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Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XI, Issue 4 – 2012

IN FLU EN CE O F CH EM IC AL COM PO SITION A ND TEM PERA TU R E ON

HON EY PHAS E A NG LE

Mircea OROIAN1

1 Faculty of Food Engineering, Stefan cel Mare University of Suceava, Romania
m.oroian@fia.usv.ro

*Corresponding author
Received 25 October 2012, accepted 27 November 2012

Abstract: Honey is a complex material which exhibits a viscoelastic behavior under oscillatory
testing. The rheological behavior of honey is influenced by moisture content, concentration and by the
temperature (all the rheological parameters are decreasing with the increasing of the temperature).
This article is about the influence of chemical composition (fructose, glucose, sucrose, moisture
content) and temperature on the honey phase angle. The honey is meeting the Codex Alimentarius
requirements regarding moisture content. The sum of fructose and glucose concentrations was 60
g/100 g in agreement with CE directive 2001/110/CE. The phase angle was measured at 30, 35, 40, 45
and 50 °C; the viscous component is maxim at low temperature (in the study case at 30 -45 °C). It can
be observed that at 30 °C, 35 °C, 40 °C and 45 °C, the phase angle evolution is not influenced by the
frequency applied; the phase angle is changing a little with the frequency. At 50 °C, the phase angle is
strongly influenced by the frequency, is decreasing its value proportionally with frequency.The
suitable precidtion of the phase angle with temperature and chemical composition has been observed
using the 3rd grade polynomial model with variables; the model achivied has reached a regression
coeffiecient (R2) 0.9915.

Keywords: honey, sugar, polynomial model

1. Introduction

Honey is a natural and nutritious food used
by many people all over the world since
ancient times, mainly because of its
significant contribution to human health.
However, the quality of honeys varies
dependent on the climate and
environmental conditions around the
foraging area of honey bees. Further
processing and improper storage condition
also influent the quality of honeys
indirectly [1].
Viscosity of honey is an important factor
that concerns both processing parameters
of honey production (e.g. velocity of
centrifuging or filtering) and its sensory
properties perceived by consumers. The
majority of fluid honeys shows Newtonian

behaviour and their viscosity strongly
depends on temperature [2-4].
The viscoelasticity is the property of
materials that exhibit viscous and elastic
characteristics when underdoing
deformation. Viscous materials, like
honey, resist shear flow and strain linearly
with time when a stress is applied [5]. The
viscoelastical parameters of a
viscoelastical materials are: elastic
modulus (G’), viscous modulus (G’’),
complex modulus (G*), complex viscosity
(η*) and phase angle (δ).
The rheological properties of honey have
been investigated by some authors in the
last decades [2-4, 6-8], however no other
papers have been reported on the phase
angle determination and the influence of
different factors on it.

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XI, Issue 4 – 2012

The aim of this study is to determine the
phase angle of different honey types, to
study the influence of the temperature on
the magnitude of it, to model the chemical
and temperature influence of the phase
angle.

2. Materials and methods

2.1. Materials

For the rheological behaviour of honeys
samples were purchased different 6
samples of different origins (floral,
polyflorals and honeydew); the samples
have been purchased from the Romanian
market. The rheological properties of
honeys can be influenced by the presence
of crystals and air bubbles [8].
Before measuring the rheological
properties, the samples were warmed to 55
°C to dissolve the crystals, and were kept
at 30 °C to eliminate the bubble airs, which
could interfere during the rheological
studies.

2.2. Concentration (°Brix) and moisture
content determination

The concentration of soluble solid

content (°Brix) and refractive index were
determined using a refractometric method.
We used Leica Mark II Plus refractometre.

The moisture content was determined
using the Chataway table [9]. The
measurement were taken in duplicate

2.3. Sugar determination

The determination of glucose, fructose

and sucrose in honey samples was made by
a HPLC 10ADVP -SHIMADZU, with RI-
detector, according to a method described
by Bogdanov [9]. The compounds were
separated on a Alltech type Alltima amino
column, 250×4.6 mm i.d. and particle size
5 µm. The samples were prepared as: 5 g
of honey were dissolved in water (40 ml)

and transferred quantitatively into a 100 ml
volumetric flask, containing 25 ml
methanol and filled up to the volume with
water. The solution was filtered through a
0.45 µm membrane filter and collect in
sample vials. Flow rate 1.3 ml/min, mobile
phase: acetonitrile/water (80:20, v/v),
column and detector temperature 30 °C,
sample volume 10 µl.

