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•Mechanical milling affects thermal properties at long milling times.•Milling increases amylose content and promotes the formation of elastic gels (Ǵ).•Modified starches show a ...non-Newtonian flow behavior as reofluidizers.•Tan δ shows the modification of starch-generated elastic gels.
This work evaluates the effect of high-energy mechanical milling time (7 levels, 20–80 min) on amylose content, crystallinity pattern, temperature and gelatinization enthalpy, morphology, and rheological properties of chayotextle (Sechium edule Sw.) starch. After 30 min of milling, granular structure was affected, and amylose values were the highest while crystallinity and gelatinization enthalpy decreased significantly. These changes allowed to obtain gels with viscoelastic properties where the elastic character (Ǵ) prevailed upon the viscous modulus (Ǵ́). Native starch showed Tan δ values of 0.6, increased significantly (0.9) after 30 min of milling due to the surge in linear chains (amylose) and loss of granular structure. Native and modified starches showed high dependence on cutting or shear speed, presenting a non-Newtonian behavior (reofluidizers). These results indicate that mechanical grinding is an alternative to obtain modified starches with applications in the food industry.
Insects are considered as alternative sources of chitosan; however, studies about the functional film-forming properties of insect chitosan are scarce. Insect chitosan films were made from Tenebrio ...molitor and Brachystola magna and were compared with commercial chitosan of different molecular weights (Mw). Mechanical properties (tensile strength, TS; elastic modulus, EM; elongation at break, %E), water vapor permeability (WVP) and physicochemical properties were characterized. The film properties of both commercial and insect chitosan were affected by Mw. Commercial chitosan films showed that at lower Mw, the TS (from 59 to 48 MPa) and EM (from 1471 to 1286 MPa) decreased; whereas WVP (from 2.9 × 10−11 to 3.4 × 10−11 g m−1s−1Pa−1), % E (from 38 to 41%) and solubility (from 30 to 33%) increased. Chitosan insect films showed lower TS and EM, and higher WPV, %E and solubility than commercial films. SEM revealed that chitosan insect films had lower porosity than commercial films. FTIR and X-ray diffraction showed not difference between insect and commercial chitosan films. These results showed that T. molitor and B. magna chitosan films could be used as a packaging material in several food products.
Low methoxyl pectin was extracted from prickly pear fruit (Opuntia albicarpa Scheinvar ‘Reyna’) by sequential extraction with water in presence of a sequestering agent. Sugar composition of the ...prickly pear pectin (PP) was (mg g−1, dry weight): 654 galacturonic acid, 195 galactose, 21.6 rhamnose, 1.2 arabinose and 1.2 glucose. The weight-average molecular weight was 10.16 × 105 g mol−1, the number-average molecular weight was 9.10 × 105 g mol−1 and the polydispersity index was 1.116. The FTIR spectrum of PP showed good agreement with that of standard citrus pectins and the degree of esterification of PP was 30.7%. Pectin dispersions in the range of 5–20 g kg−1 showed a non-Newtonian rheological behaviour which had good fitting to the Cross equation. The gelling ability of PP was evaluated by dynamic oscillatory rheometry. The addition of Ca2+ (0.25–0.75 mM) to 4 g L−1 PP dispersions led to the gel formation.
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•Low methoxyl pectin (DE 30.7%) was extracted from prickly pear fruit (Opuntia albicarpa S.).•The weight-average molecular weight was 10.16 × 105 g/mol.•Prickly pear pectin solutions (0.5–2% w/w) showed a non-Newtonian behaviour.•Prickly pear pectin showed gelling properties in the presence of CaCl2.•Prickly pear peel can be a source of pectin with high potential as thickening and gelling additive in food.
The objective of this paper was to perform a copolymerization between polyethylene and starch in order to obtain new environmentally friendly materials. The copolymer obtained was characterized ...thermally, morphologically and structurally, including its pasting profile. The starch-g-PE copolymer showed lower thermal stability compared to the control materials. FTIR analysis determined that the chemical bond signal between the starch and polyethylene in the copolymer overlaps with the native starch signals. The signal from this chemical bond was assigned by proton NMR spectroscopy at δ 4.45 ppm. X-ray studies of the copolymer showed a material with more amorphous characteristics compared to native starch. SEM analysis demonstrated the presence of cracks in the starch granules which favored the chemical interaction between the polymers. The pasting behavior of the copolymer was less pronounced compared to native starch. Therefore, the copolymerization of both polymers could be an alternative to recycle polyethylene and make biodegradable materials.
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•The copolymerization of the starch and polyethylene was achieved by the bulk method.•The incorporation of polyethylene decreased the crystallinity in the starch.•The copolymer obtained had a lower thermal stability than the homopolymers.•Interaction of the starch with the polyethylene generated a low viscosity copolymer.
