INTRODUCTION
Honey export is an important
trade in the World market. The leading honey-producing countries are the
USA, Canada, Australia, Argentina, Mexico and China. The contribution
of Pakistan is highly insignificant. NWFP has good global position and
climate conditions for producing the honey and exporting it to Western
countries and Middle East. In order to have a respectable place in the
world market of honey, our local honey must fulfill international quality
standards.
Different kinds of honey differ for their color, flavor
and density. However, the quality of honey produced, matters to a great
extent (Krell et al., 1989). Only slight deviation in the color,
flavor and aroma from the usual quality associated with the brand can
cause the product to be rejected by the consumer. In order to have uniform
standard of honey, an International Honey Commission (IHC) was found in
1990. Its main objective was to revise the methods and standards for honey.
International honey standards are specified in a European
Honey Directive and in Codex Alimentarius Standard for honey. According
to the definition of Codex Alimentarius Commission Standards (2001), honey
shall not have added any food ingredient other than honey to it, nor shall
any particular constituent be removed from it. Honey shall not have any
objectionable matter, flavor aroma or taint from foreign matter during
its processing and storage with no fermentation or effervescence. No pollen
or constituent particular to honey may be removed except where this is
unavoidable in the removal of foreign or organic matter. Honey shall not
be heated or processed to such an extent that its essential composition
is changed and/or its quality impaired.
Certain quality parameters are used to determinate honey
quality. Countries strictly following certain these quality standards
earn an appreciable amount of foreign exchange through honey export. The
most important is the water-sugar relationship due to its effect on silty
against fermentation and granulation (White, 1978). Sugars are the principal
constituents of honey, which aside from determining its nutritious and
energetic value, also influences some of its important physical characteristics
such as crystallization, hygroscopicity and viscosity. Ash value indicates
the botanical origin; the blossom honey has lower mineral content than
honeydew honey. Temperature effect is recognized by the production of
5-hydroxymethyl furfural (HMF). The HMF is inversely proportional to the
quality of honey, which depends on pH and moisture value of honey, heat
process after harvesting and storage time temperature. Since Hydroxyl
Methyl Furfural (HMF) is formed during acid hydrolysis of sucrose, the
presence of high levels of this compound suggests the possibility that
the honey has been adulterated with invert syrup (Swallow and Low, 1994).
The present study was conducted to assess quality of different
honey samples produced in Peshawar valley, using for quality parameters
for assessment of their feasibility for foreign export through comparison
with international standards.
MATERIALS AND METHODS
The present internship was designed to evaluate different
honey samples obtained from local market for their quality parameters
so that to assess their feasibility for foreign export by comparing it
with international standards. The study was conducted at Pakistan Council
for Scientific and Industrial Research laboratories complex, Peshawar,
during 2006.
Sample collection and preparation:
Honey samples were obtained directly from producers
in Peshawar valley. Ten samples of locally produced honey were collected
from the market and were named as HS-1 through HS-10, where HS refers
to Honey Sample and the number shows the sample number. Each sample was
mixed thoroughly and kept in glass containers at room temperature till
final analysis was carried out.
Sample analysis: The collected samples were analyzed in the Food Chemistry
lab of PCSIR for quality parameters i.e., moisture content, Ash percentage,
acid content, HMF and reducing sugars percentage. Samples were analyzed
for the above parameters according to the standard methods mentioned in
Codex Alimentarius Commission Standards (2001).
The moisture content of the test samples was determined
with the help of Oven at a constant temperature of 100°C through calculation
of weight loss at 100°C for 3 h. Ash content was determined through ignition
of honey samples in a muffle furnace at 550°C to a constant weight. Reducing
sugars and non-reducing sugars were determined according to the standard
method of Codex Alimentarius Commission Standards (2001). HMF was determined
by the method of Winkler (1995). Acidity was following standard method
of Codex Alimentarius Commission Standards (2001). The data was determined
in triplicate for each sample and was then analyzed for differences using
F-test appropriate for Completely Randomized Design.
RESULTS
AND DISCUSSION
The results of moisture, ash, acidity,
reducing sugar and Hydroxyl Methyl Furfural (HMF) contents of locally
produced honey are discussed here:
Moisture (%): The moisture content of honey is related to its
degree of fermentation. The control of the water content is an important
requirement of proposed Codex Alimentarius Commission Standards for honey
(2001), which sets an upper limit for moisture of 21% for honey in general.
All of the samples examined contained moisture content within the standard
limits. The moisture content of locally produced honey was in the range
of 14.5 to 18.23% (Fig.
1). According to the present results the differences between moisture
content of different locally produced honey brands were non-significant.
