Modulation of the emulsifying and foaming properties of pH-shifted rice glutelin by controlled thermal processing: insights from interfacial adsorption.

Electrostatic complexation of β-lactoglobulin aggregates with κ-carrageenan and the resulting emulsifying and foaming properties

Emulsion and foam properties of plasmin derived β-casein peptides

Improvement on gel properties of chicken myofibrillar protein with electron beam irradiation: Based on protein structure, gel quality, water state

Collagen is an important biopolymer widely used in food, cosmetics and biomedical applications. Understanding the effect of pH on the structure and properties of collagen is beneficial for its further processing and exploitation. In this study, greenfin horse-faced filefish skin collagen (GHSC) was prepared and identified as a type I collagen. We systematically investigated the effect of pH on the structural, functional and rheological properties of GHSC. Scanning electron microscopy showed that the collagen morphology changed from an ordered stacked sheet structure to a rough silk-like structure as pH increased. Gaussian-fitted Fourier infrared spectroscopy results of the collagen revealed that it unfolded with increasing pH. Moreover, the ordered structure was reduced, and random coils became the dominant conformation. Its β-sheet and random coil contents increased from 18.43 ± 0.08 and 33.62 ± 0.17 to 19.72 ± 0.02 and 39.53 ± 1.03%, respectively, with increasing pH. α-helices and β-turns decreased from 35.00 ± 0.26 and 12.95 ± 0.01 to 29.39 ± 0.92 and 11.36 ± 0.10%, respectively. The increase in β-sheets and random coils allowed the pI-treated collagen to exhibit maximum water contact angle. The emulsification and foaming properties decreased and then increased with increasing pH in a V-shape. The increased net surface charge and β-sheets in collagen benefited its emulsification and foaming properties. The rheological results showed that the protoprotein exhibited shear-thinning properties in all pH ranges. The collagen solutions showed liquid-like behaviour in low-pH (2, 4) solutions and solid-like behaviour in high-pH (6, 7.83 and 10) solutions. Moreover, the frequency-dependent properties of the storage modulus (G') and loss modulus (G″) of the collagen solutions weakened with increasing pH. Collagen has considerable frequency-dependent properties of G' and G″ at low pH (2, 4). Thus, the importance of collagen raw material preparation for subsequent processing was emphasised, which may provide new insights into applying collagen-based materials in food, biomaterials and tissue engineering.

A state-of-the-art review on the application of natural surfactants in enhanced oil recovery

Dynamic high pressure microfluidization (DHPM) was applied to treat fish gelatin from bighead carp (Hypophthalmichthys nobilis) scale. The effects of various pressures from 40 to 160 MPa on the functional properties and structural characteristics of fish gelatin were evaluated. The results showed that DHPM significantly improved the emulsifying and foaming properties, as well as the in vitro pepsin digestibility. Surface hydrophobicity of treated fish gelatin was considered to be highly correlated to emulsifying activity with R2 of .99933. DHPM could not change gel strength and molecular weight distribution of fish gelatin, but decreased its melting temperature with the increased pressures. Micro-structural analysis showed that DHPM endowed fish gelatin with polyporous, rough but uncracked microstructure. Practical applications In spite of possessing relatively low melting temperature, fish gelatin is a suitable replacement for mammalian gelatin in low-temperature stored foods including milk and yogurt. At this time, surface-active properties including foaming and emulsifying properties are generally the most important factor for ensuring food quality. However, fish gelatin shows relatively weaker surface-active properties, especially emulsifying/stabilizing function. Our results show DHPM is a physical technology to enhance the surface-active properties of fish gelatin. DHPM will be promising to promote fish gelatin for its applications in the food industry.

Two cowpea varieties (Ife-brown and Kano-white varieties) were used for the study. The effects of insect infestation on the chemical composition and physicochemical properties of these cowpea seeds were studied. The proximate composition, mineral content, total starch, total soluble sugars, bulk density, fat and water absorption capacities, viscosity, gelation capacity and emulsion properties of infested cowpea varieties were compared with those of uninfested cowpeas. Effects of infestation on nitrogen solubility and on the protein fractions were also determined. Infestation depleted the protein, starch and soluble sugar contents of cowpeas. Oil and water absorption capacities were increased while emulsification, foam and viscosity properties were reduced. The nitrogen solubility pattern was altered. Uninfested Kano-white cowpeas (UKW) possessed better foam properties than uninfested Ife-brown cowpeas (UFB). On the other hand, UFB had better emulsification properties than UKW.

