Efekti osmotske dehidratacije na poboljšanje održivosti, nutritivna i antioksidativna svojstva korena i lista celera (Apium graveolens)

Abstract

U ovom radu proučavana je osmotska dehidratacija korena i lista celera u dva različita osmotska rastvora: vodenom rastvoru saharoze i natrijum hlorida i melasi šećerne repe. Ispitivan je uticaj temperature procesa (20°C, 35°C i 50°C) i vremena imerzije (1, 3 i 5h) na gubitak vode, priraštaj suve materije, sadržaj suve materije, vrednosti aktivnosti vode, promenu antioksidativne aktivnosti, promenu boje i promenu mineralnog sastava (K, Mg, Ca, Fe) tokom osmotske dehidratacije korena i lista celera. Dokazano je da se povećanjem temperature i produženjem vremena trajanja procesa pospešuje prenos mase tj. migracija molekula vode iz tretiranog biljnog materijala u okolni rastvor, i prodiranje molekula rastvorene supstance iz osmotskog rastvora u tretirano biljno tkivo. Snižene aw vrednosti u svim ispitivanim uzorcima ukazuju na pozitivan uticaj osmotske dehidratacije na mikrobiološku stabilnost tretiranog korena i lista celera, što je potvrdila i mikrobiološka analiza. Nasuprot rastvoru saharoze i natrijum hlorida koji je uticao na opadanje ukupne antioksidativnosti osmotski dehidriranih uzoraka, melasa šećerne repe, kao bogat izvor prirodnih antioksidanasa, doprinosi povećanju antioksidativnosti i poboljšanju funkcionalnog kvaliteta dehidriranog produkta. Usled transfera bojenih materija (melanoidina) iz melase, dolazi do tamnjenja tretiranih uzoraka. Bojene materije iz melase, zbog svojih antioksidativnih svojstava takođe doprinose poboljšanju antioksidativnosti krajnjeg produkta. Dobijeni rezultati su pokazali značajno poboljšanje mineralnog sastava korena i lista celera, dehidriranih u melasi šećerne repe, dok je kod uzoraka tretiranih u rastvoru saharoze i natrijumhlorida uočeno smanjenje sadržaja ispitivanih mineralnih materija. Statističkom obradom rezultata, uočeno je da su optimalni procesni parametri u pogledu efikasnosti procesa, kao i mikrobiološkog, nutritivnog, senzornog i funkcionalnog kvaliteta osmotski dehidriranog korena i lista celera, vreme trajanja procesa od 5h, na temperaturi od 50°C, u melasi šećerne repe kao osmotskom rastvoru.

In this thesis, the osmotic dehydration of celery leaves and root in two different osmotic solutions (sucrose and sodium chloride dissolved in water and sugar beet molasses), was investigated. The effect of process temperature (20°C, 35°C i 50°C) and immersion time (1, 3 and 5h) on water loss, solid gain, dry matter content, value of water activity, change of antioxidant activity, change of color parameters and change of mineral composition (K, Mg, Ca, Fe) was investigated. It was found that increasing of process temperature and immersion time enhance mass transfer, intesifying migration of water molecules from the treated plant material into the surrounding solution and penetration of dissolved substances molecules from the osmotic solution into the treated plant tissue. Reduced aw values in all examined samples indicate a positive effect of osmotic dehydration on the microbiological stability of the treated celery leaves and root, which was also confirmed by the microbiological analysis. Contrary to the solution of sucrose and sodium chloride, which was contributed to the decrease in total antioxidantivity of osmotically dehydrated samples, sugar beet molasses, as a rich source of natural antioxidants, contributed to an increase in antioxidant activity and an improvement in the functional quality of the dehydrated products. Due to the transfer of colored substances (melanoidins) from the molasses, the color of treated samples was darker. The colored substances from molasses, due to their antioxidant properties, also contribute to the enhancement of the antioxidativity of the final product. The results showed a significant improvement of the mineral content of celery leaves and root dehydrated in sugar beet molasses, while the samples treated in sucrose and sodium chloride solution show reduction of the examined mineral matters. Statistical analysis revealed that optimal process parameters in terms of process efficiency, as well as the microbiological, nutritive, sensory and functional quality of the osmotically dehydrated celery leaves and root were: the process time of 5 hours, at a temperature of 50°C, in sugar beet molasses as an osmotic solution.