Chemical and sensory variability in table grapes
Authors
K. E. NelsonG. A. Baker
A. J. Winkler
M. A. Amerine
H. B. Richardson
Frances R. Jones
Publication Information
Hilgardia 34(1):1-42. DOI:10.3733/hilg.v34n01p001. January 1963.
PDF of full article, Cite this article
Abstract
Introduction
Consumer acceptance of grapes is based on a number of factors, including color, flavor, size, bloom, and texture. This study is concerned directly with the first two factors only, although textural changes associated with the maturity level of the fruit could possibly influence over-all sensory impressions. Flavor is defined as the complex reaction of taste and olfactory receptors; the olfactory aspect is believed to be secondary with non-muscat varieties. In this study, only the taste aspect of flavor will be considered.
There are four possible tastes in grapes: acidness (tart, or sour), sweetness, saltiness, and bitterness. White grapes are very low in tannins and other bitter-tasting substances. Red grapes have more bitter-tasting substances, but these are mainly in the skins and unless skins are vigorously chewed little bitter taste is experienced. Grapes have very little salty taste, though tartrates give a reaction. Tartrates as buffer agents repressing the ionization of malic and tartaric acids may, however, influence the acid taste.
The characteristic gustatory sensation of grapes is their sweet-sour taste. The main sugars found in grapes, levulose and dextrose, are of very unequal sweetness (about 1.5:1) and presumably the ratio as well as the total amount of the two may be of importance to the sweet taste (Amerine and Thoukis, 1958).
The acid taste is produced by the organic acids, chiefly tartaric and malic, whose relative as well as total amounts in the fruit are influenced by the variety and by the temperature during the ripening period; these acids are of unequal sourness. For a discussion of the effect of variety, region, and time of maturity on the tartrate/malate ratio see (Amerine and Winkler (1942)).Color is particularly significant as an acceptability factor in table grapes as it is the primary factor of the grapes’ appearance, and appearance is of prime importance. In fact, color is usually used as an index of maturity in red and black grapes (United States Code of Federal Regulations, 1962). Its significance in white grapes is much less clearly defined, however. The subtle changes in color from grass-green to yellowish-amber as maturity advances are much less pronounced than with pigmented fruit, but there are strong indications that consumers do detect these color differences, associating the yellow tones with greater sweetness. The importance of the other appearance factors—size and shape of berry, amount of bloom, etc., have not been investigated thus far. It would also be desirable to have information on the importance to
Literature Cited
Amerine M. A., Thoukis G. The glucose-fructose ratio of California grapes. Vitis. 1958. 1:224-29.
Amerine M. A., Winkler A. J. Maturity studies with California grapes. II. The titratable acidity, pH, and organic acid content. Proc. Amer. Soc. Hort. Sci. 1942. 40:313-24.
Baker G. A., Mrak V., Amerine M. A. Errors of the second kind in an acid threshold test. Food Research. 1958. 23:150-54. DOI: 10.1111/j.1365-2621.1958.tb17552.x [CrossRef]
Bell H. P. Preferences for canned grapefruit juices. Proc. Fla. State Hort. Soc. 1955. 68:151-55.
Bioletti F. T. The basis of grape standardization. Calif. Agr. Exp. Sta. Cir. 1925. 293:1-16.
California, Laws and Statutes. California Statutes and Amendments to the Codes, 1915, Chap. 659 (pertaining to the Fruit, Nut and Vegetable Standardization Act, 1915) 1915. Sacramento, Calif
California, Laws and Statutes. Agricultural Code, Bureau of Fruit and Vegetable Standardization 1959a. Dept. of Agr. Sections 795.1, 796.0
California, Laws and Statutes. Agricultural Code, Bureau of Fruit and Vegetable Standardization 1959b. Dept. of Agr. Section 802
Dalmasso G., Venezia M. Il controllo del grado di maturita delle uve da tavola e l’applicazione del rifrattometro. Annuario Staz. Sperm. Vitic. e Enol., Conegliano. 1937. 7:339-96.
Florida, Laws and Statutes. Florida Citrus Code of 1949, Senate Bill 123 1949. Chap. 25149 (No. 153), Sections 16-22, Tallahassee, Florida
Florida, Laws and Statutes. Citrus fruit laws, Florida Citrus Code, Chap. 601, Sections 601.16-601.232. 1961. Lakeland, Florida: Florida Citrus Commission.
Guymon J. F., Ough C. S. A uniform method for total acid determination in wines. Amer. J. Enol. and Vitic. 1962. 13:40-45.
Hughes E., Bouffard E. Sur le degreé de maturité des raisins de table. Ann. fals. et fraudes. 1937. 30:91-94.
Kendall M. G. The advanced theory of statistics. 1955. 3 edit. New York: Hafner Pub. Co. DOI: 10.2307/2986781 [CrossRef]
Kilburn R. W. The taste of citrus juice. I. Relationship between Brix, acid, and pH. Proc. Fla. State Hort. Soc. 1958. 71:251-54.
Morse R. L. D. Consumer preferences for canned orange juice of 12 to 22 Brix/acid ratios. Proc. Fla. State Hort. Soc. 1954. 67:186-92.
Mrak V., Amerine M. A., Ough C. S., Baker G. A. Odor difference test with applications to consumer preferences. Food Research. 1959. 24:574-78. DOI: 10.1111/j.1365-2621.1959.tb17309.x [CrossRef]
Nedelchev N., Kondarev M. Maturity standards for the Chaouch and Dattier de Beyruth grapes (transl.). Ann. Univ. Sofia, Faculty Agron. et Sylvie. 1934. 12:487-504.
Snedecor G. W. Statistical methods. 1956. 5 edit. Ames, Iowa: State College Press. DOI: 10.1097/00010694-195702000-00023 [CrossRef]
U.S. Code of Federal Regulations. Brine flotation test for separating peas according to maturity 1959. Title 7, Agriculture, Sections 52.2291, 52.2292
U.S. Code of Federal Regulations. Standards for grades of table grapes (European or Vinifera type). Title 7 1962. Agriculture, Sections 51.880-51.912
Westbrook G. F., Stenstrom E. C. A study of the degree Brix and Brix/acid ratios of grapefruit utilized by Florida citrus processors for the seasons 1952-1953 through 1955-1956. Proc. Fla. State Hort. Soc. 1956. 69:113-120.
Westbrook G. F., Stenstrom E. C. A study of the degree Brix and Brix/acid ratios of oranges utilized by Florida processors for the seasons 1952-1953 through 1956-1957. Proc. Fla. State Hort. Soc. 1957. 70:247-59.
Winkler A. J. Maturity tests for table grapes. Calif. Agr. Exp. Sta. Bul. 1932. 529:1-35.
Winkler A. J. Maturity tests for table grapes—the relation of heat summation to time of maturing and palatability. Proc. Amer. Soc. Hort. Sci. 1948. 51:295-98.
Also in this issue:
An old but enduring argumentOf men and machines: Technological change and people in agriculture Part 1: Changes in farm enterprises and farm families
Sprinkler irrigation raises yields— and costs—of Imperial Valley alfalfa
Coming: More corporate farms in California
Selection improves Sevin resistance in spider mite predator