Food Structure-Netherlands最新文献

Pea protein isolates (PPI) mainly contain globulin proteins responsible for forming fragile gels affecting the texture properties of plant-based foods like extruded meat analogs. This study aims to extract a soluble protein fraction (SPF) from air-classified pea protein concentrate (PPC) containing globulins and albumins and use it directly in its liquid form to enhance the elasticity of PPI gels and extrudates produced by high moisture extrusion (HME). Two commercially available PPIs and one PPC were characterized by protein solubility, differential scanning calorimetry, and heat-induced gelation capacity by rotational rheology. Gel characterization was done by small amplitude oscillation rheology. Protein extraction at concentrations between 5% and 10% w/w and mildly alkaline pH was the most efficient way to produce functional SPF with high protein yield (> 67%). The SPF had a positive effect on the yield strain of PPI gels. However, the effect on the elastic modulus (G’) depended on the degree of protein isolate purification. Moreover, adding SPF directly as wet feed in HME reduced the brittleness of PPI extrudates. This research highlights the texture formation potential of minimally pre-processed pea protein ingredients in plant-based foods (e.g., meat analogs) manufactured with HME.

In this study, red lentil isolate protein (RLPI, 3 %, w/v) was treated at pH 2 and 7 at 85 °C for a period of 0–24 h. The TEM and SDS-PAGE results indicated that the molecular weight of RLPI was steadily reduced and hydrolyzed into peptides over the prolonged heating time, eventually forming fibrillar and particulate aggregates at pH 2 and 7, respectively. The FTIR results showed an increased level of the proteins’ random coil motifs due to the excessive heating. According to the results of emulsifying properties, the emulsifying capabilities of fibrillar proteins were higher than those of the particle proteins at the same protein concentration due to the proteins’ structure and their surface charge. Notably, the fibrillar aggregates formed a gel network structure and stronger interactions in fibrillar aggregates compared to the particulate aggregates at pH 2. This study provides references for the processing and utilization of plant proteins in beverages and dietary supplements.

The contributions and importance of the water-in-oil-in-water (W1/O/W2; W1:W2 = 40:60; W1/O: W2 = 20:80) type double emulsion (DE) to the physicochemical characteristics of almond-based gel were identified in this study. This study investigated from two perspectives: 1) the effect of the amount of DE addition on the gel properties of almond-based yoghurt and 2) the comparison between samples made with and without DE. The hardness, water holding capacity, and viscosity value of almond-based gel increased when the DE addition increased from 5, 10, 20, to 30 % due to the composition variance. Comparing the sample made with DE structure and made without DE, a significant difference was only found between samples incorporated with 30 % DE (D30) and its counterpart control sample C30. A significantly higher (p < 0.05) apparent viscosity and hardness values were observed in sample D30 (0.27 Pa·s; 18.25 g) compared to its counterpart control sample C30 (0.21 Pa·s; 15.09 g). A sensory evaluation revealed similar preferences for both samples (D30 and C30). In summary, the presence of a double emulsion structure contributed to the improved texture, microstructure and quality of almond-based gels. This approach can potentially guide the future production of double emulsion-incorporated plant-based gels.

The effect of High Intensity Ultrasound (HIU) on the structure and stability of soybean (SO) and avocado (AO) oleogels was evaluated. HIU treatments (25% and 50% amplitude and 15 and 30 s) were applied and oleogels were analyzed by crystal morphology, melting behavior, solid fat content (SFC), texture, oil binding capacity (OBC), and viscoelasticity (G’ and G’’). A PCA analysis was also performed. Results showed that HIU reduced crystals size and formed needle-like small crystals in all treated samples when compared to control, regardless the oil source. The lowest enthalpy values were presented in control samples, due to a small number of crystals. HIU treatments increased hardness of all samples in contrast to control. Regarding the OBC, AO samples were less stable compared to SO samples. PCA analysis showed a clear difference among the oil source samples, as well as the HIU treated samples compared to the control samples.

Reconstituted rice composed of rice starch and glutelin was prepared under varied screw speeds by a twin-screw extruder, and the structure and physicochemical properties were analyzed. When the screw speed ranged from 265 to 345 rpm, the expansion ratio and cooking loss of reconstituted rice separately increased from 219.20% and 6.30–238.40% and 11.50%, while the bulk density reduced from 2.39 to 1.27 g/mL accompanying the color became darker. The water solubility index of reconstituted rice changed insignificantly with increasing screw speed. Clusters of gelatinized starch granules were observed, and the inner structure of reconstituted rice became rough and cracked. Increasing screw speed was not conducive to maintaining the viscoelasticity of reconstituted rice pastes due to the decrease in pasting parameters, and their frequency dependence was lower than raw rice paste. The relative crystallinity of reconstituted rice decreased from 13.45% to 4.50% as the screw speed increased, resulting in corresponding changes in thermal properties. Furthermore, the texture of cooked reconstituted rice was closely associated to screw speed. This study supplies theoretical guidance for producing extruded reconstituted rice.

