Evaluation of Maturity Indices Based on Pressure -Test Readings 

 For Eastern-Groxm Peaches^ 19$h 



SUMI/lRY 



Ifeturitj'' standards are proposed for C comraercial varieties of eastern-grom 

 peaches on the basis of ti/o seasons' Tiork. Tlie standards are given in terms 

 of firmness of the pared cheeks and suture as measured by a pressure tester 

 Trjith a 5/16 -inch -diameter plunger at harvest. Tne maturity was determined 

 from the tine required for peaches to ripen at room temperature (70° to 90°F,)« 

 From the first season's uork it was more or less arbitrarily established that 

 a peach was mature if it ripened to at least an acceptable flavor in 8 d&js 

 or less. Peaches requiring longer to ripen were scored immature. Peaches of 

 each variety were picked at all stages of maturity and ripened after harvest* 

 The times required by the peaches to ripen after harvest were correlated with 

 the pressure-test readings at harvest on the assumption that the softest 

 peaches at harvest ripened in the shortest time and the hardest ones in the 

 longest time« The pressure-test readings at harvest of the peaches requiring 

 8 days to ripen (6 days for Ciolden Jubilee) were taken as the upper liiiiits of 

 the maturity stand3.rdse For the 6 varieties the ranges in the proposed 

 standards are lU.O to 15,0 pounds or less on the suture and l6e^ to 17«0 pounds 

 or less on the cheeks (average), Tae best proposal that can be made for a 

 comiaon standard for the 8 varieties is lIi.o5 pounds or less on the suture or an 

 average of l6<,5 pounds or less on the cheeks <, Peaches firmer than the standard 

 should not be picked for commercial shipment* At present the proposed standards 

 based on firrmess ( pre ssiire -test readings) are objective indices th^t shouJ.d be 

 supplemented hj subjective tests of maturity based on ground color., flesh 

 texture and taste , shape, and pit freedom and color, 



INTRODUCTION 



During the peach seasons of 1953—- and 19^h the U, S. Department of Agriculture 

 made a study of possible tests that might lead to an objective measurement of 

 ma.turity in peaches, A satisfactory measure or index of maturity would help 

 growers in deciding when to begin picking and enable the Inspection Service to 

 set up more definite standards. It is generally agreed that adequate maturity 

 of peaches is necessary for the attainment of highest qualityo 



The maturity of peaches is difficult to measure. Growth often continues after 

 the fruit begins to soften along the suture line. The rates of growth and 

 ripening of individual peaches vary from tree to tree, orchard to orchard and 

 year to year and depend upon the xxeather and growth conditions prevailing. 

 However, we do know that maturity is closely associated T^Jith ripening and that 



1/ Ilaller, IL H. and Graft, C. G, Ilaturity indices for peaches, 

 Dept. Agr, H. T, T: 0. Office Report 310, 28 pp, 19$ho Processed. 



