Effect of Insect Infestation on Safety Foods

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• Effect of Insect Infestation on Safety Foods

By Prof. Dr. Ali Shahien Plant Protection Dep.,
Faculty of Agriculture, Zagazig University
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Introduction

• Safety food in Egypt is now considered as a main
  concept for all types of food either a fresh food
  consumed or manufactured.
• This concept plays currently an important role in
  Egypts policy especially to increase the food
  export to different foreign countries.
• For instance, in 10th of Ramadan Zone, more than
  2500 factories are willing to export their
  products, which meet with this concept.

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Introduction
Contd

• The current work indicated the relation between
  insect infestation and safety food under two
  items
• Effect of tribolium beetles on the rhiological
  and chemical properties on flour and its products
  especially bread.
• The capabilities of some stored product insects
  to penetrate different types of pack materials
  different package foods.

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1. Effect of tribolium beetles on the rhiological
and chemical properties on flour and its products
especially bread

• 1.1 Preparation of Wheat Flour
• 1.2 Treatment

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1.1 Preparation of Wheat Flour

• The wheat kernels samples were go out the
  refrigerator and sieved to get rid of any foreign
  matters or dust.
• Kernels were then dried to below 10 moisture
  content and was then adjusted to the moisture
  content required which was 14.
• The quantity of water added to the quantity of
  grains to reach the level 14 moisture content
  was according to the formula mentioned by Ahmed
  et al., (1982).

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1.2 Treatment

• Chemical analysis and biological monitoring were
  first carried out to ensure that the grains and
  the flours were not already infested, and
  contained no residual insecticides according to
  the methods of Domenichini et al., (1994) as
  follows

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1.2 Treatment contd

• For insecticides residue testing, specimens of
  Choetospila elegans Westw. (Hymenoptera
  Pteromalidae), which is very sensitive to
  insecticides, were used in this investigation
  four 100 grams samples of grains to be used in
  the experiments were placed in petri dishes (15
  cm diameter), plus 10 specimens of Choetospila
  elegans Westw. Over a period of 3 weeks, almost
  all of these specimens of insects were survived.

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1.2 Treatment contd

• For insects residue investigation, five 100 grams
  samples of flour to be used in the experiments
  were placed in petri dishes (15 cm diameter) and
  incubated at 25C with 60 humidity. Over a
  period of 5-7 weeks all of these dishes were
  examined by using lens (20x) and they were free
  against insects residue.

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1.2 Treatment contd

• Thirty jars with 600 gm of flour were used and
  divided into two groups, 15 jars filled with
  flour 82 and the other with 72 for each group,
  60 adults of Tribolium confusum were put into
  each jar and 3 jars, not infested, were kept as
  control.

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Proximate analysis of wheat flour (extraction 82
) infested by Tribolium confusum their
contents of protein energy compared to RDA
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Proximate analysis of wheat flour (extraction 72
) infested by Tribolium confusum their
contents of protein energy compared to RDA
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Table ResultsI. Effect of chemical analysis

• The moisture content of wheat flour was changed
  by different rates during the period of
  infestation.
• The low levels of moisture content 37.60 and
  29.27 were recorded after 6 weeks of infestation
  for wheat flour 82 extraction, and 2 weeks for
  wheat flour 72 extraction respectively.
• In the end of infestation period this level were
  increased again and reached to 20.18 and 18.6
  for wheat flours 82 and 72 extraction
  respectively.

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I. Effect of chemical analysis contd

• There was a gradual increase in protein content
  in the infested wheat flours with the increasing
  of the infestation period.
• In the end of the infestation period, 8 weeks the
  protein content were increased by the rate of
  25.68 and 25 for wheat flours 82 and 72
  respectively.
• It could be noticed that after 8 weeks of
  infestation the fat content of wheat flours was
  decreased by the rate of 21.62 and 1.91
  respectively.

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II. Effect of infestation on the rheological
properties

• Farinograph properties
• Obtained results indicated that the water
  absorption in the end of infestation period was
  increased by the rate of 3.45 and 6.23 for
  wheat flours 82 and 72 respectively.
• Results of peak dough development time (mixing
  time, min) indicated that the infestation with
  insects had a significant effect on the mixing
  time, which was 54.5 increasing and 55
  decreasing in wheat flours 82 and 72
  respectively.
• Dough stability in minutes is the most important
  index for dough strength. Infested wheat flour
  samples with insects showed markedly shorter
  stability period than the control.
• At the end of infestation period a decrease of
  14.7 and 76.7 min. instability was observed for
  the same flours.

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Results of the farinograph analysis on wheat
flour (extraction 82) infested by Tribolium
confusum
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Results of the farinograph analysis on wheat
flour (extraction 72) infested by Tribolium
confusum
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II. Effect of infestation on the rheological
properties

• Extensograph properties
• Infestation of wheat flours with insects
  decreased dough resistance to extension and
  consequently its ability to retain gas.
• The same trend of dough extensibility was also
  observed.

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Results of the extensograph analysis on wheat
flour (extraction 82) infested by Tribolium
confusum
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Results of the extensograph analysis on wheat
flour (extraction 72) infested by Tribolium
confusum
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II. Effect of infestation on the rheological
properties

• Amylograph tests
• The obtained results indicated that max.
  viscosity increased 16.45 and 156.25 for wheat
  flours 82 and 72 extraction after 8 weeks.
• At the same time the pasting temperature
  decreased by the rate of 5 and 7.69 for wheat
  flour 82 and 72 extraction respectively.

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Results of the amylogram analysis on wheat flour
(extraction 82) infested by Tribolium confusum
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Results of the Amylogram analysis on wheat flour
(extraction 72) infested by Tribolium confusum
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III. Sensory evaluation (average scores) of
Baladi Afrangi bread baked from fresh and
infested wheat flour

• Data revealed that baladi bread produced from
  fresh wheat flour 82 extraction was found to
  have excellent quality grade (9-9.6) for all the
  evaluated characters.
• These grades decreased significantly after 4
  weeks of insect infestation and becomes (6.1 and
  7.5).
• The same results by afrangi was recorded bread
  but after 6 weeks of insect infestation these
  quality grades were decreased and become
  (5.1-7.1).

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Baladi Bread
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Afrangi Bread
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IV. The presence of some carcinogenic compounds
on wheat flour infested by Tribolium confusum

• The obtained data demonstrated that the level
  content of malonaldehyde represent one of the
  major products of the oxidation of
  polyunsaturated fatty acids in the infested
  flours was started to increase with the 2nd week
  of infestation.
• In the end of infestation period malonaldehyde
  content was increased by 300 and 263 for wheat
  flours 82 and 72 respectively.

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Levels of malonaldehyde in wheat flour infested
by Tribolium confusum
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IV. The presence of some carcinogenic compounds
on wheat flour infested by Tribolium
confusum contd

• The pH values majored as mg of potassium
  hydroxide required to neutralize the free fatty
  acid released in 100 gm of flour, which increased
  by 57.55 and 82.18 for wheat flours 82 and 72
  respectively.
• The Egyptian standard of specification of wheat
  flours (1992) determined this value which should
  not be more than 30 mg.

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IV. The presence of some carcinogenic compounds
on wheat flour infested by Tribolium
confusum contd

• All of these data means lipids of wheat flours
  82 and 72 extraction becomes rancid as a
  consequence of oxidation and oxidative rancidity
  initiated by infestation with insect after 6-8
  weeks of infestation respectively.
• Also obtained data represented a good
  relationship between levels of malonaldehyde in
  the wheat flour samples and their fat content.

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