Effect of polyphenols from Ascophyllum nodosum seaweeds on the rheology and digestion of corn starch gels and gluten-free bread features.

The main objective of this work is to study the effect of polyphenols, from the brown seaweed Ascophyllum nodosum, on the structure and digestion behaviour of gels at two corn starch concentrations (1.95 and 5.00% w/w) as well as the structure, color and texture features of crumbs from gluten-free breads. Adsorption isotherms of polyphenols on native and gelled starches were carried out and modelled by means of Langmuir and Henry models, respectively. The formation and characteristics of tested gels were rheologically monitored by means of heating ramp, time sweep at high temperature, cooling ramp and frequency sweep at 25 °C. Elastic modulus values decreased with the presence of polyphenols. Additionally, the polyphenols significantly decreased the digestion rate, measured by both chemical and rheological procedures, and the final concentration of digested starch. Finally, the presence of polyphenols in breads increased the hardness and chewiness values and decreased the cohesiveness and resilience values as well as the crumb hardening during storage.

Relationship between Physicochemical and Cooking Quality Parameters with Estimated Glycaemic Index of Rice Varieties.

Rice is a significant staple food in the basic diet of the global population that is considered to have a high glycaemic index. The study of the physical and chemical parameters in rice that are related to the starch digestion process, which allows us to quickly predict the glycaemic index of varieties, is a major challenge, particularly in the classification and selection process. In this context, and with the goal of establishing a relationship between physicochemical properties and starch digestibility rates, thus shedding light on the connections between quality indicators and their glycaemic impact, we evaluated various commercial rice types based on their basic chemical composition, physicochemical properties, cooking parameters, and the correlations with digestibility rates. The resistant starch, the gelatinization temperature and the retrogradation (setback) emerge as potent predictors of rice starch digestibility and estimated glycaemic index, exhibiting robust correlations of r = -0.90, r = -0.90, and r = -0.70 (p ≤ 0.05), respectively. Among the rice types, Long B and Basmati stand out with the lowest estimated glycaemic index values (68.44 and 68.10), elevated levels of resistant starch, gelatinization temperature, and setback values. Furthermore, the Long B showcases the highest amylose, while the Basmati with intermediate, revealing intriguingly strong grain integrity during cooking, setting it apart from other rice varieties.

Unraveling the impact of viscosity and starch type on the in vitro starch digestibility of different gels.

Starch is one of the most important carbohydrates that is present in many foods. Gelatinization is an important property of starch, associated with physical changes that promote an increase in viscosity. The objective of this research was to understand how the viscosity of starch gels affects their hydrolysis and whether that effect was dependent on the type of starch. Different gels (corn, wheat, and rice) with variable or constant viscosity were analyzed using diverse methodologies to determine the changes in the pasting behavior. A rapid force analyzer, a vibration viscometer and a rheometer were used to differentiate the gels based on the starch source and concentration. At a fixed starch concentration, corn gel displayed the highest viscosity, slowing the enzymatic starch hydrolysis. The higher viscosity of those gels prepared with a fixed starch concentration significantly enhanced the slowly digestible starch (SDS) and reduced the kinetic constant (k). Nevertheless, gels with constant viscosity (550 mPa s) showed comparable hydrolysis kinetics, obtaining similar SDS, total hydrolyzed starch and k. The correlation matrix confirmed the relationship between k and gel viscosity (r = -0.82), gelatinization rate (α-slope) (r = -0.87), breakdown (r = -0.84) and elastic modulus (G' 37 °C) (r = -0.73). Therefore, these parameters could be used as predictors of the hydrolysis performance of starch gels as well as in reverse engineering for the design of healthy foods.

Estimation of viscosity and hydrolysis kinetics of corn starch gels based on microstructural features using a simplified model.

Viscosity is an important rheological property, which may have impact on the glycemic response of starchy foods. However, the relationship between starch gels viscosity on its hydrolysis has not been elucidated. The aim of this work was to assess the effect of gels viscosity on the microstructure, and the kinetics of enzymatic hydrolysis of starch. Corn starch gels were prepared from starch:water ratios varying from 1:4 to 1:16. A structural model was proposed that correlated (R-square = 0.98) the porous structure (cavity sizes, thickness walls) of gels and its viscosity. Kinetics constants of hydrolysis decreased with increasing starch content and consequently with gel viscosity. Relationships of viscosity with the microstructural features of gels suggested that enzyme diffusion into the gel was hindered, with the subsequent impact on the hydrolysis kinetics. Therefore, starch digestibility could be governed by starch gels viscosity, which also affected their microstructure.

