Cold mash conditioning is achieving the standard moisture and water activity at the mixer level. Water is a
key ingredient in the feed and generally, the feed is formulated keeping a certain moisture level (Dry mat- ter) in mind. It is vital in feed-chemical changes that take place and interaction between ingredients during
Processing and therefore, has a determining effect on quality and nutritional value of the final feed. Water also has a significant impact on the overall efficiency of the feed mill.
Not only does the final moisture of the feed, but also the trend of moisture during the processing plays a crucial role in feed processing.
Moisture impacts feed processing in following ways:
Operational Effect
In some processing steps, moisture at a certain level is required just to make that specific pro- cessing step work in the right way(for example, achieving proper cooking at the level of condi- tioner).
Nutritional Effect
Moisture plays a very crucial role for various feed-chemical changes happening during the feed processing e.g. starch gelatinization.
Economic Effect
Feed products are sold by weight. Producing feed products with high moisture content may neg-
atively affect quality and nutrition which leads to Mold Growth and other moisture related problems. At the same time, selling feed products at moisture content lower than what is necessary means the Processor loses income as a result of unnecessary weight loss.
13 key points to ponder for better cold mash conditioning & moisture management
Better Cooking and Starch Gelatinization
One of the chief reasons to pre-condition the mash before pelleting is to achieve starch gelatinization. Moisture is a participant in the process of starch gelatinization along with heat and retention time. Optimum moisture of ~12% at the mixer level will help in achieving the higher starch gelatinization at the conditioner level. This process can be accentuated by the use of surfactant based products in the mixer.
Better throughput
Higher throughput means better capacity utilization of the plant. Better capacity utilization helps in easing supply-demand pressure and early break even for the feed millers. It’s im- portant to note that capacity always has a cost and surfactant based liquid products can help in achieving better capacity utilization and reducing the unproductive capacity cost.
Higher Pellet Durability Index (PDI)
Pellet Durability Index (PDI) is being synonymously used with pellet quality. Optimum moisture during processing leads to better PDI. Better PDI is directly related to body weight gain and inversely related to FCR in broilers. South-Asian countries still have a lot of scope to improve PDI.
Lesser fines
Better moisture management during processing also has an impact on fines. Fines are “finer feed particles” which could not be converted into pellets and has to be reprocessed.
Reprocessing not only involves cost but also have detrimental effect on micro nutrients.
Importance of moisture trend
Achieving standard moisture of final feed is important but it is also important to maintain the standard moisture trend during the various feed processing steps. The trend impacts the overall feed mill efficiency as well as the quality of final feed.
Role of surfactants
Addition of surfactants at the level of mixer increases the penetration of steam inside the feed particle. This in turn helps in achieving better starch gelatinization of the core. This also reduces the water activity by making more water molecules bound. Apart from these benefits surfactant based liquid products also have an impact on throughput, specific energy, PDI and fines etc.
Water Activity
Water activity (aw) is the partial vapor pressure of water in a substance divided by the standard state partial vapor pressure of water. This basically is the indicator for water available for growth of microorganisms i.e. more the water activity higher are the chances for microbial growth. During feed processing we should target for lower water activity while maintaining the standard moisture levels.
Consistency of quality
Consistency in quality is the major mandate for any feed producer. Fluctuation in final feed moisture or during the process may hamper the quality of final product. Excess moisture leads to nutrient dilution while less moisture leads to nutrient concentration.
Molds
Threat of molds is always lurking over feed. It is very necessary to maintain the final feed moisture in the optimum range (~12%). Positive deviation in moisture may lead to mold growth. It’s always beneficial to use a liquid mold inhibitor at the mixer level to avoid any mold growth from bagging till feeders.
Specific Energy of pellet mill
It is the energy required to produce per unit of feed. Optimum moisture content in mash will facilitate better pelleting with lesser specific energy. Usage of surfactant based product will further reduce the specific energy.
Process loss recovery
Feed milling involves lot of abrasion for feed particles. These processes lead to moisture loss during the process. There should be some mechanism to recover this lost moisture, or else this will impact the final quality of feed by making it nutrient dense. Feed Mill Efficiency improvement program can help in improving the process loss recovery.
Life of pellet die
Pellet dies and rollers are recurrent variable cost for a feed plant. Better moisture management during feed processing can help in extending the life of rollers and dies.
Nutrient loss at pellet die
More friction at pellet die level may lead to loss of nutrients. One way to reduce the friction is to maintain the optimum level of moisture in the mash while entering the pellet die.
Moisture has a key role to play in feed milling. It has to be measured, analyzed and controlled at various critical points inside the feed mill. The power of moisture can be accentuated by use of surfactant based liquid products inside the mixer.
References are available on request.
by Dr. Prince Nanda, Kemin
