Food Hydrocolloids最新文献

This study aims to assess the compositional characteristics of British Kabuli chickpea aquafaba (AF) by conducting a comprehensive analysis from raw chickpeas to centrifugation fractions of AF and its potential use in forming and stabilising capsaicin-loaded O/W Pickering systems by exploiting the presence of self-assembled nanoparticles and proteins, which act as natural-coating agent. To this end, chickpeas were soaked (16 h, 4 °C, 1:4 chickpea: water) and pressure-cooked (20 min, 113 °C, 10 psig, 1:5 chickpea: water). The dry weight-based (DWB) compositions included total carbohydrate (76.33 ± 4.20%), protein (16.29 ± 0.43%), total phenolics (7.05–8.77 mg/g) and saponins (39.95 ± 0.89 mg/g), thus confirming the leaching of these components from seeds to AF. SDS-PAGE electrophoresis analysis revealed the presence of low MW proteins (≤∼16 kDa). The monosaccharides comprised d-glucose, d-galactose, l-arabinose, d-xylose and d-fructose. AF's particle size distribution revealed the occurrence of a bimodal population of nanoparticles (D_h ≤∼1000 nm and D_h ≤∼100 nm), further characterised by SAXS and TEM imaging. O/W emulsions were prepared with three chilli oleoresin types (capsicum, chilli birds' eye, and chilli ancho) by high-pressure homogenisation. The emulsion with the highest capsaicin content (capsicum oleoresin) was the most stable while the emulsion with the lowest capsaicin content (chilli ancho oleoresin) was the least stable. The presence of incidental nanoparticles and denatured proteins in AF was reasoned to account for the formation and stabilisation of chilli oleoresin-in-water Pickering emulsions, a newly offered explanation for its interfacial properties that will be pursued further in future studies.

With the different amount (0%, 0.25%, 0.5%, 1%, 1.5%, 2%) of phytic acid (PA) added, the changes of structure, properties and oil absorption characteristics of wheat flour (WF) were studied. First of all, the phosphorus content in flour increased after PA treatment, which proved that the modification was successful. SEM images showed there were aggregation in the WF modified by PA (PA-WF). The surface of starch showed gradually rough, but the shape of starch particles remained relatively intact. Moreover, XRD and FTIR patterns of all samples showed no significant difference. It was proved that the degree of structural modification of flour by PA was small in the non-gelatinizing system, and it mainly occurred in the non-crystalline region. In terms of properties, the thermal stability and hydrophilicity of PA-WF were improved because the phosphate groups of PA reacted with the hydroxyl groups on the starch to form more stable covalent bonds instead of the hydrogen bonds, and the phosphate groups were hydrophilic. Not only that, the peak viscosity of PA-WF-1.5% was higher than that of the control group, and the other PA-WF were the opposite. With the increase of phosphorus content, the peak viscosity were lower than that of the control group, suggesting that the system mainly consisted of crosslinked starch rather than esterified starch. In terms of oil absorption characteristics, the total oil absorption and surface oil distribution of PA-WF were decreased after frying, which proved that using PA to modify WF was beneficial to reduce oil absorption.

Hydrocolloids such as hydroxypropyl methylcellulose (HPMC) are commonly used in gluten-free (GF) products to mimic the viscoelastic properties of gluten. However, GF products must meet current consumer expectations by not only being tasty and nutritious, but also adhering to ‘clean label’ principles, which involve minimizing ingredients and additives and favoring natural over chemical components. Modifying GF flours via hydrothermal treatments offers an alternative approach to reduce the use of additives in GF products. This work applied response surface methodology to study the potential reduction in HPMC dose in the formulation of GF-breads by the addition of microwave-treated rice flour (MWF) (treatment conditions: 8 min, 9 W/g, 30% moisture), without impairing their appearance, volume, and texture. The optimization study also included Water level and HPMC dose, and evaluated the dough's rheological properties at constant hydration. GF breads were made by varying the amount of native flour substituted with MWF, water level, and HPMC dose. Replacing 50% or 80% of native rice flour by MWF allowed to reduce the usual HPMC dose by more than half. This resulted in higher loaf volume and a softer crumb than their counterparts made with untreated flour and baked with the usual dose of additive (2%). Doses of HPMC as low as 0.7% with 80% MWF still resulted in breads with good texture and acceptable volume. Therefore, the structuring effect of MWF and its good performance in GF baking have been concluded, allowing to reduce the dose of additives required in formulating GF bread.

