Effect of Damaged Starch and Wheat-Bran Arabinoxylans on Wheat Starch and Wheat Starch-Gluten Systems.

This study investigated the impact of damaged starch and arabinoxylans on the thermal and pasting behavior of mixtures containing starch and gluten. The mixtures containing starch, arabinoxylans, and gluten were dispersed in water and a 50% sucrose solution. When arabinoxylans were added to native starch in water, it did not modify the viscosity profiles. An increase in viscosity parameters was observed due to the addition of arabinoxylans to starch with a higher level of damage. Gluten did not influence the effects caused by arabinoxylans. In the sucrose solution, arabinoxylans caused an increase in the viscosity parameters of native starch and starch with higher damage content dispersions. Gluten caused greater viscosity increases when arabinoxylans were added. In water, the addition of arabinoxylans to native starch caused a decrease in the enthalpy of gelatinization and an increase in the onset temperature. Adding arabinoxylans to starch with a higher level of damage caused the opposite effects. In the presence of sucrose, arabinoxylans caused a decrease in the enthalpy of gelatinization. These results lay the foundations for studying the influence of damaged starch and arabinoxylans in water-rich systems characterized by the presence of substantial proportions of sucrose, such as batter formulations.

Chia Oil Microencapsulation Using Tannic Acid and Soy Protein Isolate as Wall Materials.

The use of proteins to produce oil-containing microcapsules has been previously analyzed; however, their chemical modification, in order to improve their performance as wall materials, is a strategy that has not been widely developed yet. This study aimed to analyze the chemical modification of the proteins through cross-linking reactions with tannic acid and to evaluate their performance as wall materials to the microencapsulation of oils rich in polyunsaturated fatty acids. The cross-linking reaction of isolated soy protein and tannic acid was carried out at pH 10-11 and 60 °C. Subsequently, emulsions were made with a high-speed homogenizer and microcapsules were obtained by spray drying. Microcapsules were characterized by particle size, morphology (SEM), total pore area and % porosity (mercury intrusion methodology), superficial properties (contact angle), and size distribution of oil droplets (by laser diffraction). Additionally, encapsulation efficiency was determined as a function of total and surface oil. Oil chemical stability and quality were studied by Rancimat, hydroperoxide values, and fatty acid profiles. In addition, a storage test was performed for 180 days, and released oil and polyphenols were determined by in vitro gastric digestion. Moreover, the fatty acid composition of the oil and the total polyphenol content and antioxidant capacity of polyphenols were analyzed. The results showed that spray-dried microcapsules had an encapsulation efficiency between 54 and 78%. The oxidative stability exhibited a positive correlation between the amount of polyphenols used and the induction time, with a maximum of 27 h. The storage assay showed that the peroxide value was lower for those cross-linked microcapsules concerning control after 180 days. After the storage time, the omega-3 content was reduced by 49% for soy protein samples, while cross-linked microcapsules maintained the initial concentration. The in-vitro digestion assay showed a decrease in the amount of oil released from the cross-linked microcapsules and an increase in the amount of polyphenols and a higher antioxidant capacity for all samples (for example, 238.10 mgGAE/g and 554.22 mg TE/g for undigested microcapsules with TA 40% versus 322.09 mgGAE/g and 663.61 mg TE/g for digested samples). The microcapsules showed a high degree of protection of the encapsulated oil, providing a high content of polyunsaturated fatty acids (PUFAS) and polyphenols even in prolonged storage times.

Sorghum (Sorghum bicolor L. Moench) Gluten-Free Bread: The Effect of Milling Conditions on the Technological Properties and In Vitro Bioaccessibility of Polyphenols and Minerals.

The absence of gluten proteins in sorghum allows for the production of baked goods that are suitable for celiacs. Previous studies have shown that the milling process affects the performance of sorghum flour in baked products, especially those that are gluten-free (GF). This study aimed to explore the effects of mill type (impact and roller) on flour properties and GF bread quality by assessing the technological quality, antioxidant activity, and mineral content of the bread. All particle populations of flour obtained via both millings presented a bimodal distribution, and the volume mean diameter (D 4,3) ranged from 431.6 µm to 561.6 µm. The partially refined milled flour obtained via polishing and impact milling produced bread with a soft crumb, fewer but larger alveoli in the crumb, and a structure that did not collapse during baking, showing the best performance in bread quality. In the in vitro bread digestibility assay, the total polyphenol content and antioxidant activity decreased during the digestion steps. High mineral (Cu, Fe, Mn, and Zn) contents were also found in a portion of the bread (120 g) made with whole sorghum flour; however, their potential bioavailability was reduced in the presence of a higher amount of bran.

