Observations on the Histology and Texture of Elberta Peaches From Trees of High and Low Levels of Nitrogen Nutrition

Abstract

Commercial canning of freestone peaches, such as Elbertas, often results in tissue sloughing and a ragged appearance by comparison with the firmly coherent texture of canned clingstone varieties. In some areas, however, plantings of freestone varieties predominate and have increased to the point that quality improvement in their use in the canned fruit market has received serious consideration. This is the situation in the state of Washington (10) where it has been found that the canning quality of Elberta peaches can be improved by orchard application of high levels of nitrogenrich fertilizers (5,13).Quality requirements for canned freestone peaches differ from those for market of the fresh fruit. The influence of nitrogen on tree growth and on yield and quality of the fresh fruit have been generally recognized at least since 1930-1931 described in detail the composition and fresh fruit qualities of high and low nitrogen, New Jersey -grown Elberta and Shipper Cling peaches. These authors considered that the high nitrogen Elberta fruit did not develop a desirable flesh color until too soft for shipment and table use. Peaches representing low to medium nitrogen levels, however, tended to be slightly elongate in shape, matured and colored more rapidly, and could be harvested earlier at a firmer texture for shipment. In general, it has been recognized that trees of high nitrogen nutrition show lush, vigorous growth and bear larger, more rounded fruit than do low nitrogen trees which have comparatively sparse growth and smaller leaves. Very similar differences in fresh fruit qualities were found by Carter et aZ. between Elberta peaches from trees of high and low levels of applied nitrogen grown in soil management plots in Washington State (5,13).However, fruit from trees receiving applied nitrogen fertilizers in amounts necessary for maximum yields was considered to be superior in canning qualities to that representing low to deficient nitrogen conditions. When canned, the high nitrogen fruit showed a firm, finely coherent texture, good color, and was less astringent that the coarse, often stringy and ragged fruit from trees of low nitrogen status.The fine and coherent versus the coarse and ragged texture of these canned Elberta peaches suggested that cellular distinctions may result from different levels of applied nitrogen. The possibility was investigated and comparative histological studies were made on selected samples of these Washington State peaches in both the canned and the fresh conditions.

Histological Development of the Green Bean Pod as Related to Culinary Texture.

“…The histological origins, development and maturation of the different tissues of the green bean pod serve to explain the wide range within which specialized tissue structure and composition may variously influence textural problems encountered in processing. Similar interrelationships between special tissue conditions and texture have been encountered in other processed fruits and vegetables (Powers et al, 1958;Reeve, 1964aReeve, ,b, 1947Reeve, , 1953Reeve, , 1959Reeve, , 1965Reeve et al, 1959Reeve et al, , 1966Sterling, 1955;and Ster-ling et al, 1961) . Textural problems encountered in green beans have centered in three major areas: (1) sloughing of the skins in cooked, canned and frozen products ; (2) stringiness and/or toughness due to over-maturity of fibrous tissues ; and (3) loss of crispness due to the influence of over-blanching and different freezing treatments.…”

Relationships of Histological Structure to Texture of Fresh and Processed Fruits and Vegetables

“…An example of the influence of cell size upon textural appearance has been described for Elberta peaches grown under high (or excessive), and low N nutritional conditions (Reeve and Neufeld, 1959). Smaller cell size and high N nutrition were associated with a firm, finely textured appearance in contrast to the larger cells and soft, ragged textural quality of those grown under conditions of low N nutrition .…”

Observations on Strawberry Texture a Three‐pronged Approach

“…Son (1959) related softening of peaches and pears to the thinning process in cell walls and to the ease of cell separation. Morphology of peaches was also studied by Sterling (1962), Reeve (1959) and Reeve and Neufeld (1959), and that of pears by Sterling (1954). Reeve and Leinbach (1953) and Reeve (1953) investigated histology of apple tissue and reported that the composition of middle lamella materials, rather than the gross chemical analysis, affects textural quality.…”