Ice structuring proteins (ISPs) are proteins that can modify and inhibit the growth of ice. ISPs may improve the quality of frozen dough by stabilizing ice crystals and maintaining the texture of frozen dough. In this study, effects of ISPs from winter wheat were examined on the thermophysical properties of dough, which include freezing point depression, freezable water fraction, apparent specific heat, and effective thermal conductivity. The thermophysical properties were measured by differential scanning calorimetry (DSC) and line source probe methods. The results showed that, compared to the control, adding 0.6% ISPs induced a maximum freezing point depression of 0.23 °C and decreased the amount of freezable water by 8%. ISPs had little effect on the apparent specific heat and the effective thermal conductivity in the unfrozen ranges. However, the thermophysical properties in the frozen ranges were significantly affected by ISPs. The determined thermophysical properties are important to model heat transfer during freezing of dough. 相似文献
Understanding ecosystem processes such as litter decomposition in response to dramatic land-use change is critical for modeling and predicting carbon (C) cycles. However, the patterns of litter decomposition along with long-term secondary succession (over 100 years) are not well reported, especially concerning nutrient limitations on litter decomposition.
Materials and methods
To clarify the response of litter decomposition to changes in soil nutrient availability, we conducted four incubation experiments involving soil and litter and nutrient addition from different successional stages and investigated the changes in microbial respiration and litter mass loss.
Results and discussion
Our results revealed that microbial respiration increased with succession without any litter addition (1.19~1.73 mg C g?1 soil), and litter addition significantly promoted microbial respiration (16.5~72.9%), especially in the early successional stage (grassland and shrubland). The decomposition rate of the same litter decreased with succession. In addition, nitrogen (N) and phosphorus (P) addition showed significant effects on litter decomposition and microbial respiration; P addition promoted litter decomposition (2.4~15.3%) and microbial respiration (10.1~34.5%) in all successional stages, while N addition promoted litter decomposition (4.0~10.3%) and microbial respiration (5.4~27.2%) in all except the last stage of succession, which showed a negative effect on litter decomposition (??7.5%) and microbial respiration (??6.1%), indicating possible N saturation of litter decomposition and microbial respiration.
Conclusions
This work highlights that soil nutrient availability and successional stages need to be taken into account to predict the changes to litter decomposition in response to global changes.