Complex coacervation and freeze drying using whey protein concentrate, soy protein isolate and arabic gum to improve the oxidative stability of chia oil.

BACKGROUND: Chia oil (CO) is popular for being the richest vegetable source of α-linolenic acid (60-66%). However, this content of polyunsaturated fatty acids (PUFA) limits the incorporation of bulk CO in food products due to its high probability of oxidation. This justifies the study of alternative wall materials for microencapsulation. No reports regarding the use of dairy protein/vegetable protein/polysaccharide blends as wall material for the microencapsulation of CO have been published. Therefore, this work analyzed the behavior of a whey protein concentrate (WPC)/soy protein isolate (SPI)/arabic gum (AG) blend as wall material. The complex coacervation (CC) process was studied: pH, 4.0; total solid content, 30% w/v; WPC/SPI/AG ratio, 8:1:1 w/w/w; stirring speed, 600 rpm; time, 30 min; room temperature. RESULTS: The oxidative stability index (OSI) of CO (3.25 ± 0.16 h) was significantly increased after microencapsulation (around four times higher). Furthermore, the well-known matrix-forming ability of AG and WPC helped increase the OSI of microencapsulated oils. Meanwhile, SPI contributed to the increase of the encapsulation efficiency due to its high viscosity. Enhanced properties were observed with CC: encapsulation efficiency (up to 79.88%), OSIs (from 11.25 to 12.52 h) and thermal stability of microcapsules given by the denaturation peak temperatures of WPC (from 77.12 to 86.00 °C). No significant differences were observed in the fatty acid composition of bulk and microencapsulated oils. CONCLUSION: Microcapsules developed from complex coacervates based on the ternary blend represent promising omega-3-rich carriers for being incorporated into functional foods.

Influence of damaged starch on thermal and rheological properties of wheat starch and wheat starch-gluten systems in water and sucrose.

BACKGROUND: The granular integrity of starch granules is affected by the mechanical action of the milling-process, thus producing what is called damaged starch (DS). The effect of DS on bakery products was extensively studied, but there is not much information about the effect of this minor flour component on batter-type products in which there is a high amount of sucrose. The objective of this work was to study the influence of damaged wheat-starch on starch and starch-gluten systems dispersed in water and sucrose 500 g kg-1 solution. RESULTS: Thermal and pasting properties and the viscoelastic behavior of the systems were evaluated. Gelatinization enthalpy decreased when DS amount increased in the samples in both solvents. In starch-gluten systems, the degree of influence of DS on the gelatinization enthalpy was solvent-dependent. The presence of gluten minimized the effect of DS on the gelatinization process in water. The viscosity profile of starch and starch-gluten samples was reduced in both solvents when DS level increased. The influence of DS on the viscosity profile was solvent-dependent in starch-gluten systems. The presence of gluten lessened the influence of DS on the viscosity profile during the pasting process in sucrose solution. Higher DS levels decreased the viscoelastic behavior of the systems in both solvents and further reduced the viscoelastic behavior of the systems in sucrose solution. CONCLUSION: These results contribute to understanding the influence of the DS levels on the batter properties of flour-based batter-type products, mainly those generated on starch and gluten-starch systems dispersed in sucrose solution. © 2022 Society of Chemical Industry.

NMR characterization of structure and moisture sorption dynamics of damaged starch granules.

Among the many biopolymers that constitute food products, starch is one of the most common. Starch granules are often damaged in the milling process, which affects the final product quality, mainly due to changes in water adsorption properties. In this work, the crystallinity degree of wheat starch samples as a function of the mechanical damage is determined by low field 1H NMR. We also introduce the use of single-sided NMR to determine granular swelling, water distribution and sorption dynamics of the samples. Results show that the crystallinity of the samples decreases with the milling. We also observed that swelling index and sorption capacity values are higher in the milled samples than in the native starch. Our experiments show how single-sided NMR is a valuable tool to provide information on dynamic processes not only in starch, but also in many carbohydrate polymeric samples with the additional benefit of spatial resolution.