To identify the key structural properties of pectic polysaccharides that affect their gut fermentation behavior, structural characteristics and fecal fermentation ability of acid-extractable pectins obtained from 8 kinds of fruit and vegetable were compared. Results showed that the peach pectin presented a single molecular weight (Mw) distribution with large Mw (706.3 kDa), and the broccoli pectin owned high contents of arabinose (99.62 mg/g) and galactose (129.11 mg/g). Fermentation with these two pectins for 24 h improved the relative abundance of Bifidobacterium (13.42 % and 13.04 %, respectively), which had positive relation (p < 0.001) with Mw, arabinose and galactose. Hawthorn pectin was featured with low Mw, which also exhibited high linearity (6.96), supporting the relative abundance of Bacteroides (40.04 %) after fermentation. It had positive relation (p < 0.05) with linearity, acetate and butyrate. Tomato pectin was characterized by tri-Mw distribution with small polydispersity index (1.231, 1.120 and 1.106, respectively). Moreover, it displayed a compact and curved conformation in terms of smaller radius of gyration (Rg, 7.88 nm) and larger cross-sectional radius (Rc, 5.28 nm). Tomato pectin generated the highest content of short-chain fatty acids (61.59 mmol/L) among all the pectins after fermentation. Meanwhile, Ruminococcus was detected as key genera in the tomato pectin substrate, which was positively correlated (p < 0.05) with acetate, propionate, Rg and Rc. The correlation analysis further confirmed that Rg and arabinose content of the pectin have the greatest impact on the microbiota modification, followed by Rc and polydispersity index, promoting a deep understanding of the relationship between pectin structure and gut fermentation.

Phase behavior of protein-polysaccharide mixtures can be controlled by adjusting parameters, such as polymer concentrations and pH. However, the relationships between these interactions and resulting microstructures and textures are not fully understood. The effects of pH (5.5, 7, and 8.5) and low-methoxyl (LM) pectin content (0.5% and 1%) on the rheological properties and microstructures of heat-induced pea protein gels were investigated. At pH 5.5, the addition of LM pectin significantly increased the size of protein aggregates, which is explained by the strong interactions between proteins and LM pectins at that pH; a quartz crystal microbalance revealed the formation of insoluble complexes with reduced solubility. The storage modulus (G′) of pea protein gels at pH 5.5 increased with 0.5% of LM pectin, whereas 1% of LM pectin led to a decreased G′ and the gels water holding capacity. At pHs 7 and 8.5, the addition of LM pectin increased the size of protein aggregates due to the segregative phase separation of negatively charged pea proteins and LM pectins. An increase in G′ with LM pectin concentrations in the gels was also observed at pHs 7 and 8.5. Gel microstructures with phase-separated zones were observed by confocal microscopy. Furthermore, the addition of LM pectin increased the digestibility of pea protein gels prepared at the three pH values under simulated gastrointestinal conditions. Better knowledge of the rheological properties and microstructures of pea protein-LM pectin mixed gels obtained under different pH conditions will allow for optimal use of protein-polysaccharide mixtures in food formulations to attain binary gel products with expected textural and nutritional properties.

The incorporation of fibre into pea protein matrices influences their microstructure, yet our understanding of their gut fermentability remains unexplored. In this study, dietary fibres and protein from yellow pea were investigated for their physico-chemical properties and impact on in vitro colonic fermentation using human inoculum. Pea fibre and pea protein blends were studied at different pH and after thermal treatment at 95 °C for 30 min with oscillatory rheology, static light scattering and confocal laser scanning microscopy. The effect on in vitro colonic fermentation was evaluated measuring gas production, ammonia, and short chain fatty acid (SCFA) production. Rheology indicated that during thermal treatment a firmer gel is formed close to the protein isoelectric point with a structure characterised by aggregation, but less particle swelling compared to other pH. Addition of fibre led to higher storage modulus (G′), with the fibre dominating the rheological properties. Fermentation of samples containing protein led to higher levels of ammonia and SCFA compared to only fibres. Blends produced higher amounts of valerate, i-valerate and caproate, and lower amounts of ammonia. Reduced fermentation of proteins in the presence of fibres was also reflected in a more intact microstructure of the protein particles in the digesta. Although thermal treatment of blends caused particle swelling and induced gelation, only small differences could be discerned in the in vitro colonic fermentation outcomes. Our results highlight that potentially harmful fermentation products from protein, such as ammonia, were reduced in the presence of pea hull fibre.