Effects of sodium tripolyphosphate modification on the structural, functional, and rheological properties of rice glutelin

Jatropha seed protein functional properties for technical applications

In this paper, the foaming and surface properties of sodium caseinate (SC), sodium caseinate/tannin acid (SC/TA), sodium caseinate/octenyl succinate starch (SC/OSA-starch), and sodium caseinate/tannin acid/octenyl succinate starch (SC/TA/OSA-starch) complex systems are described. First, foaming properties of different samples were compared at pH 6.0. The interface adsorption and linear surface dilatational rheological of different samples were characterized in the linear viscoelastic region to explore the relationship between macroscopic foaming properties and surface properties. At equal protein concentrations, the foamability and foam stability of the SC/TA/OSA-starch complex was markedly higher than that of the SC/TA complex. Meanwhile, the surface properties of the SC/TA/OSA-starch complex were also superior to those of the SC/TA complex. Finally, to investigate the nonlinear surface dilatational rheological behavior of the air/water interface stabilized by complex systems, the large-amplitude oscillatory dilatational rheology and Lissajous plots were studied. For the SC/TA/OSA-starch complex, the OSA-starch increases the degree of strain softening in extension, suggesting that the surface structure may change from a surface gel to a mixed phase of SC/TA patches and OSA-starch domains. These findings indicate that the complex formed between polyphenols, proteins, and polysaccharides could be used as a good alternative to understand and, consequently, improve the surface and foaming properties in food matrices.

Investigating the effect of roasting on functional properties of defatted hazelnut flour by response surface methodology (RSM)

Emulsifying and foaming properties of β-lactoglobulin modified by heat treatment

Rice Bran Protein Fractions (RBPFs) albumin, globulin, glutelin and prolamin were extracted from untreated and parboiled rice bran and their comparative studies were made for the yield, protein content, bulk densities, water absorption capacities, Nitrogen Solubility Index (NSI), emulsion property and least gelation concentration. The maximum yield of the protein fractions were obtained in parboiled rice bran. The protein content in untreated rice bran protein fractions (URBPFs) albumin, globulin, glutelin and prolamin protein fractions were 44.16, 29.66, 9.42 and 7.76% whereas Parboiled Rice Bran Protein Fractions (PRBPFs) contained 28.39, 18.70, 31.01 and 6.91% protein, respectively. Bulk densities of all. Untreated Rice Bran Protein Fractions (URBPFs) were 0.121, 0.366, 0.354 and 0.219 whereas bulk densities of corresponding PRBPFs were 0.132, 0.278, 0.279 and 0.243, respectively. NSI values at pH 7 of all the URBPFs except globulin were greater than those of (PRBPFs). Parboiled rice bran protein fractions (PRBPFs) were found to be superior by emulsion and least gelation concentration properties than (URBPFs) Untreated rice brain fractions (protein fractions) URBPFs. All the values were found to be significantly different (p<0.05).

High-value resources beyond oil extraction for the olive industry need to be developed due to increased olive production. Soluble dietary fibers (SDFs) and olive proteins (OPIs) are important components of olives. However, the commercial production process partially damages OPIs' emulsifying and foaming properties. Thus, the preparation of SDF-OPI complexes would help protect and even improve the emulsifying and foaming properties. The effects of pH and thermal-ultrasonic treatment on the complexation were explored, which showed that the SDF-OPI complexes prepared at pH 5 exhibited superior solubility (p < 0.05). SDF addition noticeably improved OPI thermal stability, emulsifying properties, and foaming properties. Moreover, the complexes prepared by thermal-ultrasonic treatment exhibited higher emulsion stability and lower emulsification activity than those prepared without thermal-ultrasonic treatment. In the acidic system, the electrostatic interaction was considered the main driving factor, assisted by the hydrophobic interaction. Additionally, after thermal-ultrasonic treatment, the covalent binding was observed by infrared spectroscopy. These results revealed the interaction mechanism between SDF and OPI, and the complexes significantly enhanced the functional properties of OPI. This study provides a reference for the high-value utilization of olives, thus broadening their potential uses in the food sector and beyond.

Palm kernel cake glutelin-1 (PKCG-1) can be used as a novel emulsifier, contingent upon enhancement of its emulsifying functionality. This study investigated the influences and underlying mechanisms of ultrasonication-assisted gallic acid-binding or arabinose-glycosylation on the emulsifying properties of PKCG-1. The results demonstrated that ultrasonication-assisted gallic acid-binding yielded the greatest improvement in emulsifying ability (from 91.03 to 159.74 m2/g), attributed to a concomitant decrease in molecular mass (from 59.2 to 48.4 kDa); increases in hydrophobicity (from 681 to 770), random coil content, and interfacial adsorption capacity (from 102.62 to 244.41 μg/mL); a reduction in the emulsion's loss factor; and augmentation of zeta-potential (from -39.55 to -65.96 mV) and centrifugal stability (from 57.80% to 84.14%). Alternatively, ultrasonication-assisted arabinose glycosylation was best at enhancing the emulsion stability of PKCG-1 (from 79.77% to 98.36%) by increasing its solubility (from 28.35 to 73.85 g/100 mL) and random coil (from 25.9% to 46.9%), enhancing zeta-potential (from -39.55 to -84.81 mV) and viscosity; and reducing droplet size (1.10 to 0.64 μm) and loss tangent. Furthermore, the solubility, emulsifying activity, and emulsion stability of PKCG-1 decreased as pH increased from 2.5 to 8.5. Nevertheless, the application of the modified PKCG-1s as gels requires further studies.