INFLUENCE OF THE CALCIUM ON MICROBIAL STABILITY AND TEXTURE OF OSMOTIC DEHYDRATED PINEAPPLE SLICES.

Abstract

The aim of this study was to analyze the effect of calcium on microbial stability and texture of osmotic dehydrated pineapple slices in the preparation of minimally processed pineapple slices by osmotic dehydration in atmospheric conditions. Pineapple slices of 10 mm thickness were treated with osmotic agents consisting of glucose solutions of 50° brix incorporated with 0, 1, and 2 % calcium lactate, until they reached 30° and 40° brix at room temperature. The effect of osmotic dehydration on mechanical properties and microbial stability of pineapple slices were analyzed throughout storage at 10 °C for 28 days. Moisture content was determined using the standard method. Mechanical properties were analyzed using a penetrometer, and microbial analysis was done according to the standard microbial tests. Compared to fresh cuts and control samples, samples treated with osmotic agents containing 2 % calcium lactate showed a significantly lower growth of mesophilic bacteria , yeast and moulds. Furthermore, the samples treated with calcium lactate had a better firmness compared to those without treatment. Out of all sample tested, 30° brix sample with 2% calcium lactate and 40° brix sample with 1% calcium lactate were identified as the better samples with good firmness and low microbial growth. Treatment of pineapple using dehydration solutions with calcium lactate has been found useful in producing osmotic dehydrated pineapple slices characterized with good firmness, high microbial stability and high keeping quality.