Interaction of dough acidity and microalga level on bread quality and antioxidant properties.

Microalgae nutritional and healthy dietary pattern might be affected by processes like breadmaking when used as ingredient. This study aims to determine the role of dough acidification on the nutritional pattern of Chlorella vulgaris enriched breads. Different levels of microalga (1%, 2% and 3%) were incorporated in the recipe in the presence of either 10% sourdough or chemically acidified doughs. Dough and bread characteristics were evaluated. Addition of microalga reduced the slice area and increased the crumb hardness, but it could be counteracted by increasing dough hydration and adapting proofing time. Doughs and breads enriched with microalga had green color. Dough acidification led to softer breads and enhanced the antioxidant activity of enriched breads. Microalgae incorporation increased the protein and ash content of the breads. Microalgae enriched breads made with chemically acidified doughs or sourdoughs had higher Total Phenolic Content and antioxidant activity as assessed by FRAP and ABTS methods.

Differential effectiveness of tyrosine kinase inhibitors in 2D/3D culture according to cell differentiation, p53 status and mitochondrial respiration in liver cancer cells.

Sorafenib and Regorafenib are the recommended first- and second-line therapies in patients with advanced hepatocellular carcinoma (HCC). Lenvatinib and Cabozantinib have shown non-inferior antitumoral activities compared with the corresponding recommended therapies. The clinical trials have established recommended doses for each treatment that lead different blood concentrations in patients for Sorafenib (10 µM), Regorafenib (1 µM), Lenvatinib (0.1 µM), and Cabozantinib (1 µM). However, very low response rates are observed in patients attributed to intrinsic resistances or upregulation of survival signaling. The aim of the study was the comparative dose-response analysis of the drugs (0-100 µM) in well-differentiated (HepG2, Hep3B, and Huh7), moderately (SNU423), and poorly (SNU449) differentiated liver cancer cells in 2D/3D cultures. Cells harbors wild-type p53 (HepG2), non-sense p53 mutation (Hep3B), inframe p53 gene deletion (SNU423), and p53 point mutation (Huh7 and SNU449). The administration of regular used in vitro dose (10 µM) in 3D and 2D cultures, as well as the dose-response analysis in 2D cultures showed Sorafenib and Regorafenib were increasingly effective in reducing cell proliferation, and inducing apoptosis in well-differentiated and expressing wild-type p53 in HCC cells. Lenvatinib and Cabozantinib were particularly effective in moderately to poorly differentiated cells with mutated or lacking p53 that have lower basal oxygen consumption rate (OCR), ATP, and maximal respiration capacity than observed in differentiated HCC cells. Sorafenib and Regorafenib downregulated, and Lenvatinib and Cabozantinib upregulated epidermal growth factor receptor (EGFR) and mesenchymal-epithelial transition factor receptor (c-Met) in HepG2 cells. Conclusions: Sorafenib and Regorafenib were especially active in well-differentiated cells, with wild-type p53 and increased mitochondrial respiration. By contrast, Lenvatinib and Cabozantinib appeared more effective in moderately to poorly differentiated cells with mutated p53 and low mitochondrial respiration. The development of strategies that allow us to deliver increased doses in tumors might potentially enhance the effectiveness of the treatments.

Evaluation of Starch⁻Protein Interactions as A Function of pH.

Protein-starch gels are becoming more common in food processing when looking for enriched foods. However, processing conditions scarcely are considered when producing those gels. The aim of this research was to study the effect of processing pH (4.5, 6.0, and 7.5) on the hydration and pasting properties, gel microstructure, and texture of corn starchy gels made with four different proteins (pea, rice, egg albumin, and whey) at a ratio of 1:1 starch/protein and a solid content of 12.28%. The water binding capacity of the starch-protein mixtures was positively influenced by low solubility of the protein used. Acidic pH decreased the apparent peak viscosity of both starch and starch-protein mixtures, with the exception of starch-albumin blends, which increased it. The gels' microstructure showed that the uniformity of the protein-enriched gels was dependent on protein type and pH, leading to diverse hardness. In general, the starchy gels containing animal proteins (albumin and whey) were more affected by pH than those obtained with vegetal proteins (pea and rice). Therefore, processing pH might be an advisable method to modify the functionality of starch-protein gels.

Understanding the effect of emulsifiers on bread aeration during breadmaking.

