ARTICLE 102 FEED & ADDITIVE MAGAZINE November 2025 applied pre-cooking, while natural origin antioxidants are used post-cooking for cost-effectiveness. As pet food manufacturers increasingly highlight natural claims on their packaging, the use of ingredients stabilized with synthetic molecules appears inconsistent and illogical. The biggest pet food manufacturers have requested Kemin Nutrisurance to develop efficient cost-effective natural origin antioxidant solutions for all ingredient stabilizations. THE CHALLENGES Trials’ Capabilities The poultry rendering industry is engaging in the processing of huge crude raw materials through continuous or batch dry rendering processes from 10 to more than 300t/day. Antioxidant molecules used before the cooking phase are mainly oil soluble. During the cooking phase, some of these molecules migrate into the extracted poultry fat. In certain processes, this fat —now containing synthetic molecules— is reused in the cooker to speed up the cooking process. As a result of this carryover effect, synthetic antioxidant molecules can contaminate subsequent batches of poultry PAP and fat. The two main rendering technologies are based on dry rendering (with protein and fat separation after water removal) and wet rendering (with water removal after protein and fat separation). The dry rendering process is more stressful for PAP and fat. To enable testing of multiple antioxidant molecules—individually, in combination, at various dose rates, in duplicate or triplicate, and across both dry and wet rendering processes while avoiding cross-contamination – Kemin Nutrisurance developed its own pilot rendering facility. Final selected solutions were tested afterward under dry rendering industrial conditions. Over the last 4 years, we conducted 203 cooking trials, tested 50 different molecules, treated more than 15 tons of crude raw materials, and carried out more than 17,500 wet chemical analyses. Cost in Use As mentioned, it’s crucial to protect the fat before it undergoes thermal stress. Applying antioxidants to crude raw materials significantly impacts cost-inuse due to the effect on protein yield, which typically ranges from 18% to 20%. For instance, if we don’t consider antioxidant migration into fat part, the cost factor for crude raw materials can range from 5 to 5.5, compared to a meal cost factor of just 1 when antioxidants are applied to dry PAP. The target is to reduce the stabilization cost of poultry crude raw materials by using the most cost-effective solution of natural origin. THE DEVELOPMENTS Pilot Trials The first phase was dedicated to the mixed raw material validation, targeting standard poultry PAP (3.5 % Moisture, 64.8% Protein, 14.6 % Fat, 17.5% Ashes) before standardizing the dry rendering process in Figure 1. RAW MATERIALS GRINDING COOKING SEPARATION COOLING GRINDING / TREATMENT MIXING Grinder Grinder Mixer AOX AOX Meal Reactor/Cooking Separation Fat Figure 1. Rendering pilot principle with different Antioxidant application points possibilities6
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