Optimization of the extrusion parameters for the production of lentil-quinoa extrudates enriched with pumpkin

This study aimed to develop a protein-fiber-rich extruded product based on yellow lentil, quinoa, and pumpkin flours. The final product quality is affected by formulation and extrusion parameters. Therefore, the effect of the pumpkin-flour ratio (A: 25-75%) and feed moisture content (C: 14-22%) besides barrel screw speed (B: 120-180 rpm) on the physical attributes of extrudates was investigated. Box-Behnken experimental design and stepwise-response surface method were used to analyze the effects of various process variables and ingredients on extrudates. The pumpkin-flour ratio had a significant positive correlation with bulk density (BD), water solubility index (WSI), and oil absorption index. Whereas the correlation between pumpkin-flour ratio with hardness, porosity, expansion ratio (ER), and water absorption index (WAI) was negative (P < 0.05). The feed moisture content positively affected the water activity (aw) and WAI and negatively affected the harness of samples (P < 0.05). The screw speed had a positive effect on ER, porosity, and WSI, whereas it negatively influenced the hardness, BD, and aw. By increasing the pumpkin-flour ratio, air cell size and wall thickness of samples had been decreased. The results showed that 44.2% pumpkin flour, 22% feed moisture, and 172.1 rpm screw speed gave an optimized product. There was no significant difference between predicted and experimental values (except for ER). The optimized snack was a good source of fiber (around 15%), protein (17.3%), and antioxidants (TPC = 15.28 mg GAE.g-1 and antiradical scavenging activity (DPPH) = 33.66%). The caloric value of the optimized snack was 362.6 cal.100g-1. The current formulation can be considered as the base of snack food or plant-based meat alternatives.

CHARACTERISTICS OF BREAD DOUGH MADE WITH THE USE OF VARIOUS MILLET FLOURSCHARACTERISTICS OF BREAD DOUGH MADE WITH THE USE OF VARIOUS MILLET FLOURS

Millets are gaining attention due to their many advantages in cultivation and overall nutritional benefits. Research has been carried out to explore the nutritional properties of various millets. However, the use of millets in today’s food processing is minimal as compared to wheat. Three minor millets, namely foxtail, proso, and pearl millets grown in Iran were used in this study. The  water  absorption characteristics and hardness of these millets have been investigated. The effect that millet flours incorporated in dough have on its rheology has been studied and compared with the effect of wheat on dough rheology. The moisture content of millets increased with an increase in the water temperature, and a regular increase in the water absorption capacity, too, was observed as the temperature rose. The hardness of the millet decreased with an increase in the moisture content of the grains. Pearl millet has been found to have the lowest hardness irrespective of the steeping time and temperature. Incorporation  of millet in the dough adversely affected the dough rheology in terms of workability and baking quality. Proso millet highly negatively affected the dough rheology in terms of dough hardness, stability, and dynamic rheological properties. This research highlights the possibility to predict the water absorption characteristics of millet grains to be used to optimise the conditions under which millets are steeped in various bioprocessing operations. It is supposed that on performing proper baking trials to compare the properties of composite flours made from these millets, the results of the rheological studies will prove beneficial and the rheological properties and behaviour will be accurately correlated when the food is applied practically.