, causing energy to dissipate in the
form of heat. However, whether the sterilization effect is solely due to
thermal heating or to the non-thermal
‘MW effect’ is still a matter of
controversy (
Kozempel, Goldberg, Cook, & Dallmer
reported non-thermal effects of MWs using Pediococcus
freudeareichii at different exposure times.
examined the possibility of athermal effects due
to MW radiation in a number of chemical, biochemical and microbial
systems and no athermal effects were detected. For the separate MW
heating, the MW irradiation time was divided in periods of 30 s, and
each 30 s treatment period was followed by an interval in which the
samples were cooled to the initial temperature and the results
demonstrated similar observations as 90 s treatment. Microwaves
induced no non-thermal lethal effects in the A. parasiticus with the
selected power source, heating induced by MW must be the primary
factor causing the lethal effects in A. parasiticus.
3.2. Physical quality properties of MW-treated hazelnut kernel
Hazelnut quality is generally measured based on its moisture and
oil content, a
flatoxin contamination and other physical properties.
shows the results of analysis performed on individual quality
attributes of MW-treated hazelnuts. In this study, drying effect of MW
treatment on hazelnut was also investigated. The changes of the
moisture content of hazelnut kernels with MW duration at 30, 60, 90,
Table 1
Physico-chemical quality parameters of control and MW-treated hazelnuts (Mean ± S.D.).
Treatment sec
(in shell)
Weight loss (%)
Color
L
⁎
a
⁎
CFU/g
0 (Control)
0
66.03a ± 2.3
2.87a ± 0.2
7.33a ± 1.2
30
0.242a ± 0.04
66.01a ± 2.6
2.99a ± 0.1
7.20a ± 1.3
60
1.14b ± 0.03
66.37a ± 2.1
2.60a ± 0.3
5.33b ± 0.9
90
2.25c ± 0.45
60.98b ± 2.3
3.35b ± 0.2
4.68c ± 0.4
120
2.14d ± 0.04
61.06b ± 2.1
2.86a ± 0.2
4.16d ± 0.6
4 × 30 (120)
2.14d ± 0.05
60.12b ± 3.2
2.95a ± 0.1
4.75b,c ± 0.9
240 s treatment results in undesirable organoleptic properties. Different letters within a
column indicate that means are signi
ficantly different (p<0.05).
114
P. Basaran, Ü. Akhan / Innovative Food Science and Emerging Technologies 11 (2010) 113-117
120 s were evaluated. MW heat treatment had no signi
ficant (effect
on weight loss upto 60 s treated hazelnuts (p
≤0.05).
Maximo, Silva, & Goncalves (2005)
applied a combined hot air and
MW drying and reached the
final moisture content of 1.5% for
macadamia nuts withing 5 h, which would certainly cause loss all
quality properties for hazelnuts.
reported that the
RF treatments signi
ficantly reduced the moisture content of the
walnut kernels and no sensorial difference was detected between
treated and untreated samples. As MW moves water molecules within
the food item very fast, and produce higher drying rates in shorter
time and reduces enegry consumption by nearly 50% (
). Unshelled hazelnuts exposed to MW
heating exhibited some changes in physical dimensions, notably in
the shrinkage in the radial direction by approximately 5%.
Freshly harvested hazelnut typically has moisture content up to 75
–
81.8% in husk and 30
–33.3% in-shell. The moisture control of hazelnuts
during storage is crucial for controlling fungal development. Furthermore,
hazelnut contains high amount of unsaturated fatty acids which are prone
to hydrolytic and oxidative rancidity when the free moisture is high. Sun
drying and later roasting processes are the common drying methods
currently employed for hazelnut, which prevent
flavor deterioration
during storage. Open air sun drying takes long time and increases
exposure risk to environmental contaminations. Recently, MW-assisted
drying operations appeared as a rapid and ef
ficient drying method as
compared to conventional open air-drying (
1999; Kiranoudis et al., 1997; Maskan, 2000; McMinn, 2006
). The degree
of interaction of microwaves with the material depends on the dielectric
properties of the chemical composition and these are described in terms
of the penetration depth (
). Furthermore material
dependent water transfer kinetics from within the material to its surface
is also critically important (
Vega-Gálvez, Lemus-Mondaca, Bilbao-Sáinz,
Changes in the color of MW-treated hazelnuts were evaluated by
measuring lightness (L
⁎), hue angle and chroma shortly after MW
treatment (
). The MW treatment did not exert any signi
ficant
color changes up to 100 s; however after 120 s nuts showed dark
brown burning color. The formation of desired color depend on the
roasting conditions, and currently the conventional roasting process
of hazelnuts is generally conducted based on earlier experiences.
