How can pass parameter in RedirectToAction?

I am working on MVC asp.net.

This is my controller action:

public ActionResult ingredientEdit(int id) {
    ProductFormulation productFormulation = db.ProductFormulation.Single(m => m.ID == id);
    return View(productFormulation);
}

//
// POST: /Admin/Edit/5

[HttpPost]
public ActionResult ingredientEdit(ProductFormulation productFormulation) {
    productFormulation.CreatedBy = "Admin";
    productFormulation.CreatedOn = DateTime.Now;
    productFormulation.ModifiedBy = "Admin";
    productFormulation.ModifiedOn = DateTime.Now;
    productFormulation.IsDeleted = false;
    productFormulation.UserIP = Request.ServerVariables["REMOTE_ADDR"];
    if (ModelState.IsValid) {
        db.ProductFormulation.Attach(productFormulation);
        db.ObjectStateManager.ChangeObjectState(productFormulation, EntityState.Modified);
        db.SaveChanges();
        **return RedirectToAction("ingredientIndex");**
    }
    return View(productFormulation);
}

I want to pass id to ingredientIndex action. How can I do this?

I want to use this id public ActionResult ingredientEdit(int id) which is coming from another page. actually I don't have id in second action, please suggest me what should I do.