Effect of Moisture Content and Particle Sizes on Physical and Thermal Properties of Roasted Bengal Gram Flour

Characterization, mathematical modeling of moisture sorption isotherms and bioactive compounds of Andean root flours

Andean roots can be used as an alternative to gluten-free food. The objective of this study was to enhance the technological and nutritional properties of Andean root flours to promote their industrial applicability. The water content and activity of the flour were lower than those required to prevent mold growth. The bulk density of the flour was comparable to that of wheat flour. The flour of Ipomoea batatas (L.) Lam. exhibited the lowest water absorption capacity of the tested samples. However, both this flour and Tropaeolum tuberosum Ruiz & Pavón showed a higher fat absorption capacity. The samples exhibited type-II isotherms, indicating that the flours were highly hygroscopic. The Guggenheim, Anderson, and de Boer GAB model showed a higher coefficient of determination in mathematical modeling. The chroma of T. tuberosum Ruiz & Pavón flour was higher than the other samples, which was related to total carotenoids and lycopene. Furthermore, I. batatas (L.) Lam. exhibited the highest phenol value.

Some physical, functional and antinutrients of breakfast cereals from blends of guinea corn, pigeon pea and mango flour using mixture-process design

Some functional, physical and anti-nutritional factors of breakfast cereals from blends of sorghum (X₁), pigeon pea (X₂) and mango (X₃) flours were evaluated using mixture-process design. The flours were blended in ratios of 1:0:0, 0:1:0, 0:0:1, 05:0.5:0, 0.5:0:0.5, 0:0.5:0.5, and 1/3:1/3:1/3, for sorghum, pigeon pea, and mango flour, respectively. Twenty-eight samples were generated from a multiplicative (2³-1) simplex centroid mixture design and a (2, 2) full factorial design. The samples were roasted at varying temperatures (Z₁) (250 and 270 °C) and times (Z₂) (4 and 7 min). The water absorption capacity (WAC), pH, bulk density (BD), foam capacity (FC), haemagglutinin, phytates, and tannins were evaluated. Significant (p < 0.05) regression models were generated to explain these responses. The temperature time-combination did not significantly (p > 0.05) affect pH changes. For WAC, BD, FC, and the antinutrients, there was no clear trend to describe the effect of mixture components and process variables. Experimental runs with the same mixture formulation, processed at different temperature-time combinations had different values for these attributes with the degree of reduction of antinutrients being a simultaneous effect of these variables. Cross interactions between the mixture and process variables showed that the selected properties were dependent both on the mixture and processing conditions.

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 (G') and loss modulus (G'') 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.

Engineering properties of Cassia tora L. seeds and meal as a function of moisture content

Engineering properties are of great importance for Cassia tora L. seeds in aspects of harvesting, handling mechanical design and product processing. The effect of moisture content (7, 10, 13, 16 and 19%) (wet basis) on the properties: physical (length, width, bulk and true density, porosity, thousand seeds mass, coefficient of static friction and angle of repose), mechanical (hardness, fragmentation energy and failure deformations), and thermal (specific heat, thermal conductivity and thermal diffusivity), were systematically studied. As the moisture contents increase from 7 to 19%, the length (L) increased from 4.52 to 5.87 mm, the thickness (T) from 2.51 to 3.21 mm and the width (W) from 2.36 to 3.02 mm, respectively. The bulk and true density of Cassia tora L. seeds decreased from 775.83 to 654.17 kg/m³ and from 1295.21 to 1154.72 kg/m³, respectively, with the moisture content raised from 7 to 19%. The thermal conductivity of Cassia tora L. seeds meal was found to be 0.068–0.098 W m⁻¹ K⁻¹, 0.078–0.112 W m⁻¹ K⁻¹, 0.089–0.125 W m⁻¹ K⁻¹, 0.098–0.136 W m⁻¹ K⁻¹, 0.108–0.148 W m⁻¹ K⁻¹, 0.119–0.159 W m⁻¹ K⁻¹, respectively, at 25 °C, 45 °C, 65 °C, 85 °C, 105 °C and 125 °C in moisture ranges of 7–19%. The thermal diffusivity was found to decrease from 5.21 × 10^–8 to 4.53 × 10^–8 m²/s, from 5.75 × 10^–8 to 4.91 × 10^–8 m²/s, from 6.11 × 10^–8 to 5.17 × 10^–8 m²/s, from 6.52 × 10^–8 to 5.36 × 10^–8 m²/s, from 7.17 × 10^–8 to 5.77 × 10^–8 m²/s, from 7.36 × 10^–8 to 5.84 × 10^–8 m²/s, respectively, at 25 °C, 45 °C, 65 °C, 85 °C, 105 °C and 125 °C in moisture ranges of 7–19%. The results suggested that physical properties exhibited linear relationships with moisture content using the regression model, while mechanical properties showed a second-order polynomial relationship with moisture content. Furthermore, significant variation existed in thermal properties because of differentiate moisture content and temperature. These data and rules are also useful for high efficiency machines design and mechanisms development.

