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Title: Studies in the growth of grapes
Author: Copeman, P. R. v. d. R.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1928
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During the grape season of 1922 in South Africa the question of the ripeness of grapes arose in connection with their export. In this country the export regulations with regard to grapes stipulate that "no unripe grapes will be passed by the Inspector ",while the general regulations concerning fruits for export provide that "all fruit shall be in a sound condition, fully developed and not too unripe." In America a legal standard has been set up whereby the sugar content of the juice must be at least 16 - 17° Balling according to the variety of the grape( 1°). This law was framed to prevent the indiscriminate marketing of green immature grapes and has apparently proved successful in practice. In view of the indefinite nature of the terms "ripe" and "unripe ", it is clear that any attempt to apply regulations, involving such terms, must be an entirely arbitrary proceeding depending to a large extent upon the personal interpretation of such factors, and consequently will undoubtedly be subject to considerable variations. The problem of what constitutes a ripe grape must therefore be solved before an attempt can be made with any chance of success to apply regulations which involve an estimation of the degree of ripeness of the fruit. Since sweetness is a desirable quality in any fruit, attention is generally focused upon the sugar- content, more especially as the flavour appears to be associated with this factor. At the same time it is important to remember that the intensity of a sensation such as sweetness is considerably '\modified by the presence of an acid or sour substance(36). It rn is, therefore, clear that the condition of ripeness of a fruit must also depend upon the acidity of the juice. It may be concluded that a high sugar-content and a low acidity are desirable for the production of a mild sweet flavour in the fruit. At the present time there is no generally established method for determining when grapes have reached a condition suitable for export. In addition to the taste which may be subject to wide variations, the colour, firmness and size all influence the picker's decision. When the appearance and attractiveness of the product are to be considered the physical aspect of the berry must be given due weight, but the final decision regarding the maturity of the fruit must depend essentially upon the quality and flavour of the juice. In order to obtain an idea of the limits of some of the factors which influence "the condition of ripeness" in connection with table varieties of grapes, an investigation into the changes which occurred during the ripening of grapes was undertake.n. Preliminary work was carried out during the 1923 season and the work was continued during the 1925 and 1926 seasons in order to determine the extent to which these limits are affected by seasonal conditions. In 1927 similar work was carried out for the purpose of studying the effects due to a variation in locality.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available