In order to improve the thermal stability of vitamin E (VE) in ultra-high temperature sterilized (UHT) milk, a complex of β-lactoglobulin (β-LG) with VE was prepared. Turbidity, particle size, zeta potential, scanning electron microscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), infrared spectroscopy and fluorescence spectroscopy were used to explore whether β-LG combined with VE. The degree of binding was further analyzed by bio-layer interferometry. The contents of VE in common fortified milk (with VE) and complex fortified milk (with β-LG/VE complex) before and after ultra-high temperature sterilization were determined by high performance liquid chromatography (HPLC) and the loss rate of VE was calculated to determine the effect of β-LG on the thermal stability of VE. The results showed that β-LG combined with VE to form a complex through hydrogen bonds and hydrophobic interaction, and that binding to β-LG reduced the aggregation of VE in aqueous solution and increased its solubility. Bio-layer interferometry corroborated the binding between β-LG and VE, and the binding constant was 7.493 × 10^-2 mol/L. The loss rate of VE in complex fortified milk was significantly lower than that in common fortified milk, (4.01 ± 0.18)% versus (10.90 ± 0.17)% (P < 0.05). The above results showed that β-LG/VE could effectively improve the thermal stability of VE, which provides a theoretical basis for the development of vitamin fortified dairy products.

In this study, untargeted metabolomics based on ultra-high performance liquid chromatography-quadrupole electrostatic field orbitrap mass spectrometry (UPLC-QE-MS) was used to explore the differences in metabolite profiles between ordinary yogurt and brown yogurt, and the differences between them were evaluated from the perspective of metabolites. The metabolite information of yogurts was collected in both the positive and negative ion modes, and the metabolites were screened by multivariate statistical analysis. A total of 117 differential metabolites were obtained. Compared with ordinary yogurt, the relative contents of 106 metabolites were up-regulated and 11 metabolites were down-regulated in brown yogurt. Compared with ordinary yogurt, the contents of 3 flavor amino acids, 8 peptides, 12 sugars, 2 Maillard reaction products and one quinone in brown yogurt changed significantly. The results of this study can provide some theoretical support for the future research and development of brown yogurt.

This study was conducted in order to explore the influence of different milks on the stability of infant formula milk powder. The physicochemical properties of infant formula milk powders made from goat milk and cow milk such as moisture content, water activity (a_w), glass transition temperature (T_g), lactose crystallinity, solubility, color, protein composition, total fatty acid and the composition of surface free fatty acids were analyzed. The surface components were determined by X-ray photoelectron spectroscopy (XPS), and the surface morphology was observed by scanning electron microscopy (SEM). The results showed that goat milk infant formula powder had good physicochemical properties. Compared with cow milk infant formula powder, goat milk infant formula powder had lower moisture content, a_w, chroma and T_g, but similar crystallinity and solubility. Fatty acid composition analysis by gas chromatography-mass spectrometry (GC-MS) showed that in both infant formula powders, unsaturated fatty acids accounted for a higher percentage of the total fatty acids, while saturated fatty acids accounted for a higher percentage of the surface free fatty acids. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the content of β-casein in goat milk infant formula powder was higher, and the difference in casein content affected the surface components of milk powder. Consistently, the XPS results showed that goat milk infant formula had a relatively low fat content and a relatively high protein content in the surface composition, which could explain the more agglomerated and denser particles of cow milkinfant formula powder observed by SEM. The above results indicated that the physicochemical properties and surface composition of infant formula powders made from different milks are different due to the difference in casein composition, affecting the stability of infant formula powder.

The soymilk powder market has a broad development prospect in China, and its industry is burgeoning. Soymilk powder has become a daily food for most people, but the allergenicity of soymilk powder is always a bottleneck for the industry. Soybean and cow milk, as raw materials for producing soymilk powder, are among the major food allergens, which limit the wide application of soymilk powder. Therefore, this paper reviews the structural properties and mechanism of action of allergenic proteins in soymilk powder as well as the techniques to detect their allergenicity, and describes the methods to reduce the allergenicity of soymilk powder. Meanwhile, it discusses recent developments and future prospects in the hypoallergenic soymilk powder industry in China. Hopefully, this review will provide a reference for new product development, quality and safety control, establishment and standardization of standards for hypoallergenic soymilk powder in China.

The purpose of this research is to microencapsulate the ARA oil by spray-drying using different wall materials. A systematic investigation was implemented to characterize the effects of microcapsules on the structure, physical and chemical properties, and stability. The ARA microcapsules were used as the core material, where whey protein (W), whey protein-glucose (WG), and whey protein-glucose syrup-lactose (WGL) were used as the wall materials. An analysis was made on the encapsulation efficiency, water content, solubility, bulk density, angle of repose, particle size distribution, micro-morphology, oxidation stability, and thermal stability of the microcapsules. The properties of the microcapsules were compared from different wall materials. The results showed that the higher encapsulation efficiency of WGL was 98.64%, indicating a significant difference between W and WG (P＜0.05). The encapsulation efficiency was increased and the embedding effect of microcapsules was good. The WGL was measured to observe a water content of 2.85% and a bulk density of 0.54 g/mL. There was no significant difference among the three kinds of ARA oil microcapsules. Microcapsule powders that are obtained in this research study were very stabile and compressible.The solubility of WGL was higher and the angle of repose of WGL was lower, which were significant differences between W and WG (P＜0.05). The solubility of WGL reached 89.83%, it was increased and the quality of microcapsules was good. The angle of repose of WGL was 35.87°, which angles of repose of WGL were 7.36° and 4.38° lower than those of W and WG. As such, the smaller the angle of repose of the WGL was, the smaller the frictional force, and the better the fluidity was, the larger particle size was, indicating the normal distribution and a narrow region. The physicochemical properties of WGL were superior to W and WG, which was beneficial to the storage stability of microcapsules. The microcapsule product shared the spherical microstructure, free-cracks, free-pores, dense structure, fullness, and complete particle morphology, which basically achieved the intended purpose of embedding. The iodine titration was used to determine the peroxide values of W, WG, and WGL. Specifically, the peroxide values of WGL increased from 2.42 to 19.92 and 32.75 mmol/kg at 25 ℃ and 50 ℃, respectively. The peroxide values of WGL were significantly lower than those of W and WG (P＜0.05), indicating that WGL with higher oxidative stability. The accelerated storage test of the ARA oil after embedding showed that the WGL improved the oxidative stability of ARA oil. The wall material of WGL was better than those of W and WG for embedding ARA oil, which hindered the influence of external conditions on ARA oil and isolated oxygen, thus slowing down the oxidation rate. The reason was the dense and void-free structure of the WGL. Therefore, the oxidative deterioration of ARA oil microcapsules was effectively delayed during storage and prolonged the shelf life. The maximum melting temperature and mass retention rate of WGL were 107 ℃ and 27.55%, respectively, according to the differential scanning calorimetry and thermal gravity analysis. The WGL shared better thermal stability than W and WG. Therefore, there were higher temperatures and energy required for the phase transition of the WGL, indicating better thermal stability. The WGL can be expected to store the stability of microcapsules at room temperature. In conclusion, the properties of WGL are better than those of W and WG, indicating a better embedding and protective effect on ARA microcapsules. The finding can also provide a strong reference for the selection of the appropriate wall materials to encapsulate ARA microcapsules.