Therefore, discrepancies in conventional roasting level could be due to
the use of direct heating but also to a lack of a standard de
finition of
roasting degree, which is currently described only by color changes.
A
flatoxins (AFs) are among the most potent mutagenic and
carcinogenic substances produced by
filamentous microfungi (
). They have unique group of highly oxygenated heterocyclic
compounds which make them resistant. In order to examine the effect of
2.450 GHz MW on the destruction of AFs, arti
ficially contaminated raw
hazelnuts were subjected to 120 s MW (
). A
flatoxin levels on
hazelnuts remained essentially unchanged (p >0.05), during 2.45 GHz
MW treatment for 120 s which was the longest period of time not causing
undesired organoleptic changes in hazelnuts. These results indicate that
unlike microbial inhibition, 120 s 2.45 GHz treatment is not effective itself
for a
flatoxin control in hazelnuts.
reported a 97% a
flatoxin reduction in animal
feed with combined treatment of hydrogen peroxide and MW radiation
(1000 W for 15 min) and the inactivation effect was dependent on the
initial level of contamination.
applied argon
plasma induced by a 2.45 GHz MW at atmospheric pressure and were
able to remove AFB1, DON, and NIV completely after 5 s of plasma
treatment (
). In their study, mycotoxins were suspended
in chloroform, and adsorbed on glass rod. Later, these rods were exposed
Fig. 1. Organoleptic Evaluation of hazelnut upon 30
–90 s MW treatment.
Fig. 2. SEM images of hazelnut a) Control and b) After 120 s microwave treatment
(
−100 µM).
115
P. Basaran, Ü. Akhan / Innovative Food Science and Emerging Technologies 11 (2010) 113-117
to plasma (
). In our earlier report (
),
SF
6
and air plasmas were also effective in reducing AF contamination on
hazelnuts. From these observations, it was concluded that sole 2.45 GHz
MW treatment is not suf
ficient to remove aflatoxin.
3.2. Microstructure characterization by SEM
To gain further insight into the effect of the MW treatment on the
hazelnut, the microstructure of the MW-treated hazelnut was
visualized with scanning electron microscopy (SEM).
shows
the scanning electron micrographs of non-irradiated and MW
irradiated hazelnuts. Micrographs indicate that the hazelnut became
porous in morphology due to the structural change caused by the MW
heat energy. Increased porosity leads to improved rehydration
characteristics and a softer product (
). This consequence is re
flected in the fact that the
oil recovery increased by 45% from the Chilean hazelnut with 240 s
MW pretreatment (
3.3. Organoleptic evaluation of the MW-treated hazelnuts
One of the most useful quality characterization of hazelnut is the
assessment of its organoleptic properties (color,
flavor, appearance and
tenderness), which are human perception encompassing many properties
or characteristics of hazelnut (
Basaran et al., 2008; Basaran, 2009-a,b
).
Sensory attributes of MW-treated hazelnut are shown in
. Hazelnut
in-shell treated with MW up to 30 s or untreated were not distinguished
by the sensory panel. There was not signi
ficant difference in kernel color
between the control and all treated nuts up to 60 s, color intensity sharply
increased after 60 s. Texture is an important quality attribute contributing
to the enjoyment and acceptance of thermally processed nuts. MW
treatment longer than 30 s surface area shrinkage resulting from water
loss could have caused loss in textural perception; on the contrary,
acceptability of product texture increased with increasing MW duration
after 60 s (p
≤0.05)
.
