This review concerns both the botanical and the practical aspects of commonly recognized texture qualities of fruits and vegetables. Interrelationships between tissue structure and composition provide a wide variety of textural qualities in fresh and processed fruits and vegetables. Structural sources of textural appearance are described for several fruits and vegetables. Various examples of specialized supporting and fibrous tissues are also described with reference to problems of texture quality in frozen and dehydrated products. The roles of plant cell wall composition and of cellular contents, such as starch, are discussed with specific examples of manipulative control of texture in several processed products.

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Changes from succulence to mealiness during ripening and storage of apples are important to the marketability of the fresh fruit. These changes also are significant t o the textural qualities of processed apples. Mealy apples frequently sauce readily when cooked. Some varieties sauce rapidly when cooked in the fresh condition ; others remain intact and relatively firm.It has been commoiily accepted that saucing of cooked apples is the direct result of cell separation when the middle lamella pectins are solubilized (7, 12). JIealiness, as a condition of cell separation in fresh apples, has long been coilsidered t o result from pectic changes during ripening and Branfoot ( 1 ) demonstrated that these changes, from insoluble "protopectin" t o vater-soluble pectins, occur in the middle Zaiiiellne betveeii ad jaceiit cells. Apples vary coiisiderably in textural qualities, howeyer : some of the conditions described by Branfoot do not agree v i t h observations made by Tetley (11) and the composition of middle lamellae, in sitii, still remains coii jectural. The exact chemical composition of Braiifoot's "protopectin" is obscure (4,7 ) and the term has little meaning other than its reference to the water-insoluble fraction remored by the C a d -Haynes method ( 2 ) . The soluble fraction, on the other hand, is extracted from the frozen. finely groand tissue and it would be erroneous t o assnme that it represents the vater-soluble pectins of only the middle lamellae.

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