Food Structure-Netherlands最新文献

The purpose of this study was to reveal the mechanism of the improvement of SPI emulsifying properties after complexation with NL. The binding between NL and SPI led to a static fluorescence quenching of SPI and the significant change of SPI FTIR spectra. It indicated that the advanced structure of SPI after interaction with NL was altered appreciably. Moreover, it was observed that the free sulfhydryl content, contact angle, particle size, zeta potential, and surface hydrophobicity of SPI after complexation increased, and the interfacial tension reduced. Hydrophobic forces and hydrogen bonds played a vital part in the interaction between NL and SPI. Furthermore, the emulsifying properties of SPI were significantly improved after complexation with NL. Emulsifying activity index (EAI) and emulsifying stability index (ESI) of SPI increased from 50.52 to 104.28 m²/g and from 17.30 to 25.10 min with the NL-to-SPI mass ratio increasing from 0:1–1:1, respectively. Meanwhile, the emulsifying properties of NL-SPI (the NL-to-SPI mass ratio at 1:1) were also influenced by environmental factors (pH, temperature, and ionic strength). The improvement of the emulsifying properties of SPI after interaction with NL derived from the alteration of advanced structure and surface characteristics of NL-SPI complexes.

Exopolysaccharides (EPS) are commonly used to improve the texture of yogurt. These polysaccharides interact with casein micelles, the major protein in milk, via electrostatic and depletion mechanisms during fermentation by lactic acid bacteria (LAB). However, the relationship between the physicochemical properties and monosaccharide composition of EPS and their impact on yogurt texture is not yet fully understood. To address this knowledge gap, we studied the effects of polysaccharides commonly used as food additives on acid-induced milk protein networks. Confocal laser scanning microscopy (CLSM) was used to image the network microstructures. Image analysis, including Fourier transform, autocorrelation, and binarization-based techniques, was applied to quantify key structural features of the mixed milk protein/polysaccharide gels. These parameters were then related to the macroscopic properties of the model food matrices, such as elastic and viscous moduli and yield point. We found that the addition of neutral polysaccharides resulted in a concentration-dependent increase in structure factor, protein domain size, and pore fraction. In contrast, the presence of charged polysaccharides led to an increase in protein domain size, a decrease in pore fraction, and a decrease in elastic and viscous moduli. These results demonstrate the use of a quantitative image analysis method for selecting LAB with favorable EPS properties to improve yogurt texture.

Peas contain valuable macronutrients, such as protein and dietary fibre, associated with health benefits. Blending pea flour (PF) with wheat flour (WT) can improve the nutritional profile of bakery products. In addition, the use of locally grown peas for food innovation activities can benefit the environment and the local economy. However, the pea milling process is of paramount importance and can affect the final flour quality. This study aims to evaluate the influence of different milling processes of Irish-grown peas on flour composition, spectral profile (Near Infrared - NIR), pasting properties and dough rheology. Three mills were used: roller (RM), hammer (HM) and cutting (CM) producing RM, HM and CM flours, respectively. A commercial strong wheat flour was used as the base flour. For producing doughs, wheat flour was blended with each pea flour at a 15:85 (pea: wheat). Flour composition, particle size, Scanning Electron Microscopy (SEM), dough mixing properties, viscosity profile, gel texture, dough extensibility and rheology were assessed for the control, all pea flours and flour blends. The hammer mill produced the highest yield of pea flour (93.9 %). Near Infrared Spectroscopy reflected the same results for proximate composition, and the PCA and was able to discriminate the main differences between flour samples. SEM demonstrated that higher particle sizes obtained from the CM tended to have larger starch and protein matrix aggregates. Pea flour from the RM presented the highest viscosity profile and hardness, most likely due to the higher starch and lower total dietary fibre content. The lower pasting viscosity profile of pea flour obtained from CM is most likely due to a high level of damaged starch present in this flour. There were no significant differences found among WT and flour blends for gel hardness. This may imply that the incorporation of 15 % HM and CM flours perhaps will not impact the staling process of the final bread products. Further research is being undertaken to examine the influence of the pea milling process on bread-making performance.

