The requirements of good quality and appetizing fast food increases continuously as a consequence of a community where food is always available. The crispiness of French fries is an issue that must be considered in this context, since it tends to decrease and give the fries a soft surface not appreciated by the consumer. To prolong the crispiness, the fries can be coated by a batter, a mix of starches. The batters used often consists of modified starches, e.g. cross-linked, acetylated and dextrinizated to increase and prolong crispiness, flour to stabilize the batter and sodium bicarbonate to make the batter “rise”. The cross-linked starch keeps the granules in a swelled state and prevents them from breaking when exposed to heat or processing: therefore, it delays the gelatinization and decreases the stickiness of the batter. The acetylated starch delays the retrogradation since it prevents amylose from packing when retrograded. It also stabilizes the batter. The dextrin added consists of heat and acid processed starch and decreases the gelatinization temperature of the batter. It also gives an appetizing color to the French fries. The aim of this project is to give further understanding of the ingredients´ functions, and to find alternative ingredients in a recipe already used, since the price of some ingredients has increased rapidly during the last few years. By studying an existing recipe and by doing a literary research some of the ideas were applied in the laboratory, followed by sensory and technical evaluations where color, appearance, crispiness, hardness and, to some degree, taste were evaluated. The viscosity of the starch solutions was measured since it indicates the pick-up (the amount of batter attached to the French fries). Pick-up and texture were also analyzed. Experiments confirmed the hypothesis that the acetylated starch was unnecessary and could be replaced by cross-linked starch. A high degree of cross-linking seemed to decrease the crispiness, which may depend on the prevented granule swelling. Replacing the cross-linked starch with native potato starch did not work since the batter became way too sticky. The flour could, to some degree, be replaced by native potato starch since the crispiness was very distinct. Too high concentrations of native starch made all batters very sticky, though, probably because of the early granule “explosion” caused by processing and high frying temperatures. Maize flour was an alternative to the flour currently used, since the color, appearance and crispiness of the French fries were very good according to the sensory evaluations. Although the difference between the batters seemed evident when evaluated sensory, statistics made sure that it was not significant. More research and tests needs to be done to assure the results of this project. It is also necessary to verify that the laboratory results are identical to those in industry. However, the study gave further understanding of the function of the ingredients and confirmed that there are several ways of improving an already good concept. / I takt med att allt större krav ställs på snabbmatsrestauranger och - producenter ökar också pressen att hitta livsmedel som lever upp till dessa. Stärkelsecoating av pommes frites används idag i många industrier i syfte att attrahera konsumenten genom en ökad krispighet och ett mer aptitligt utseende. Som namnet Clear-coat batter anger, ska battern inte synas utan används enbart i syfte att ge en förbättrad struktur. Syftet med det här examensarbetet är att hitta billigare ersättningar till de stärkelsevarianter som i dagsläget används i ett fungerande koncept, samt att öka förståelsen för de ingående komponenternas påverkan på slutresultatet. Arbetet tar sin början med en litteratursökning för att sedan fortsätta med appliceringsförsök och påföljande sensorisk och teknisk analys. De sensoriska analyserna, baserade på färg, utseende, krispighet och hårdhet hos pommes frites coatade med batter, stärkelseblandning, låg till grund för vidare försök och avgjorde vilka receptmodifieringar som skulle granskas ytterligare genom viskositets - pick-up - och texturmätningar. Den acetylerade stärkelse som används i referensreceptet hade inte någon tydlig påverkan på slutresultatet, utan kunde ersättas med tvärbunden stärkelse. Det framgick även att det rismjöl som används till viss del kunde ersättas med nativ potatisstärkelse, samt att majsmjöl gav ett mycket tillfredsställande resultat. Testerna visade att den tvärbundna stärkelsen var oumbärlig då klistrigheten blev för hög utan denna ingrediens. Det förelåg ingen signifikant skillnad mellan de olika recepten vid texturmätning, men fler försök behövs för att säkerställa denna slutsats.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:lnu-12151 |
| Date | January 2011 |
| Creators | Lennartsson, Hanna |
| Publisher | Linnéuniversitetet, Institutionen för naturvetenskap, NV |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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