Application of Chokeberry Pomace in the Production of Extruded Snack Products

Trop aronije predstavlja kruti ostatak nakon prešanja aronije. Ovaj vrijedni nusproizvod bogat je izvor prvenstveno polifenolnih komponenti, ali i prehrambenih vlakana, vitamina i minerala. Cilj ovog diplomskog rada je ispitati mogućnost primjene tropa aronije u proizvodnji ekstrudiranih snack proizvoda na bazi kukuruzne krupice. Osušeni trop aronije dodavan je u kukuruznu krupicu u udjelima 4, 8 i 12 % s. tv. te su zamjesi pripremljeni na 15 % vlage i ekstrudirani u laboratorijskom jednopužnom ekstruderu uz primjenu parametara ekstruzije prikladnih za proizvodnju direktno ekspandiranih snack proizvoda. Rezultati ovog istraživanja pokazuju kako se dodatkom nusproizvoda tropa aronije smanjio ekspanzijski omjer i tvrdoća, nasipna masa ekstrudata se povećala, dok se lomljivost nije značajno promijenila. Također, dodatak tropa aronije kao i sam postupak ekstruzije iznimno su utjecali na boju ekstrudata. Procesom ekstruzije se značajno povećao indeks apsorpcije i indeks topljivosti u vodi te je došlo do smanjenja udjela netopljivih vlakana, a povećanja udjela topljivih vlakana. Proces ekstruzije uzrokovao je smanjenje udjela ukupnih polifenola i antioksidativne aktivnosti kod većine uzoraka.The chokeberry pomace is a solid residue after pressing the chokeberry. This valuable by-product is primarily a rich source of polyphenolic components, but also dietary fiber, vitamins and minerals. Therefore, the aim of this thesis is to examine the possibility of using chokeberry pomace in the production of extruded snack products based on corn grits. Dried chokeberry pomace was added in proportions of 4, 8 and 12%, in production of corn snack products. These mixtures were prepared at 15% moisture and extruded in a laboratory single-screw extruder using extrusion parameters suitable for the production of expanded snack products. The results of this study show that the addition of chokeberry pomace decreased the expansion ratio and hardness, the bulk density of the extrudate increased, while the fracturability did not change significantly. Also, the addition of chokeberry pomace as well as the extrusion process itself had an exceptional effect on the color of the extrudates. The extrusion process significantly increased the water absorption index and water solubility index, and the content of insoluble fibers decreased, while the content of soluble fibers increased. The extrusion process caused a decrease in the content of total polyphenols and antioxidant activity in most samples