Optimization of Extrusion Cooking Process for Rice-Fish Extrudates with an Underutilized Fish Mince Based on Physical, Functional and Textural Properties

Abstract

Extrudates were prepared with Sea bass, an underutilized fish and rice flour using a twin screw extruder. Different process parameters viz. moisture content of feed (10%, 15%, 20% and 30%), fish content in feed (10%, 15%, 20% and 30%) and barrel temperatures (100°C and 110°C) were used for extrusion. The physical properties viz., bulk density, expansion ratio and moisture content of extrudates, functional properties such as water absorption index, water solubility index and textural properties of the extrudates were studied. The results shown that the expansion ratio and bulk density of the extrudates were in the range from 2.85 to 4.10 and 130 to 225 kg/m3 respectively. The WAI and WSI of the extrudates varied from 5.2 to 6.7g•g-1 and 17% to 30% respectively. Maximum hardness was observed at 30% feed moisture, 30% fish mince content and 110°C barrel temperature. Analysis of Variance (ANOVA) revealed that all the process parameters significantly affected the physical, functional and textural properties of extrudates. The optimum process parameter to extrude rice fish extrudates were obtained at 10% feed moisture, 10% fish content and barrel temperatures of 110°C.

Ekstrudati su pripremljeni od neiskorišćenih delova brancina i pirinčanog brašna pomoću dvopužnog ekstrudera. Različiti parametri procesa: sadržaj vlage u hrani (10%, 15%, 20% i 30%), procenat količine ribe u hrani (10%, 15%, 20% i 30%) i temperatura (100 °C i 110 °C) su menjani pri ekstrudiranju. Proučavane su fizičke osobine: gustina, nivo ekspanzije i sadržaj vlage ekstrudata, kao i funkcionalna svojstva kao što su: indeks apsorpcije vode, indeks rastvorljivosti u vodi i teksturna svojstva ekstrudata. Rezultati su pokazali da su odnos ekspanzije i gustina ekstrudata u opsegu od 2.85 do 4.10 i 130 do 225 kg•m-3, redom. WAI i WSI ekstrudata variraju od 5.2 do 6.7 g•g-1 i 17% do 30%, respektivno. Najveća tvrdoća je primećena na 30% vlage u hrani, 30% riba mlevenog sadržaja i temperaturi od 110°C u cevi. Analiza varijanse (ANOVA) je pokazala da su svi parametri procesa značajno uticali na fizička, funkcionalna i teksturna svojstva ekstrudata. Optimalni parametri procesa ekstruzije pirinča i ribe su iznosili: vlaga u hrani 10%, sadržaj ribe 10% i temperaturi u cevi od 110°C.