ACTA ALIMENTARIA VOL. 3 (A QUARTERLY OF THE COMMITTEE ON FOOD SCIENCE OF THE HUNGARIAN ACADEMY OF SCIENCES, 1974)
1974 / 1. sz. - KOVÁCS, E.-VAS, K.: Methodological studies on the determination of respiration and ethylene production of fruits and vegetables
Acta Alimentaria, Vol. 3. (1), pp. 1—9 (1974) METHODOLOGICAL STUDIES ON THE DETERMINATION OF RESPIRATION AND ETHYLENE PRODUCTION OF FRUITS AND VEGETABLES E. KOVÁCS and K. VAS (Received May 8, 1972) Methodological studies were carried out to determine the respiration and ethylene production of fruits and vegetables. Oxygen consumption was measured by a modified version of the Warburg method. Changes in gas volume taking place during a given time period were related to unit (a) weight, (b) surface or (c) volume of the fruit. Standard deviation was lowest with the values calculated for unit weight. Values calculated for unit volume scarcely differed from the former, but the accurate determination of volume is difficult. Carbon dioxide and ethylene production were determined by gas chromatography. Both gases were determined simultaneously, using a heat conductivity detector for carbon dioxide and a flame ionization detector for ethylene. Air samples containing the carbon dioxide and the ethylene are transported by the carrier gas (helium) and a distributor to the two types of detector. The method is rapid and its range can be extended between wide limits by changing the sensitivity of the detectors. To follow up the ripening processes of fruits and vegetables is important, because apart from the quality of the raw material, the efficiency of storage also depends on the stage of ripeness. The knowledge of respiration and ethylene production of sound fruits and vegetables is important from the point of view of storage physiology. Respiration can be measured by colorimetric determination of C02 formation or 02 consumption (CLAYPOOL & KEEFER, 1942), by titrimetry (BIALE et ed., 1954; MEIGH et ed., 1967), by spectrophotometry (GREEN et ed., 1969), by gas chromatography (LUH & CHATTDRY, 1961; MAXIE et ál., 1966; MEIGH & FILMER, 1969), or by an oxygen analyzer, on the basis of the paramagnetic properties of oxygen (LEE et ál., 1968; ROBINSON & COOPER, 1970). Ethylene is either determined chemically by volumetric analysis (YOUNG et al., 1952) or by gas chromatography (MEIGH, 1960; MEIGH et ed., 1967, 1969; LEEeí al., 1968; etc.) The aim of the present studies was to elaborate a rapid, accurate method facilitating the parallel study of a sufficient number of samples and the statistical evaluation of the results. Acta Alimentaria 3, 1974