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The impact of heat-moisture treatment carried out at moisture content basis of 20%, 25%, and 30% on the physicochemical, textural, pasting and rheological characteristics of foxtail millet starch was evaluated. The swelling capacity and solubility index of modified starches accelerated with temperature but decreased significantly (p≤0.05) with increased moisture percent. The decreased swelling capacity and solubility could be caused by the reduced stability of granules arising due to the disentanglement of double helices in the crystalline region of the starch granules. The heat-moisture treated foxtail millet starch depicted a decrease in the birefringence intensity at the granular centre and remained unaltered at the periphery. The reorientation of molecules of heat-moisture treated starches resulted in a significant (p≤0.05) decrease in peak viscosity, breakdown, and final viscosity. The significant (p≤0.05) increase in the gel hardness was observed for HMT20 as comparison to native starch. Dynamic rheological properties of the native and modified foxtail millet starches revealed the fragile gel structure. The increase in loss tangent of paste resulted in the gummy nature of starches. [ABSTRACT FROM AUTHOR]

The present study aims to prepare starch nanocrystals (SNCs) from sweet potato tuber starch and study their morphological, crystalline, rheological, and thermal properties. The platelet‐like SNCs are obtained using acid hydrolysis of round or polygonal native sweet potato starch granules. The average hydrodynamic diameter of SNCs is 184 nm as measured using the dynamic light scattering technique. The polydispersity index value based upon molecular weight distribution as determined using gel permeation chromatography increases from 1.386 for native starch (NS) to 2.958 for SNCs, indicating the heterogenous molecular weight distribution of acid hydrolyzed starch. The zero value of the radius of gyration for nanocrystals indicates the formation of anisotropic platelet‐like SNCs. The gelatinization temperature and melting enthalpy significantly increased after the nanoconversion of starch granules; thus, SNC's thermal properties are improved after acid hydrolysis of NS. The SNCs exhibit shear‐thinning behavior (lower viscosity) at high concentrations; the visco‐elastic behavior of SNCs dispersions is frequency‐dependent, with elastic character prevalence over viscous at lower frequencies. [ABSTRACT FROM AUTHOR]

The effect of different cooking treatments and extracting solvents on the antioxidant activity of M. charantia was assessed by measuring total phenol content (TPC), total flavonoids, tannin content and carotenoid content and the antioxidant activity using different assays. A densitometric HPTLC analysis was performed for the analysis of phenolic acids and flavonoids. In general, the recovery of TPC and antioxidant activity was highest in methanolic extract. The most of cooking treatments exerted the decreasing effect on antioxidant activity. Correlation studies indicated that the phenols were mainly responsible for ferric reducing power ( r = 0.872, P < 0.01). However, the flavonoids were responsible for radical scavenging activity ( r = 0.857, P < 0.01). HPTLC analysis of the methanolic extracts revealed the prominent presence of caffeic acid, vanillic acid, quercetin, catechin, etc., in the native form and destruction, transformation and formation of new phenolics was observed after the cooking treatments. Practical Applications In the present study, three cooking treatments such as pressure cooking, microwave cooking and frying were compared in respect to the retention of antioxidant potential of Momordica charantia fruit. The findings of the present study suggested that pressure cooking and frying could be developed as effective heat processing techniques to retain the maximum antioxidant potential of M. charantia fruit. This report can also serve as a database giving information about retention of polyphenolic compounds after cooking which may help in the establishment of recommended daily allowance value of polyphenolic compounds particularly for the population relying heavily on the consumption of M. charantia. Since, the beneficial health effects of consumption of M. charantia are well established in the Indian Ayurveda, this study can be instrumental in adding new scientific dimension in understanding the beneficial health aspects of M. charantia. [ABSTRACT FROM AUTHOR]