OIL AND FAT TECHNOLOGY LECTURES II Handling

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OIL AND FAT TECHNOLOGY LECTURES II
(Handling Storage of Oil-Bearing Materials -
Pretreatments)

• Prof.Dr.Aytaç SAYGIN GÜMÜSKESEN
• Yrd.Doç.Dr.Fahri YEMISÇIOGLU

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Handling Storage of Oil-Bearing Materials

• The handling and storage of oil-bearing materials
  is one of the most important phases of oil seed
  processing.
• The vegetable oils and feed industries are
  dependent for successful operation upon obtaining
  high yields and product of good quality from
  their raw material.
• Excessive biological activity in the seeds,
  either in the field prior to harvesting or
  subsequently during storage, will result in a
  reduction both in the quality and the yield of
  oil and meal.

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• The handling and control of the raw materials for
  the oil seed industry can be primarily
  characterized by the short harvest season, by the
  necessity to move them into protected storage in
  minimum time, and by the required care before
  they can be processed. But they can be treated
  and stored successfully with minimal
  deterioration long enough to allow the processing
  industry to operate throughout the year.

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• Sunflower seed, soybeans, cottonseed, rape seed
  and other oil seeds are subject to damage
  primarily from biological actions, which are
  accelerated by high moisture content, foreign
  material, physical damage, and such adverse
  climatic conditions as frost or rain before
  harvest.

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• Effects accompanying deterioration of seed during
  storage
• Respiration In the presence of oxygen as the
  oxidizing agent, organic food stuffs are oxidized
  to form water and carbon dioxide as the end
  product.
• 
  exothermic reaction
• C6 H12O 6 O2 6 CO2
  6 H2O energy
• Respiration intensity
• Sound seed low m.c. 0.1ml CO2 /g
  seed.day
• Damaged seed high m.c. 5.0ml CO2 /g
  seed.day

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• The respiratory quotient, defined as the ratio of
  carbon dioxide evolved to oxygen absorbed, is an
  indication of the class of substances undergoing
  oxidation.
• In aerobic respiration
• it is theoretically unity if the subctances
  are carbonhydrates,
• but less than unity if they are proteins or
  fats, which are less rich in oxygen.

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• Enzymes
• (a)Lipase. This enzyme catalyzes the reaction
  
• 
  1
• glycerol 3 fatty acid
  triglycerid 3 water
• 
  2
• 1 synthesis t.g
  2 hydrolysis t.g
• (b) Catalase and peroxidase. Both of these
  enzymes react with hydrogen peroxide.Catalase
  will decompose hydrogen peroxide while peroxidase
  utilizes it for further oxidation.
• 2 hydrogen peroxide
  2 water oxygen

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• Influence of moisture content
• Oil seeds are best stored at low moistures where
  respirotary and enzymic activities, germination
  and mold growth are inhibited. This maximum
  acceptable moisture level is known as critical
  moisture level (CML) .
• The moisture content of the non-oil portion of
  the seed rather than the whole seed is the
  important factor in oil seed deterioration.
• CML is relatively high for seeds of low oil
  content.
• CML is relatively low for seeds of high oil
  content.

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• Safe humidity for starchy food grains
  
• 16
• Oil content of soybean . 22
• Non-oily part of soybean . 78
• Critical moisture level 0.78 x 16 12.5

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• CML of oil seeds
• Hulls () Fat ()
  CML()
• Rape seed 14 40
  7.0
• Palm kernel - 52
  8.0
• Sunflower seed 28 43
  8.5
• Cottonseed 48 18
  10.0
• Soya beans 8 20
  12.0

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• Influence of temperature.
• In the case of soya beans and similar oilseeds
  where deterioration appears to be primarily a
  result of the growth of microflora, the storage
  temperature does not appear to be a major factor.
  However, temperature is very important factor in
  storage of cotton seed. The respiration of cotton
  seed is markedly temperature-dependent. The
  insulating effect of linters on cottonseed
  contributes to the peculiar tendency of this seed
  to heat in storage.
• It is because of the undesirable effect of high
  temperature that most seed houses are equipped
  with aeration ducts and large ventilating blowers
  to cool the seed.

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• Storage method
• Warehouses (Muskogee type seed houses)
• Bulk storage in warehouses on flat floors has the
  advantage of easy control of oil seeds, like
  cottonseeds, sunflower seed, corn germ, further
  meals etc. To prevent self heating or
  autocombustion of the seeds, recycling by
  horizontal and vertical transportation means is
  recomended.

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• Muskogee type seed store

Oil seed
Belt conveyer
Oil seed bulk
Section through storage building
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• Preparation of Oil-bearing Materials
• Cleaning foreign materials
• Delinting for cottonseed lints
• Dehulling hulls
• Flaking
• Cooking moist

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• CLEANING
• Cleaning is important not only to ensure the
  good quality of the final products oil and meal
  but also to avoid premature wear of the
  preparation equipment.
• The removal of foreign materials from oil seeds
  is done by cleaning machines working on
  mechanical, pneumatic and magnetic principles.
• Cleaning machines
• Screens
• Aspirators
• Magnets
• Shape sorters

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• SCREENS
• Screening is the seperation of mixtures of
  different sizes into fractions the portion
  staying behind being oversize, the portion
  passing through being undersize.
• Rotating screens
• Vibrating screens

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Drum screen
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• Vibrating screen

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• ASPIRATORS
• In order to seperate impurities or fractions of
  different density, pneumatic means, like air
  nozzles and aspirators are used.

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• MAGNETS
• Permenant or electromagnets enclosed in a
  rotating aluminium drum are used in feeders to
  distribute the material uniformly over the whole
  active width of the drum. The magnetic material
  collected is removed by a blade on the
  ono-magnetized half and, in this way, it remains
  seperated even in the case of power failure.

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• Self cleaning rotary magnets

aspirator
Seed inlet
Rotating drum
Stationary magnet
Iron parts
Cleaned seed
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• DELINTING
• (for cottonseed)

cottonseed
lints (8-12)
Hull (40-45)
Delinting process to remove the
remaining lint from cotton seed
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Delinter
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• A method of delinting cotton seed comprises the
  steps of passing the cotton seed through a saw
  delinter to remove a substantial portion of the
  lint, preferably at least 40, therefrom, and
  thereafter passing the partially delinted seed
  through a brush delinter to remove substantially
  all of the remaining lint therefrom.