Submitted to: Food and Bioprocess Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2021
Publication Date: 5/27/2021
Citation: Alhomodi, A.F., Zavadil, A., Berhow, M.A., Gibbons, W.R., Karki, B. 2021. Daily development of nutritional composition of canola sprouts followed by solid-state fungal fermentation. Food and Bioprocess Technology. 14:1673-1683. https://doi.org/10.1007/s11947-021-02667-2.
DOI: https://doi.org/10.1007/s11947-021-02667-2

Interpretive Summary: This study characterized the daily compositional changes in canola seeds during sprouting and evaluated the effect of fungal fermentation on sprouts under solid state fermentation conditions. Canola is a major oilseed crop, and the seed meal that remains after oil extraction has an excellent protein composition for animal feed applications. However, there are anti-nutritional factors such as glucosinolates, phytic acid, and high fiber that limit its use in animal feed. Sprouting and fermentation are two treatments that may help to improve the nutritional value of the seed meal and aid in the removal of undesirable anti-nutritional components. This study demonstrated that sprouting reduced the crude fiber, and phytic acid content, while increasing protein, glucosinolates, and total sugars in the canola seeds over six days. The oil content was reduced slightly. Fermentation further reduced fiber content, and two of the three fungal species used for fermentation further reduced the phytic acid content. These results provide insight for optimizing the germination interval for using sprouted canola seeds in feed or food applications and will allow for the development of new uses of canola meal for food and feed products with improved nutritional characteristics.

Technical Abstract: Sprouting is a beneficial way to increase the nutritional value of the original seeds. Besides, fungal fermentation of sprouts can further improve sprouts composition by reducing antinutritional factors and concentrating protein content. Thus, this study characterized the daily nutritional changes in canola sprouts and further evaluated the effect of fungal fermentation on 144 h sprouts under solid state fermentation conditions. Sprouting process resulted in high moisture containing sprouts (75.3%) due to water uptake by seeds. The oil content of sprouts (27.2% at 144 h) was significantly (p'='0.05) reduced when compared to raw seeds (39.6%). Likewise, phytic acid, crude fiber, acid detergent fiber, and neutral detergent fibers were reduced by 49.7, 32.8, 19.7, and 16.6%, respectively, when compared to raw seeds. There were significant increases in protein and carbohydrate contents of sprouts, and glucosinolates also increased from 1.3 to 3.5 µM/g post sprouting. Fungal fermentation with Neurospora crassa resulted in the highest protein increase (32.8%). Heat-sterilization reduced total glucosinolates by 38.8%, and a further reduction (4.0%) was obtained by fermentation with Trichoderma reesei. A reduction in phytic acid content of 81.4, 45.8, and 10.2% was achieved by fermentation with N. crassa, T. reesei, and Aureobasidium pullulans, respectively. Total carbohydrates was reduced by 3.3 mg/mL post heat-sterilization, and fungal fermentation led to the further reduction of total carbohydrates, but total fibers were found to be increased post fermentation. These results highlight the enhancement of nutritional values of sprouted seeds and further fermented sprouts compared to ungerminated seeds and unfermented sprouts, respectively.