The aim of this study was to evaluate the effect of extrusion factors on the properties of extruded nixtamalized corn flours (ENCFs), determine the optimal conditions, and produce a tortilla with ...texture and nutraceutical characteristics acceptable for consumers. The processing factors used were feed moisture (FM, 15 to 30%), extruder temperature (T, 70 to 110 °C), and screw speed (SS, 50 to 145 rpm). The properties evaluated in the flours were total anthocyanins (TA), subjective water absorption capacity, and peak viscosity (PV). Response surface methodology and analysis of variance were used in the evaluation. The linear and quadratic terms of FM had a greater effect on all evaluated parameters. The optimization was performed using the numerical method of global desirability. The response variables that were optimized in the ENCF were TAs (maximize) and PV (maximize). The optimal region was the following: FM (18.17%), T (92.03 °C), and SS (76.61 rpm). The experimental value for the TA in the optimized ENCF was 226.07 mg/kg, and the PV was 1063.9 cP. The results of this study could help develop nixtamalized corn flours with desirable characteristics to make tortillas using the extrusion process.
Practical Application
The results obtained would be useful for the tortilla industry, developing nixtamalized corn flours with desirable characteristics to make healthy tortillas using the extrusion process, with minimum losses in biologically active compounds such as anthocyanins (health promoters) without affect negatively the eating quality of the product (good texture).
A mixture of blue corn, black bean, and chard with a moisture content (MC) of 22.3–35.7% is extruded at different extrusion temperatures (ET) (102—142 °C) using screw speeds (SP) of 96–172 rpm, and ...the extruded mixtures are subsequently expanded using microwave radiation to produce third‐generation (3G) snacks. The degree of starch gelatinization (DG); in vitro starch digestibility (SD); specific mechanical energy (SME); physical properties: radial expansion (RE), flexural modulus (Ef), and bulk density (BD); and rheological properties: storage modulus (G′) and loss modulus (G″) are evaluated and optimized. In addition, X‐ray and microstructure analyses are studied to correlate the chemical and structural changes. The SP and MC affect most variables in the unexpanded snack (UETS) and microwave‐expanded snacks (MWES). Increased MC results in UETS with low SD, DG, rheological properties, and mechanical resistance. An increase in SP at low MC results in MWES with high RE, low BD, and Ef while an increase in MC lowers SD. Micrographs and X‐ray diffraction spectra reveals that the extrusion results in a V‐type starch crystalline structure. The optimal conditions (24% MC, 133 rpm, and 122 °C) result in good expansion and moderate SD, DG, and SME products.
The present study mainly investigates the effect of extrusion processing on the properties rheological, structural, thermo‐mechanical, and in vitro starch digestibility of extruded and microwave‐expanded in a matrix based on blue corn, black beans, and chard third‐generation snack.
The objective was to determine the adequate conditions for the microwave-assisted extraction of antioxidant compounds from the seed hull of sunflower hybrids. The existence of genetic and ...environmental variability in the phenolic content obtained under the selected extraction conditions was also analyzed. The extractions were carried out at 70 °C-20 and 90 °C-10 min, using water as solvent and a power of 600 W. The total phenol, flavonoid and antioxidant activity were evaluated. The microwave extraction process at 90 °C-10 min gave significantly higher values of total phenol (407.13 ± 6.11–512.71 ± 23.54 mg gallic acid⋅100 g
−1
hull), flavonoids (210.09 ± 6.15–297.64 ± 5.68 mg catechin⋅100 g
−1
hull) and antioxidant activity (76.73 ± 4.40–110.80 ± 3.51 μmol TE⋅g
−1
hull) than those obtained at 70 °C-20 min. The cultivation environment also significantly affected the antioxidant yield, with total phenol and flavonoid contents being significantly higher for the hybrids grown in Balcarce than for those from Tandil. A significant interaction between hybrids and cultivation environmental was also observed for the antioxidant activity, indicating that the environmental effects were not similar among hybrids. The results of this study provide valuable information related to giving added value to a residue of the oil industry.
Effects of extrusion cooking process (ECP) with citric acid (CA) addition on the physicochemical changes and resistant starch (RS) formation in native corn starch (NCS) are evaluated. NCS at ...different feed moisture levels (18–32%) and CA concentrations (0–10.3%), are subject ECP under constant conditions of screw speed (233 rpm) and die temperature (127 °C). The obtained extrudates are stored at 4 °C for 120 h and then at room temperature. The water absorption index (WAI), water solubility index (WSI), RS content, peak temperature (Tp), ∆H, peak viscosity (PV), setback viscosity (SV), FT‐IR, X‐ray analysis and microstructural (SEM) properties are evaluated. RS content and WSI increased with decreasing moisture content (MC), WAI, PV and SV shows that increases in MC caused an increase, while ∆H and Tp decreases with decreasing MC. SEM shows that ECP with CA destroys the granular structure of NCS generated amorphous structures owing to gelatinization and dextrinization. FT‐IR analysis shows that extruded samples with CA cause starch hydrolysis, increasing the intensity of bands 994 and 1016 cm−1 in comparison to NCS. The highest RS yield (1.15 g/100 g) is obtained at 18% moisture content and 5.2% of CA: an increase of 71% with respect to NCS.
The aims of this study are to evaluate and optimize the conditions of extrusion with addition of citric acid (CA) to determine their effects on physical, chemical, structural, rheological properties and resistant starch formation (RSF). It is found the highest RS yield reaches an increase of 71%. These results indicate that addition of CA during extrusion may be advantageous for RSF.