Many
flavor compounds are generated during roasting of hazelnuts
which include the lipid peroxidation compounds, Strecker degradation
products, as well as compounds derived from the Maillard reaction
(
). As shown in
, after MW treatment
aroma changes were the least in 30 s (score 2.1
–2.5) while most
pronounced changes in taste were recorded in nuts exposed to MW for
90 s (score 3.5
–3.8). No off-flavors were detected by the panellists on
the day of treatment up to 90 s, and durations longer than 120 s
produced sensorily unacceptable products so much as the MW
treatment for 120 s and longer changed taste of nuts to that of
“burned”
nuts and produced undesirable change in color, taste and aroma of
hazelnuts. The results suggested that MW heating (within 100
–120 s) is
bene
ficial for availability of the organoleptic substances, but prolonged
heating results in adverse effects on those substances.
3.4. GC
–MS and oil content
Hazelnut kernels like all other nuts, are typically high in fat (40
–
50 %) of which 93% consists of polyunsaturated fatty acids, and due to
unsaturated fatty acid pro
file, frequent consumption of hazelnuts is
recommended for lower risk of coronary heart diseases (
). The high unsaturated fatty acid content of the hazelnut makes it a
nutritious product, but also more susceptible to lipid peroxidation and
rancidity (
), especially when it contains high moisture and
therefore drying is applied to reduce the free moisture content.
Microbial growth and enzymatic activity and resulting oil hydrolysis is
responsible for off-
flavors during hazelnut storage.
The fatty acid composition of non treated hazelnuts in this study is in
good agreement with that reported in the literature (
). The main fatty acid components are oleic and linoleic acids, which
represent 90% of total fatty acids (
). No signi
ficant
in
fluence was observed in fatty acid composition when hazelnuts were
exposed to MW for the maximum duration of 120 s (Table 2). By
conventional roasting at 120
–160 °C for 15min, the structure of lipid
storage cells is damaged and oil exposure to oxidation rate increases
(
), therefore MW roasting for 120 s would
Fig. 3. Schematic view of the industrial scale (UV-C & MW) unit designed based on current hazelnut processing methodology (1. Conveyor belt, 2. UV-C treatment unit, 3. UV-C
source, 4. Fan, 5. MW treatment unit, 6. Mixer, 7. Nut feeder, 8. Exhaust air, 9. Combined UV-C & MW Treatment Unit, 10. Cooling, and 11. Discharge of treated nuts).
116
P. Basaran, Ü. Akhan / Innovative Food Science and Emerging Technologies 11 (2010) 113-117
signi
ficantly decreases the risk of oil exposure to thermal oxidation. In an
earlier study, differences in the fatty acid composition of Chilean hazelnut
oil were observed between the untreated and a MW pretreated oil
samples for a treatment time of 4min (
). However, in
this study with a maximum duration of 120 s, no dfference was observed.
3.5. Designing continuous
flow UV-C-MW roasting unit
The world production of hazelnut is mainly (85%) located in Turkey
). There is an increasing interest into improve
conventional drying and roasting processes with the intent of taking
advantage of the emerging novel processing methods. Our results
demonstrate that the use of MW for duration of 120 s reduced fungi
from nut surface as a result mycotoxin contamination would eventually
be reduced. Hard shell provides a strong protection layer against
invasion of microorganisms and therefore nuts are stored inshell. MW is
effective not only for the surface treatment of but also the kernel inside
and that nut kernel can be heated directly and rapidly without removing
the shell. MW roasting removed the pellicle of the kernel, which is a
desired and expected result of the conventional heat roasting.
Furthermore, compared to traditional thermal roasting, the organoleptic
properties (color, aroma, texture, and appearance) developed during
short MW treatment were similar or improved. The general advantages
of MW roasting of hazelnuts include: rapid heating, internal heating
without cracking the shell, hygienic and uniform drying, a clean source
of energy, and reduced processing time and costs.
In recent studies, our team has concentrated on various applications
for post harvest control of a
flatoxigenic strains of Aspergillus spp. on
hazelnuts (
Basaran et al, 2008; Basaran, 2009-a,b
). When, the reduction
in counts of Aspergillus spp. and a
flatoxin production was assessed on
hazelnuts after 254 nm UV-C treatment, a 2-log reduction in Aspergillus
spp. counts and nearly 25% decrease in a
flatoxin B1 and G1 were
observed (
). Practical and economical post harvest
procedures would require integrating several of processing approaches.
