Shalini Gaur Rudra

Effect of Extrusion Processing on Phenolics, Flavonoids and Antioxidant Activity of Millets

The study was aimed to evaluate the effect of different extrusion treatments on total phenolic content, total flavonoids and antioxidant activity of finger millet and sorghum. The flours were subjected to eight different extrusion treatments at varying feed moisture, die head temperature and screw speed. Statistical analysis revealed that the total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity (FRAP, DPPH, TEAC) of extruded finger millet and sorghum flours was reduced significantly (p < 0.05) over their native counterparts. However, extrusion at high feed moisture, low temp and high screw speed (HM/LT/HS) retained considerable percentage of bioactives. Maximum retention of TPC, TFC and FRAP was observed as: 54%, 78% and 57% in finger millet respectively and 87%, 89% and 86% in sorghum, respectively. High retention of bioactives in extruded millet flours demonstrated their enormous potential for the development of phenolic and antioxidant rich ready-to-eat snacks.

Extrusion Conditions Effects Functional and Pasting Properties of Finger Millet

Extrusion Conditions Effects Functional and Pasting Properties of Finger Millet Extrusion is an effective tool for modifying functionality of coarse cereals for various food applications. Response surface methodology (RSM) was used to evaluate the effect of different extrusion variables on functional and pasting properties of finger millet. The experiment was conducted using a five level Central Composite Design (CCD).The expansion ratio (EX) of extrudates was found to significantly increase with decreasing feed moisture and increasing barrel temperature. Increasing feed moisture significantly (p 0.05) effects on responses. WAI and WSI of extruded flour increased specifically by 2.0 to 14.0 fold over raw flour. WAI had a significant negative linear association (r=-0.96, p<0.01) with WSI and a positive linear correlation with peak and final viscosity. Results suggest that tailoring extrusion conditions offer opportunity for obtaining finger millet extrudates and pregelatinized flour with varied functionality...

Phenolics, Antioxidant and Pasting Properties of Various Pearl Millet and Finger Millet varieties Varying in Amylose Content

Pearl millet and fingermillet are micronutrient rich staple foods for millions in arid regions of Asia and Africa. India being the largest producer of these millets, extruded products based on these can ensure both food and economic security amongst the malnutrition prone areas. Of the total phenols in pearlmillet (720–874 mg GAE/100g), approximately 40% of the phenols were present in the free form. While in fingermillet, total phenols ranged from 326–743.8 mg GAE/100 g, with approximately 48% in the free form. Positive correlations were found between phenols and antioxidant activity of millets through CUPRAC assay (p=0.00) and FRAP assay (p=0.005). The effect of starch composition in terms of amylose level on the pasting properties of four pearl millet varieties and ten fingermillet varieties was analysed and correlated to their X ray diffraction pattern. Amylose content showed a negative correlation to the percentage crystallinity, while it showed positive correlation to the pasting temperature (p< 0.05). X ray diffraction was found to give more accurate correlation to the pasting properties compared to amylose especially for fingermillet varieties. Percentage crystallinity had a negative correlation to the pea viscosity, holding strength, breakdown viscosity, final viscosity and setback from peak. The findings of this study formidate the effect of amylose content in raw material on the cooking attributes flours and shall prove to be a useful tool for industrial product development and design from the pearl millet and fingermillet sources.