Guanhao Bu

Milk processing as a tool to reduce cow’s milk allergenicity: a mini-review

Milk processing technologies for the control of cow’s milk protein allergens are reviewed in this paper. Cow’s milk is a high nutritious food; however, it is also one of the most common food allergens. The major allergens from cow’s milk have been found to be β-lactoglobulin, α-lactalbumin and caseins. Strategies for destroying or modifying these allergens to eliminate milk allergy are being sought by scientists all over the world. In this paper, the main processing technologies used to prevent and eliminate cow’s milk allergy are presented and discussed, including heat treatment, glycation reaction, high pressure, enzymatic hydrolysis and lactic acid fermentation. Additionally, how regulating and optimizing the processing conditions can help reduce cow’s milk protein allergenicity is being investigated. These strategies should provide valuable support for the development of hypoallergenic milk products in the future.

Effects of different factors on the forward extraction of soy protein in reverse micelle systems

Reverse micelle extraction is a new technology for the extraction of protein. In this research, three kinds of reverse micelle systems, anionic surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) reverse micelle system, sodium dodecyl sulfate (SDS) reverse micelle system, and cationic surfactant cetyltrimethyl ammonium bromide (CTAB) reverse micelle system, were used to extract soy protein respectively. Effects of soy flour concentration, Wo ([H 2 O]/[AOT]), temperature, time, pH, ionic strength and ultrasonic power on forward extraction efficiency of soy protein were investigated. The effect of AOT reverse micelle diameter was studied as well. AOT reverse micelle system had higher extraction efficiency than SDS and CTAB systems. The main factors that affected the forward extraction were soy flour concentration, temperature and pH. The optimal conditions in AOT system were soy flour concentration being 0.007 g/ml, Wo 16, pH 6.5, temperature 34°C, time 20 min, KCl concentration of 0.1 mol/L and ultrasound power of 240 W. Under these conditions, the extraction efficiency of soy protein was 85.5%. The forward extraction efficiency of soy protein in AOT reverse micelle system increased with the increase of the reverse micelle diameter. Reverse micelle extraction is an effective way to extract soy protein. Key words: Soy protein, reverse micelle, forward extraction, sodium bis(2-ethylhexyl) sulfosuccinate (AOT), sodium dodecyl sulfate (SDS), cetyltrimethyl ammonium bromide (CTAB).

The structural properties and antigenicity of soybean glycinin by glycation with xylose.

BACKGROUND Soybean glycinin is considered a major allergenic protein, and glycation is widely used to reduce the allergenic potential of present allergens. Glycation of soybean glycinin with xylose at 55 °C for different lengths of time was investigated. The extent of Maillard reaction was reflected through the content changing of free amino groups, color analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Alteration in the structural properties of glycinin was characterized by Fourier transform infrared spectroscopy, and antigenicity was evaluated by indirect competitive enzyme-linked immunosorbent assay. RESULTS The changes in the color of glycinin-xylose samples and the reduction of free amino group content in proteins indicated that the Maillard reaction occurred. The degree of glycation increased in glycated samples with the increase in reaction time. Glycation induced the changes in the secondary structure of glycinin and the ordered structure of proteins increased during the glycation reaction. The antigenicity of glycinin was reduced with the increase in reaction time. After glycation for 12 h, the antigenicity of glycinin declined about 18% compared with native glycinin. CONCLUSION The application of glycation may be an efficient method to reduce the antigenicity of soybean glycinin.

Effects of Extruded Soy Protein on the Quality of Chinese Steamed Bread

Five different extruded soy protein isolates (ESPIs) were obtained by extrusion and denoted by IVD1, IVD2, IVD3, IVD4, and IVD5. Then the SDS-PAGE results showed that the subunits of SPI decreased after extrusion, especially the subunits of 90.8, 32.8, and 31.3 kDa, whereas no isopeptide bond was formed. Although SPI improved both the development time (DT) and stability (S) of dough, ESPIs increased S but the DT decreased from 4.3 min to 1.8–2.0 min. Texture profile analysis (TPA) results showed that the hardness and chewiness of Chinese steamed bread (CSB) decreased in the order wheat flour

Comparison of Two Soy Globulins on the Dynamic-Mechanical Properties of the Dough and the Quality of Steamed Bread

To investigate the effect of the soy protein concentrate (CSP) and 7S and 11S soy globulin on wheat dough and steamed bread (SB), mixing properties of the dough were assessed by farinograph and dynamic-mechanical analyzer (DMA). The quality attributes of SB were assessed by texture profile analyzer (TPA), sensory analysis, and scanning electron microscope (SEM). The results showed that CSP, 7S, or 11S (each from 2.0 to 4.0%) significantly decreased gluten content (from 29.4 to 26.0, 36.7 to 31.8, and 31.6 to 30.7%), when those were added to wheat flour. The CSP/wheat dough stability was increased (from 6.5 to 8.4, 6.5 to 8.5, and 6.5 to 8.3 min) and the degree of softening was decreased (from 71.0 to 68.0, 71.0 to 64.0, and 71.0 to 62.0 min), but 7S or 11S had the opposite result. Moreover, the ratio of 7S and 11S has a significant effect on the quality of the dough. The storage modulus and loss modulus of soy/wheat dough decreased in the order of CSP, control, 11S soy globulin, and 7S soy globulin. The hardness, chewiness, and cohesiveness of SB decreased in the order of control, CSP, 11S soy globulin, and 7S soy globulin. Microstructure demonstrated that gluten network was interfered by SPC, 7S, and 11S soy protein, which was in agreement with the texture analysis index. The quality of SB with 3% 11S was the best in texture, microstructure, and sensory. These findings indicate that 11S has the potential to be used as a special soy protein for SB making.