Relationship between microstructure formation and in vitro starch digestibility in baked gluten-starch matrices.

Increased prevalence of diabetes prompts the development of foods with reduced starch digestibility. This study analyzed the impact of adding soluble dietary fiber (inulin-IN; polydextrose-PD) to baked gluten-starch matrices (7.5-13%) on microstructure formation and in vitro starch digestibility. IN and PD enhanced water-holding capacity, the hardness of baked matrices, and lowered water activity in the formulated matrices, potentially explaining the reduced starch gelatinization degree as IN or PD concentration increased. A maximum gelatinization decrease (26%) occurred in formulations with 13% IN. Micro-CT analysis showed a reduction in total and open porosity, which, along with the lower gelatinization degree, may account for the reduced in vitro starch digestibility. Samples with 13% IN exhibited a significantly lower rapidly available glucose fraction (8.56 g/100 g) and higher unavailable glucose fraction (87.76 g/100 g) compared to the control (34.85 g/100 g and 47.59 g/100 g, respectively). These findings suggest the potential for developing healthier, starch-rich baked foods with a reduced glycemic impact.

Conformational and Structural Changes in Chickpea Proteins Caused by Simulated Salivary Alterations in the Elderly.

The impact of salivary alterations on chickpea protein structure in the elderly has not been well documented. This study aimed to understand the role of simulated salivary alterations in the conformational properties and secondary structure of the chickpea protein isolate (CPI). Whey protein isolate (WPI) was used as the reference. Protein dispersions (10%) were subjected to in vitro oral processing under simulated salivary conditions in both the elderly and adult subjects. Proteins and their oral counterparts were characterized in terms of their composition, charge, size, solubility, water absorption, molecular weight (MW), and secondary structure (Circular Dichroism and Raman spectroscopy). Under condition of simulated oral digestion in the elderly population, the ordered secondary protein structure was significantly affected, decreasing α-helix by ~36% and ~29% in CPI and WPI compared to the control (adult) population, respectively. An increase in the unordered random coil state was observed. These results could be attributed to an increase in electrolytes in the salivary composition. The structure of CPI is more stable than that of WPI because of its higher MW, more rigid structure, less charged surface, and different amino acid compositions. This study is meaningful in understanding how alterations in the elderly oral system affect protein conformation and is expected to improve the understanding of plant-based protein digestibility.

An advanced biphasic porous and injectable scaffold displays a fine balance between mechanical strength and remodeling capabilities essential for cartilage regeneration.

An important challenge in tissue engineering is the regeneration of functional articular cartilage (AC). In the field, biomimetic hydrogels are being extensively studied as scaffolds that recapitulate microenvironmental features or as mechanical supports for transplanted cells. New advanced hydrogel formulations based on salmon methacrylate gelatin (sGelMA), a cold-adapted biomaterial, are presented in this work. The psychrophilic nature of this biomaterial provides rheological advantages allowing the fabrication of scaffolds with high concentrations of the biopolymer and high mechanical strength, suitable for formulating injectable hydrogels with high mechanical strength for cartilage regeneration. However, highly intricate cell-laden scaffolds derived from highly concentrated sGelMA solutions could be deleterious for cells and scaffold remodeling. On this account, the current study proposes the use of sGelMA supplemented with a mesophilic sacrificial porogenic component. The cytocompatibility of different sGelMA-based formulations is tested through the encapsulation of osteoarthritic chondrocytes (OACs) and stimulated to synthesize extracellular matrix (ECM) components in vitro and in vivo. The sGelMA-derived scaffolds reach high levels of stiffness, and the inclusion of porogens impacts positively the scaffold degradability and molecular diffusion, improved fitness of OACs, increased the expression of cartilage-related genes, increased glycosaminoglycan (GAG) synthesis, and improved remodeling toward cartilage-like tissues. Altogether, these data support the use of sGelMA solutions in combination with mammalian solid gelatin beads for highly injectable formulations for cartilage regeneration, strengthening the importance of the balance between mechanical properties and remodeling capabilities.

Structuring of oils with high PUFA content: Evaluation of the formulation conditions on the oxidative stability and structural properties of ethylcellulose oleogels.

