The Relationship between Glass Transition and Quality in Foods (Turkish with English Abstract)

Abstract

Glass transition is a state change that is defined as the transition of an amorphous solid from a rubbery and viscous structure to a glassy and hard structure. This state transition takes place at a characteristic temperature range for the solid. State changes in amorphous solids are dependent on temperature and water content. Carbohydrates and proteins in foods exhibit glass transition. When water activity is high in foods, deterioration reactions can be explained by water activity. However, in foods at low water activity containing amorphous components, glass transition temperature (Tg) becomes a factor determining stability. When these types of foods are stored at temperatures lower than the Tg, rates of deterioration reactions can be minimized and by this way the stability can be maximized. Glass transition has been related with physical and some chemical deterioration reactions in foods. Microbial deteriorations have not been completely related to glass transition as they occur at high water activity values. Critical water content/water activity values that depress the Tg value to storage temperature can be determined for foods and stability can be increased by considering these values during processing and storage.

Keywords

• Glass transition, quality, stability

Gıdalarda Camsılığa Geçiş ve Kalite İlişkisi

Abstract

Camsılığa geçiş amorf bir katının kauçuğumsu ve viskoz bir yapıdan camsı ve sert bir yapıya geçişi olarak ifade edilen bir hal değişimidir. Bu hal değişimi katı için karakteristik bir sıcaklık aralığında meydana gelir. Amorf katılardaki hal değişimleri sıcaklık ve su içeriğine bağlıdır. Gıdalarda karbonhidratlar ve proteinler camsılığa geçiş göstermektedirler. Gıdadaki su aktivitesi yüksek olduğunda bozulma reaksiyonları su aktivitesi ile açıklanabilmektedir. Ancak su aktivitesinin düşük olduğu ve amorf katı bileşen içeren gıdalarda camsılığa geçiş sıcaklığı (Tg) dayanıklılığı belirleyen bir faktör olabilmektedir. Bu tip gıdalar Tg'nın altındaki sıcaklıklarda depolandıklarında bozulma reaksiyonlarının hızı minimize edilmekte ve bu şekilde dayanıklılık maksimize edilebilmektedir. Camsılığa geçiş ile gıdalardaki fiziksel ve bazı kimyasal bozulmalar ilişkilendirilmiştir. Mikrobiyal bozulmalar yüksek su aktivitelerinde meydana geldiği için camsılığa geçiş ile tam olarak ilişkilendirilememektedir. Gıdalar için Tg değerini depolama sıcaklığına düşüren kritik su içeriği/su aktivitesi değerleri belirlenebilmekte ve işleme ve depolama sırasında bu değerler göz önünde bulundurularak dayanıklılık artırılabilmektedir.

Keywords

• Camsılığa geçiş, kalite, dayanıklılık  

References

1. Champion D, Le Meste M, Simatos D. 2000. Towards an improved understanding of glass transition and relaxations in foods: molecular mobility in the glass transition range. Trends Food Sci. Technol, 11: 41—44.
2. Nelson KA, Labuza TP. 1994. Water activity and food polymer soience:lmplications of state on Arrhenius and models in predicting shelf life. J. Food Eng, 22: 271-289.
3. Hoes YH, Karel M, Kokini JL. 1996. Glass transitions in low moisture and frozen foods: effects on shelf life and quality. Food Technol. 50(11):.95—108.
4. Bhandan‘ BR, Howes T. 1999. implication of glass transition for the drying and stability of dried foods. J. Food Eng, 40: 99.
5. Farhat IA. 2004. Measuring and modeling the glass transition temperature. ln Understanding and Measuring The Shelf
6. Life of Foods, Ft Steele (ed), pp. 218-232, Woodhead Publishing Limited, Cambridge, İngiltere. Fioos YH. 1995. Water activity and Tg: How do they complement and how do they differ. In Food preservation by moisture control: Fundamentals and Applications — lSOPOW Practicum ll. GV Barbosa-Canovas and J Weill-Chartes
7. (eds), pp. 133-150, Technomic Publishing Company. Pennsylvania, ABD. Khalloufi S, Ei-Maslouhi Y, Fiatti C. 2000. Mathematical model for prediction of glass transition temperature of fruit powders. J. Food Sci, 65(5): 842-848. .
8. B. Chuy LE, Labuza TP. 1994. Caking and stickiness ol dairy-based food powders as related to glass transition. J. Food Sci, 59(1): 43-46.

9. Karmas Fl, Buera MP, Karel M. 1992. [Effect of glass transition on rates of nonenzymatic browning in food systems. J.
10. Agric. Food Chem. 40(5): 873-879. ' Jouppila K, Kansikas J, Ftoos YH. 1997. Glass transition, water plasticization, and lactose crystallization in skim milk powder. J. Dairy Sci. 80(12): 3152-3160.
11. Floos YH. 2002. importance of glass transition and water activity to spray drying and stability of dairy powders. Lait, 82: —484.
12. Roos YH. 1993. Water activity and physical state effects on amorphous food stability. J. Food Proc. Pres, 16: 433—447.
13. Katz EE, Labuza TP. 1981. Effect of water activity onthe sensory crispness and mechanical deformation of snack food products. J. Food Sci. 46: 403-409.
14. Bell LN. 1996. Kinetics of non-enzymatic browning in amorphous solid systems: distinguishing the effects of water activity and the glass transition. Food Research int. 28(6): 591—597.
15. Craig ID, Parker Fl, Fligby NM, Cairns P, Fling SG. 2001. Maillard reaction kinetics in model preservation systems in the vicinity of the glass transition: experiment and theory. J. Agric. Food Chem. 49(10): 4706—4712.
16. Miao S, Fioos YH. 2004. Comparison of nonenzymatic browning kinetics in spray-dried and freeze-dried carbohydrate- based food model systems. J. Food Sci, 69(7): 322-331.
17. Burin L, Jouppila K. Fioos Y, Kansikas J, del Pilar—Buera M. 2000. Color formation in dehydrated modified whey powder systems as affected by compression and Tg. J. Agric. Food Chem. 48(11): 5263-5268.
18. Shimada Y, Ftoos Y, Karel M. 1991. Oxidation of methyl linoleate encapsulated in amorphous lactose-based food model. J. Agric. Food Chem. 39: 637-641.
19. Labrousse S, Recs Y, Karel M. 1992. Collapse and crystallization o| amorphous matrices with encapsulated compounds. Sci. des Aliments, 12: 757-769.
20. Moreau DL, Rosenberg M. 1996. Oxidative stability of anhydrous milkfat microencapsulated in whey proteins. J. Food Sci, 61(1): 39-43.
21. Grattarcl N. Salaun F, Champion D, Floudaut G, Le Meste M. 2002. influence of physical state and molecular mobility of freeze-dried maltodextrin matrices on the oxidation rate of encapsulated lipids. J. Food Sci, 67(8): 3002-3010.
22. Orlisn V, Ftisbo J, Fiantanen H, Skibsted LF. 2006. Temperature-dependence of rate of oxidation of rapeseed oil encapsulated in a glassy food matrix. J. Food Chem, 94: 37-46.
23. Le Meste M, Champion D. Floudaut G,’ Blond G, Smatos D. 2002. Glass transition and food technology: A critical appraisal. J. Food Sci, 67(7): 2444-2458.