Proximate analysis of cold-press oil cakes after biological treatment with Trametes versicolor and Humicola grisea

In order to increase the current knowledge on cold-press oil cakes composition, the present study aims to determine the chemical composition of oil cakes from hull-less pumpkin (Cucurbita pepo L.), flax (Linum usitatissimum L.), and hemp (Canabis sativa L.) before and after the biological treatment with Trametes versicolor and Humicola grisea using fungal-based solid-state technology. After 10 days of treatment, the content of ash, total nitrogen, total proteins, and total organic carbon increased in all the three oil cakes, while the content of ether extracts decreased. After treatment, the concentration of soluble carbohydrates decreased in pumpkin and hemp seed oil cakes, whereas it increased in flaxseed oil cake. During treatment with T. versicolor, the content of fructose significantly increased in hull-less pumpkin seed oil cake. Fiber content decreased in pumpkin and flaxseed oil cakes after treatment with both of the fungi, whereas it increased in flaxseed oil cake.

Keywords: Cold‐pressed oil cake; Humicola grisea; Proximate analysis; Trametes versicolor; Waste/by‐product.