ESAV - DIA - Artigo em revista científica, não indexada ao WoS/Scopus
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Browsing ESAV - DIA - Artigo em revista científica, não indexada ao WoS/Scopus by Author "Almeida, Cátia"
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- Effect of packaging and conservation conditions on some physical-chemical properties of almondsPublication . Guiné, Raquel; Almeida, Cátia; Correia, PaulaFood quality is a concept that has attracted the attention of Industries and consumers, hence the concern to preserve the products under appropriate conditions, avoiding physical and chemical changes that jeopardize the integrity of the food. In this context, assessments were made of the physical and chemical properties in order to investigate the effects of storage in almonds, under certain conditions of temperature, relative humidity and packaging. The almonds used were from different origins, namely Spain, Portugal and United States and the conservation processes tested were: storage at room temperature, in a stove at 30 and 50 °C without control over relative humidity, in a chamber at 30 and 50 °C with relative humidity of 90 %; refrigeration and freezing. The packages used were two types of plastic: linear low density polyethylene (LLDPE) and low density polyethylene (LDPE). The properties evaluated were moisture content, water activity, colour and texture. The principal results show that the storage conditions that best preserve the characteristics of almonds are those at low temperatures, because, while the treatments at high temperatures induced in general more changes, the refrigeration and freezing systems had a lower effect on the products characteristics, particularly moisture, water activity, hardness and friability. From the results obtained it was concluded that for a good preservation of almonds during storage should be used a packaging material, preferably LDPE, and that with respect to storage conditions the best methods are at room temperature or, alternatively, in refrigeration or freezing.
- Influence of packaging and storage on some properties of HazelnutsPublication . Guiné, Raquel; Almeida, Cátia; Correia, PaulaThe evaluation of some physical and chemical properties was done in order to investigate the effects of storage in hazelnuts, under certain conditions of tempera- ture, relative humidity and packaging. The fruit samples used were original from Spain, Portugal and Turkey. The storage of the nuts lasted for a month and a half, and the conditions tested were: at room temperature; at 30 and 50 C without control over relative humidity of the air; 30 and 50 C with relative humidity of 90 %, refrigeration and freezing. The two types of plastic package tested were low density polyethylene (LDPE) and linear low density poly- ethylene The water activity was measured by a hygrometer; moisture by oven drying until constant weight, colour with a colorimeter and texture with a texturometer. From the results obtained it was concluded that for a good preservation of the hazelnuts it must be chosen the LDPE type of package and with respect to storage conditions it should be done at room temperature, or alternatively in refrigeration or freezing.
- Influence of storage conditions and type of package on some properties of walnutsPublication . Guiné, Raquel; Almeida, Cátia; Correia, PaulaThe quality of dehydrated products is a concern because, due to their very low moisture content, they tend to rehydrate quite easily, thus compromising the chemical, enzymatic or microbial stabilities, as well as the nutritional and sensorial properties. Having this in mind, this study was undertaken to evaluate the effects of storage in walnuts, under certain conditions of temperature, relative humidity and different types of packaging. The fruit samples used were from Chile, Portugal, Romania and United States. The storage of the walnuts lasted for 90 days, and the conditions tested were: room temperature; a stove at 30 and 50 °C without control over relative humidity of the air; refrigeration and freezing. The two types of plastic package tested were low density polyethylene (LDPE) and linear low density polyethylene (LLDPE). The water activity was measured by a hygrometer; moisture content by oven drying until constant weight and colour with a colorimeter. From the results obtained it was concluded that the samples from the different origins are different with respect to moisture content, water activity and colour, regardless of the storage conditions and type of package. Furthermore, it was verified that to assure the good preservation of the walnuts the storage at 50 ºC should be avoided, since it caused an extensive dehydration of the product and a high change in colour in comparison to the unstored samples. Finally, regarding the type of package, it was observed that the use of plastic bags did not really improve the products characteristic in relation to the unpacked samples.