Structural, physicochemical and functional properties of high-pressure modified white finger millet starch

The effect of high-pressure processing (HPP) modification (200, 400, and 600 MPa for 10 min) on the physico-chemical, functional, structural, and rheological properties of white finger millet starch (WFMS) was studied. Measured amylose content, water, and oil absorption capacity, alkaline water retention, and pasting temperature increased significantly with the intensity of pressure. All color parameters (L, a, b values, and ΔC) were affected by HPP treatment, and paste clarity of modified starch decreased significantly with an increase in storage time. The samples' least gelation concentration (LGC) is in the range of 8-14 %. An increasing solubility and swelling power are noted, further intensifying at the elevated temperature (90 °C). The structural changes of WFMS were characterized by XRD, SEM, and FTIR spectroscopy. Starch modified at 600 MPa showed a similar pattern as 'B'-type crystalline, and the surfaces of starch deformed because of the gelatinization. Applied pressure of 600 MPa affected the FTIR characteristic bands at 3330, 2358, and 997 cm-1, indicating a lower crystallinity of the HPP-600 modified sample. According to DSC analysis, even at 600 MPa, WFMS is only partially gelatinized. This work provides insights for producing modified WFM starches by a novel physical modification method.

White finger millet starch: Hydrothermal and microwave modification and its characterisation

White finger millet (WFM) starch was modified by hydrothermal (HS) and microwave (MS) methods. Modification methods had a significant change in the b* value observed in the HS sample, and it caused the higher chroma (∆C) value. The treatments have not significantly changed the chemical composition and water activity (aw) of native starch (NS) but reduced the pH value. The gel hydration properties of modified starch enhanced significantly, especially in the HS sample. The least NS gelation concentration (LGC) of 13.63 % increased to 17.74 % in HS and 16.41 % in MS. The pasting temperature of the NS got reduced during the modification process and altered the setback viscosity. The starch samples exhibit the shear thinning behavior and reduce starch molecules' consistency index (K). FTIR results exhibit that the modification process highly altered the short-range order of starch molecules more than the double helix structure. A significant reduction in relative crystallinity was observed in the XRD diffractogram, and the DSC thermogram depicts the significant change in the hydrogen bonding of starch granules. It can be inferred that the HS and MS modification method significantly alters the properties of starch, which can increase the food applications of WFM starch.

Thermal properties of different types of starch: A review

Starch is present in high amount in various cereals, fruits and roots & tubers which finds major application in industry. Commercially, starch is rarely consumed or processed in its native form, thus modification of starch is widely used method for increasing its application and process stability. Due to the high demand for starch in industrial applications, researchers were driven to hunt for new sources of starch, including modification of starch through green processing. Thermal properties are significant reference parameters for evaluating the quality of starch when it comes to cooking and processing. Modification of starches affects the thermal properties, which are widely studied using Differential scanning calorimeter or Thermogravimetric analysis. It could lead to a better understanding of starch's thermal properties including factors influencing and expand its commercial applications as a thickener, extender, fat replacer, etc. in more depth. Therefore, the review presents the classification of starches, factors influencing the thermal properties, measurement methods and thermal properties of starch in its native and modified form. Further, this review concludes that extensive research on the thermal properties of new sources of starch, as well as modified starch, is required to boost thermal stability and extend industrial applications.

Effect of process parameters of microwave-assisted hot air drying on characteristics of fried black gram papad

Papad is a crunchy wafer-like snack food consumed all over India and other Asian countries. Traditionally, sun-drying requires more drying time and reduces less moisture from papad, which absorbs more oil during frying. The current study was carried out using microwave-assisted hot air drying (MAHD) to reduce fried papad oil content. Box-Behnken design (BBD) was selected to perform 17 trials for drying of papad using MAHD along with different power levels (300, 600, and 900 W), exposure times (30, 60, and 90 s) and hot air temperatures (40, 50 and 60 °C). The fried papad characteristics were evaluated in terms of oil content, oil uptake ratio, porosity, expansion and texture using standard procedures. MAHD helped reduce higher than 30% of fried papad oil content compared to the traditional method. Scanning electron microscope (SEM) confirmed that the MAHD papad has fewer pore structures than sun dried-fried papad. Using response surface methodology (RSM), the optimized parameters of MAHD was found to be 653 W power level with an exposure time of 56 s at 43 °C of drying temperature, which reduced oil content (7.90 ± 0.02%), oil uptake ratio (1.50 ± 0.03), porosity (16.33 ± 0.29%) and expansion (7.97 ± 0.02%) of fried papad.