Lupin is a legume seed rich in proteins and presents high nutritional and health benefits but is little used in the human diet. In this work, lupin proteins were extracted using an alkaline-saline solution followed by dialysis. Then, globulins were separated by isoelectric precipitation to give lupin globulin isolate (LGI). The solubility, zeta potential and interfacial properties of LGI were evaluated at pH of 3.4 and 6.8 in the presence of NaCl or CaCl₂. The solubility of LGI was dependent on the pH and type of salt, with lower solubility in the isoelectric region (pH ∼ 5), with lower solubility in the presence of NaCl (42.81 ± 1.23 %). The lowest value of interfacial tension was at pH 3.4 and absence of salts (41.79 ± 0.63 mN m⁻¹). Indicating the type of salt changes the electrostatic shielding of the LGI electrical double layer, which leads to a decrease in electrostatic potential at the surface of LGI. The rate of diffusion is highest at pH 6.8 under conditions without salts or in the presence of NaCl (0.57 ± 0.01 and 0.55 ± 0.05 mN m⁻¹ s^−0.5 respectively). When the salt was changed to CaCl₂ diffusion was decreased, probably due to protein-protein interactions. On the other hand, the protein adsorption rate is lower at pH 6.8 under all conditions studied. Apparently, it is influenced by the type of surface electrical charge of the proteins and the rate of rearrangement is greater than the rate of adsorption. The results obtained demonstrate that the lupin protein isolate can be used in multiphase food systems, such as foams, due to its interfacial properties.

Fats and oils provide flavour and texture to food while also promoting satiety. Despite the recommendation to consume primarily unsaturated lipid sources, the liquid state of unsaturated lipids at ambient temperature precludes numerous industrial applications. Moreover, the issue of the adverse effects of trans fatty acids has become more apparent due to research demonstrating their association with coronary diseases, obesity, and type 2 diabetes. Oleogels are liquid oils encapsulated within a thermoreversible, three-dimensional gel network using oleogelators such as waxes, monoglycerides, phospholipids, and phytosterols. Oleogels have been used extensively in numerous food formulations to reduce the amount of saturated and trans fatty acids. In recent decades, oleogel research has been active, producing numerous oleogels with desirable characteristics such as thermal resistance, texture, and structural stability. In addition, oleogels have been incorporated into several food matrices. In some instances, oleogels in these food products resemble the textural characteristics of products made with conventional hardstock fat, improve dietary nutrition, exhibit high physical and oxidative stability, and have a high oil-binding capacity. These advancements demonstrate the potential of oleogels, but certain disadvantages and a lack of in-depth information on various aspects have delayed their commercialization in the food industry. This narrative review aims to outline the preparation of oleogels, their application in selected food products, their digestibility, other applications of oleogels, such as bioactive delivery in wound healing and antibacterial properties, and the existing challenges in exploring oleogels. Therefore, the content presented in this article offers insights and opportunities for broadening the range of potential uses of oleogels in the food industry and beyond.

In this study, paprika carotenoids were encapsulated by coacervation with a nanostructured material (NE) prepared with alginate/zeolite and another non-nanostructured (AA) made only with alginate to study the effect of nanocavities in the microstructure on the energy interactions of adsorbed water and the chemical stability of carotenoids. Capsules were characterized through fractal analysis of image, water sorption isotherms, water melting point, thermodynamic properties, and chemical stability during storage. Surface fractal dimensions were between 2.75 and 2.8 for NE and were larger than those obtained for AA, which were between 2.57 and 2.7. NE capsules showed the endothermic fusion peak at −4.42 °C, while AA capsules around 0.97 °C. Adsorbed water enthalpies calculated from adsorption isotherms of the capsules showed the maximum stability of total carotenoids at the crossing of the integral and differential enthalpy intercross ₍$a_w$ = 0.121 for AA and 0.443 for NE) and at the water adsorption at Langmuir-type primary sites. NE capsules improved carotenoid retention two-fold compared to AA after 63 days of storage. These results confirmed that controlling the nanoporous at the food microstructure improved the chemical stability of carotenoids during storage.

