Breaking Strength Index Research Articles

Effect of extrusion processing and hydrocolloids on the stability of added vitamin B12 and physico-functional properties of the fortified puffed extrudates

An alarming rate of increase in the prevalence of vitamin B12 deficiency has generated the demand for fortified foods therewith. This work focused on the development of vitamin B12 fortified rice extrudates wherein the effect of extrusion variables viz. die temperature (oC), screw speed (rpm) and feed rate (kg/h) on the stability of vitamin B12 and physico-functional properties were evaluated. The stability of vitamin B12 was greatly affected by die temperature and unaffected by screw speed and feed rate. The product with best physico-functional properties as obtained from experimental design (168 °C/229 rpm/4.6 kg/h) gave 54% retention of vitamin B12, while the product with best retention of 77% vitamin B12 (140 °C/150 rpm/4 kg/h) gave extrudates with low expansion ratio, WAI, WSI and high bulk density, hardness, breaking strength index and fracturability. To achieve the desirable combination of high retention of vitamin B12 and best physico-functional properties, hydrocolloids such as guar gum, xanthan gum or carboxymethyl cellulose were added at 5 and 10 g/kg of rice flour. Although all the hydrocolloids improved the physico-functional properties without affecting vitamin B12 stability, carboxymethyl cellulose at 5 g/Kg is recommended for such fortified snacks.

Production and quality evaluation of extruded snack from blends of bambara groundnut flour, cassava starch, and corn bran flour

Protein dense, fiber-rich extruded snacks were produced from blend of bambara groundnut flour, cassava starch, and corn bran flour using a single screw cooking extruder. The snacks were analyzed for their physical properties and proximate composition using standard laboratory procedures. The expansion ratio, specific volume, breaking force, and breaking strength index (BSI) of the snacks ranged from 0.85 to 1.22, 0.75 to 1.30 g/cm3, 3.95 to 36.45 N, and 0.99 to 9.11 N/mm, respectively. The breaking force and BSI were high and increased at increasing levels of cassava starch and corn bran inclusion. Moisture, protein, fat, carbohydrates, crude fiber, and total dietary fiber contents of the snacks were 5.40–10.80, 3.26–17.62, 0.68–10.35%, 60.56–85.03, 0.32–4.78, and 7.36–28.74%, respectively. The study revealed a great potential of obtaining a nutrient dense extruded snack from underutilized plant commodity (bambara groundnut) and waste from corn milling (corn bran).

Modeling the Inclusion of Fish Powder and Fish Oil into Extruded Snacks by Response Surface Methodology

ABSTRACTExtrusion cooking plays an important role in the production of puffed snacks, which enjoy wide acceptance all over the world and are potential vehicles for increasing the consumption of n-3 fatty acids. Response surface methodology (RSM) with central composite design was adopted to investigate the effects of four independent variables (fish powder, fish oil, moisture, and screw speed) at five levels on expansion ratio, breaking strength index, hardness, color, and thiobarbituric acid reactive substances (TBARS). A second order polynomial model was used to study the main, interactive, and quadratic effects of the independent variables and to explain the relationship between the responses and independent variables. Moisture was found to be the most significant factor (p < 0.001) influencing expansion ratio, breaking strength index, and color. Inclusion of fish powder and fish oil were found to be negatively associated with the expansion characteristics, resulting in decreased lipid oxidation due to less exposed surface area of the extrudates to air. Further, the absence of linear effect of fish powder and fish oil on TBARS demonstrated the possibility to incorporate higher levels of these ingredients to produce oxidatively stable extruded snacks rich in fish proteins.