BACKGROUND: Much research has been done to explain the action of emulsifiers during breadmaking, but there is still plenty unknown to elucidate their functionality despite their diverse chemical structure. The aim of the present study was to provide some light on the role of emulsifiers on air incorporation into the dough and gas bubbles progress during baking and their relationship with bread features. Emulsifiers like diacetyl tartaric acid ester of monoglycerides (DATEM), sodium stearoyl lactylate (SSL), distilled monoglyceride (DMG-45 and DMG-75), lecithin and polyglycerol esters of fatty acids (PGEF) were tested in very hydrated doughs. RESULTS: Emulsifiers increase the maximum dough volume during proofing. Emulsifiers increase the number of bubbles incorporated during mixing, observing higher number of bubbles, particularly with PGEF. Major changes in dough occurred at 70 K when bubble size augmented, becoming more heterogeneous. DMG-75 produced the biggest bubbles. As a consequence, emulsifiers tend to increase the number of gas cells with lower size in the bread crumb, but led to greater crumb firmness, which suggested different interactions between emulsifiers and gluten, affecting protein polymerization during baking. CONCLUSION: The progress of the bubbles during baking allowed the differentiation of emulsifiers, which could explain their performance in breadmaking. © 2018 Society of Chemical Industry.

Use of high hydrostatic pressure to inactivate natural contaminating microorganisms and inoculated E. coli O157:H7 on Hermetia illucens larvae.

A chemical and microbiological characterization on Hermetia illucens larvae was carried out as well as an inactivation study of natural contaminating microorganisms and inoculated E. coli O157:H7 in black soldier larvae by using High Hydrostatic Pressure (250 to 400 MPa, for 1.5 to 15 min). Hermetia illucens was mainly composed of proteins (46.49%, d.m.) followed by fat (37.88%, d.m.). Larvae had a high contamination load of Total Aerobic Mesophilic bacteria (AMB) (1.58x107 cfu/g) and Enterobacteriaceae (1.15x106cfu/g). The presence of pathogenic microorganism varied: no Listeria spp. were found, but Salmonella (1.15x106 cfu/g) and E. coli (7.08x105 cfu/g) were detected in the larvae extract. High Hydrostatic Pressure (HHP) was effective against natural contaminating yeasts and molds producing more than 5 log cycle reductions at 400 MPa for any of the times considered (2.5 to 7 min), but a low reduction of total microbial load was achieved. The inactivation level of larvae inoculated with E. coli O157:H7 varied. At 400 MPa for 7 min more than 5 log cycle reductions were achieved. Among the three inactivation models studied, the one that best described the inactivation pattern of the cells, according to the Akaike index, was the Biphasic model.

Mimicking gluten functionality with ß-conglycinin concentrate: Evaluation in gluten free yeast-leavened breads.

Fractionation of soy proteins has proved to produce protein concentrates with viscoelastic properties. In the present study, a ß-conglycinin concentrate (ßCC) obtained by a pH fractionation of soy flour was tested as structuring agent in gluten-free yeast-leavened bread model. A lean formulation with ßCC and corn starch was used to produce gluten-free breads with two hydration conditions and three levels of protein (5%, 10% and 15%). Vital gluten was used to compare the functionality of ßCC protein and its performance for breadmaking. Breads were characterized in moisture, color, textural parameters and image analysis. ßCC presented lower hydration properties and higher emulsifying activity compared to vital gluten. Blends ßCC:starch had higher water binding capacity compared to vital gluten blends. The hydration conditions tested affected the moisture, color and cell density of breads. Breads produced with ßCC presented higher 2D area and height and presented higher crumb softness and cohesiveness, and did not present significant differences in springiness and resilience compared to vital gluten breads. The image analysis of crumbs showed higher cell density but lower porosity and mean cell areas in ßCC breads. Thus, ßCC proved to have potential as a structuring agent in gluten-free breads.

Germinated, toasted and cooked chickpea as ingredients for breadmaking.

The effect of processing (germination, toasting and cooking) of chickpea beans was investigated on the resulting flours characteristics and their potential for obtaining gluten free breads. Rheological properties of dough were recorded using Mixolab(®) and breads were analyzed for their instrumental quality, nutritional and sensory properties. Chickpea based doughs showed low consistency and their rheological behavior was defined by the starch gelatinization and gelification. The bread made with cooked chickpea flour exhibited the lowest specific volume (0.58 mL/g), brightest crumb (L* = 76.20) and the softest texture, but cooking decreased the content of carbohydrates, ash and protein, although increased the protein digestibility. The highest specific volume was obtained in bread made with toasted chickpea flour, although crumb hardness was higher. Overall, processing of chickpea beans, concretely toasting and cooking led to flours that could be used for obtaining gluten free breads with the nutritional characteristics of the legumes and acceptable sensory characteristics.