Present results are similar with those of Latif et al. (1956) who
have reported the moisture content of Pakistani honey to be within the
range of 14.3 and 18.6%. Similarly, Duthil (1983) has also assessed different
honey samples for their moisture content and reported their moisture content
to be within the standard limits.
Ash (%): Certain nitrogen compounds, minerals, vitamins, pigments
and aromatic substances contribute to the ash content of honey. The ash
content of honey averages about 0.2122% of its weight, but varies widely
from 0.02 to over 1.0%. Codex Alimentarius Commission Standards (2001)
for honey, proposed ash content not more than 0.6% for normal honey. The
ash content of locally produced honey samples ranged between 0.047-0.35
which is within the standard limits (Fig.
2). These results are in line with those of Cranel (1976) who reported
ash content of honey samples to be within the range of 0.1-1.0%. Similarly,
Mclellan (1975) evaluated honey samples for their ash content and different
minerals.
Acidity (meq kg-1): The flavor of honey results from
the blending of many notes, not the least being a slight
 |
Fig. 1: |
Moisture content
(%) of different honey samples locally produced in Peshawar
valley |
 |
Fig. 2: |
Ash content
(%) of different honey samples locally produced in Peshawar
valley |
 |
Fig. 3: |
Acidity (meq kg-1) of different
honey samples locally produced in Peshawar valley
|
tartness or acidity. It also gives some history of the sample.
It is thought that high acidity figure may mean that honey had fermented
sometimes and the resulting alcohol had been changed to acetic acid by
bacterial action. The limit quoted in the proposed codex regulations for
acidity is not more than 40 meq. acid per 1000 of honey as determined
by direct titration. The acid content of locally produced honey is shown
in the les, which ranged between 19.5 and 38.0 meq kg-1 (Fig.
3). None of the samples examined had titrale acidity more than the
proposed limits. Our results are endorsed by those of Latif et al.
(1956) who also reported formic acid content of Pakistani honey to be
within the permissible limits of international standards. Similarly, Stinson
et al. (1960) evaluated honey samples for their acid components
and found these to contain butyric, acetic, formic, lactic, succinic,
pyrogutamic, malic and citric acids.
HMF (mg kg-1): This compound is formed by the decomposition
of fructose in the presence of acid. Small amount of HMF (0.06-0.2 mg
kg-1) is present naturally even in fresh honeys. Codex Alimentarius
Commission Standards (2001) of honey proposed a limit of 40 mg kg-1
as an indication of heated honeys and content more than 150 mg kg-1
is taken to indicate adulteration with invert sugar. The HMF contents
of locally produced honeys ranged between 5.3 and 23.20 mg kg-1
(Fig.
4). None of the examined samples had HMF contents
 |
Fig. 4: |
HMF (mg kg-1)
of different honey samples locally produced in Peshawar valley |
 |
Fig. 5: |
Reducing sugars
(%) of different honey samples locally produced in Peshawar
valley |
more than 40 mg kg-1 and hence all of the samples
meet the HMF standard for quality. Previously Bricage (1908) analyzed
118 samples of honey for HMF content and reported that 32 samples had
an HMF content below 15 mg kg-1. Similarly, Duthil (1983) have
also reported that mean HMF content of different honey samples ranged
from 5.47 to 5.95 mg kg-1.
Reducing sugars (%): In nearly all honey samples, two important
monosaccharide glucose and fructose predominate, which are defined as
reducing sugars and accounts for around 75% of honey. According to proposed
Codex Alimentarius Commission Standards (2001), a minimum reducing sugar
content of 65% is required for flower honey and 60% for honey dew honey.
The results of the analysis showed that the reducing sugar content of
honey ranged between 43.14-81.40% for the tested samples of locally produced
honey (Fig.
5). Comparison between honey samples showed that all of the locally
produced honeys met the quality standard for reducing sugar except the
one having 43.14%, which was lower than the standard permissible limit.
These results are in agreement with that of Nauta(1983) who also reported
that reducing sugars in honey were in the range of 60 to 65%. Similarly,
Walton (1942) reported that a general sample of honey contained moisture
as 19%, levulose 40%, dextrose 35%, sucrose about 2%, acidic substances
0.1%, ash or mineral 0.1% and undetermined as 4%.
CONCLUSION AND RECOMMENDATIONS
During the present internship different honey samples
were evaluated for their quality parameters for assessment of their feasibility
for foreign export by comparing it with international standards. All of
the samples were found to be in acceptable range of international standards
for all of the tested parameters except for reducing sugars which was
lower in only one sample. These samples were marked to be according to
the international standards and are safe for human consumption. These
may be allowed for marketing and if possible for foreign export.