The combined effect of mild pretreatment and fungal fermentation on the proximate composition of cold-pressed camelina meal

Abstract: The cold pressed camelina meal (CPCM) is a protein-rich (30-35%, db) co-product of the camelina seed oil extraction process. CPCM is highly nutritious yet underutilized co-product due to the presence of several undesirable plant components like glucosinolates, tannins, phytic acid, fiber, and trypsin inhibitors. This study aims to upgrade the nutritional composition of CPCM by applying mild pretreatment and fungal fermentation under submerged fermentation mode. Firstly, CPCM at 5% solid loading rate was washed with water to remove the soluble antinutritional factors (ANFs). The mild wash process concentrated the protein in CPCM when compared to the raw CPCM. The washed and unwashed CPCM were then subjected to the submerged fungal fermentation using the mono- and co-cultures of Aureobasidium pullulans, Neurospora crassa. Post fermentation samples were analyzed for cellulosic enzyme (cellulase, endoglucanase, β-glucosidase) activity, protein yield, and ANFs reduction in both the raw and washed CPCM. The results indicated that the enzymatic activity varied depending on the substrates and microbial cultures. Cellulase and endoglucanase activity of mono- and co-cultures were similar with all inoculated substrates; however, the β-glucosidase activity was significantly higher in washed CPCM than raw CPCM. On the other hand, the protein yield increased with mono-and co-culture in washed CPCM compared to inoculated or uninoculated raw CPCM. Moreover, both mono- and co-cultures on raw and washed CPCM reduced ANFs at different levels. However, the phytic acid concentration reduced significantly on washed meals after fermentation compared to the raw CPCM. Overall, these findings demonstrated that pretreatment with mild water washing followed by fermentation improves the nutritional value of CPCM.