Influence of protein level and starch type on an extrusion‐expanded whey product

Abstract

A whey-based puffed snack food was produced on a twin-screw extruder to determine the effect of varying starch type (normal corn and pregelatinised waxy), protein type (regular and instantised whey protein concentrate) and protein concentration (16%, 32% and 40%) on the physical and chemical characteristics of an extruded-expanded snack food. Increasing protein concentration and normal cornstarch significantly reduced extrudate expansion ratio, air cell size, water solubility index and increased extrudate density, and breaking force. Protein concentration and starch type significantly affected the water absorption index and water-soluble carbohydrate. Total soluble protein was influenced by protein concentration and the interaction of starch type and protein type. With normal corn starch, a covalent complex between amylose and protein was likely formed while protein:protein interactions were favoured with low pregalatinised waxy starch concentrations.

Effects of process parameters on the properties of barley containing snacks enriched with brewer’s spent grain

“…Addition of WPI increased expansion also in the studies of Agbisit (2007) and Kirjoranta et al (2012). On the contrary, in the studies of Matthey and Hanna (1997); Onwulata et al (1998Onwulata et al ( , 2001 and Allen et al (2007) addition of whey protein concentrate (WPC) decreased expansion of extrudates. It has been speculated that other components in WPC, such as lactose, caused low expansion (Onwulata et al 2001).…”

“…26 %), which has a mainly linear structure (Moraru and Kokini 2003). It has been suggested that linear amylose molecules may align themselves or form complexes with other molecules such as whey proteins by hydrogen bonds causing decrease in expansion and increase in hardness (Allen et al 2007;Matthey and Hanna 1997). On the contrary, with waxy starch, protein-protein interactions are favoured instead, which is found to increase expansion and decrease hardness (Allen et al 2007;Matthey and Hanna 1997).…”

“…Similarly, extrudates made of waxy corn starch had higher expansion and smaller hardness than extrudates made of regular corn starch (Allen et al 2007;Matthey and Hanna 1997). Waxy starch contains mostly amylopectin which is a branched molecule whereas regular starch contains also amylose (ca.…”

“…In order to produce snacks with high protein content whey proteins have been previously used as additives in extruded snacks (Agbisit 2007;Allen et al 2007;Brnčić et al 2011;Cheng et al 2007;Kirjoranta et al 2012;Matthey and Hanna 1997;Onwulata et al 1998Onwulata et al , 2001aOnwulata and Konstance 2006;Taylor et al 2006). However, there are no published studies, in which whey proteins have been used together with BSG and whole grain barley flour.…”

Extrusion of blends of cassava leaves and cassava flour: physical characteristics of extrudates

“…Fibers also affect the expansion of the product. Fibrous fragments disrupt the starchy film of air cell walls, reducing their formation and swelling and altering air cell size (Huber, 2001;Allen et al, 2007).…”