Η υψηλή διατροφική αξία του φραγκόσυκου (Opuntia ficus-indica) τα τελευταία χρόνια έχει προσελκύσει το ερευνητικό ενδιαφέρον. Οι περισσότερες μελέτες επικεντρώνονται στον καρπό ενώ υπάρχουν ενδείξεις για πλήρη εκμετάλλευση του φυτού. Σκοπός της παρούσας μεταπτυχιακής μελέτης είναι η διερεύνηση των επιδράσεων της ξήρανσης στα φυσικά χαρακτηριστικά του βλαστού και του καρπού φραγκοσυκιάς έτσι ώστε να παραχθούν αφυδατωμένα προϊόντα με αποδεκτά χαρακτηριστικά ώστε να διατηρούνται για μεγαλύτερο διάστημα και για πιθανή ενσωμάτωση σε τρόφιμα, όπως μπισκότα. Στόχος είναι η εύρεση τρόπων αξιοποίησης του φυτού αυτού, το οποίο μπορεί να αναπτυχθεί σε πληθώρα διαφορετικών συνθηκών, και μάλιστα σε ξηρές περιοχές, όπως είναι το μεγαλύτερο μέρος της Ελλάδας.
In recent years the high nutritional value of Opuntia ficus-indica has attracted
research interest. Most studies concentrate on the fruit while there are indications of
exploitation of the whole plant too. Purpose of this study was to investigate the effects
of drying on the physical characteristics of the fruit and cladodes so as to produce
dehydrated products with acceptable characteristics to maintain for a longer time and
for possible use in foods, such as biscuits. The aim is to find ways to exploit this
plant, which can grow in a variety of different conditions - especially in dry areas,
such as a large part of Greece - whose cladodes is used in Greece only for animal feed
so far.
Initially, drying of cladodes was carried out by various drying methods in order to
select the most suitable one. Cladodes were dried by hot-air-drying and lyophilization
methods, and fruits were dried by spray drying and lyophilization methods.
Composition, colour, solubility, density, moisture and water activity and other
physical characteristics of the flour produced were determined.
Best results in drying of cladodes were obtained by lyophilization, which creates a
safe microbial product with high fiber content that has retained its colour. Drying of
fruit was done by the addition of maltodextrin at concentrations of 25% and 35%. In
drying of fruits, lyophilization products exhibit better physical properties than those of
spray drying with lower moisture and water activity and better colour preservation
while solubility has high values in all samples. After reconstitution of the juice, it is
observed that the colour has not changed, indicating the preservation of pigments.
