xii Preface Much of the emphasis is on extraction of macromolecules, increasing the added value of foods and recovering valuable components from by-products and fermentation media Many of the methods discussed are now in commercial practice, whilst others are being S. Grandison and M.j. Lewisxii Preface Much of the emphasis is on extraction of macromolecules, increasing the added value of foods and recovering valuable components from by-products and fermentation media. Many of the methods discussed are now in commercial practice, whilst others are being vigorously researched. A. S. Grandison and M. J. Lewis