The effect of spray drying on physico-chemical parameters of prickly pear juice

Cilj ovog istraživanja bio je provesti sušenje raspršivanjem uz pomoć tri različita nosača, maltodekstrina, arapske gume i chitosana te mješavine ova tri sredstva kako bi ispitali utjecaj na fizikalno-kemijske parametre. Prije sušenja raspršivanjem, uzorci soka su karakterizirani vrijednostima pH (3.5-4.7), °Brix (4.5-13) viskoznosti, boja (L*20.30-21.04, a*0.52-2.12, b*-1.14-1.52), reducirajući šećeri (6.15-9.76 g/100g soka) i sadržaj ukupnih fenola (96.97-236.88 mg/100g soka). Vlažnost (prah sa 10% AG, niska vlažnost), aktivitet vode (prah mješavina najniže vrijednosti), veličina čestica, topljivost i boja (L*31.35-35.93, a*21.84-35.61, b*-7.27-10.29), iskorištenje (50.2-69.8), reducirajući šećeri (39.42-61.45 g/100g praha) i sadržaj ukupnih fenola (783.63-1953.38 mg/100g praha) analizirani su u dobivenom prahu. Sok indijske smokve sadrži 9.76 mg/100g reducirajućih šećera i 236.9 mg/100g ukupnih fenola. Na veličinu čestica praha utječe odabir enkapsulirajućeg sredstva. Prah sa 10% arapske gume je najtopljiviji. Prah sa 1.25% chitosana sadrži najveći udio reducirajućih šećera i ukupnih fenola. Dobiveni prahovi bi se mogli upotrebljavati kao bojila i/ili visokovrijedni prehrambeni aditivi u razvoju novih proizvoda i na taj način promovirati proizvode sa visokim udjelom bioaktivnih tvari.The aim of this thesis was to conduct spray drying of prickly pear juice with maltodextrin, Arabic gum, chitosan and a mixture of the three encapsulating agents and to study the effect on physico-chemical parameters. Before spray drying, juice solutions were characterized in terms of pH (3.5-4.7), °Brix (4.5-13), viscosity, color (L*20.30-21.04, a*0.52-2.12, b*-1.14-1.52), reducing sugars (6.15-9.76 g/100g juice) and total phenolic content (96.97-236.88 mg/100g juice). Humidity (powder with 10% AG, low humidity), water activity (mixture powder showed lowest values) particle size, solubility and color (L*31.35-35.93, a*21.84-35.61, b*-7.27-10.29), yield (50.2-69.8), reducing sugars (39.42-61.45 g/100g powder) and total phenolic content (783.63-1953.38 mg/100g powder) were analyzed in the obtained powders. Prickly pear juice presented values of 9.76 mg/100g of juice and 236.9 mg/100g of reducing sugars and total phenolic content, respectively. Particle size showed to be affected by type of encapsulating agents. In terms of solubility the powder with 10% Arabic gum showed to be the most soluble. Powder with 1.25% chitosan showed the highest amount of reducing sugars and total phenolic content. The obtained powders can be used as colorants and/or valuable food additives in the development of new food product formulations and thus promote products with high content of bioactive compounds