Breakfast cereal moisture

Cereal Products. Breakfast cereals are susceptible to moisture absorption and require good water-vapor- and fat-barrier packagiag that retains dehcate flavors. Breakfast cereals are packaged in polyolefin coextmsion films in the form of pouches or bags within paperboard carton outer sheUs. 

FIG. 17 Water activity (or relative vapor pressure) and moisture content (%, wb) values plotted for a variety of food materials ( as is ), resulting in a composite (or universal) food isotherm. Potato chip and nonfat dry milk (NFDM) data are from van den Berg (1986). All other data are from the author s laboratory (at 20 or 25 1 °C). Water activity and moisture content values for the breakfast cereal and fruit and vegetable categories had the largest ranges (expressed here as standard deviation) 0.311 0.073 aw and 2.94 1.55% me (wb) and 0.995 0.004 aw and 89.8 3.90% me (wb), respectively. The curve is to guide the eye—it is not a fitted line. 

A simple attempt to correlate the two critical parameters of melt and glass transition temperatures of extruded raw materials with the structure of the final extrudate has been made. (Strahm et al. 2000). They measured glass transition temperatures (Tg) and melt temperatures T on a breakfast cereal formulation by rheometry. Tg s were observed as broad transition commencing at 67°C at 9.7% moisture and 14.6 C at 20% moisture. r , s for the same formulations were 146 and 54.5 , respectively. While these temperatures are obviously relevant to mass flow, it is not obvious how they relate to molecular events. Comparable measurements by DSC and NMR on the same samples would be extremely illuminating. 

Crispness is a desirable sensory property in many cereal foods such as toast, the crust of bread, crispbreads, crisps, biscuits, extruded snacks and breakfast cereals. Since it is a subjective sensory assessment crispness is difficult to define unambiguously and its perception varies greatly between individuals and also between countries (Bourne 2002). In general it is known that crisp foods are at low moisture, in the brittle or glassy state well above Tg and fracture rapidly (see also Chapters 5 and 7). We can... 

Spray oils— When applied to the surface of food products, the high-stability oils protect the product from moisture and oxygen invasion, prevent clumping, and impart a glossy appearance. Specific applications include raisins and other fruits, breakfast cereals, nut meats, croutons, bread crumbs, spices, seasonings, crackers, and others. 

Extmsion cooking is used to manufacture from cereals a wide range of products including breakfast cereals, snack foods and pet foods. In these products, texture and density are key quality requirements that are controlled by the processing conditions summarized by the term degree of cook. Conventionally, control is attempted by measurement of inputs such as the moisture content, screw speed, barrel temperature and so forth on the basis that the relationship between these and the product quality is understood. However, a more direct means of control is highly desirable. 

Chicory inulin has 10% of the sweetness of sugar and is used as a fat and sugar replacement, fiber, and probiotic in dairy products, frozen desserts, fruit preparations, breads and baked goods, and dietetic products also as a fat replacement in table spreads, salad dressings, meat products, and fillings as a fiber and probiotic in breakfast cereals sugar replacement and fiber in chocolate also used to provide form stability, moisture retention, texture improvement, texture, crispness, and mouthfeel in diverse foods. ... 

In cosmetics and lotions, chemicals are used to moisturize, prevent deterioration of the product, fight bacteria, and thicken the product. Your clothes may be made of natural materials such as cotton or synthetic substances such as nylon or polyester. Perhaps you wear a ring or watch made of gold, silver, or platinum. Your breakfast cereal is probably fortified with iron, calcium, and phosphorus, while the milk you drink is enriched with vitamins A and D. Antioxidants are chemicals added to food to prevent it from spoiling. Some of the chemicals you may encounter when you cook in the kitchen are shown in Figure 1.1. 

---