Effect of synergism of sucrose ester and xanthan gum on the stability of walnut milk

BACKGROUND

Single emulsifiers have an effect on the stability of plant protein drinks, giving some improvement. Emulsifiers are more effective in maintaining emulsion stability when combined with polysaccharides such as xanthan gum. In this paper, we studied the food-grade emulsifier sucrose ester and measured the average particle size, polydispersity value, zeta potential, microrheological properties, microstructure and creaming index related to walnut protein emulsion by constructing a walnut protein emulsion simulation system. SDS-PAGE and low-field NMR were used to analyze the relative molecular masses of emulsions and the water distribution of emulsions, respectively, to further investigate the synergistic effects of sucrose esters and xanthan gum on the ease of emulsification and intrinsic mechanisms of different molecular weight proteins of walnut protein emulsions.

RESULTS

The results indicate that the synergistic effect of sucrose esters and xanthan gum was to stabilize emulsions better than single emulsifiers. Xanthan gum and protein may form protein-polysaccharide complexes, as well as the hydrophobic interaction between sucrose ester and xanthan gum. The properties of xanthan gum can improve the stability of the emulsion by affecting the mechanical properties of walnut protein emulsion, and the combination of sucrose ester and xanthan gum can better stabilize large protein molecules.

CONCLUSION

The results not only provide a theoretical basis for the stability of plant protein emulsion systems, but also provide technical support for the production and processing of large-molecule plant proteins into emulsions in this field for improving their stability, and also provide more possibilities for other types of emulsions. © 2023 Society of Chemical Industry.

The Protein Level and Molecular Weight Analysis in Different Children's Toothpaste, which Probably Induced Hypersensitivity

CONTEXT

A new case of an allergic reaction due to the use of toothpaste was found in California, United States, causing the death of an 11-year-old girl. Ingredients contained in toothpaste suspected as a cause of allergies are milk protein compounds.

AIMS

The aim is to compare the protein level and molecular weight in children's toothpaste.

SETTINGS AND DESIGN

Stratified random sampling.

SUBJECTS AND METHODS

Samples used were children's toothpaste products in society, namely, Pepsodent®, Cussons®, Enzyme®, Kodomo®, Formula®, Colgate®, the toothpaste contain recaldent of GC Tooth Moose® and pure cow's milk. Those samples were divided into eight groups, randomly selected according to the purpose (stratified random sampling), and then coded to maintain product confidentiality. Meanwhile, samples used as comparison groups were recaldent paste and pure cow's milk.

RESULTS

Each sample was analyzed for protein content using a biuret test and protein molecular weight using the sodium dodecyl sulfate-polyacrylamide gel electrophoresis test. The protein content in toothpaste is compared with the similarity of the molecular protein weight in toothpaste that contains recaldent. Protein was found in samples 2, 3, 5, 6, 7, and 8 through a biuret test, with a concentration of 1.82; 1.53; 2.76; 1.92; 1.85; and 3.2 μg/mL. However, the protein bands were only found in sample 5 with a molecular weight of 20.7 kDa, sample 6 with a molecular weight of 19.1 kDa, sample 7 with a molecular weight of 17.7 kDa, and sample 8 with 2 bands, namely, 28.7 and 39.7 kDa.

CONCLUSIONS

We found the presence of protein in children's toothpaste. The protein molecular weight of recaldent paste is 17.7 kDa. Toothpaste containing protein with its molecular weight similar to recaldent's are found in samples 5 and 6.

In vitro digestibility of proteins from historical and modern wheat cultivars

BACKGROUND

Previous research has suggested that proteins and other quality parameters of wheats may have changed over a century of wheat breeding. These changes may affect protein digestibility. The in vitro protein digestibility of breads made with 21 cultivars of wheat introduced or released in the USA between 1870 and 2013 was therefore evaluated.

RESULTS

Protein digestibility increased with release year, but was not normally distributed; three older cultivars had significantly lower digestibility than the other cultivars: 42.0 ± 0.3 mol% (primary amino N/total N) versus 34.7 ± 0.7 mol%; P < 0.001. High molecular weight (MW) protein fractions increased and low MW protein fractions decreased with release year, but these changes were not related to protein digestibility. Thus, other differences in protein composition or other flour components may contribute to diminished digestibility of the three older cultivars.

CONCLUSIONS

This study identified differences in protein digestibility among wheat cultivars that may have important implications for human nutrition. Further investigation is required to determine the specific characteristics that differentiate high- and low-digestibility wheat cultivars. © 2020 Society of Chemical Industry.

Mechanism study of silver nanoparticle production using Neurospora intermedia

Elucidation of the molecular mechanism of silver nanoparticle (AgNP) synthesis is necessary to control nanoparticle size, shape, and monodispersity. In this study, the mechanism of AgNP formation by Neurospora intermedia was investigated. The higher production rate of AgNP formation using a culture supernatant heat-treated at 100° and 121°C relative to that with an un-treated culture supernatant indicated that the native form of the molecular species is not essential. The effect of the protein molecular weight (MW) on the nanoparticle size distribution and average size was studied by means of ultraviolet-visible spectroscopy and dynamic light scattering. Using un-treated and concentrated cell-free filtrate passed through 10 and 20 kDa cut-off filters led to the production of AgNPs with average sizes of 25, 30, and 34 nm, respectively. Also, using the permeate fraction of cell-free filtrate passed through a 100 kDa cut-off filter led to the formation of the smallest nanoparticles with the narrowest size distribution (average size of 16 nm and polydispersity index of 0.18). Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis of the fungal extracellular proteins showed two notable bands with the MWs of 15 and 23 kDa that are involved in the reduction and stabilisation of the nanoparticles, respectively.