OIL AND FAT TECHNOLOGY LECTURES II (Handling & Storage of Oil-Bearing Materials - Pretreatments) Prof.Dr.Aytaç SAYGIN GÜMÜŞKESEN Yrd.Doç.Dr.Fahri YEMİŞÇİOĞLU

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.

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.

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.

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 exothermic reaction C 6 H 12 O 6 + O 2 6 CO H 2 O + energy C 6 H 12 O 6 + O 2 6 CO H 2 O + energy Respiration intensity; Sound seed – low m.c. 0.1ml CO 2 /g seed.day Damaged seed – high m.c. 5.0ml CO 2 /g seed.day

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, 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. but less than unity if they are proteins or fats, which are less rich in oxygen.

 Enzymes : (a)Lipase. This enzyme catalyzes the reaction; 1 glycerol + 3 fatty acid triglycerid + 3 water glycerol + 3 fatty acid triglycerid + 3 water 2 1 synthesis t.g 2 hydrolysis t.g 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 2 hydrogen peroxide 2 water + oxygen

 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.

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

CML of oil seeds CML of oil seeds Hulls (%) Fat (%) CML(%) Hulls (%) Fat (%) CML(%) Rape seed Palm kernel Sunflower seed Cottonseed Soya beans

 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.

 Storage method Warehouses (Muskogee type seed houses) 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.

Muskogee type seed store Belt conveyer Section through storage building Oil seed Oil seed bulk

Preparation of Oil-bearing Materials   Cleaning foreign materials   Delinting for cottonseed lints   Dehulling hulls   Flaking   Cooking moist

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

 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

Drum screen

Vibrating screen

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

 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.

Self cleaning rotary magnets Seed inlet aspirator Rotating drum Stationary magnet İron parts Cleaned seed

DELINTING (for cottonseed) cottonseed lints (8-12%) Hull (40-45%) Delinting process to remove the remaining lint from cotton seed

Delinter

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.