Effect of microwave and hot air treatment on enzyme activity, oil fraction quality and antioxidant activity of wheat germ.

The aim of this work was to study the effects of microwaves (MW) and hot air (HA) treatments on enzyme activities and quality parameters in wheat germ (WG). Both MW and HA were effective at inactivating lipases. MW treatment inactivated lipases more at lower temperatures (60 and 70 °C) than HA (150-200 °C). Peroxide values, acidity, and fatty acid profiles of WG oil remained unaltered after HA and MW treatments. Loss of α-tocopherol contents was observed following HA treatment, but total tocopherol content remained above 77% baselines values in all treated samples. The main antioxidant mechanism of WG extracts was associated with inactivation of radicals, rather than reducing capacity. MW treatment at 60 and 70 °C enhanced radical scavenging activity, while total polyphenol contents and reducing capacities were negatively affected. Therefore, MW treatment is a promising technology to stabilise WG, retaining quality and antioxidant activity.

Sorghum Pasta and Noodles: Technological and Nutritional Aspects.

Sorghum is a major cereal crop with various agronomic advantages, contains health-promoting compounds and is gluten-free. There is a growing tendency to use sorghum in pasta and noodle formulations, which are among the most widely consumed products in the world, but its potential benefits in human diet are not being fully exploited. Here we review research carried out during the past few years on the use of sorghum as the main ingredient or as an additive in pasta and noodles, highlighting its properties and production technology. Pasta and noodles can be produced with 5 to 100% of sorghum at laboratory, pilot or industrial scale with suitable cooking and textural quality coupled with distinctive sensory attributes. Cooking loss shows minimum values of 0.85 and 1.9 g/100 g for pasta and noodles, respectively, and high water absorption (up to 345 g/100 g). The interesting nutritional profile of the products generally includes up to 45% resistant starch (RS) and phenolic compound content with high antioxidant activity. In addition, tannins decrease starch digestibility 15-20%, producing low glycemic index (GI) products (below 65). This is especially important for celiac people, offering them the alternative of gluten-free sorghum pasta and noodles.

Physico-chemical characterization of protein fraction from stabilized wheat germ.

Wheat germ shows the highest nutritional value of the kernel. It is highly susceptible to rancidity due to high content of unsaturated fat and presence of oxidative and hydrolytic enzymes. In order to improve its shelf life, it is necessary to inactivate these enzymes by a thermal process. In this work the functional properties and some characteristics of the protein fraction of treated wheat germ were evaluated. Sequential extraction of proteins showed loss of protein solubility and formation of aggregates after heating. DSC thermograms showed that wheat germ treated for 20 min at 175 °C reached a protein denaturation degree of ~ 77%. The stabilization process of wheat germ affected significantly some functional properties, such as foaming stability and protein solubility at pH 2 and pH 8. Nevertheless, heating did not affect the water holding, oil holding and foaming capacity of protein isolates.

Impact of chemical modifications in pilot-scale isolated sorghum starch and commercial cassava starch.

The aim of this work was to evaluate the impact of different chemical modification methods on starch from different botanical sources. Brown and white sorghum starch was isolated throughout a time saving process and avoiding the use of dangerous compounds. Brown and white sorghum and commercial cassava starch were treated using acetic acid, acetic anhydride and octanoyl chloride. Its chemical, morphological and thermal characterization was afterwards carried out. The modifications reduced amylose content and increased damaged starch. Both acetylation and acid treatment produced no significant changes in the size and shape of granules; yet, they increased superficial pores. SEM observations supported the results, indicating that octanoyl modification causes a partial destruction of the granule structure. Thus, particle size distribution changes significantly. Crystallinity degree decreased with all the modifications. However, the effect was more pronounced in octanoyl esterification. In general, modifications increase the water absorption of the native starch but no considerable effect was found over oil absorption, and gelatinization parameters were significantly altered as a result of modifications. Starch from these subtilized sources was successfully modified, which could arouse interest in its industrial production.

Enhancement of Composition and Oxidative Stability of Chia (Salvia hispanica L.) Seed Oil by Blending with Specialty Oils.

