Influence of temperature and additives on physical, chemical and sensory properties of corn extrudates

Cilj ovog rada bio je primjena različitih vrsta sušenog povrća (rajčice, mrkve i bundeve) i askorbinske kiseline u svrhu unaprjeđenja i razvoja ekstrudiranih snack proizvoda. Provedeno je praćenje utjecaja ekstruzije na fizikalne i kemijske promjene pojedinih sastojaka proizvoda. Rezultati su pokazali kako primjena višeg temperaturnog režima procesa ekstruzije (135/170/170 °C) povoljnije utječe na fizikalna svojstva ekstrudata od nižih temperatura (100/150/150 °C). Dodatak povrća i askorbinske kiseline djelovao je na smanjenje tvrdoće, lomljivosti i ekspanzije ekstrudata, a na povećanje nasipne mase. Dodatkom povrća proizveden je proizvod sa povećanim udjelom pepela, vlakana, proteina, polifenola i antioksidativne aktivnosti, a sa smanjenim udjelom masti u odnosu na ekstrudate od čiste kukuruzne krupice. Ksantofili su stabilniji od karotena tijekom ekstruzije, a dodatak askorbinske kiseline smanjio je degradaciju karotenoida uslijed djelovanja termomehaničkih uvjeta u ekstruderu. Ekstrudati proizvedeni pri višoj temperaturi ekstruzije dobili su vrlo visoke ocjene pri senzorskom ocjenjivanju.The aim of this research was the use of different dried vegetables (tomato, carrots and pumpkins) and ascorbic acid in order to enhance and develop the production of extruded snack products. Research of extrusion influence on physical and chemical changes of product ingredients is done. Results showed that applying higher temperature of extrusion process (135/170/170 °C) had favourable effect on physical properties of extrudates compared to lower temperature (100/150/150 °C). The addition of vegetables and ascorbic acid resulted in decreased hardness, fracturability and expansion, but increased bulk density of extrudates. The addition of vegetables produced product with a higher share of ash, fibre, proteins, polyphenols and antioxidant activity, but lower fat compared to pure corn extrudates. Xanthophylls were more stable than carotenes during extrusion. Ascorbic acid reduced carotenoid degradation due to thermomechanical conditions within the extruder. Extrudates produced at higher extrusion temperature had high marks in sensory evaluation