Search

We review recent applications of atomic force microscopy (AFM) to characterize microstructural and textural properties of food materials. Based on interaction between probe and sample, AFM can image in three dimensions with nanoscale resolution especially in the vertical orientation. When the scanning probe is used as an indenter, mechanical features such as stiffness and elasticity can be analyzed. The linkage between structure and texture can thus be elucidated, providing the basis for many further future applications of AFM. Microstructure of simple systems such as polysaccharides, proteins, or lipids separately, as characterized by AFM, is discussed. Interaction of component mixtures gives rise to novel properties in complex food systems due to development of structure. AFM has been used to explore the morphological characteristics of such complexes and to investigate the effect of such characteristics on properties. Based on insights from such investigations, development of food products and manufacturing can be facilitated. Mechanical analysis is often carried out to evaluate the suitability of natural or artificial materials in food formulations. The textural properties of cellular tissues, food colloids, and biodegradable films can all be explored at nanometer scale, leading to the potential to connect texture to this fine structural level. More profound understanding of natural food materials will enable new classes of fabricated food products to be developed.

This chapter examines how Xinglongwa jades in the sixth millennium bce mark the beginning of nephrite’s preeminence in East Asia. Their carefully selected raw material, color, and texture, as well as established standards in form and production technologies, laid down the foundations for later jade cultures across a wide region in East Asia. In particular, the Xinglongwa jade slit rings are the early known circular slit earrings in the world. The influence of Xinglongwa jade culture on notable jade cultures across North China is evident, as key characteristics that distinguish Xinglongwa jades from other prehistoric jade traditions were preserved.

We examine the relation between star analyst rankings and analysts’ forecast performance. To strengthen identification, we explore the exogenous variation in analysts’ incentives generated by the suspension of the New Fortune Star Analyst Contest in China. We find that the reduction in rankings-related incentives has a positive impact on analysts’ forecast accuracy and the likelihood of analysts conducting site visits. The evidence is consistent with the view that star analyst rankings are largely popularity contests that induce analysts to allocate time and effort to attention grabbing and relationship building activities.

Waxy maize (a standard starch of normal granule size) and five small granule starches from different botanical sources (rice, wheat B type, oat, quinoa and amaranth) were subjected to 2-octenyl-1-succinic anhydride (OSA) modification. Changes of pasting, gel texture, thermal and rheological properties were investigated. Different small granule starches showed quite different property changes after OSA modification. Pasting viscosity was generally increased in OSA starches, among which OSA oat starch had notably high peak and breakdown viscosity but low setback viscosity. Gel hardness of rice, wheat B type, oat and quinoa starches was reduced by OSA treatment, whereas that of waxy maize and amaranth starches was increased. Amylose content was considered to be the major factor influencing pasting, gel and thermal property of OSA starches. Esterification increased pseudoplastic flow behavior of all starches, while OSA oat starch uniquely had reduced flow consistency coefficient. The dynamic rheological properties were also changed differentially among OSA starches. Viscoelastic properties of rice, wheat B type, oat and quinoa starches were increased after OSA treatment, whereas those of waxy maize and amaranth starches were decreased. This study showed that diverse functionalities from OSA small granule starches may fulfil different demands in product development.

In the existing wireless network coding mechanism, the packets used to coded are always with equal length, which is always called symmetric network coding. This coding method can effectively improve the network performance. But it also limits the further improvement of network performance in the multimedia application environment, where data packets length is usually unequal. Here we propose an asymmetric network coding mechanism. Through splicing combination of the packets, asymmetric network coding could overcome the shortage of symmetric network coding.