Amparo Quiles

Impact of High Hydrostatic Pressure and Pasteurization on the Structure and the Extractability of Bioactive Compounds of Persimmon “Rojo Brillante”

Rojo Brillante is an astringent oriental persimmon variety with high levels of bioactive compounds such as soluble tannins, carotenoids, phenolic acids, and dietary fiber. The purpose of this study was to investigate the effects of high hydrostatic pressure (HHP) and pasteurization on the structure of the fruit and on the extractability of certain bioactive compounds. The microstructure was studied using light microscopy, transmission electron microscopy, and low temperature scanning electron microscopy, and certain physicochemical properties (carotenoid and total soluble tannin content, antioxidant activity, fiber content, color, and texture properties) were measured. The structural changes induced by HHP caused a rise in solute circulation in the tissues that could be responsible for the increased carotenoid level and the unchanged antioxidant activity in comparison with the untreated persimmon. In contrast, the changes that took place during pasteurization lowered the tannin content and antioxidant activity. Consequently, HHP treatment could improve the extraction of potentially bioactive compoundsxsts from persimmons. A high nutritional value ingredient to be used when formulating new functional foods could be obtained using HHP.

Changes in the structure and antioxidant properties of onions by high pressure treatment

Onions have antioxidant properties and they are an important source of bioactive compounds such as phenols. The aim of this work was to study the effect of high hydrostatic pressure (HHP) (100-600 MPa/1-3 min/25 °C) on the microstructure and antioxidant properties of onions (cv. Doux) and its relationship with changes in the extractability of potential health-related compounds. Cryo scanning electron microscopy was used to study the microstructure. Vitamin C, total phenolic content and antioxidant activity (DPPH˙, ABTS˙(+), FRAP) were also analyzed. Tonoplast, plasmalemma and cell walls were affected by the HHP treatment and it favored the diffusion of the cellular content to the intercellular spaces. Vitamin C did not show significant changes, whereas the extracted phenolic content and antioxidant activity increased at pressures of 300 or 600 MPa. Therefore, it could be concluded that HHP produced changes in membrane permeability and disruption of cell walls favoring the release of phenolic compounds from tissue and, in consequence, improving their extractability.

Microstructural, Physical, and Sensory Impact of Starch, Inulin, and Soy Protein in Low‐Fat Gluten and Lactose Free White Sauces

UNLABELLED The microstructural, physical, and sensory properties of low-fat sauces made with different starches, soy protein, and inulin as a fat replacer were analyzed. Gluten-free waxy starches-rice and corn-were selected as well as soy protein to obtain sauces suitable for celiac and lactose intolerant consumers. Light microscopy was used to visualize the swollen starch granules dispersed in a protein-amylopectin-inulin phase. Inulin seemed to limit protein network development, which was related with a higher dispersion of starch granules within the sauce matrix. Therefore, the sauces made with inulin had a lower apparent viscosity (η(app)) values (P < 0.05) in comparison with oil sauces. The sauces made with rice starches also exhibited a lower viscosity (P < 0.05) since these granules did not swell as corn granules do. All the sauces had a remarkable physical stability since there were no syneresis phenomena and color did not change significantly (P < 0.05) after 15 d of refrigeration storage (4 °C). Finally, the sensory test suggests that oil could be substituted by inulin in the preparation of low-fat sauces since no significant differences (P < 0.05) in texture and flavor were found. These results encourage further research to optimize the formulations of these types of alternative white sauces. PRACTICAL APPLICATION Nowadays there is a great demand of ready-to-eat products due to new consumptions habits. In this context, it would be interesting to develop low-fat sauces with inulin that could be used in this type of products improving their nutritional profile. The requirement of processed food for specific groups of population, such as celiac and lactose intolerant consumers, makes it necessary to use gluten free starches and soy protein in the formulation of sauces. The characterization of structural, physical and sensory properties is required to understand the product acceptability and its behavior during its shelf life.

Designing dairy desserts for weight management: Structure, physical properties and in vitro gastric digestion

The first aim of this study was to observe the effect of adding dairy proteins and reducing the cream content in order to obtain healthier dairy desserts for use in weight management. The extra-whey protein low-cream sample had the densest, firmest matrix, which is related to increased satiety. The second aim was to investigate the in vitro gastric digestion behavior of whey and casein proteins in a heat-treated semisolid real food. The extra-casein protein sample matrix broke down more slowly than the others because the caseins clotted at the gastric pH. Despite being heated, the whey proteins in the panna cottas were more resistant to pepsin digestion than caseins; this is related with a higher satiety capacity. These findings suggest that the combination of reducing fat content (to obtain a reduced energy density product) and adding whey protein (to increase satiety capacity) allows obtaining dairy desserts for weight management.

Fiber from fruit pomace: A review of applications in cereal-based products

ABSTRACT Fruit pomace is a by-product of the fruit processing industry composed of cell wall compounds, stems, and seeds of the fruit; after washing, drying, and milling, a material high in fiber and bioactive compounds is obtained. In bakery products, dried fruit pomace can be added to replace flour, sugar, or fat and thus reduce energy load while enhancing fiber and antioxidant contents. The high fiber content of fruit pomace, however, results in techno-functional interactions that affect physicochemical and sensory properties. In this article, different sources of fruit pomace are discussed along with their application in bread, brittle and soft bakery products, and extrudates.

