Comparación de dos técnicas de deshidratación de guayaba-pera (Psidium guajava L.) sobre los efectos del contenido de vitamina C y el comportamiento de las propiedades técnico-funcionales de la fibra dietaria
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Date
2015-08-24
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Publisher
Corporación Universitaria Lasallista
Abstract
Introduction: “Pear” guava is, nationally, a very
important fruit, given its production levels and its
nutritional value. Its high humidity content makes this
fruit highly perishable, so it requires conservation
processes. Dehydration by drying and lyophilization
are two techniques currently being used to dehydrate
fruits and each one has certain benefits for the product
and for its operative costs. Objective. Compare the effects of lyophilization and forced convection drying
on the technical and functional properties of the dietary
fiber (DF) and on the vitamin C content of the “pear”
guava (Psidium guajava L.). Materials and methods.
“Pear” guavas at a 6 maturity level, according to
the color table, were chosen and dehydrated by
means of convection drying, evaluating five different
temperatures (30, 40, 50, 60 and 70°C), and also
dehydrated by means of lyophilization, evaluating four
freezing times (6, 12, 18 and 24 hours). Vitamin C
was quantified by the use of the 2-nitroaniline method
and the following technical-functional properties of
the DF were determined: swelling capacity (SC),
water retention capacity (WRC) and lipid adsorption
capacity (LAC). Results. The biggest loss of vitamin
C took place in the dehydration by drying at 60 and
70 °C and -in a general way- the best results for the
behavior of the technical and functional properties
were obtained during the dehydration by lyophilization.
Conclusion. Despite the fact that some of the
properties evaluated had no significant differences in
some of the treatments, this study concludes that in the
dehydration by lyophilization, which freezing process
was performed during six hours, the “pear” guava had
higher technical and functional characteristics while
the drying treatment at 40 °C and the lyophilization by
freezing during 24 hours allowed a better conservation
of the vitamin C.
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Keywords
Corporación Universitaria Lasallista, Guayaba pera, Guayaba - Procesamiento, Secado - Alimentos, Secado - Alimentos - Métodos