White Finger Millet (KMR-340): A comparative study to determine the effect of processing and their characterisation

The white finger millet (WFM) KMR-340 flour: native (untreated), roasted (120 °C, 5 min) and germinated (30 ± 3 °C, 48 hrs) were characterised (nutritional, functional, thermal, pasting and rheological properties, X-ray diffraction, and FTIR). Germination significantly increased the protein, fibre, calcium, magnesium and antioxidant activity (14.66%) whereas decreased total ash, carbohydrate and fat. However, roasting significantly increased the carbohydrate, ash, fat, fibre and protein content. Roasting and germination significantly increased the non-essential amino acid contents, whereas the essential amino acid contents were reduced upon pretreatments. Though, processing methods improved the functional properties of millet flours, the pasting properties of the roasted and germinated flours were significantly varied from native flour. Rheological measurements revealed that all flour samples showed shear thinning behaviour (n < 1). The XRD patterns revealed that the percentage crystallinity reduced in the processed flours.

Partially defatted tomato seed flour as a fat replacer: effect on physicochemical and sensory characteristics of millet-based cookies

ABSTRACT

Fat is an essential component for cookies structure and sensory attributes, but there is a necessity to replace or mimic fat in order to prevent lifestyle diseases. Hence, this study investigated the effect of industrial by-product, i.e., Partially defatted tomato seed flour (PDTSF) as a fat replacer on physicochemical and sensory characteristics of millet-based cookies at 10, 20, 30, and 40% (w/w) fat replacement levels. The physicochemical and functional properties of PDTSF were analyzed. PDTSF exhibited excellent nutritional profile and functional properties. PDTSF supplemented cookies showed a significant increase (p ≤ 0.05) in hardness, protein, ash, and carbohydrate content and the significant decrease in spread ratio, fat, and energy value with an increment of PDTSF. Descriptive sensory evaluation of millet-based cookies at all fat replacement levels showed good acceptability. Storage analysis for 30 days revealed as acceptance of cookies is not affected due to moisture intake and hardness. Hence, the results confirmed the positive effect on PDTSF as a whole food fat replacer to produce Reduced- fat millet cookies at 10 and 20% fat replacement levels.

GRAPHICAL ABSTRACT

Effect of ultrasound treatment on dehulling efficiency of blackgram

Present study was conducted to evaluate the effect of Power ultrasound, on dehulling efficiency, dhal yield, dehulling loss and total colour difference of black gram using response surface methodology. Nine treatments were performed with variation in ultrasound power 343-525 W and treatment time 1-3.5 h. It was observed that ultrasound treatment significantly improved the dehulling efficiency and dhal yield of the black gram and reduced the dehulling loss. The optimized treatment condition obtained for optimum dehulling yield (75.71%), dhal yield (74.63%) dehulling loss (12.72%), and total colour difference (5.08) was ultrasound power of 513.39 W and exposure time of 2.12 h. Moreover the blackgram pretreated with ultrasound required lesser cooking time when compared to soaked alone sample. The SEM analysis revealed the significant effect of ultrasound on the blackgram kernel which led to uniform cavitation of the surface of the kernel compared to the soaked sample without ultrasound treatment. In food industry blackgram is preprocessed i.e. soaked and cooked to produce various soups, canned products, batter, snack foods etc. Hence ultrasonic treatment can be applied to improve and facilitate a faster dehulling efficiency, with added advantage of increased soaking rate and a decrease in the cooking time for blackgram.