Snack crispness

Products where this is the sole expansion system are extruded products. This sort of cooking is used for the production of breakfast cereals, savoury snacks and some crisp breads. Of these, only the crisp breads are really within the scope of this book. 

Trans fatty acids are produced during the commercial hydrogenation of plant oils (Chapter 11). Some margarines contain these fatty acids, as do some commercially prepared snack foods (e.g. biscnits, cookies, cakes, crisps, chips). In addition, bacteria in the rnmen of rnminants prodnce trans fatty acids, which are therefore present in dairy prodnce and meat. Trans fatty acids can be incorporated into the phospholipids of the plasma membrane of endothelial and other cells, resulting in damage to the membranes. Furthermore, these abnormal fatty acids can interfere in the production of thromboxanes, prostacyclins or leucotrienes and hence interfere in control of blood clotting, immune cell activity and inflammation (Chapter 11). 

Rapid cook (microwaveable) foods Ready-to-eat meals Crispness agent Breakfast cereals Extruded snacks... 

Starches have been used by the cereal and snack industries to achieve specific textures, e.g. increased crispness, especially in high-temperature, short-time processes.135,179 Snack market trends emphasize lower fat, including fried textures from baked products, high fiber and simpler processes. Starch can contribute significantly to the achievement of each of these targets. 

Figure 1-25 Modified State Diagram Showing Relationship Between Glass Transition Temperature (Tg), Water Activity (GAB isotherm), and Water Content for an Extruded Snack Food Model. Crispness is lost as water plasticization depresses Tg to below 24X2. Plasticization is indicated with critical values for water activity and water content. Source Reprinted with permission from Y.H. Roos, Glass Transition-Related Physico-Chemical Changes in Foods, Food Technology, Vol. 49, No. 10, p. 99, 1995, Institute of Food Technologists.

Figure 8-46 Relationship Between Water Activity and Crispness of Popcorn. Source. Reprinted with permission from E.E. Katz and T.P. Labuza, Effect of Water Activity on the Sensory Crispness and Mechanical Deformation of Snack Food Properties, J. Food Sci., Vol. 46, p. 403, 1981, Institute of Food Technologists.

Katz, E.E., and T.P. Labuza. 1981. Effect of water activity on the sensory crispness and mechanical deformation of snack food properties. J. Food Sci. 46 403-409. 

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... 

Packaging for crisps and other dry snacks typically utilise laminates with the structure orientated polypropylene (OPP) 18 pm)/print 5 pm/adhesive 2 pm/aluminium metallised OPP ( 18 pm). 

When applying the conventional food contact ratio the worst-case migration potential did not exceed the SML for any of the substances derived from plastics nor did the calculated worst-case exposure exceed the ADI/TDI or other exposure restriction value in any products. However, when the actual food contact ratio was applied the ADI/TDI or other exposure restriction value of several substances could theoretically be exceeded. The worst-case calculations assume that intimate contact is made with the entire surface of the packaging. This is not the case for the majority of snack foods that are solids or semi-solids and so the actual area of contact made will be less than the total area available for contact (e.g. crisps). The levels of those migrants (diisobutyl phthalate, dicyclohexyl phthalate, dibutyl sebacate, diphenyl 2-ethylhexyl phosphate and 2-ethyl-1-hexanol) that had the potential to exceed the assigned restrictions, assuming 100% migration, were determined in foods. Of the five substances tested for, only one, dicyclohexyl phthalate, was detected in one of the foodstuffs (tortilla corn chips), at a concentration of 0.60 ppm. 

Mintel market research report Crisps and Snacks - UK - May 2005. 

High-oleic sunflower oil is sprayed on cereals, crackers, and cookies to retain freshness and crispness. It is also used in the manufacture of non-dairy creamers, snack foods, and frozen desserts. Special properties of oleic acid make high-oleic sunflower oil a choice ingredient for cosmetic formulations. The AOM value of... 

Roos, Y.H., Roininen, K., Jouppila, K., and Tuorila, H. Glass transition and water plasticization effects on crispness of a snack food extrudate, Int. J. Food Prop., 1, 163, 1998. 

Srisawas, W. and Jindal, V.K. Acoustic testing of snack food crispness using neural networks, /. Texture Stud., 34, 401, 2003. 

Another important quality defect of fried snacks is the reduction of crispness during storage due to absorption of moisture. In addition, moisture gain accelerates rancidity. Data concerning the effect of water activity (a ) on oxidation rate are presented by Labusa [39]. As a increases above the monolayer, the reaction is slowed up to the value where intermediate moisture foods begin (i.e., approximately 0.4). A further moisture increase tends to increase the rate of oxidation. Data on water activity that results in loss of crispness to an extent where the chips are perceived as not acceptable are not available, but Labusa comments that it probably occurs at an of 0.4-0.5. 

Highly crisp, fat-free snacks may be produced through the combined use of LPSSD and far-infrared radiation (FIR). For example, Nimmol et al. (2007a, 2007b) applied FIR-assisted LPSSD (LPSSD-FIR) to produce dried banana chips, while FIR-assisted vacuum drying (VACUUM-FIR) and LPSSD were also evaluated over... 

---