If your goal for 2016 is to do a profitable feed milling and produce quality pellets, then this is a pelleting challenge for you Outdo Your Feed Mill in 2016! If you are you up for the challenge, there is a way to achieve it.
Since the introduction of the pelleting process, feed technology development is primarily focused on improving pellet quality while maintaining an acceptable rate of production. Even in the current situation, for a profitable and competitive production, feed miller should fix below two challenges:
to outdo your pellet mill by producing more feed in 2016 compared to last year production by enhancing milling efficiency, and
to produce quality pellets with higher moisture and lesser fines by producing harder and better quality, cooked pellets
As the feed production cost is a major portion of total cost of chicken production, so feed miller may also pick other challenges that is acting as limiting factors in feed milling. Remember, the idea here is to challenge and outdo the feed mill.
Tips for better milling efficiency and improved pellet quality
1. Monitoring and maintaining total moisture in the mixer:
Most of the time, tropical feed pelleting is just about dealing with dried up raw materials with its minimum bound moisture available. Because average moisture content of most of available ingredients varies in the range of 10-11% and the average moisture of the meal in the mixer also lies in the same range. Calculating reversely, if we start with 11% moisture in mixer targeting to reach 15-16% moisture in the conditioner for starting gelatinization process and moist the raw materials properly to lubricate, minimum 4-5% moisture should be added in the conditioner through steam.
After survey of almost 150 feed mills in the tropical region, it is confidently assumed that the average moisture addition through steam hardly varies from 1.5-2% in the conditioner, which is not enough for proper lubrication and gelatinization. Both bound and steam added moisture* in the mash meal takes total moisture of the meal (after conditioning) up to 13-14%. which still remains 2-3% lesser for complete gelatinization process in the die, which usually prompt the meal in the conditioner to a moisture level of 16-17% and mash meal temperature to range of 79-82°C.
To get 2-3% of moisture in mash meal, following points can be considered:
preserving bound moisture in the raw materials
efficient storage for not losing bound moisture
adding enough water in the mixer
getting right quality and quantity of steam to harness maximum moisture from the steam
Higher the moisture in the mixture is, better is the chance to reach trigger point for starch gelatinization in the conditioner, which is highly important not only for better lubrication and milling efficiency but also for better digestibility and pelletability of different raw materials. While the addition of this extra moisture can be accomplished through any of the above mentioned methods or a combination of methods, the two most important points to be considered is to check choke point of the machine and stability of the pellets (molds, freshness and storage shrink) after packing (points to be discussed in upcoming editions).
2. Measure Degree of Starch Gelatinization:
In poultry (or other high grain based formulas) through pelleting we always try to initiate Starch Gelatinization- process which starts once the mash meal temperatures reaches 79-82°C and moisture level of around 16-17%.
While analyzing moisture content (mc%), PDI and fines might give some level of indication about the produced pellet quality at the feed mill; real factor for limiting feed processing and pellet quality is the measure of degree of starch gelatinization.
Major three ways to analyze the degree of starch gelatinization in the feed include enzymatic method, x-ray diffraction method and DSC (Differential Scanning Calorimetery) method. It would certainly be innovative decision to move beyond in-house lab analysis and reach out to some external testing facility to identify degree of starch gelatinization in feed. Several surveys using enzymatic or calorimetric methods, have shown that due to limited moisture content and moderate temperature achieved during conventional pelleting, only a small amount of starch gelatinization varying between 5-20% is achieved in tropical feed milling.
Basically, starch gelatinization has three important roles to play during or after pelleting in feed processing:
it enhances the ability of starch to absorb large quantities of water which leads to improved digestibility and feed conversion in many cases (a starch granule can hold moisture up to 300% than its weight).
it increases the speed at which enzymes (amylases) can break down the linkages of starch, thus converting starch into simpler and more soluble carbohydrates (higher gelatinized starch or feed is digested faster and assimilated faster in the bird’s body).
it provides natural binding effect to the feed particles, which improves pellet hardness, enhances PDI and reduces fines hugely during transit and storage.
3. Proper Steam Conditioning:
Steam conditioning is the most important element in achieving high quality pellets with higher production rates at a lower cost. The basic objective of steam conditioning is to achieve enough lubrication for faster production rate, extended die life, reduce energy costs and gelatinize starch for higher nutritional value. It has been proved now that except to few feed formulations rich in minerals, urea, sugar or whey, use of steam increases the production of a pellet mill on almost all feed formulations which also reduces the fines at the pellet mill as enough added steam makes the materials softer and pliable to stick together. Properly steam conditioned meal produces pellets with more uniform length, little darker color and a gummy texture which may prove better commercial feed.
4. Right Steam Quality:
A good pellet system needs to have a measured supply of essential steam for good pelleting operation. Three areas to be considered while adding steam include good steam quantity, quality and adequate steam pressure. High-pressure boilers are preferable because it allow for smaller piping control valves, pressure regulators, etc which can keep the cost on a lower side. The distance between boiler and pelleting operation and the system’s ability to deliver steam in a highly gaseous state when it enters the pellet mill conditioner are the main points to be considered. The lower the pressure is, the lower the temperature is which consequently turns the steam turns to water quickly.
The steam harness must be of adequate size to provide a constant steam flow without pressure variation and it should have the capability to provide a range of 1 bar(low pressure)-10 bar(high pressure) steam. Pressure gauges and thermometers are also essential to monitor supply and flow of the steam.
5. Trained Feed Mill Operators:
It has been rightly said that pelleting is almost a daily exercise in ability and knowledge. While large machinery and equipments are necessary to complete the pelleting process, it also become obvious at this point that the operator is, unquestionably, the most important factor in achieving a good pellet production and good pellet quality. A mill operator must understand the pelleting process and be able to fine-tune as much times as required in a particular day according to the ambient temperature, humidity, formulation, conditions of ingredients, and bound or inbound moisture levels of these ingredients.
Operators should be trained about the fundamentals of steam application for different formulations produced in the pellet mill. Until the operator don’t understand the relationship between meal moisture and temperature for steam addition, maximum results cannot be obtained.
*Bound moisture is moisture in the ingredients before the arrival of meal in the pellet mill. Added moisture is the moisture added at the pellet mill in form of water or steam. Total moisture of the meal is the sum of the bound and added moisture.
The tips offered here focused only on the key challenges faced by tropical feed millers in the region and to contribute positively to feed pelleting for better production efficiencies, pellet quality, and feed quality / feeding values. We hope that the suggested guidelines help you outdo your feed milling business to the next level in 2016.
by Dr Naveen Kumar, Delst Asia