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Wang C.,Iowa State University | Yu C.,Iowa State University | Han Z.,Beijing DQY Agriculture Technology Co.
LWT - Food Science and Technology | Year: 2016

Protein modification with combined pre-heating, sonication, and the addition of octenyl succinic anhydride (OSA) was performed on egg albumen to improve its thermal stability. The treatments applied to fresh egg white (FEW, or albumen) led to an increased stability. The pre-heating step and high level of OSA addition, such as 20% relative to protein, were beneficial when the stability of protein was evaluated at a higher temperature of 95 °C or 121 °C compared to that of 75 °C. The low level of OSA treatment, such as 5%, showed improved thermal stability evaluated by turbidity and protein solubility at 75 °C. Thus, the optimal level of OSA addition would depend on the degree of thermal stability improvement needed. The use of Raman spectroscopy method revealed that there were strong interactions between OSA and albumen protein and that this complex was more resistant to structural changes by heating. A mechanistic explanation of thermal stabilization based on experimental observations was illustrated. This is the first study that utilizes OSA along with other physical means to complex and stabilize egg proteins. © 2016 Elsevier Ltd.

Huang L.,Beijing DQY Agriculture Technology Co. | Wang T.,Iowa State University | Han Z.,Beijing DQY Agriculture Technology Co. | Meng Y.,Beijing DQY Agriculture Technology Co. | Lu X.,Beijing DQY Agriculture Technology Co.
Food Hydrocolloids | Year: 2016

We hypothesized that the properties of mayonnaise will be affected by egg yolk with different freezing storage time. In this work, liquid yolk was stored at temperature of -18 °C for 0, 30, 60, 90, 120 days. The properties of mayonnaise prepared with frozen yolks were characterized. Mayonnaise heat stability, color and rheological characteristics were evaluated. The microstructure, and sensory properties of the mayonnaise were also examined. The secondary structure of proteins of the yolk stored for different time was characterized using circular dichroism spectra (CD). Compared with mayonnaise prepared with fresh yolk, mayonnaise made with frozen yolk had increased values of hardness. Color determination showed that the lightness of the mayonnaise increased, but redness/yellowness decreased. The rheological measurements indicated that flow behaviors of all samples could be modeled by the Herschel-Bulkley law model. Microscopic observation showed the size of oil droplet in mayonnaise became bigger at 30 d freezing (M3). The secondary structure evaluation of frozen yolk showed that after 60 days freezing storage, the yolk protein became markedly more hydrophobic. Furthermore, sensory evaluation showed that mayonnaise made with frozen yolk was more acceptable than that made with fresh yolk. © 2015 Elsevier Ltd.

Kulchaiyawat C.,Iowa State University | Wang T.,Iowa State University | Han Z.,Beijing DQY Agriculture Technology Co.
LWT - Food Science and Technology | Year: 2016

Modification of egg white proteins with octenyl succinic anhydride (OSA) was investigated for improving thermal stability of the albumen. The reaction occurred at pH 8.5 for 3 h at 35 °C, and the degree of reaction was quantified by determining the amine group quantity. The effect of sonication pretreatment and OSA addition level on degree of reaction and product heat stability were evaluated, and they were found to have significant impact on product quality. Three different egg white materials were tested; they were rehydrated commercial egg white protein (EWP), fresh egg white (FEW), and commercial de-glucosed egg white (CFEW). They behaved differently toward this chemical modification. At 5% OSA addition, CFEW did not show significant change in amine group concentration, but at 4% OSA use EWP and FEW had 30–40% reduction of amine group. The use of sonication for the FEW at 4% OSA led to 60% amine reduction. At higher temperature of thermal stability evaluation, 95 °C compared to 75 °C, the sonicated and 10% OSA succinylated FEW showed significant stability improvement with a turbidity 30% of that of the control. For the 4% OSA succinylated EWP, its turbidity was only 20% of the control. Therefore, thermal stability improvement was achieved by OSA modification of egg albumen. © 2016 Elsevier Ltd

Liu W.,Beijing DQY Agriculture Technology Co. | Wang F.,Beijing DQY Agriculture Technology Co. | Guo L.,Beijing DQY Agriculture Technology Co. | Huang L.,Beijing DQY Agriculture Technology Co. | And 2 more authors.
Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery | Year: 2013

In order to promote the application of low-temperature pasteurization in the heat thermosensitive materials, the equipment was designed. The design principle, its structural characteristics and processes were proposed, and the thermal power, heat transfer and flow resistance were analyzed. The maximum processing capacity was 13800 mL/h with 230 mL/min of maximum flow velocity. Taking water as treatment material, the temperature of water can reach to 52°C from 4°C in 4.5 s, and reduce to 20°C from 52°C in 3 s or 10°C in 6 s. And the bacterium concentration of liquid egg white could lessen to 100 CFU/mL in 2.5 min at 55°C. The performance test shows that the system possesses a good heat-transfer capability, and a high sterilizing effect. Results provide the technical basis for the design and manufacture of low-temperature pasteurization equipment.

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