Effect of Tempering Conditions on White Sorghum Milling, Flour, and Bread Properties

The effects of room temperature water, hot water, and steam tempering methods were investigated on sorghum kernel physical properties, milling, flour, and bread-making properties. Overall tempering condition and tempering moisture content were found to have a significant effect on the physical properties. Milling properties were evaluated using a laboratory-scale roller milling flowsheet consisting of four break rolls and eight reduction rolls. Room temperature tempering (18% moisture for 24 h) led to better separation of bran and endosperm without negatively impacting flour quality characteristics i.e., particle size distribution, flour yield, protein, ash, damaged starch, and moisture content. Bread produced from the flour obtained from milling sorghum kernels tempered with room temperature water (18% m.c for 24 h) and hot water (16% m.c at 60 °C for 18 h) displayed better bread-making properties i.e., high firmness, resilience, volume index, higher number of cells, and thinner cell walls when compared to other tempering conditions. Room temperature water tempering treatment (18% m.c for 24 h) could be a better pretreatment process for milling white sorghum kernels without negatively impacting the flour and bread-making quality characteristics.

Modeling of Dielectric and Thermal Properties of Protein-Enriched Instant Noodles as a Function of Food Chemical Composition

Dielectric property measurement instruments are expensive and not readily available. Hence, models of the dielectric and thermal properties of protein-enriched instant noodles (PEIN) were developed as a function of the product moisture, protein, ash, fat, carbohydrate, and crude fiber contents. The chicken meat, egg yolk, and seaweed in PEIN varied from 0 to 30, 0 to 15, and 0 to 6 g/100 g flour, respectively. Results revealed that protein, fat, and ash contents of PEIN increased by chicken meat, egg yolk, and seaweed supplementation. Regression equations indicated that the moisture and protein contents significantly (P ≤ 0.05) increased, while the fat content decreased the dielectric and thermal properties. The R2 values of the dielectric constant and loss factor, thermal conductivity, and specific heat equations were 0.75, 0.87, 0.78, and 0.98, respectively. Finally, no significant differences (P > 0.05) between the properties values predicted from the model equations and the experimental data (not included in the development of model equations) was observed which indicated a good model fit.

Optimization of microwave roasting of peanuts and evaluation of its physicochemical and sensory attributes

In this study, the microwave (MW) roasting (MWR) of peanuts (Arachis hypogaea L.) is attempted, optimized and compared with conventional drum roasting. A two factor/three level face centered composite design based MWR experiments was conducted at different roasting time (60, 180 and 300 s) and MW power levels (180, 540 and 900 W). The roasting quality was analyzed by physicochemical and sensory attributes of roasted peanuts and extracted oil viz., moisture loss, hardness, browning index (BI), induction period (IP) based on Rancimat, peroxide value (PV) and overall acceptability (OA), respectively. A roasting time and MW power dependent improvement in the desired quality of roasted peanuts and extracted oil was observed attributable to the formation of antioxidant Maillard reaction compounds. A second order polynomial model adequately described the roasting experimental data (p < 0.0001, R² > 0.90) with an insignificant lack of fit (p > 0.05). Using response surface methodology, the MWR was optimized at roasting time of 201 s and MW power level of 900 W which yielded favorable values of quality attributes (moisture loss, 3.06%; hardness, 4528.34 g; BI, 58.89; IP, 8.12 h; PV, 8.80 milliequivalents O₂/kg; OA, 6.40). Furthermore, the quality assessment of ground peanuts for selected time-power combinations (low, optimum and high roasts) was attempted using scanning electron microscopy, electronic nose and Fourier transform infrared spectroscopy which revealed better quality of optimized MWR peanuts.