Potato starch becomes versatile new pellet binder

Owned by Danish potato farmers, KMC specializes in transforming potato protein and starch into high-value products for use in food, livestock feed and pet food. Annette Lake Voergaard, agronomist and Ron Fris Christensen, commercial director in KMC’s feed and pet food division have been working on an exciting new application of potato starch recently. “At KMC, we modify potato starch so that it is an easily digestible energy source, ideal for feeding pigs to promote growth while avoiding excess undigested starch in order to support proper intestinal conditions. But we have found that this ingredient is also an excellent pellet binder and adds many other benefits to the process. Also,” Voergaard explains.

Christensen: “Our new pellet pelletizer is a very technical product and the implementation for each feed mill is always tailor-made.” Photo: KMC

Shrinkage Challenge

The incentive for KMC to develop a new pellet binder is to help feed mills prevent unnecessary loss of nutrients during processing and storage and better control moisture. Christensen explains: “To produce high-quality feed pellets, the right mixture of steam and water must be used. Not only to stimulate a homogeneous mixture of feed mass, but also to ensure that the starches gelatinize perfectly by absorbing moisture. When you can ensure that moisture is evenly distributed in the pellets Feed, you prevent production shrinkage during processing or during storage.10 tons of feed pellets stored in a silo can easily be reduced by hundreds of kilograms within 10 weeks due to water evaporation.Moreover, if the pellets are not properly bonded, a large part of the Fines, which may cause problems in different areas – nutritionally and economically in relation to feed spillage.

Chemical binders do not have any nutritional value and take up an important space in the recipe. This is called the empty component

Adding more water can prevent this from happening, but most equipment can’t handle a lot of excess water, and it takes up valuable space in the feed formula. This is why feed mills often add granular (chemical) binders to control this process. Voergaard adds: “The problem is that the chemicals don’t have any nutritional value and take up a lot of space in the recipe. This is called the blank ingredient. Adding 1% of the chemical granule binder means you have to make up for that by increasing the energy concentration in the feed. What? If we could apply a non-chemical granular binder that also adds nutritional value?” KMC combined its long-standing experience in potato starch and added lessons learned from using potato starch in food as gelling and stabilizing agents that led to a new non-chemical granular binder for the feed industry.

Looking inside the granules

KMC conducted an experiment earlier this year to compare the new modified potato starch granule binder with a commonly used chemical granule binder (lignosulfonate). Christensen: “Of course we looked at the physical toughness of the granules (pellet toughness index: PDI) and hardness (Kahl), but primarily we looked inside the feed pellets to determine the moisture distribution and state of the starch gelatin at different processing temperatures. The different temperatures were chosen to mimic the diversity in processing. Feeds in the feed industry.Determining the surface of the granules and the cutting edge does not tell you the whole story when it comes to moisture distribution.So we used microscopy which takes pictures of the granules under a microscope.It allowed us to see to what degree the starch becomes gelatinous and what effect the sub-processes have on the specific feed pellets from during the formation of crystals (lack of gelatinization) or gelatinous structures (successful gelatinization).

“We used microscopy to look inside the pellets. This is a new way to look at the feed pellets and give a soluble stimulation of the gelatinization process”

Voergaard adds: “Through microscopy, we have gained valuable knowledge about the level of hydration which provides us with insight into how individual factors affect binding ability. It is a different way of looking at granules.” The experiment and associated imaging showed – compared to the chemical – that the potato starch binder resulted in better moisture distribution and a lighter color, indicating lower Maillard product (heat spoilage) and consequently the accompanying loss of nutritional value. Christensen adds: “Using potato starch binder also showed a better PDI for pellets at a lower processing temperature compared to chemical. Interestingly, the binder we used also resulted in easier machine cleaning after curing (less dust) and less friction (which can lead to Theoretically lower energy consumption).

Voergaard: “In feed processing, you can easily destroy and lose valuable nutrients. We often focus on PDI alone when we talk about pellet quality.” Photo: KMC

Talking PDI and Nutrition

A new potato starch binder was introduced to the market and has since aroused the interest of several large feed mills in Europe, which are currently testing the binder for their own processing conditions. KMC is also preparing for follow-up trials in December 2021 to consider further processing parameters and the impact of shrinkage over time. Christensen: “The new pellet binder is a very technical product and every feed mill is always made to order. But the goal of most feed mills is the same: better control of water (moisture) to better reduce shrinkage and nutrient loss and not be forgotten; an effective pellet binder when the need. “

pellet quality

Voergaard adds that improving feed handling is very important to be able to improve nutrition and produce cost-effective diets. “In feed processing, you can easily damage and lose valuable nutrients. We often focus on PDI alone when we talk about pellet quality. Although PDI is a recognized parameter in the feed industry and understood by everyone, it does not say anything about the nutritional value of pellets , and whether moisture is well distributed within the granules and whether the starch gels perfectly. We must not forget that our goal is to feed the animals and provide them with all the necessary nutrients they need, while formulating cost-effective diets. We hope through the new pellet link concept That we also open up the discussion between feed mills and nutritionists to talk about PDI, but also often discuss how we can improve and maintain the nutritional value of feed pellets during processing,” concludes Voergaard.

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