Ingredient fractionation for monogastric animal nutrition: the worth of sum of parts versus the whole

Abstract

Basic agricultural commodities such as cereal grains, pulses and oilseeds can be fractionated into separate products that can be targeted to high value markets within or outside the feed industry. Resulting nutrient-dense fractions that are enriched in starch, protein, fat, or fibre can then be targeted to animals with different nutritional demands. These value-added nutrient fractions might be targeted at the start of fractionating the commodities or result from human food or biofuel production. Fractions enriched in fibre might be targeted to the feed, paper, or wood industries. Two categories of processes can fractionate cereals, pulses, or oilseeds: (1) an up-front process that produces solely or mostly high value ingredient fractions, or (2) a process that separates one fraction for a high-value market. Examples of category 1 include air classification and sieving. Examples of category 2 include bioethanol production from cereal grains and oil extraction from soybean and canola seed. The resulting non-human edible co-products can be fed to livestock. Dry separation is useful to produce protein-rich fractions from pulse grains. Advantages of dry over wet fractionation are continuous flow rather than batch fractionation, absence of effluents and no drying cost. However, wet fractionation creates more concentrated fractions (isolates) of the nutrient of interest, e.g., protein. Category 1 and 2 processes can occur in tandem. For example, oil can be first extracted from soybeans, resulting in soy oil and soybean meal. Subsequently, soybean meal can be fractionated into protein concentrates or isolates with greater protein content than soybean meal. Fractionation usually has at least one main fraction with a target market in food or industry processes yielding products for human use. This approach is logical, because the feed industry is focussed mostly on small margins and large volumes, whereas higher margins per unit of product can be achieved in markets for food, petfood and feed for fish or animals with high nutritional demands. Animal agriculture remains an ideal approach to convert by-products from ingredient fractionation into high value animal protein. The economic implications of value-added processing are thus important, and sustainable animal agriculture plays a key role turning waste streams into a success story. Although ingredients can be fractionated successfully for animal nutrition, especially for higher margin markets such as aquaculture, petfood or animals with high nutritional demands, most ingredients are fractionated for the human food supply or industrial processes. Using the latter approach with at least one high value fraction targeted to human food or industry and then using non-human edible fractions for feed applications, will ensure that the sum of the parts can be worth more than the whole.