501 Bulletin USAMV Agriculture, 67(2)/2010 Print ISSN 1843-5246; Electronic ISSN 1843-5386 Post-Harvest Cuticular Permeability (Dehydration Kinetics) Regulation Of Plums Călin JIANU, Ileana COCAN, Teodor TRACĂ, Maria CHI, Mihaela CAZACU, Ionel JIANU Banat’s University of Agricultural Sciences and Veterinary Medicine Timisoara, negreaileana@gmail.com Keywords: cuticular permeability, dehydration kinetics, epicuticular waxes. SUMMARY This work analyzes the major alternative effects of the physical and biochemical changes on plums (Prunus domestica) partially dehydrated by storage at 2-3°C under controlled atmosphere (2-3% CO 2 ; 6-7% O 2 ) for 10-40 days [total acidity 1.24%; total carbohydrates 14.36%; vitamin C 5.4 mg%; vitamins A, E, PP (0.34-0.95 mg%)]. The respiration of stored plums was controlled knowing the quantitative change in time of a bioactive principle (glucose). If the evaluated bioprinciple was glucose, 180 g sugar were lost for every 264 g CO 2 released. The rate of the loss of dehydrated mass was estimated as follows: dry mass weight loss (g/kg/h) = mg CO 2 /kg/h x 10 -3 x 68 or dry mass loss (%) (g/100/g/h) = mg CO 2 /kg x 68 x 10 -6 . Plums stored at 30°C released 35 mg CO 2 kg/h. After one month of storage the dry mass loss of the stored mass of plums was 35 m 3 x 68 = 0.024 g/kg/h or 0.024 x 24 x 30 = 77.2 g/kg/month, or percentally (%) = 1,72 % dry mass/month. Practically the methods of evaluation of aerobic respiration of vegetal tissues in stored plums involved the estimation of the volume of carbon dioxide released by the tissue ( a simple and non-destructive method, it is also recommended for plums undetached completely from the “mother plant”). Two general approaches became necessary, simulating the technological reality: the static and dynamic systems. In this work only the first variant was approached. The respiration rates were expressed as the weight and volume, respectively, of gas generated or consumed per kg freshly picked plums per hour (125 mg CO 2 /kg/h or 25 mL CO 2 /kg/h). To determine the aerobic respiration kinetics in a static system it was necessary to know the volume of the sealed space (m 3 ); amount of vegetal tissue studied (plums) (g); initial concentration of carbon dioxide (L, m 3 ); evaluation period (days); final concentration of carbon dioxide (L, m 3 ). For 280 g plums introduced in the respirometer’s enclosure with a capacity of 1560 mL, after 15 minutes, the concentration of CO 2 increased from 0.03% to 0.23 % (by 0.2%). Converting the units of weight and time into kg and hours, respectively, the amount of 0.28 kg and a sampling period of 15/60 = 0.25 hours were obtained. The volume of carbon dioxide released was represented by the evaluated percentile increase of CO 2 and the total volume of the sealed space (0.2 % x 1560 mL = 3.12 mL CO 2 ). Reporting then this to the weight (kg) and the sampling period (hours) the unitary production of carbon dioxide was obtained: 3.12 mL (0.28 kg x 0.25 h) = 44.6 mL CO 2 /kg/h. REFERENCES 1. Carlos H. Crisosto, David Garner, Gayle M. Crisosto and Earl Bowerman, Increasing, Blackamber’ plum (Prunus salicina Lindell) consumer acceptance, (2004), Postharvest Biology and Technology, Vol. 34, Issue 3, p. 237-244. 2. M. Guerra and P. A. Casquero, 2008, Effect of harvest date on cold storage and postharvest quality of plum cv. Green Gage, Postharvest Biology and Technology, Vol. 47, Issue 3, p. 325-33. brought to you by CORE View metadata, citation and similar papers at core.ac.uk