Based on these earlier studies, a UV-C combined with a vacuum assisted
MW air
flow unit is proposed for industrial processing of (
), in
which MW initial electromagnetic heating would reduce process time
and improve post harvest product quality of hazelnut more econom-
ically. In the future studies, the critical process parameters (heat and
mass transfer (e.g., moisture diffusion), light intensity, air
flow rate) of
the commercial size UV-C-MW-heating system will be determined as an
alternative to heat roasting.
References
Akgul, N. B., Basaran, P., & Rasco, B. A. (2008). The effect of temperature (
−5 to 130 °C)
and
fiber direction on the dielectric properties of beef Semitendinosus at radio
frequency and microwave frequencies. Journal of Food Science, 73, 243
–249.
Alasalvar, C., Shahidi, F., Ohshima, T., Wanasundara, U., Yurttas, H. C., Liyanapathirana, C. M.,
et al. (2003). Turkish tombul hazelnut (Corylus avellana L.). lipid characteristics and
oxidative stability. Journal of Agriculture and Food Chemistry, 51, 3797
–3805.
Arino, A., Herrera, M., Estopañan, G., Rota, M. C., Carraminana, J. J., Juan, T., et al. (2009).
A
flatoxins in bulk and pre-packed pistachios sold in Spain and effect of roasting. Food
Control., 20, 811
–814.
Basaran, P. (2009a). Reduction of Aspergillus parasiticus on hazelnut surface by UV-C
Treatment. International Journal of Food Sciecne and Technology, 44, 1857
–1863.
Basaran, P. (2009b). Antifungal effect of acid and surface active compounds for post-harvest
control of Aspergillus parasiticus growth on hazelnut. Journal of Food Processing and
Preservation, 20, 811
–814.
Basaran, P., Akgul, B. N., & Oksuz, L. (2008). Elimination of Aspergillus parasiticus from
nut surface with low pressure cold plasma (LPCP) treatment. Food Microbiology, 25,
626
–632.
Basaran, P., & Ozcan, M. (2009). Occurrence of a
flatoxins in various nuts commercial-
ized in Turkey. Journal of Food Safety, 29, 95
–105.
Brody, A. L. (1992). Microwave food pasteurization, sterilization and packaging. Food
Technology International Europe, 67
–71.
Cammerer, B., & Kroh, L. W. (2009). Shelf life of linseeds and peanuts in relation to
roasting. LWT - Food Science Technology, 42, 545
–549.
Cunningham, S. E., Mcminn, W. A. M., Magee, T. R. A., & Richardson, P. S. (2008). Effect of
processing conditions on the water absorption and texture kinetics of potato.
Journal of Food Engineering, 84, 214
–223.
Das, C., & Mishra, H. N. (2000). Effect of afatoxin B1 detoxi
fication on the physicochemical
properties and quality of ground nut meal. Food Chemistry, 70, 483
–487.
Demir, A. D., Celayeta, J. M. F., Cronin, K., & Abodayeh, K. (2002). Modelling of the kinetics of
colour change in hazelnuts during air roasting. Journal of Food Engineering, 55,
283
–292.
Demir, A. D., Baucour, P., Cronin, K., & Abodayeh, K. (2003). Analysis of temperature
variability during the thermal processing of hazelnuts. Innovative Food Science and
Emerging Technologies, 4, 69
–84.
Drouzas, A. E., Tsami, E., & Saravacos, G. D. (1999). Microwave/vacuum drying of model
fruit gels. Journal of Food Engineering, 39, 117
–122.
Frankel, E. N. (1993). In search of better methods to evaluate natural antioxidants and
oxidative stability in food lipids. Trends in Food Science and Technology, 4, 220
–225.
Hong, S. M., Park, J. K., & Lee, Y. O. (2004). Mechanisms of MW irradiation involved in
the destruction of fecal coliforms from biosolids. Water Research, 38, 1615
–1625.
Kiranoudis, C. T., Tsami, E., & Maroulis, Z. B. (1997). MW vacuum drying kinetics of some
fruits. Drying Technology, 15, 2421
–2440.
Kozempel, M., Goldberg, N., Cook, R., Dallmer, M. (1999). Nonthermal energy treatment for
the reduction of microbial population in liquid food products. U.S. Patent 5962054.
