EVALUATION OF COLOUR AND TEXTURE OF A PORTUGUESE TRADITIONAL SWEET: “EGG CHESTNUT”

This work aimed to evaluate the colour and texture of a Portuguese traditional sweet “egg chestnuts” along a storage period of 12 days under refrigeration. For this, the colour coordinates were measured through a colorimeter and the textural parameters were evaluated by compression and puncture tests using a textutrometer. The results showed that the colour coordinates do not vary along time, corresponding to very low values of total colour difference. Hardness, chewiness and springiness decreased in the first 3 days but after that the values were maintained approximately constant. In contrast, resilience and cohesiveness did not change along time. While crust firmness increased along storage, both the flesh firmness and stickiness did not change. The adhesiveness measured through the penetration test decreased considerably from the first to the last day. Hence, it was concluded that colour is better preserved than texture along a 12 day storage period under refrigeration.

Evaluation of morphological and physical characteristics of hazelnut varieties

In this study 15 hazelnut varieties existing in a collection of Viseu Agricultural Station were evaluated. The nuts were studied in respect of their morphological characteristics, such as fruit and kernel weight, index of compression and of shape and shell thickness. The study was complemented with analysis of physical properties such as colour and texture, and the determination of moisture content and water activity, given the importance that these parameters take in the conservation capacity of the fruits. All experiments followed standard methods, being also used the following equipment: texturometer, colorimeter and hygrometer. The results obtained allowed to know the expectable ranges for each color parameters in the shell, film and kernels: L*, a*, b* chroma and hue, having been found statistically significant differences among the cultivars studied. As regards the textural parameters evaluated by crust crushing and crumb cutting tests (hardness, friability and resilience) there were also significant differences. Evaluation of moisture was of great importance because confirmed that the solar drying, used to extract the excess of moisture from the fruits, was sufficient to reach low values, between 1.66% and 4.52%, being so a guarantee of preservation.