Plant proteins are becoming increasingly popular as functional ingredients in foods because of their health, sustainability, and environmental benefits. The functional performance of plant proteins can often be improved by combining them with other food ingredients. For instance, they can be combined with polyphenols and metal ions to form surface active protein-polyphenol-iron complexes with biological activity. In this study, ternary complexes of pea protein isolate (PPI), epigallocatechin-3-gallate (EGCG) and iron (Fe³⁺) was prepared using a simple molecular self-assembly method. The formation mechanism, characteristics, and functional properties of these complexes were then characterized. Our results showed that PPI, EGCG, and Fe³⁺ could spontaneously combine to form nano-sheet networks held together by hydrogen bonds, phenolic hydroxyl coordination bonds, and electrostatic interactions. The addition of Fe³⁺ increased the fraction of disordered secondary structures, reduced the thermal denaturation temperature, reduced the surface hydrophobicity, increased the particle size, and altered the surface potential of the proteins in a dose dependent manner. Optimizing the EGCG-to-Fe³⁺ ratio in the complexes (1:2 w/w) led to the formation of protein composites with improved surface, antioxidant, and antibacterial activities. This study provided valuable insights into the interaction mechanisms of proteins, polyphenols, and metal ions in ternary complexes. These complexes may be used as multifunctional ingredients in plant-based foods because of their beneficial antioxidant, antimicrobial, nutritional, and emulsification properties.

Canary seed, a gluten-free cereal, is renowned for its high content of fats, starch, and proteins. The extraction of oil is often necessary to extend flour shelf life or obtain purified starch and protein fractions. Similar to many gluten-free flours, it may require additional thermal treatments to enhance its suitability to formulate several food products. Thus, this study investigated the impact of ultrasound (US) treatment on the techno-functional and physicochemical properties of both whole (WCS) and defatted (DWCS) canary seed flours. The US treatment slightly increased water and oil absorption capacities in WCS. Lipids in the flour and treatment temperature affected the surfactant properties. Untreated and treated defatted DWCS flours exhibited higher emulsifying activity (up to +36%) and foaming capacity (up to +340%) than WCS. The presence of lipids and US treatment influenced protein extraction, with changes in albumins (WCS and DWCS), globulins (DWCS) and prolamins (WCS) recovery. US treatment altered pasting and rheological properties of all studied flours, impacting viscosity and starch-lipid complex formation. Rheological properties were lipid-dependent, and defatted samples formed stronger gels. US treatment decreased gelatinization enthalpy in WCS (up to −9.5%) and increased it in DWCS (up to +11.3%) flours. Moreover, lipids significantly influenced retrogradation, which was absent in untreated and treated WCS flours. US-treated flours displayed similar diffraction patterns to untreated samples, but with reduced intensities as temperature increased. The untreated defatted sample exhibited a 9% lower crystallinity. These findings highlight the benefits of US treatment and defatting for improving gluten-free food products formulated with canary seed flour.

This study aimed to investigate the effects of different plant polysaccharides (inulin, κ-carrageenan, and konjac glucomannan) as fat substitutes on the gel properties, microstructure, and digestion characteristics of myofibrillar protein (MP). The results revealed that incorporating inulin, κ-carrageenan, and konjac glucomannan significantly improved the water holding capacity, texture profiles, and rheological behavior of MP gels while limiting water fluidity. Among them, the MP-konjac glucomannan gel (1%, w/w) showed superior water retention and gel strength, demonstrating the most notable restriction on water translocation. Microstructural analysis observed that the MP gels with inulin, κ-carrageenan, and konjac glucomannan displayed a dense and well-clustered network structure, resulting in a more even distribution and compact gel structure. However, including 1.5% and 2% konjac glucomannan in MP mixed gels resulted in block-like clustering and larger agglomeration. Furthermore, the protein digestibility assessment indicated that polysaccharides incorporation significantly reduced the digestibility of MP, with konjac glucomannan demonstrating higher digestibility compared to inulin and κ-carrageenan groups. Overall, incorporating konjac glucomannan at a 1% incorporation (w/w) can effectively serve as a fat substitute in muscle food. This study will provide valuable insights for utilizing konjac glucomannan as a fat substitute in meat products.

In the present work, the rheological properties of model boli were analysed based on the granular matter physics. Polysaccharide microgels mixed with artificial saliva were prepared as model boli. The storage modulus G′ of alginate gel beads increased and then decreased with increasing content of artificial saliva. Surface of alginate gel beads prepared by dripping into calcium chloride solution were wiped to remove the moisture to mimic the oral condition of the Sjögren's syndrome. G′ decreased monotonically with increasing artificial saliva beyond a certain amount of the added saliva, which is similar to the widely observed characteristic of wet granular materials. Although the analysis is limited to a model bolus at a certain stage of oral processing mimicked by instrumentally prepared microgels of uniform size and shape, it revealed some fundamental aspects highlighting the implication of a wet granular matter as a useful concept for further understanding of the bolus rheology.