According to the present invention there is disclosed a process for the production of a storage stable onion fibre mixture from onion, comprising the steps: - dry removal and sorting-away of soil, stones, defect material and any other contaminants and foliage from onions; - washing and peeling of the onions in a washer/onion peeler; - disintegration of the onions to a mixture comprising small onion fibres which have intact fibre structure and onion juice in an onion disintegrator; - separation of at least a part of the onion juice from the mixture in an onion fibre dewater device for the production of an onion fibre mixture; and - fermentation of the onion fibre mixture in at least one fermentor to a pH-value between 3.5 and 5 for the production of a storage stable onion fibre mixture and optionally fermentation of the separated onion juice in at least one separate fermentor to a pH-value between 5 and 6.