Maskan, M. (2000). Microwave/air and microwave
finish drying of banana. Journal of
Food Engineering, 44, 71
–78.
McLoughlin, C. M., McMinn, W. A. M., & Magee, T. R. A. (2003). MW drying of
multicomponent powder systems. Drying Technology, 21, 293
–309.
McMinn, W. A. M. (2006). Thin-layer modelling of the convective, MW, MW-convective
and MW-vacuum drying of lactose powder. Journal of Food Engineering, 72, 113
–123.
Oh, T. -J., Shotwell, J. L., & Billy, E. J. (2006). Effect of
flapless implant surgery on soft
tissue pro
file: A randomized controlled clinical trial. Journal of Periodontology, 77,
874
–882.
Ozdemir, M., & Devres, O. (2000). Kinetics of color changes of hazelnuts during roasting.
Journal of Food Engineering, 44, 31
–38.
Park, B. J., Takatori, K., Sugita-Konishi, Y., Kim, I. -H., Lee, M. -H., Han, D. -W., et al.
(2007). Degradation of mycotoxins using MW-induced argon plasma at atmo-
spheric pressure. Surface Coating Technology, 201, 5733
–5737.
Siegmund, B., & Murkovic, M. (2004). Changes in chemical composition of pumpkin seeds
during the roasting process for production of pumpkin seed oil. Food Chemistry, 84,
367
–374.
Silva, F. A., Marsaioli, A. J., Maximo, G. J., Silva, M. A. A. P., & Goncalves, L. A. G. (2005).
Microwave assisted drying of macadamia nuts. Jorunal of Food Engineering, 77, 550
–558.
Shazman, A., Mizrahi, S., Cogan, U., & Shimoni, E. (2007). Examining for possible non-
thermal effects during heating in a microwave oven. Food Chemistry, 103, 444
–453.
Uquiche, E., Jeréz, M., & Ortíz, J. (2008). Effect of pretreatment with microwaves on
mechanical extraction yield and quality of vegetable oil from Chilean hazelnuts (Gevuina
avellana Mol). Innovative Food Science and Emerging Technology, 9, 495
–500.
Vega-Gálvez, A., Lemus-Mondaca, R., Bilbao-Sáinz, C., Fito, P., & Andrés, A. (2008). Effect of air
drying temperature on the quality of rehydrated dried red bell pepper (var. Lamuyo).
Journal of Food Engineering, 85, 42
–50.
Wang, S., Tang, J., Johnson, J. A., Mitcham, E., Hansen, J. D., Cavalieri, R. P., et al. (2002).
Process protocols based on radio frequency energy to control
field and storage
pests in in-shell walnuts. Postharvest Biological Technology, 26, 265
–273.
117
P. Basaran, Ü. Akhan / Innovative Food Science and Emerging Technologies 11 (2010) 113-117
Document Outline
- Microwave irradiation of hazelnuts for the control of aflatoxin producing Aspergillus parasitic.....
Wyszukiwarka
Podobne podstrony:
SMeyer WO8901464A3 Controlled Process for the Production of Thermal Energy from Gases and Apparatus
The American Society for the Prevention of Cruelty
[Pargament & Mahoney] Sacred matters Sanctification as a vital topic for the psychology of religion
International Convention for the Safety of Life at Sea
Broad; Arguments for the Existence of God(1)
ESL Seminars Preparation Guide For The Test of Spoken Engl
Kinesio taping compared to physical therapy modalities for the treatment of shoulder impingement syn
GB1008594A process for the production of amines tryptophan tryptamine
Popper Two Autonomous Axiom Systems for the Calculus of Probabilities
Anatomical evidence for the antiquity of human footwear use
The Reasons for the?ll of SocialismCommunism in Russia
Dynamic gadolinium enhanced subtraction MR imaging – a simple technique for the early diagnosis of L
APA practice guideline for the treatment of patients with Borderline Personality Disorder
Criteria for the description of sounds
Evolution in Brownian space a model for the origin of the bacterial flagellum N J Mtzke
Hutter, Crisp Implications of Cognitive Busyness for the Perception of Category Conjunctions
Apparatus for the Disposal of Waste Gases Disposal Baphomet sm
więcej podobnych podstron