The income is split between the joint-venturers and taxed accordingly.
Joint ventures are not taxed as a separate entity. A corporate joint venture is a company and is taxed as such.
Foundations set up as Companies and Associations are taxed as Corporations/Companies under the Corporation Tax Act.
Some Foundations are set up as trusts in which case the Trustee is charged to tax on the income. Most Foundations are set up for charitable purposes in which case they may obtain an exemption from corporation tax on income which does not arise from trade or business.
The relevant material on corporations and individuals will apply.