Acid hydrolysis process (AHPS) combined with hydrothermal storage process (HSPS) and extrusion cooking process (ECPS) are performed to obtain resistant starch (RS) from corn starch (CS). CS is ...subjected to AHPS citric, phosphoric acids, and HCl and thermal processes: 1) ECPS at 100 °C, 18% moisture content, and 220 rpm; 2) HSPS at 120 °C for 1 h, then storing at low temperature (4 °C) for 24 h. Evaluations in the different treatments are: RS, water absorption index (WAI) and solubility index (WSI); rheological, thermal, and microstructural properties. Treatment HAL results in the highest yield of RS (13.19 g/100 g), which increases WAI and WSI, low viscosity, gel hardness, ΔH and microstructural analysis showing agglomerated structures (30 µm) of diameter. On the other hand, HAC and HAP generated values of RS (8.47–9.19 g/100 g), respectively. Results show that pre‐treatment by AHPS combined with HSPS is an alternative for obtaining RS, which exhibits suitable physical properties and is applicable to different dietary matrixes, at a 20‐fold increased yield.
The application of acid hydrolysis, extrusion‐cooking or hydrothermal processes, individual or combined, could represent an advantage for the production of resistant starch. The acid hydrolysis combined with hydrothermal processes are shown to be the most adequate, delivering high yields of resistant starch from corn starch.
The effect of temperature and toasting time of blue maize was evaluated to develop and optimize a pinole mixture. For toasting, total anthocyanins (TA), polyphenols (TP), antioxidant activity (AA), ...color, viscosity, and microscopic analysis of starch were determined. With the best conditions, a pinole formulation was developed by adding amaranth, chickpea, chia, and oat through a D‐optimal mixture design. High temperature and toasting time decreased the TA, TP, lightness, and viscosity; and increased the AA, color (a*, b*), and starch damage. Toasting at 200°C for 4.5 min was adequate, with TA, color (a*), and viscosity retention of 55.68%, 86.83%, and 81.11%, respectively. All four ingredients had significant effects and the special cubic model described the nutritional, physicochemical, functional, and rheological properties. Optimum pinole mixture (1.0% amaranth, 4.97% chickpea, 7.80% chia, and 4.63%) based on reaching the maximum contents of protein, fiber, AA, and TP, had better properties than a local blue maize pinole.
Novelty impact statement
This study informs about the importance of establishing the temperature and time conditions for toasting blue maize in order to obtain a base of toasted maize for the formulation of pinole with minimal losses of bioactive compounds and color, but with adequate physical and rheological properties. In addition, contributes to the development of a blue maize pinole with ingredients that improve its color, nutritional, rheological, and functional properties; representing an alternative of healthy consumption.
Oregano essential oils from Lippia berlandieri Schauer (Lb) and Poliomintha longiflora Gray (Pl) were tested against the antioxidant butylated hydroxytoluene (Bht) to evaluate effects on the shelf ...life of ground beef (GB) over 7 days of storage at 4°C. The treatments were GB1 = GB control, GB2 = GB +100 mg/kg of Bht, GB3 = GB +100 mg/kg of Lb, and GB4 = GB +100 mg/kg of Pl. Lightness, redness, hardness, and springiness showed differences (p < .05) between treatments and days interaction, which serve as indicators of ground beef preserved quality and consumer acceptance. Mesophilic, psychrophilic, and lactic acid bacteria numbers and antioxidant activity showed differences (p < .05) for treatments and days. Sensory attributes showed no differences between treatments. The oregano oils may provide extended shelf life for packaged meat products treated with these natural additives and hence may be used for ground beef preservation.
•UAE is an efficient method to obtain betalains and polyphenols with high AA.•BT, BC, BX, TP, AA, b*, KLa, and A were affected by temperature and UPD.•Optimal UAE conditions were 41.80 °C and 188.84 ...mW/mL.•Optimal conditions showed that BC, BX, BT, TP, AA, L*, a*, b*, KLa, A, and IA agreed with predicted values.
The present study optimised the ultrasound-assisted extraction (UAE) of bioactive compounds from Amaranthus hypochondriacus var. Nutrisol. Influence of temperature (25.86–54.14 °C) and ultrasonic power densities (UPD) (76.01–273.99 mW/mL) on total betalains (BT), betacyanins (BC), betaxanthins (BX), total polyphenols (TP), antioxidant activity (AA), colour parameters (L*, a*, and b*), amaranthine (A), and isoamaranthine (IA) were evaluated using response surface methodology. Moreover, betalain extraction kinetics and mass transfer coefficients (KLa) were determined for each experimental condition. BT, BC, BX, TP, AA, b*, KLa, and A were significantly affected (p < 0.05) by temperature extraction and UPD, whereas L*, a*, and IA were only affected (p < 0.05) by temperature. All response models were significantly validated with regression coefficients (R2) ranging from 87.46 to 99.29%. BT, A, IA, and KLa in UAE were 1.38, 1.65, 1.50, and 29.93 times higher than determined using conventional extraction, respectively. Optimal UAE conditions were obtained at 41.80 °C and 188.84 mW/mL using the desired function methodology. Under these conditions, the experimental values for BC, BX, BT, TP, AA, L*, a*, b*, KLa, A, and IA were closely related to the predicted values, indicating the suitability of the developed quadratic models. This study proposes a simple and efficient UAE method to obtain betalains and polyphenols with high antioxidant activity, which can be used in several applications within the food industry.
PDF