Chia seed (Salvia hispanica L.) oil is mainly composed of ω-3 fatty acids (61% to 70%). Despite being nutritionally favorable, higher amounts of polyunsaturated fatty acids result in poorer oxidative stability. Thus, the aim of this work was to produce edible vegetable oil blends rich in ω-3 fatty acids and with greater oxidative stability than pure chia oil. Blending of chia with other specialty oils (walnut, almond, virgin, and roasted sesame oils) was assessed in the following respective proportions: 20:80, 30:70, and 40:60 (v/v). An accelerated storage test was conducted (40 ± 1 °C, 12 days). Primary and secondary oxidation products, free fatty acid content, antioxidant compounds, fatty acid composition, and induction time were determined. The blends presented higher oxidative stability indices than chia oil. Sensory analysis showed that, given a pure oil, judges did not identify statistically significant differences among the blends. The results suggest that blending of chia oil is an adequate alternative to obtain ω-3-enriched oils with higher oxidative stability indices. PRACTICAL APPLICATION: Vegetable oil blending is a widely used practice in the edible oil industry to produce blended oils with enhanced stability and nutritional and sensory properties at affordable prices. The blends developed in this study from chia, sesame, walnut, and almond oils take advantage of the properties of each parent oil to yield products with improved oxidative stability, essential fatty acid presence, and sensory characteristics. To achieve a daily intake of 2.22 g/day of ω-3 fatty acids as recommended by the Intl. Society for the Study of Fatty Acids and Lipids (ISSFAL), it is necessary to consume approximately one spoonful of the formulated mixtures.

Effect of Ingredients on the Quality of Gluten-Free Sorghum Pasta.

Sorghum is an underutilized cereal in human food production, despite its flour being a potential gluten-free (GF) source in the development of several foods. Thus, the aim of the present investigation was to evaluate the effects and interactions of different ingredients on cooking quality and texture of GF pasta. Egg albumen (A), egg powder (E), xanthan gum (X), and pregelatinized corn starch (P) were used as ingredients, and Box-Behnken experimental design was applied to study the effects of these ingredients on pasta cooking behavior, color, and texture attributes. Responses were fitted to a second order polynomial equation, and multivariable optimization was performed using maximization of general desirability. Next, optimal formulations were validated, compared with two commercial gluten-free pastas by sensory evaluation, and finally, an industrial assay was carried out. Regression coefficients indicated that A and P improved cooking properties while A and E contributed the most to improving the pasta textural properties. As, X and P effects varied depending on the kind of sorghum flour used, the optimal formulations levels were different, but in both cases these models were satisfactory and capable of predicting responses. The industrial assay was carried out with white sorghum flour because it showed a higher acceptability in the sensory evaluation than brown sorghum flour pasta. This industrially made pasta resulted in slightly better cooking properties than the laboratory produced one, with the formulation adapting well to the conventional wheat pasta industrial process. Gluten-free sorghum pasta was produced, showing good cooking and textural properties and being a suitable option for gluten-sensitive individuals.

Differential scanning calorimetry (DSC) studies on the thermal properties of peanut proteins.

Studies related to the functional and thermal properties of peanut proteins are limited if compared with other vegetable protein sources. The aim of this work was to study the thermal denaturation of peanut protein isolates (PPI) by DSC. The thermal profile of PPI showed two endothermic peaks (assigned to denaturation of arachin and conarachin fractions). The thermal stability of arachin and conarachin increased when water content decreased, and a critical water level was found for both fractions. The effect of protein denaturants was studied. Low contents of urea stabilized protein fractions, but lower T(d) values were found with increasing concentrations. DeltaH values of arachin were affected by urea. SDS affected DeltaH values and thermal stability of conarachin; the arachin fraction showed higher resistance to SDS-induced denaturation. DTT addition did not affect conarachin stability, although enthalpy values decreased significantly. On the other hand, arachin was greatly affected by DTT. In summary, thermal denaturation parameters of PPI were sensitive to water content, indicating that polar groups of arachin and conarachin contribute to structure stabilization. Urea addition mainly affected the structure of the arachin fraction, which was attributed to its higher surface hydrophobicity. Results obtained from SDS and DTT suggest that hydrophobic interactions and disulfide bonds play an important role in structure maintenance of arachin and conarachin.