Characteristics of resistant starch in water chestnut flour as improved by preconditioning process

Development of low glycemic index instant Phirni (pudding) mix-its visco-thermal, morphological and rheological characterization

High amylose rice (HAR) and carboxymethyl cellulose (CMC) are the preferred choices for enhancement of resistant starch content and lowering of glycemic index in dairy desserts. The effects of different levels of skimmed milk powder (SMP): HAR flour (45:55 to 75:25) and CMC (0.1 to 1%) were investigated on physical characteristics of dry-mix and on texture profile parameters, resistant starch (RS), predicted glycemic index (pGI), glycemic load (GL) and overall acceptability of phirni (a traditional milk pudding). Design expert predicted SMP (70): HAR (30) and CMC (0.8%) as optimum levels for reducing the pGI and maximizing the RS content and other quality characteristics in phirni. RS content of phirni (4.38%) prepared from optimized dry-mix (ODM) was higher while pGI (48.12) and GL (7.50) were lower as compared to phirni prepared from market dry-mix (MDM). The visco-thermal properties of ODM and MDM also showed significant variations. Storage modulus (Gʹ) and loss modulus (Gʹʹ) indicated that ODM phirni was less solid than MDM phirni. Scanning electron micrographs showed fused structures in ODM, while coarse sheet like structures were observed across the surface of MDM. Thus, ODM can be a promising substitute for the available milk desserts for diabetic patients.

Enrichment in Different Health Components of Barley Flour Using Twin-Screw Extrusion Technology to Support Nutritionally Balanced Diets

Due to its good dietary role, barley has attracted a growing amount of interest for the manufacture of functional foods in recent years. In barley, a number of bioactive components, including as phenolic compounds, have been discovered, and barley extrudates could be used to formulate various processed foods, including ready-to-eat cereals, baby, and pet foods and support nutritionally balanced diets. This study was conducted to investigate the effect of extrusion processing on resistant starch (RS), glycemic index (GI), and antioxidant compounds of barley flour. The L^* and ΔE values of barley flours decreased significantly (p < 0.05) after extrusion is done at 150 and 180°C. The a^* and b^* values, however, increased after extrusion. Extrusion increased antioxidant activity (AOA), metal chelating activity (MCA), and ABTS⁺ scavenging activity, whereas total phenolic content (TPC) and total flavonoids content (TFC) decreased. Barley extrudates at 150 and 180°C showed decreased TPC by 16.4–34.2% and 23.4–38.1%. Moreover, improved RS and reduced GI values were recorded for barley extrudates as compared to barley non-extrudates. Therefore, extrusion of barley could be an alternative to produce pregelatinized barley flour with improved RS low GI values and improved antioxidant potential.

Visco-thermal and structural characterization of water chestnut flour

In order to increase flour recovery, resistant starch content and to lower the glycemic index and glycemic load, the water chestnuts were subjected to pre-optimized conditions of pre-conditioning. The low glycemic index water chestnut flour (F1) obtained thereafter was analyzed for different functional, viscous, thermal and structural properties. F1 exhibited improved functional properties due to gelatinization of starch followed by retrogradation during pre-conditioning which confirms its feasibility for development of diverse food products in comparison to commercially available market flour (F2). Pasting properties-peak viscosity, hold viscosity, breakdown viscosity, final viscosity and set back viscosity (SBV) were found significantly (p < 0.01) higher in case of F1 than F2. Higher peak viscosity of F1 can be accorded to its higher swelling capacity than F2. Further, higher SBV of F1 suggests its susceptibility towards retrogradation and gel formation. Differential scanning calorimetry results revealed that gelatinization temperature, endothermic peak width, onset, peak and conclusion temperatures were significantly (p < 0.01) lower, whereas enthalpy of gelatinization and peak height index were significantly (p < 0.01) higher in case of F1 as compared to F2. Lower gelatinization transition temperatures of F1 could be attributed to its more water absorption ability than F2 which suggests its potential as a thickening agent in foods. ATR-FTIR studies revealed high absorbance ratio at 1047/1022 cm^-1 in F1 as compared to F2 which confirmed the presence of packed double helices within the starch crystalline regions in F1 sample. Scanning electron microscopy showed the smooth, plumper and fused granules in F1 whereas disintegrated granules were observed in F2.