chilled foods(全英文版冷冻食品保存方法).pdfVIP

Part I Raw materials 1 Raw material selection – fruits and vegetables L. Bedford, Campden and Chorleywood Food Research Association 1.1 Introduction Fresh fruits and vegetables are utilised in a wide range of chilled products. They may be sold whole, or peeled (for example peeled potatoes and onions) or further prepared (e.g. carrot batons). After washing or further preparation they form ingredients for mixes such as mixed fruit or salad packs or for further processing in a wide range of products. From this it can be seen that raw material requirements can be very varied but are specific to each end use. Sourcing of suitable raw material is essential for the production of final products of consistently high quality and for this both the producer and the user need to have a clear understanding of the requirements. In this chapter some of the criteria for selection will be discussed. The examples are drawn from a range of fruit and vegetable crops. Most whole fruits and vegetables are best stored at chill temperatures and thus come naturally under the scope of this book. Some however, such as potatoes and tomatoes and some other fruits are low-temperature sensitive and should ideally be kept at higher temperatures. However even these items, once they are cut and prepared need to be kept chilled, to avoid enzyme-mediated changes and disease-related spoilage, both of which proceed more rapidly at higher temperatures. Supply of suitable raw material requires collaboration between the grower and the purchaser of the produce. In effect, the grower forms the first link in the food chain. The decisions made, including variety selection and agronomic practices and the grower’s skill in harvesting and where appropriate in storing the crop are crucial steps in the supply of high-quality raw material for chilled fruit and vegetable prod