tailieunhanh - Handbook of industrial and hazardous wastes treatment - Part 6

Các ngành công nghiệp bánh là một trong những ngành công nghiệp thực phẩm lớn của thế giới và rất khác nhau về quy mô sản xuất và quá trình. Theo truyền thống, các sản phẩm bánh mì có thể được phân loại như các sản phẩm bánh mì cuộn và bánh mì, sản phẩm bánh ngọt (ví dụ, bánh nướng và pasties), và các sản phẩm đặc biệt (ví dụ, bánh ngọt, bánh quy, bánh rán, và bánh mì đặc biệt). Trong tháng 3 năm 2003, đã có hơn 7000 hoạt động tiệm bánh ở Hoa Kỳ (Bảng 1). | 25 Bakery Waste Treatment J. Paul Chen Lei Yang and Renbi Bai National University of Singapore Singapore Yung-Tse Hung Cleveland State University Cleveland Ohio . INTRODUCTION The bakery industry is one of the world s major food industries and varies widely in terms of production scale and process. Traditionally bakery products may be categorized as bread and bread roll products pastry products . pies and pasties and specialty products . cake biscuits donuts and specialty breads . In March 2003 there were more than 7000 bakery operations in the United States Table 1 with more than 220 000 employees. More than 50 of bakery businesses are small having fewer than 100 employees 1 . The bakery industry has had a relatively low growth rate. Annual industry sales were billion billion and billion in 1998 2000 and 2002 respectively the average weekly unit sales were 9 890 10 040 and 10 859 during the same periods. Industry sales increased only ahead of the compounded rate of inflation according to . Production by large plant bakers contributes more than 80 of the market s supply while master bakers sell less than 5 1 . The principles of baking bread have been established for several thousand years. A typical bakery process is illustrated in Fig. 1. The major equipment includes miller mixer kneading machine bun and bread former fermentor bake ovens cold stage and boilers 2-4 . The main processes are milling mixing fermentation baking and storage. Fermentation and baking are normally operated at 40 C and 160-260 C respectively. Depending on logistics and the market the products can be stored at 4-20 C. Flour yeast salt water and oil fat are the basic ingredients while bread improver flour treatment agents usually vitamin C ascorbic acid and preservatives are included in the commercial bakery production process. Flour made from wheat . hard wheats in the United States and Canada contains a higher protein and gluten .