8.1 Introduction The question of why it is necessary to improve the nutritional value of plant foods is one that at first hand might seem difficult to justify. What evidence is there that this is a problem? In the developed world there are no overt signs of malnutri￾tion even amongst strict

Vitamins, by their definition, are essential to health and have to be obtained from the diet on a regular basis because, with the exception of vitamin D, they cannot be produced by the body. In terms of medicine and nutrition, our knowledge of vitamins is relatively recent. Although James Lind discovered an association

Frying, especially deep fat frying, has become the most popular food prepara￾tion technology during the last five decades. The reason is that the preparation is easy even for less experienced cooks, the procedure is rapid, and the finished product is highly palatable. In the frying procedure, fat is the medium of heat transfer. Two main frying methods exist, namely shallow frying and deep frying

Extrusion cooking is a relatively recent form of food processing. Forcing material through a hole is the process of extrusion. Sausage extruders were devel￾oped in the nineteenth century as simple forming machines. Eventually pasta was produced in extruders. Flour and water were added at one end of the machine

Modified atmosphere packaging (MAP) may be defined as ‘the enclosure of food products in gas-barrier materials, in which the gaseous environment has been changed’ (Young et al, 1988). Because of its substantial shelf-life extending effect, MAP has been one of the most significant and innovative growth areas in retail food packaging over the past two decades. The potential advantages and disadvantages of MAP have been presented by both Farber (1991) and Parry (1993), and summarised by Davies (1995) in Table 16.1

Generally, the effects of microwave energy can be classified as either ‘macro￾scopic’ or ‘microscopic’. When the energy is used for heating food the effect is macroscopic and results in a specific heating pattern. However, the causes of certain features are due to microscopic effects, i.e. to physics at the atomic level

Introduction: the principles of infrared heating Sir William Herschel discovered infrared – or heat radiation – in the 1800s when he was attempting to determine the part of the visible spectrum with the minimum associated heat in connection with the astronomical observations he was making

The continuous-flow heat process is a thermal heat-hold-cool process where the foodstuff to be treated is pumped in continuous flow through heat exchanger systems where it is heated to a desired temperature, held at that temperature for a pre-determined time, then cooled to around ambient temperature. After heat treatment, the product is then packaged in an appropriate manner. This process

本章主要讨论了经典单方程回归模型的几个专门题。 第一个专题是虚拟解释变量问题。虚拟变量将经济现象中的一些定性因素引入到可以 进行定量分析的回归模型，拓展了回归模型的功能。本专题的重点是如何引入不同类型的虚 拟变量来解决相关的定性因素影响的分析问题，主要介绍了引入虚拟变量的加法方式、乘法 方式以及二者的组合方式

在各种液压起货机中，回转式起货机的液压系统比较复杂， 因此，下面就选择较具典型意义的回转式起货机的液压系统加以说明。有关的技术数据请参阅说明书