A calibration curve was made for each
sugar using standard solutions of different
concentrations (0.5–80 mg/ml). The linear
regression factor of the calibration curves
was higher than 0.9982 for all sugars.
Sugars were quantified by comparison of
the peak area obtained with those of
standard sugars.

The results for each sugar were
expressed as g/100 g honey. Values of
parameters were expressed as the mean ±
standard deviation to a confidence interval
for mean of 95 %.

2.4. Phase angle determination (δ)

Phase angle determination was made

using the device designed and realised at
Food Engineering Faculty, at a frequency
ranged between 0.1-10 Hz, and a
amplitude of 2 dB.

2.5. Statistical analysis

The statistical analysis was made

using the next software packs: Excel 2007
and Unscrambler X 10.1. The variables
were weighted with the inverse of the
standard deviation of all objects in order to
compensate for the different scales of the
variables.

3. Results and discussions

In this study have been analysed 6
honey samples, each one with a different
chemical composition. The phase angle
was measured at 5 temperatures 30 °C, 35

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XI, Issue 4 – 2012

°C, 40 °C, 45 °C and 50 °C). In table 1 is
presented the chemical composition of the
honeys samples. The honey is meeting the
Codex Alimentarius requirements

regarding moisture content The sum of
fructose and glucose concentrations was 60
g/100 g in agreement with CE directive
2001/110/CE [10].

Table 1

Chemical composition of honey
Acacia Dandelion Honeydew Polyfloral Sun flower Tilia

Moisture (g/100g) 18.6 16.9 17.7 19.2 19.3 19.0

°Brix 80.2 81.9 81.4 80.0 79.9 79.8

Fructose (g/100g) 47.3 40.2 35.9 35.3 38.6 43.3

Glucose (g/100g) 27.6 33.2 34.5 31.3 34.8 32.4

Sucrose (g/100g) 2.0 1.2 0 2.2 1.6 1.1

Fructose + glucose (g/100g) 74.9 73.4 70.4 66.6 73.4 75.7

F/G 1.7 1.2 1.0 1.1 1.1 1.3

The samples were analysed at a
frequency ranging 0.1 – 10 Hz. In figure 1
is presented the evolution of phase angle
with temperature and frequency. The phase
angle ranged between 75,16 – 89,98°. The
phase angle is ranging between 0 and 90°,
the region between 0 – 45° corresponds to
viscoelastical materials with elastic part
dominant, and the region between 45-90°
corresponds to viscoelastical materials
with viscous part dominant. From phase
angle point of view honey is a
viscoelastical material with the viscous
part dominant. The viscous component is
maxim at low temperature (in the study
case at 30 -45 °C). It can be observed that
at 30 °C, 35 °C, 40 °C and 45 °C, the
phase angle evolution is not influenced by
the frequency applied; the phase angle is
changing a little with the frequency. At 50
°C, the phase angle is strongly influenced
by the frequency, is decreasing its value
proportionally with frequency.

3rd grade multivariable polynomial

modelling of the influence of chemical
composition and temperature on phase
angle of honeys

The data model regarding the

prediction of phase angle (δ) of honey,
measured at 1 Hz, in function of its

chemical composition (fructose, glucose,
sucrose, sugars (the difference between
Brix concentration –reported as dry mater
– and the sum of fructose, glucose and
sucrose), non-sugars components (the
difference, reported to 100 g, between 100
g and the sum of moisture content and Brix
concentration), moisture content and
temperature was been made using a 3rd
grade polynomial equation with seven
variables. The measured and predicted
values have been compared to see the
suitability of the model. The equation of
the model is as given (eq. 1):

where δ the phase angle predicted, b0 is a
constant that fixes the response at point of
the experiments, bi – regression coefficient
for the linear effect terms, bij – interaction
effect terms, bii – quadratic effect terms
and biii – cubic effect terms.
In table 2 are presented the correspondence
between actual and coded values of design
variables.

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XI, Issue 4 – 2012

Fig. 1. Phase angle variation with temperature and frequency a. acacia, b. dandelion, c. honeydew, d.
polyfloral, e. sun flower, f. tilia

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XI, Issue 4 – 2012

Table 2
Correspondence between actual and coded values of design variables

Actual values of coded levels Variable Symbol
-1 +1

Temperature (°C) X1 30 50
Fructose (g/100g) X2 35,29 42,85
Glucose (g/100g) X3 27,65 35,36
Sucrose (g/100g) X4 0 2,22
Sugars (g/100g) X5 2,95 11,21
Non-sugar substances (g/100g) X6 1,64 1,76
Moisture (g/100g) X7 16,24 17,96

The design parameters (X1-X7) have

been modeled in order to achieve the
model. The model summary is presented in
tabel 5.36. The coefficient of regresion of
the proposed model represents 99.91 (R2
adjustat 99.82) (Table 3).