This work aimed to formulate oil-in-water Pickering emulsions using carboxylated-cellulose nanocrystal (cCNC) to encapsulate sesamolin to overcome sesamolin’s poor solubility. The formulations were prepared by varying the oil/water ratio, cCNC, and sesamolin concentrations. Their droplet size, charge, morphology, stability, and an in vitro tyrosinase inhibitory activity were investigated. Sesamolin was successfully loaded at a concentration 21 times greater than that found naturally in sesame oil. The droplet size of the emulsion was a micron size (38–95 µm), with a higher oil concentration and a zeta potential between − 26 to − 36 mV. Formulation with 1%w/v of cCNC and 10%v/v of oil showed the best stability during storage under the condition studied. High-loaded-sesamolin emulsion showed a similar creaming index to an emulsion containing only sesame oil, demonstrating that high-loaded sesamolin did not decrease the stability. The most stable formulation exerted anti-tyrosinase activity 11 times higher than pure sesamolin. The Pickering emulsion successfully loaded and enhanced the solubility of sesamolin in the aqueous system. The obtained stable emulsion was compatible with the hydrophilic phase. Consequently, Cellulose-based Pickering emulsion has the potential as a sesamolin delivery system in vitro or in vivo further studies.

This study introduces a cold-set lentil protein (LP) gel with significantly improved mechanical strength prepared from protein fibrillar aggregates. First, fibrillar aggregates were formed by thermal treatment at an alkaline pH. Subsequently, glucono-δ-lactone (GDL), transglutaminase (TG), or their sequential combination (GDL/TG) was applied to induce the gelation of LP aggregates at room temperature. The gelling mechanism study revealed the formation of covalent bonds in the gel network induced by TG, which was then reinforced by hydrophobic interactions among the protein aggregates induced by GDL. As expected, the sequentially addition of TG and GDL enabled formation of interconnected networks with thick walls and significantly improved gel hardness. This research has provided a new strategy to develop strong lentil protein gels for food texturization thus potentially expanding food applications of lentil protein as an advantageous plant source of protein.

Protein digestion is commonly studied using in vitro models. Validating these models with more complex in vivo observations remains challenging, in particular due to the need for non-invasive techniques. Here, we explore Magnetization Transfer (MT) and Chemical Exchange Saturation Transfer (CEST) MRI for non-invasive monitoring of protein solubilization and hydrolysis during static in vitro digestion using skim milk (SM). We measured CEST spectra of unheated and heated SM during gastric digestion, from which the relative amount of soluble proteins/peptides was estimated by calculating the asymmetric MT ratio (MTR_asym). We also obtained semi-solid volume fractions (v_ss), MT ratio (MTR) and MTR_asym from the same measurement, within 1.3 min. The MTR_asym area increased with gastric digestion, due to solubilization of the initially-formed coagulum, yielding a mean difference of 20 ± 7% between unheated and heated SM (p < 0.005). The v_ss and MTR decreased during gastric digestion and can be used to monitor changes in the coagulum, but not for assessment of soluble proteins/peptides. The MTR_asym increased for heated SM during gastro-intestinal digestion, proving sensitive to protein solubilization and hydrolysis, and is suitable for monitoring protein hydrolysis at later digestion stages. Future steps will include similar MT and CEST studies under dynamic conditions.

There is a growing interest in sustainable and green technology for the improvement of functional properties of grain proteins by altering their composition and structure. This study investigated the structure, physicochemical and functional properties of Bambara groundnut globulin after hydration with plasma-activated water (PAW). Bambara groundnut globulin was dispersed in PAW and hydrated at 4 ℃ for about 12 h. The exposure of Bambara groundnut globulin to plasma resulted in a significant loss of helical structure and over 3-fold increase in β-turns in comparison with the untreated Bambara groundnut protein. Amino acid data for the plasma-treated globulin showed 20 % reduction in glutamic acid content. A slight redshift was observed in fluorescence intensity data of the plasma-treated Bambara groundnut protein. This suggested an unfolding of the protein structure, which also correlated with the observed increased hydrophobicity. However, protein profiles by gel electrophoresis, surface charge, and pH-solubility patterns appeared similar for both plasma-treated and untreated Bambara groundnut globulin samples. Bambara groundnut globulin had reduced emulsifying ability after exposure to plasma as indicated by an increase in the average oil droplet sizes. However, foaming capacities were significantly better and stable at up to 15 mg protein/mL. The hydration of Bambara groundnut globulin with plasma-activated water modifies the structural conformation, reduces the proportion of acidic amino acids of the protein, and improves the foaming properties. Cold plasma treatment by hydration does not seem to improve the emulsifying properties of Bambara groundnut globulin.

Effects of phenolic compounds with different structural complexity (including protocatechuic acid, naringin and tannic acid) on the properties and functions of maize starch-based film were determined, and the intermolecular force between starch and different phenolic compounds was further analyzed. Different phenolic compounds exhibited varying effects on the thickness (0.101–0.141 mm), moisture content (8.32–9.53 %), color (ΔE value: 1.70–5.01), light transmittance (50–63 %), crystalline structure, thermal resistance characteristics, intermolecular force, microstructure, surface morphology, mechanical properties (tensile strength: 3.2–8.8 MPa; elongation at break: 18–38 %), moisture barrier (6.44–10.12 ×10⁻¹¹ g m⁻¹ s⁻¹ Pa⁻¹) and antioxidant activity of film, owing to the differences in the amount of phenolic hydroxyl groups, molecular size and steric hindrance of phenolic compounds. The present results showed that the proper increase of phenolic hydroxyl number, molecular size and addition dose could improve the binding affinity between phenolic compounds and polysaccharides, so as to promote phenolic compounds to aggregate polysaccharide molecules with themselves as the core, resulting in the change of aggregation and disorder degrees among components in film matrix. Meanwhile, the differences on the interactions between phenolic compounds and polysaccharides could lead to the variation of the dispersion and compatibility of film matrix, as well as the crystallinity, spatial structure, hydrophilic domains of film. Furthermore, phenolic compounds with high amount of hydroxyl groups could enhance the antioxidant activities of film. All present results suggested that phenolic compounds had potential value to enhance the properties and function of maize starch-based film.