Introduction

Extruders offer food scientists a palette of conditions and ingredients from which new foods may be created. Although snack foods were among the first commercially successful extruded foods, today extruders produce many foods of nutritional importance. Specific product categories are described elsewhere in this book, yet in this chapter the numerous factors that influence nutritional quality in all products will be explored. Emphasis will be placed on human foods, but extrusion effects...

Macronutrients 621 Carbohydrates

Starchy tubers and grains provide important energy and satiation in most diets. Sugars provide sweetness and are involved in numerous chemical reactions during extrusion. Control of carbohydrates during extrusion is critical for product nutritional and sensory quality. Extrusion conditions and feed materials must be selected carefully to produce desired results. For example, a weaning food should be highly digestible, yet a snack for obese adults should contain little digestible material. A...

Introduction and terminology

Basic extruder technology has been used in various forms and industries for many years. New equipment designs have increased the range of extrusion applications in food processing. Today's consumers are demanding a broader selection of foods. Extrusion processing equipment has become the standard in many food industries throughout the world (Riaz et al., 1996). Food extrusion is a process in which food ingredients are forced to flow, under one or several conditions of mixing, heating and shear,...

Socioeconomical future of baby food production

One of the major dependencies of developing countries is the source of food for their young population. In the USA as well as Europe, extensive fund raising has been going on from the private sector to buy food in order to feed the young population of the developing world. These are certainly meritorious, well-intentioned projects. However, the need is growing and to date these projects have not proven an efficient means to lessen the dependence of the populations of developing countries on...

Proteins and amino acids

Extrusion improves protein digestibility via denaturation, which exposes enzyme-access sites. Most proteins such as enzymes and enzyme inhibitors lose activity due to denaturation. The extent of denaturation is typically assessed as change in protein solubility in water or aqueous solutions. These changes are more pronounced under high shear extrusion conditions (Della Valle et al., 1994), although mass temperature and moisture are also important influences. For example, wheat protein...

References and further reading

AKDOGAN H (1999), 'High moisture food extrusion', Intl J Food Sci Technol, 34(3), 195-207. ALBERTS DS, MARTINEZ ME, ROE DJ, GUILLEN-RODRIGUEZ JM, MARSHALL JR, VAN LEEUWEN J B, REIDME, RITENBAUGHC, VARGAS PA, BHATTACHARYYA AB, EARNEST DJ and SAMPLINERRE (2000), 'Lack of effect of a high-fiber cereal supplement on the recurrence of colorectal adenomas. Phoenix Colon Cancer Prevention Physicians' Network', N Engl J Med, 342(16), 1156-62. ALONSO R, GRANT G, DEWET P and MARZO F (2000), 'Nutritional...

Baby food products

Other products that are relatively new to the toddler or baby food market are snacks designed to be held easily by the child, such as a three-inch stick. These sticks melt and become gummy once in contact with the child's saliva. These products are usually cookie type recipes with similar texture and taste. Cheesy pretzels are common as well. They may be formed into long sticks of 3-4 inches, which are filled with jam. The contrasting texture between the pretzel on the outside and the jam-like...

Classification of ingredients by their functional roles in extrusion cooking

The complex mixture of materials present in a recipe may appear very confusing to the extrusion cooking technologist and machine operator. One of the first steps taken at CCFRA in developing a better understanding of the extrusion cooking process was the introduction of the Guy Classification System for ingredients. This was published in 19943 and is based on the grouping of ingredients according to their functional role using a physicochemical approach. Originally six groups were selected to...