This study aimed to investigate the impact of emulsion particle size (micro vs. submicron) on the physicochemical and rheological properties of myofibrillar protein (MP) gels. MP-based oil-in-water micro-emulsions (∼2,091 nm) and submicron-emulsions (∼522 nm) were compared with each other and with lecithin-stabilized micro-emulsions (∼1,330 nm) and submicron-emulsions (∼543 nm). Emulsion particle size, ζ-potential, and morphological properties using transmission and confocal microscopies) were measured. Additionally, dynamic rheological behavior, mechanical strength, water-holding capacity (WHC), water mobility, and protein secondary structures of the emulsion gels containing 2.5% protein and 5% oil) were analyzed. The results showed that emulsion droplet size had no significant effect on gel strength and storage modulus, regardless of the surfactants used. However, the MP-coated submicron-emulsion exhibited a greater improvement in gel WHC (p < 0.05) compared to its micro-emulsion counterpart. Overall, emulsion gels displayed greater strength than oil-free control gels. MP-based emulsions proved more effective than lecithin-stabilized emulsions in modifying the gelling properties, primarily due to the formation of a visible interfacial protein film that prevented oil droplet aggregation. Based on these findings, protein-based emulsions were preferred over lecithin-based emulsions, with MP submicron-emulsions offering the advantage of enhanced moisture retention in cooked MP gels.

Clementine by-products are an important source of dietary fiber, which has different technofunctional properties depending on its chemical composition and structure. These properties can be modified through different treatments. In this work, the impact of treatments such as hot air drying (HAD), homogenization (HOM), freeze drying (FD), and extrusion (EXT) was evaluated on the structure and technofunctional properties of clementine by-products’ powders, to promote their use as ingredients in food development as a way of valorization. The structure of by-products was studied using microscopy (Light Microscopy and Field Emission Scanning Electron Microscopy) and vibrational spectroscopic (FTIR and FT-Raman) techniques. The technofunctional properties, water and oil holding capacities, water solubility, swelling capacity, and emulsifying capacity, as well as particle size were evaluated. HOM and EXT showed a more stratified and porous structure than HAD and FD. FTIR and FT-Raman showed that the by-products mainly comprised pectin and cellulose. Regarding technofunctional properties, HOM powders had high water retention and swelling capacities, and good emulsifying capacity even when using high amounts of oil in an emulsion (75 %). FD powders showed the highest oil retention capacity and EXT powders the highest water solubility.

White and sweet potatoes can elicit different blood glucose responses depending on whether they are boiled or baked. This work investigated how microstructure and starch digestion in vitro relate to these differences. The main methods were INFOGEST’s semi-dynamic digestion protocol, Scanning Electron Microscopy and Confocal Laser Scanning Microscopy. The cooking method impacted microstructure, thereby significantly influencing starch digestion. Boiling and baking led to similar types of microstructural changes, including cell expansion and separation and disruption to cell walls, with the differences lying on the magnitude of such changes. Hydrolysis of white potato starch into oligosaccharides during oro-gastric digestion stabilized at around 75% when boiled compared to 50% when baked. In sweet potato, hydrolysis during this stage represented 30% and 40% of the total starch after boiling or baking, respectively. Overall, the effect can be summarized as boiled white potato > baked white potato > baked sweet potato > boiled sweet potato. Our results show how structural transformations that occur during cooking can drive differences in starch release and hydrolysis during in vitro digestions. This work therefore provides a structural and biochemical basis to better understand the impact of boiling and baking on the glycemic responses to these foods.

The aim of this study was to investigate the impact of the addition of a non-gelling non-ionic surfactant, Tween 20 (Tw20), at varying weight ratios with monoglycerides, MGs (0 – 20 g Tw20 to 10 g of MGs as structurant /100 g olive oil) in the crystalline network of the MGs-based oleogels. Several analytical methods such as differential scanning calorimetry (DSC), confocal and polarized optical microscopy, rheometry, and infrared spectroscopy were employed for the characterization of the oleogel structures. The DSC and FT-IR provided evidence that Tween 20 affects the MGs network structure in the oleogels. With addition of Tween 20 the crystal size and the melting/crystallization temperatures of the MGs crystal polymorphs were altered, along with a strengthening of the oleogel structure. Moreover, the presence of Tween 20 in the MGs oleogels accelerated the transformation of the higher free energy crystal forms (α-crystals) to the more thermodynamically stable β-polymorph of the MGs. Apparently, an oil-in-oil emulsion gel is being formed with the MG crystalline entities acting as Pickering particles around the oil/Tween 20 droplets in the oleogel structure. These findings provide valuable information on the synergistic effect of a non-ionic surfactant on monoglyceride-based oleogels, which could be beneficial in constructing multi-component lipid-phases for potential food or cosmetic applications.