Abstract The aimed of this study was quantified total phenols content, total flavonoids, and antioxidant activity in extruded ready-to-eat products made from yellow corn added with apple pomace ...powder. A central composite rotatable experimental design was used. The variables tested were exit die temperature (140-180 °C), feed moisture (14-20 g/100 g) and apple pomace concentration (0-30 g/100 g). The effect of the process variables on the total contents of phenols, flavonols, flavanols and flavonoids and antioxidant activity was evaluated using the response surface methodology. The data of each response were fitted to a second-order model with determination coefficients ≥ 0.71. The extruded product with no added apple bagasse showed the lowest values of the evaluated phytochemicals but had higher antioxidant activity by DPPH. The addition of apple pomace increased the phytochemical content and antioxidant activity in extruded ready-to-eat products made with yellow corn. This makes it possible to obtain a formulation of an extruded food rich in phenolic compounds with potential to contribute to prevention of oxidative stress, while making use of agro-industrial waste from apple juice extraction.
•Water vapour permeability values decreased in films with cellulose nanoparticle (CN).•Starch films (chayote and potato) with CN had the highest tensile strength.•Melting temperature of starch films ...increased for addition of CN.•Reduction in ΔH value indicated no ordering in double helices of the polysaccharides.
The aim of this study was to characterize chayotextle starch films reinforced with cellulose (C) and cellulose nanoparticle (CN) (at concentrations of 0.3%, 0.5%, 0.8% and 1.2%), using thermal, mechanical, physicochemical, permeability, and water solubility tests. C was acid-treated to obtain CN. The films were prepared by casting; potato starch and C were used as the control. The solubility of the starch films decreased with the addition of C and CN compared with its respective film without C and CN. No statistical difference (α=0.05) was found in the films added with different concentrations of C and CN. In general, the mechanical properties were improved with the addition of C and CN, and higher values of tensile strength and elastic modulus were determined in the films reinforced with CN. The melting temperature and enthalpy increased with the addition of C and CN, and the values of both thermal parameters were higher in the films with CN than with C; the enthalpy value of the film decreased when the concentration of C or CN increased in the composite. Low concentration of C and CN is better distributed in the matrix film. The addition of C and CN in the starch films improved some mechanical, barrier, and functional properties.
•Additives, 1-MCP and edible coatings decrease microbial growth in bulbs.•The weight loss and respiration rate were lower in treated bulbs.•The physicochemical and bioactive compounds were maintained ...in treated bulbs.•Edible coatings, additives and 1-MCP extend shelf life of jackfruit bulbs.
The aim of this study was to investigate the effect of pretreatment with 1-methylcyclopropene (1-MCP) and the application of edible coatings (xanthan, sodium alginate or gellan) on the ripening rate, quality parameters and shelf life of pre-cut jackfruit. The jackfruit bulbs dipped in potassium sorbate/calcium chloride “PS/CC” (T1) and PS/CC/1-MCP (T2) showed a more rapid ripening and greater microbial growth at 7 and 12days of storage. However, jackfruit bulbs with PS/CC/1-MCP and covered with xanthan, sodium alginate or gellan (T3, T4, and T5, respectively), showed a decrease in the ripening rate; thus weight loss and respiration rate were lower and the higher quality values as colour (°Hue), total soluble solids (TSS), titratable acidity (TA) as well as pH were achieved until 12days of storage. Firmness values were higher in bulbs under T3, T4, and T5 compared to bulbs under T1 and T2. Microbial growth was delayed until the 12th day of storage in jackfruit bulbs with T3, T4, and T5. In general, manually peeled jackfruit stored at 5°C and coated with 1-MCP/edible coatings, maintained the quality and sensory acceptability of fresh-cut jackfruit and with a longer shelf life than previously reported.
In Mexico, consumption of beans represents 15% of the normal diet of the population in rural zones. Four common bean varieties cultivated in Mexico were studied regarding their chemical composition, ...starch digestibility and indigestible fraction. The protein level in the samples Huasteco, Tacana and TLP 19 was not different (α = 0.05), but Veracruz cultivar had the highest protein and ash content, and the lowest lipid level. Differences in chemical composition were determined in the cultivars studied. Total starch (TS) ranged between 33.6 and 36.7%, and the cultivars Tacana, TLP 19 and Veracruz were not different in starch content (α = 0.05). The available starch (AS) determined represented between 74 and 87% of TS, due to the resistant starch content and perhaps some complex formed between starch and protein or starch and polyphenols, by the high level of the indigestible fraction determined in the beans. The in vitro α‐amylolysis rate was similar for the different varieties, except for Veracruz cultivar which presented a slightly lower hydrolysis rate.
Abstract The aim of this research was to evaluate the influence of germination in Lupinus angustifolius L. seeds on protein profile, functional properties (FP), protein digestibility, phytic acid ...concentration and trypsin inhibitory activity, the latter due to its influence on protein digestibility. The germination was development at 26 ºC for 2-7 days. The ungerminated sample showed a protein content of 24.06% that was increased at 3 days of germination. Electrophoretic profile showed that the germination time generates a reduction in the intensity of the bands with molecular weight of 40, 50, 97 and 116 kDa, corresponding to the β and γ-conglutin subunits. At day 7 of germination, the water and oil absorption capacities increased by 146 and 95.23% respectively. The emulsion and foam capacities also increased by 94.04 and 36.24%, respectively. The swelling capacity was reduced by 51.44%. The protein digestibility remained unchanged after germination due to the presence compounds as phytic acid and trypsin inhibitors activity. Three days of germination in Lupinus angustifolius are necessary to observe changes in the FP. Germinated Lupinus angustifolius flours can have multiple applications in the development of food. Germination time will depend specifically on the application, since the FP change with the germination time.
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