Tissue microstructure, physicochemical properties, and bioactive compound locations in different sweet pepper types:

This article focuses on the location and content of some bioactive compounds in three different California sweet pepper types (red, green and yellow). The location was studied using different microscopic techniques, such as scanning electron microscopy at low temperatures (cryo-SEM) and light microscopy. Several physicochemical properties of the samples (carotenoid content, total soluble phenol content, antioxidant activity, dietary fibre content, total soluble solids content, pH and textural properties) were also examined. The degree of compaction and structuring of the cell wall was found to be indirectly related to solute transport at the cellular level and directly related to total dietary fibre content. The three types of pepper displayed formation and accumulation of phenolic aggregates and an active circulation of solutes. Yellow pepper tissue had the most labile cell walls and the highest transport of solutes. Red peppers could be suitable for obtaining extracts rich in carotenoid compounds, yellow peppers for obtaining phenolic compounds with a high antioxidant activity and green peppers for extracts with high dietary fibre content.

New formulations of functional white sauces enriched with red sweet pepper: a rheological, microstructural and sensory study

Red sweet peppers are good sources of antioxidant compounds, such as fibre and carotenoids. Therefore, innovative products that may replace traditional ones, such as white sauces enriched with red sweet pepper, should be developed to improve their functionality. The aim of this work was to study the rheological behaviour, microstructure, syneresis, colour, sensory characteristics and consumer acceptability of new white sauces enriched with red sweet pepper. The results of the rheological studies (viscoelastic behaviour) showed that in the available frequency window all the sauces showed a predominance of the elastic modulus versus the viscous modulus. The effect of incorporating red pepper on the rheological properties depended upon the type of starch used. Microstructure of native starch sauces showed a complex matrix composed of protein and amylose and amylopectin leached from the granules that have been disintegrated during the sauce elaboration. Fat globules were homogenously dispersed and associated with the protein phase. Modified starch sauces showed more swollen starch granules compared with native starch sauces and a protein matrix stabilising the fat globules. All the sauces exhibited considerable intrinsic autofluorescence due to the presence of carotenoids from the red pepper. Consumers scored the modified starch sauces regardless of the starch concentrations based on their highest overall liking and found them beneficial for health. Therefore, new white sauces with high nutritional value, high acceptability, good rheological properties and stability against syneresis could be formulated using red pepper and modified starch.

Designing a Clean Label Sponge Cake with Reduced Fat Content

The fat in a sponge cake formulation was partially replaced (0%, 30%, 50%, and 70%) with OptiSol™5300.This natural functional ingredient derived from flax seeds, rich in fiber and alpha-linoleic acid, provides a natural substitute for guar and xanthan gums, avoiding E-numbers on labels. The structure and some physicochemical properties of the formulations were examined, sensory analysis was conducted and changes in starch digestibility due to adding this ingredient were determined. Increasing quantities of OptiSol™5300 gave harder cakes, with less weight loss during baking, without affecting the final cake height. There were no significant differences (P > 0.05) in texture, flavor and overall acceptance between the control and the 30% substitution cake, nor in the rapidly digestible starch values. Consequently, replacing up to 30% of the fat with OptiSol™5300 gives a new product with health benefits and a clean label that resembles the full-fat sponge cake.

High hydrostatic pressure as a method to preserve fresh-cut Hachiya persimmons: A structural approach

The “Hachiya” persimmon is the most common astringent cultivar grown in California and it is rich in tannins and carotenoids. Changes in the microstructure and some physicochemical properties during high hydrostatic pressure processing (200–400 MPa, 3 min, 25 ℃) and subsequent refrigerated storage were analyzed in this study in order to evaluate the suitability of this non-thermal technology for preservation of fresh-cut Hachiya persimmons. The effects of high-hydrostatic pressure treatment on the integrity and location of carotenoids and tannins during storage were also analyzed. Significant changes, in particular diffusion of soluble compounds which were released as a result of cell wall and membrane damage, were followed using confocal microscopy. The high-hydrostatic pressure process also induced changes in physicochemical properties, e.g. electrolyte leakage, texture, total soluble solids, pH and color, which were a function of the amount of applied hydrostatic pressure and may affect the consumer acceptance of the product. Nevertheless, the results indicate that the application of 200 MPa could be a suitable preservation treatment for Hachiya persimmon. This treatment seems to improve carotenoid extractability and tannin polymerization, which could improve functionality and remove astringency of the fruit, respectively.

Structural changes in biscuits made with cellulose emulsions as fat replacers

Biscuits are a popular baked cereal food much appreciated by consumers. In the last few years, cellulose derivatives have been successfully used as fat replacers in biscuits. In this way, not only is the total amount of fat reduced but also the saturated fatty acids and the trans fatty acids are eliminated. The aim of this study is to increase understanding of the functionality of different cellulose ether emulsions used as fat replacers in biscuits. For this purpose, three emulsions with different cellulose ethers were designed: hydroxypropyl methylcellulose, methylcellulose and methylcellulose with greater methoxyl substitution (MCH). The microstructure and textural properties of the doughs and biscuits prepared with these emulsions were studied and the effects of cellulose types and glycerol as textural improver were also analysed. The results showed that the incorporation of glycerol in the doughs made with methylcellulose and hydroxypropyl methylcellulose cellulose emulsions seems to make the dough softer, bringing the values closer to those of the control dough; however, this effect disappears once the dough is baked. The presence of glycerol does not seem to have an effect on the hardness of the doughs and biscuits made using the methylcellulose with greater methoxyl substitution (MCH) emulsion.