Mineral Content, Functional, Thermo-Pasting, and Microstructural Properties of Spontaneously Fermented Finger Millet Flours

Abstract

Finger millet is a cereal grain which is superior to wheat and rice in terms of dietary fibre, minerals, and micronutrients. Fermentation is one of the oldest methods of food processing, and it has been used to ferment cereal grains such as finger millet (FM) for centuries. The aim of this study was to investigate the impact of spontaneous fermentation (SF) on mineral content, functional, thermo-pasting, and microstructural properties of light- and dark-brown FM flours. Spontaneous fermentation exhibited a significant increase in the macro-minerals and micro-minerals of FM flours. In terms of functional properties, SF decreased the packed bulk density and swelling capacity, and it increased the water/oil absorption capacity of both FM flours. Spontaneous fermentation had no effect on the cold paste viscosity of FM flours. However, significant decreases from 421.61 to 265.33 cP and 320.67 to 253.67 cP were observed in the cooked paste viscosity of light- and dark-brown FM flours, respectively. Moreover, SF induced alterations in the thermal properties of FM flours as increments in gelatinisation temperatures and gelatinisation enthalpy were observed. The results of pasting properties exhibited the low peak viscosities (1709.67 and 2695.67 cP), through viscosities (1349.67 and 2480.33 cP), and final viscosities (1616.33 and 2754.67 cP), along with high breakdown viscosities (360.00 and 215.33 cP) and setback viscosity (349.33 and 274.33 cP), of spontaneously fermented FM flours. Scanning electron microscopy showed that SF influenced changes in the microstructural properties of FM flours. The changes induced by SF in FM flours suggest that flours can be used in the food industry to produce weaning foods, jelly foods, and gluten-free products that are rich in minerals.

Study on Various Treatments to Improve Nutritional and Rheological Properties of Finger Millet Porridge

“…FTD-DH and FTD-WM showed a reduced breakdown and setback viscosity compared to those of their respective NAT flours. The breakdown viscosity is in line with previous results for fermented light-brown FM . The reduced setback viscosity indicates a reduced ability of amylose for retrogradation, which could be due to starch hydrolysis.…”

“…The HTT, STD, and FTD treatments significantly increased the onset pasting temperature compared to the corresponding NAT flours. HTT was previously shown to increase gelatinization temperature by increasing the interaction of amylose polymers with amylopectin chains in the branched crystalline regions, which reduced the mobility of amylopectin polymers. , The increased pasting onset temperature of FTD flours can be attributed to the changes in granule size, morphology, starch distribution, and internal starch fraction organization, resulting in an increased energy requirement to induce gelatinization. , In addition, the release of amino acids by the microorganisms can affect the pasting temperature . In contrast, onset temperatures of AKT and CAS treatments were similar to those of the corresponding NAT flours, which is in line with previous reports. , …”

“…FTD-DH and FTD-WM showed similar peak and final viscosities to those of the respective NAT flours. Previously, lower viscosity of fermented flours was reported . However, since spontaneous fermentation was applied, substantial differences between the studies regarding the present microorganisms are possible and can impact the pasting behavior.…”

“…53,54 The increased pasting onset temperature of FTD flours can be attributed to the changes in granule size, morphology, starch distribution, and internal starch fraction organization, resulting in an increased energy requirement to induce gelatinization. 55,56 In addition, the release of amino acids by the microorganisms can affect the pasting temperature. 57 In contrast, onset temperatures of AKT and CAS treatments were similar to those of the corresponding NAT flours, which is in line with previous reports.…”

Impact of Treatment with Superheated Steam on the Structural, Thermal, and Functional Characteristics of Quinoa Starch

“…According to Mudau et al. [ 51 ] these values ​​obtained in this study are desirable, as it means that the quinoa starches obtained have the potential to be used in food preparation, since high values ​​of this parameter indicate better quality, such as greater flavor retention in the final product. The differences observed between the starch formulations untreated and treated with superheated steam, according to Pérez et al., [ 52 ] are related to the different levels of association forces within the granule, which depend on the proportion of amylose and amylopectin, molecular weight, conformation, degree of polymerization of both fractions, and degree of branching of amylopectin.…”