This edition has many interesting articles on a number of topics. Functional Ingredient trends by Dr Maygane Ronsmans, Product Manager Animal Nutrition, Beneo, cover a few areas that merit review. The term, functional ingredients, has a number of possible meanings.
Initially this phrase was used with regards to petfoods to define ingredients, mainly proteins, that offered something extra to the formula. Specifically with their use and the ability of that ingredient to assist in making a kibble with the same physical characteristics while achieving the nutritional needs and reducing costs. Extrude ability of the ingredient and binding qualities into acceptable kibbles. Years ago, as examples, protein sources such as soybean meal, fishmeal and meat products were used on a wide basis. All worked well until formulas started to change, pushing meat and protein levels upwards, and studies showed that the processing method to make ingredients had an effect on the extrude ability factor specially at higher levels.
Increased protein levels usually reduced the starchy ingredients, the ingredients which greatly assist in binding the kibbles together in good fashion.
Unlike starches, when proteins are heated, they become denatured, the protein is there but its structure has been changed. An example is a fried egg, same protein as a raw egg but when cooked alone it will now not bind ingredients combined with the raw egg before cooking. Well, many proteins as mentioned above are heated at some point when being made into ingredients. Specifically, SBM, meat and bone meal and fishmeal, which usually have the valuable oil removed and thus a downstream heating process is used to dry or assist in solvent removal. If a high temperature is used, then the protein becomes at least partially denatured. These proteins are harder to use in an extruder as the binding effect when not overheated before extrusion are lost. More water and more energy usually assist in overcoming this effect. The solution was lower temperature use in drying ingredients increasing their binding functionality. There are tests to determine extrude ability of some proteins both mechanical and chemical tests.
Dr Ronsmans goes into a number of ingredients that have multiple use functionality as in assisting with pet health. Most interesting is the discussion on faba beans. Beans have both carbohydrates and proteins making them a most interesting ingredient for pets. Rice proteins and wheat gluten as also similar in that they offer benefits for the animal and the process as well. Process benefits you ask, yes, better kibble appearance, same nutrition and possibility of making higher production rates with less energy consumption.
Precision Drying by Del Williams is a review of petfood drying. Perhaps a bit of discussion and history might assist with regards to dryers in this industry. The statement “Dryers unchanged for decades” can’t go without a bit of discussion. Let’s start with Geelen, Buhler’s Aeroglide Division, Wenger, Extru-Tech, Fansum, IDAH and many others as well have all advanced dryers for decades with constant advancements in drying technology. Historically dryers were all single pass and long. Multiple pass which started as two pass and grew as the need required balancing machine cost and factory related costs usually related to required floor space. With existing FDA requirements and segregation of processes for bacteria control multiple pass dryers seem to be popular. Dryers have advanced where floors are constructed between passes effectively making them similar to a single pass dryer. Improvements in the technology of air flow control has allowed designs where dryer can be zoned in both airflow and temperature. Drying studies of petfood show the moistest kibble, just entered the dryer, can be dried at elevated temperatures driving off the relatively free moisture. Downstream zones are then controlled effectively lowering the temperature to match the moisture removal requirement. These zones are designed in a way so the airflow being recirculated is constantly changing along the length of dryer yielding extremely even drying as in +/- 0.5 percent variance. Verified by testing at the discharge end of the dryer.
This is now the standard of the industry met by all the major dryer manufacturers. VFD drives, varispeed, on fans allow for exacting airflow pressure through the all-important extremely even bed depth delivered into the dryer. Another advancement evenness in dryer product spreading with electric eyes and cameras to verify results. VFD’s on fans also allows for adjustment in the desired volume of air needed based on the actual product and its size. Small products need higher air pressure, whilst for larger products, air pressure can be reduced to the meters per second thru the bed desired.
Additional advancements in the area of controls are amazing. Checking moisture into the dryer and moisture out with the computer system, receiving and sending data, making adjustments for the desired end moisture content, and while you are at it do a density check to verify this spec all at the same time. This feedback can change and monitor dryer temperature and belt speed with the density information being sent back to the extruder for possible adjustments. Couple this with wet bulb, dry bulb and humidity reading so the dryer can automatically control itself from daytime atmospheric conditions to night conditions as well as different seasons. Making a run with a different formula and shape which might require running it at a lower rate, control packages can take this into account and adjust the exhaust air volumes to maximise efficiency based on the amount of water needed to be removed.
Many new and developing advancements in drying and cooling are constantly coming forth as mentioned above and even the use of heat pumps and energy recovery of exhaust air streams by many manufacturers. Yes, an attached cooler to a dryer can greatly assist in getting the temperature to a good coating temperature but an after/coating cooler is what guarantees to get to within 15 degrees of ambient or less to avoid spoilage from condensation in the bag.
Congratulations to Laitram Machinery for entering into the dryer business, pushing the limits and boundaries for more efficient dryer operations.
Dr Yunior Acosta Aragon, Strategic Growth Manager, nu.biom Pet Nutrition, nu.ance
Biotechnology, Switzerland presents a review of postbiotics. The definition of postbiotics and the possibilities of what they can include without live bacteria in the product. The advantages of these products and the best way to choose the correct postbiotic.
Published in the March 2025 issue of International Petfood.