Quality evaluation of millet-soy blended extrudates formulated through linear programming

Effects of Wet Processing on Physicochemical and Functional Characteristics of Millet Flour

In recent times, millet emerged as a gluten-free alternative cereal with a rich nutritional profile. However, the nutritional value is hindered by antinutritional factors, like tannin and phytic acid, present in the grain. In the current work, wet pre-processing methods, namely steeping, fermentation, germination, and a combination of germination-fermentation were studied for their effect on these antinutritional factors along with other functional and chemical properties of millet flour. Starch hydrolysation due to these wet pre-treatments was found to improve various aspects of the functional properties of millet flour. Steeping and fermentation resulted in increased protein and fat fraction in the treated flour with better water absorption capacity and hygroscopicity. At the same time, germination improved the protein and fibre content with better water solubility and oil absorption capacity. The aqueous environment during these pre-treatments was also found to reduce gelatinisation temperature and content of antinutritional factors in the treated flour samples. The present study indicated that wet pre-processing could be a good value addition to millet flour preparation with better functional and nutritional properties.

Development of grain-based carbonated beverage premix using maize (Zea Mays), Bengal gram (Cicer Arietinum), and finger millet (Eleusine Coracana)

A grain based carbonated beverage premix with adequate nutritional composition and fizzing effect in the form of dry powder has been developed in the current study. Maize and Bengal gram were roasted at temperature 160-180 °C while finger millet at 80-120 °C for 10-30 min. The optimized conditions for the roasting of maize, Bengal gram and finger millet were 180 °C for 10 min, 180 °C for 27 min and 110 °C for 30 min, respectively using face centred composite design and response surface methodology (RSM). The formulation of the beverage premix obtained using linear programming was in the proportion of 30 g, 30 g, 10 g, 20 g and 10 g of roasted maize, Bengal gram, finger millet flours, sugar (powdered) and pea protein isolate, respectively. The effect of carbonation was found to be best with 8% carbonation powder concentration and 1:4 beverage premix to water ratio which showed an overall acceptability of 7.7. The developed carbonated beverage premix was light in color with a positive L* value of 79.01 ± 0.12 and slightly acidic with a pH of 5.56 ± 0.10. The nutritional composition of the final product comprised of 16% protein and several minerals viz. Fe (11.67 mg/100 g), Ca (36.67 mg/100 g) and Mg (86.26 mg/100 g).

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13197-021-05175-5.

Investigation of functional properties and color changes of corn extrudates enriched with broccoli or olive paste

Following the tendency of replacing common food snacks with healthier food products, extruded snacks with corn flour and broccoli (4-10%) or olive paste (4-8%) were investigated in this study. The effect of material characteristics, including feed moisture content (14-19%), and broccoli or olive paste concentration, and extrusion conditions, including screw speed (150-250 r/min), and extrusion temperature (140-180 ℃), on the functional properties (water absorption index, water solubility index, and oil absorption index), as well as color change (ΔE) of the extruded snacks was studied. Regression analysis showed that screw speed did not significantly influence (p > 0.05) the properties. After mathematical modelling it was found that broccoli and olive paste concentration, as well as temperature increment, caused a decrease in water absorption index (minimum of 5.6 and 6.4 g/g sample, respectively) and an increase in water solubility index (maximum of 18.7 and 10.9 g/100 g sample, respectively), while feed moisture presented opposite tendency. Higher extrusion temperature led to an increment of oil absorption index (approximately to 1.2 and 1 mL/g sample) and decrement of color changes. Finally, feed moisture and broccoli concentration lowered oil absorption index and color of corn/broccoli extrudates, while olive paste concentration caused their increment.