RESEARCH CONCERNING THE INFLUENCE OF HEAT TREATMENTS ON PHYSICO - MECHANICAL AND TEXTURAL CHARACTERISTICS OF PEARS

The objective of this research was to investigate h ow the texture of pears (Pyrus communis L) is affected during heat treatmen t. The following parameters were varied: temperature t = 70÷100 °C and time, τ = 5÷20 minutes. During heat treatment pears were immersed in a sugar syrup (two variants of suc rose source were used - granulated sugar and brown sugar). Were analyzed several physi co-mechanical properties (moisture, fruit dimensions, aspect ratio, geometric mean diam eter, sphericity, surface area, fruit mass, fruit volume, fruit density, bulk density, density ratio, porosity). The structure of heat treated pears was examined by fluorescence and phase contra st combination microscopy and texture was measured with a penetrometer type Fruit Texture Analysis (FTA). The average fruit mass ranged from 115.55 to 136.5 g. The bulk densit y, porosity and fruit hardness determined as 365.84 - 543.12 kg/m 3 ; 78.81 - 95.28 % and 9.87 - 13.74 N/mm between samples. A better firmness and a higher temperature in the center of the sample were observed for brown sugar syrup treated pears.