Raspberry powder production technology based on heat exchange

U posljednje vrijeme na tržištu se javlja sve veća potražnja za suhim prahom od voća zbog široke mogućnosti njegove primjene. Tehnologiju proizvodnje suhog praha je potrebno prilagoditi i oblikovati s ciljem što boljeg zadržavanja kvalitete i nutritivnih karakteristika finalnog proizvoda. Jedan od postupaka termičke dorade u procesu proizvodnje suhog praha je konvekcijsko sušenje do ravnotežne vlažnosti. Pored navedenoga, tehnologija proizvodnje praha od malina iznimno je zahtjevna i uključuje postupke: prihvata, čišćenja, pranja, ocjeđivanja, inspekcije, sušenja, kondicioniranja, usitnjavanja, vaganja, pakiranja i skladištenja. Cilj ovoga rada bio je utvrditi kvalitativne (fizikalno - kemijske) karakteristike plodova prije i nakon termičkog procesa konvekcijskog sušenja, kao i utjecaj temperature sušenja na kvalitetu finalnog proizvoda. Plodovi malina s početnim udjelom vode od 87,17 % osušeni su u laboratorijskom sušioniku „INKO” ST 40 pri temperaturi od 40 °C i atmosferskom tlaku 1013 hPa do postizanja sadržaja vode od približno 15 %. Iz dobivenih rezultata vidljivo je da tijekom proizvodnje suhog praha u finalnom proizvodu došlo do smanjenja udjela vitamina C za 85,59 %, ukupnih fenola za 32,32 %, flavonoida za 40,09 %, neflavonoida za 24,61 %, antocijana za 2,78 % i antioksidacijskog kapaciteta za 18,98 %. Iz čega se može zaključiti da parametri sušenja značajno utječu na sadržaj pojedinih bioaktivnih spojeva.Recently, there has been an increasing demand for dry fruit powder on the market due to its wide range of applications. The technology of dry powder production needs to be adapted and shaped with the aim of maintaining the quality and nutritional characteristics of the final product as well as possible. One of the thermal finishing procedures in the dry powder production process is convection drying to equilibrium humidity. In addition to the above, the technology of raspberry powder production is extremely demanding and includes the following procedures: acceptance, cleaning, washing, draining, inspection, drying, conditioning, shredding, weighing, packaging and storage. The aim of this work was to determine the qualitative (physical-chemical) characteristics of the fruits before and after the thermal process of convection drying, as well as the influence of the drying temperature on the quality of the final product. Raspberry fruits with an initial water content of 87,17 % were dried in a laboratory dryer "INKO" ST 40 at a temperature of 40 °C and an atmospheric pressure of 1013 hPa until a water content of approximately 15 % was reached. From the obtained results it is evident that during the production of dry powder in the final product there was a decrease in the proportion of vitamin C by 85.59 %, total phenols by 32,32 %, flavonoids by 40,09 %, non-flavonoids by 24,61 %, anthocyanins by 2,78 % and antioxidant capacity by 18,98 %. From which it can be concluded that drying parameters significantly affect the content of individual bioactive compounds