Enhancing the nutritional value of by-products through steam explosion

Researcher: Dr. Rex Newkirk & Antoniel Franco, University of Saskatchewan

Project Code: CUP ADF 2016.208

Final Report: July 2020

Summary: Canola meal comprises approximately 60% weight of the original seed and is widely used in livestock production as an important source of protein. However, the meal is discounted relative to that of soybean meal due to low digestible energy in the meal. In addition, lower amounts of meal are exported due to limited maximum inclusion levels of canola meal in livestock diets. Canola hulls contain significant quantities of highly lignified fibre that appears to encapsulate nutrients and impairs their digestion by animals, especially monogastric species such as poultry and swine. To improve the value of canola meal and create greater market demand, it is important to increase the energy content of canola meal. The objective of this research is to study ways to improve the digestibility of high fibre canola products such as seed, meal and hulls using steam explosion technology combined with or without pre-treatments.

In this research, industrial use of steam explosion processing with high temperature was modified by using pre-treatments with low temperature to minimize protein damage within seed and meals. Two types of pre-treatments were tested on canola seed, meal and hulls. A digestibility study using broiler chickens was also conducted to determine the effect of steam explosion on digestibility of nutrients in canola and hull fractions before and after dehulling.

A wide range of treatments were included to use canola meal as the initial starting point to approximate steam explosion of meal obtained from the desolventizer/toaster step from canola crushing plants. Research results showed that steam explosion of canola meal is not effective due to the high levels of water absorbed during the process. Improving nutritional value of canola by dehulling is effective, but dehulling canola seed through steam explosion is challenging due to the excessive lignified hulls that are resistant to delignification and fiber modification. Pre-treatment of hulls did not appear to improve the effectiveness of steam explosion and has negative consequences due to excess water handling and drying. According to the digestibility study conducted on broiler chickens, inclusion of steam exploded canola hulls in the diet at 6% inclusion level significantly reduced the apparent metabolizable energy (AME), dry matter digestibility and Energy digestibility. After the application of steam explosion treatments on canola hulls with little success, researchers developed a new method to dehull canola seed using smooth rolls in a roller mill combined with air fractionation. Removing the hulls with this method showed significant improvement in the nutritional content and digestibility of the remainder of the canola meal. Overall, this research successfully developed a method to dehull canola seed to improve the nutritional content and digestibility of canola meal.

Click the links below to download a short version of the report, the full detailed long version of the report, or the related Canola Digest PDF.

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