This study evaluated the formulation of ethylcellulose oleogels as a fat substitute, based on oils with a high content of polyunsaturated fatty acids. Optimal processing conditions for canola, linseed, and chia oil oleogels were determined. The results showed that the oxidative stability was affected to a greater extent in chia oil oleogel, however, the addition of BHT improved the oxidative stability, mainly the peroxide value. Linseed and chia oil oleogels with a high content of polyunsaturated fatty acids (64.28 and 73.02 g/100 g, respectively) were obtained despite the reduction of these with respect to their oils, and no trans fatty acids were produced. Chia oil oleogels were shown to exhibit similar physical properties to linseed oil oleogels in terms of firmness (463.51 ± 7.42 g and 443.03 ± 7.14 g respectively) and rheological behavior. Such a structure led to a dominant elastic character of the oleogels to mimic the mechanical properties of animal fat.

Food-Grade Bigels with Potential to Replace Saturated and Trans Fats in Cookies.

Fats play multiple roles in determining the desirable characteristics of foods. However, there are health concerns about saturated and trans fats. Bigels have been proposed as a novel fat replacer in foods. This research evaluated the role of the type of hydrogel in the development of bigels to be used as fat replacers in cookies. Bigels were made with beeswax/canola oil oleogel and sodium alginate and carboxymethylcellulose hydrogels. The results showed that the peroxide value and binding capacity of bigels were affected by the type of hydrogel used. However, their fatty acid profile, p-anisidine value, oxidative stability, and texture remained unchanged. Using bigels as fat replacers, cookies were obtained with a hardness similar to those with original shortening, showing the potential of bigels for use in foods.

Effect of Extrusion Temperature and Feed Moisture Content on the Microstructural Properties of Rice-Flour Pellets and Their Impact on the Expanded Product.

Extrusion can lead to an expanded product or to a slightly expanded pellet, known as a third-generation (3G) snack. In this case, expansion occurs subsequently, in an independent thermal device (e.g., oven), out of the extruded pellet. During both processes, several structural changes occur which are linked to processing conditions, including cooking temperature, screw speed, formulation, and initial moisture content. However, a clear relationship between processing variables and the structure of pellets and expanded products has not yet been identified. Accordingly, this work aimed to study the effect of extrusion temperature (110, 135, and 150 °C) and moisture content (27, 29, and 31%) in rice-flour pellets and their microwave expansion, through a microstructural approach using micro-CT. The results showed that the lowest moisture content (27%) and the highest extrusion temperature (150 °C) led to the highest pellet volume and the highest wall thickness, which in turn led to the highest expansion after microwave heating (50 s, 800 W). Interestingly, no significant differences were observed when analyzing the ratio between the volume of the expanded products and the volume of the pellet (~2.4) when using the different processing conditions.

In vivo study on the slow release of glucose in vacuum fried matrices.

In vitro studies have shown that vacuum frying may be an effective process to reduce starch digestibility as it may limit gelatinization; this is significant as overconsumption of starchy foods contributes to obesity and type 2 diabetes. Although in vitro studies are an instrumental tool, in vivo studies allow observation of the overall effect on a living organism. The aim of this research was to assess how in vivo starch digestibility can be reduced when frying under vacuum (9.9 kPa), after feeding Sprague-Dawley rats, while also understanding its relationship to in vitro starch digestibility. Results showed that vacuum-fried dough has a lower degree of gelatinization (∼53.8%) and a maximal blood glucose level at 60 min (slower glycemic response) than atmospheric counterparts (∼98.3% degree of gelatinization and maximal blood glucose level at 30 min). Similarly, in vitro procedures exhibited less rapidly available glucose and higher unavailable glucose fractions in vacuum-fried dough.

The effect of vacuum frying on starch gelatinization and its in vitro digestibility in starch-gluten matrices.

Starch digestibility in a food matrix depends on processing conditions that may affect its physical state and microstructure. Starch gelatinization is one critical change that takes place during frying which could be affected during low-pressure processing. This study assessed the effect of vacuum frying on starch gelatinization and its in vitro digestibility. Laminated dough was made of a reconstituted blend of wheat starch (88% d.b.) and gluten (12% d.b.). Samples were fried under vacuum (6.5 kPa, Twater-boiling-point=38°C) or atmospheric conditions up to bubble-end point, maintaining a thermal driving force of 70°C (Toil-Twater-boiling-point=70°C). Vacuum fried samples showed less starch gelatinization (28%), less rapidly available glucose (27%), and more unavailable glucose (70%) than their atmospheric counterparts (which presented 99% starch gelatinization, 40% rapidly available glucose, and 46% unavailable glucose), and the values were close to those of raw dough. These results show how vacuum processing may be used to control the degree of starch gelatinization and related digestibility.