Table 3
Model summary

Model Standard deviation R
2 R

2
adjusted P

Cubic 0.19 0.9915 0.9812 0.0001

Fig. 2. Measured vs. predicted of phase angle of honey using polynomial equations

In figure 2 are plotted the predicted

values versus measured values of the phase
angle. It can be seen that the pairs of
values are closed to the line with the
equation x = y, this fact confirms the
validity of the model based on chemical
composition and temperature modelling of
the phase angle of honey.

Parameter optimization

The optimization of the parameters
simultaneously is very important for
product quality. The desirability function
approach is used to optimize the multiple
characteristics concurrently. In the
desirability function approach, first each
characteristic, yi, is converted into an

Food and Environment Safety - Journal of Faculty of Food Engineering, Ştefan cel Mare University - Suceava
Volume XI, Issue 4 – 2012

individual desirability function, di, that
varies over the range (eq. 3.)

(3)

If the characteristic yi i is at its target,

then di = 1. If the characteristic is outside
an acceptable region, then di = 0. Finally,
the design variables can be chosen to
maximize the overall desirability (eq. 4)

(4)

where n is the number of

characteristics. When the target (T) for the
characteristic y is a maximum value and
the lower limit is denoted by L,

(5)

when the target (T) for the

characteristic y is a minimum value and
the upper limit is denoted by U (Mo,’05).

(6)

where r = 1.
The phase angle value would be

maxim at 42.85% fructose, 30.27%
glucose, 1.13% sucrose, 7.66% sugars,
16.39% moisture, 1.69% non-sugar
substances and 32.1 °C respectively.

4. Conclusions

According to the phase angle, honey is
a viscous viscoelastical material, having a
viscous part much greater than the elastic
part (δ > 45°). It can be observed that at 30
°C, 35 °C, 40 °C and 45 °C, the phase
angle evolution is not influenced by the
frequency applied; the phase angle is

changing a little with the frequency. At 50
°C, the phase angle is strongly influenced
by the frequency, is decreasing its value
proportionally with frequency. The phase
angle value would be maxim at 42.85%
fructose, 30.27% glucose, 1.13% sucrose,
7.66% sugars, 16.39% moisture, 1.69%
non-sugar substances and 32.1 °C
respectively

5. References

[1] CHUA, L. S., ABDUL-RAHAMAN, N.-L.,
SARMIDI, M. R., AZIZ, R., 2012, Multi-elemental
composition and physical properties of honey
samples from Malaysia, Food Chemistry, 135, 880-
887
[2] WITCZAK, M., JUSZCZAK, L.,
GALGOWSKA, D., 2011, Non-Newtonian
behaviour of heather honey, Journal of Food
Engineering, 104(4), 532-537
[3] OROIAN, M., 2012, Physicochemical and
rheological properties of Romanian honeys, Food
Biophysics,7(4), 296-307
[4] YOO, B., 2004, Effect of temperature on
dynamic rheology of Korean honeys, Journal of
Food Engineering, 65, 459-463
[5] MEYERS, M. A., CHAWLA, K. K., 2008,
Mehcanical Behavior of Materials, Cambridge
University Press, UK.
[6] LAZARIDOU, A., BILIADERIS, C.
G., BECANDRITSOS, N., SABATINI, A.
G., 2004, Composition, thermal and
rheological behaviour of selected Greek
honeys. Journal of Food Engineering, 64
(1), 9-21
[7] KANG, K. M., YOO, B., 2008, Dynamic
rheological properties of honeys at low
temperatures as affected by moisture content and
temperature, Food Science and Biotechnology,
17(1), 90-94
[8] MOSSEL, B., BHANDARI, B., D´ARCY, B.,
CAFFIN, N., 2000, Use of Arrhenius model to
predict theological behaviour in some Australian
honeys, LWT – Food Science and Technology, 33,
545-552
[9] BOGDANOV, S. 2002, Harmonised methods of
the international honey commission (Swiss Bee
Research Centre, FAM, Liebefeld, CH- 3003 Bern,
Switzerland)
[10] Codex Standard (Codex Alimentarius), 2001,
12-1981, Rev. 2 Revised codex standard for honey