Physicochemistry of Lactose Crystallization (Turkish with English Abstract)

Öz

Crystallization of lactose has a critical importance in production and storage of various dairy products. Physical properties of lactose are crucial for stabilization of food products during processing and storage. Lactose and protein components in foods are often in amorphous state, which is excessively hygroscopic. For this reason, with the rapid increase in temperature and water content, time-dependent changes occur in their structures. Researches are carried out in order to determine the physicochemistry of these changes. Two different crystal form of lactose (α- and β-) can be found in products. Besides, amorphous lactose can be produced from a solution by rapid cooling or removal of solvent water, as in the cases of spray-drying and freeze-drying (lyophilisation), and it is in glassy form. Crystallization is a phase transition occurring in spray or freeze-drying of amorphous lactose, and it should be under control as crystallization of solid phase influences self-life of the product. Therefore, principles and physicochemistry of lactose crystallization should be well understood and applied in dairy processing for production of high quality and stable products.

Anahtar Kelimeler

• Lactose crystallization, physicochemistry of crystallization

Laktoz Kristalleşmesinin Fizikokimyası

Öz

Laktozun kristalleşmesi ceşitli sut urunlerinin uretiminde ve depolanmasında kritik bir oneme sahiptir. Gıda urunlerinin işlenmesi ve depolanması sırasında stabilizasyonun sağlanması acışından laktozun fiziksel ozellikleri cok onemlidir. Gıdalardaki laktoz ve protein bileşenleri genellikle aşırı higroskobik ve amorf haldedirler. Bu nedenle sıcaklığın ve su iceriğinin hızla artmasıyla birlikte, zamana bağlı olarak yapılarında değişimler meydana gelir. Bu değişimlerin fizikokimyasının belirlenmesi icin araştırmalar yapılmaktadır. Urunlerde laktozun iki farklı kristal formu (α- ve β- ) ortaya cıabilmektedir. Ayrıa amorf laktoz; puskurterek kurutma ve dondurarak kurutmada (liyofilizasyon) olduğ gibi, cozeltinin hılıkurutulmasıla veya cozucu suyun uzaklaşıımasıla elde edilebilir ve camsıhalde bulunur. Kristalleşe, amorf laktozun puskurterek veya dondurarak kurutmada ortaya cıan bir faz geciş olup kontrol altıda olmalıı. Cunku katıfazı kristalleşirilmesi, urunun raf omrunu etkilemektedir. Bu nedenle laktozu kristalleşirmenin prensipleri ve fizikokimyasıcok iyi anlaşımalıve sut urunlerinin işenmesinde yuksek kalitede stabil urunlerin uretimi icin uygulanmalıdır.

Anahtar Kelimeler

• Laktoz kristalleşesi, kristalleşenin fizikokimyası

Kaynakça

1. Vuataz G. 2002. The phase diagram of milk: A new tool for optimising the drying process. Lait, 82(4): 485- 500.
2. Tarakçı Z, Küçüköner E. 2005. Lactose, lactose derives and applications in food industry. GIDA, 30(4): 261-267.
3. Fox PF. 1997. Advanced Dairy Chemistry: Lactose, Water, Salts and Vitamins. Volume 3, 2nd Edition, Chapman& Hall, London, pp. 1-31, 195-197, 324-334.
4. Nickerson TA. 1965. Lactose. In Fundamentals of Dairy Chemistry, BH Webb and AH Johnson (eds), The Avi Publishing Company, Inc., London, pp. 228-246, 780787, 806-810.
5. Dincer TD, Ogden MI, Parkinson GM. 2009. In situ investigation of growth rates and growh rate dispersion of α-lactose monohydrate crystals. J Cryst Growth, 311(5): 1352-1358.
6. Haque MK, Ross YH. 2005. Differences in the physical state and thermal behavior of sprey-dried and frezedried lactose and lactose/ protein mixtures. Innov Food Sci Emerg Tech, 7(1-2): 62-73.
7. Ross Y. 1993. Melting and glass transitions of low molecular weight carbohydrates. Carbohydr Res, 238:39.
8. Sadıkoğlu H, Özdemir M. 2003. Dondurarak kurutma teknolojisi ve evreleri. GIDA, 28(6): 643-649.

9. Jouppila K, Ross YH. 1994. Glass transitions and crystallization in milk powders. J Dairy Sci, 77:29072915.
10. Nasirpour A, Scher J, Linder M, Desobry S. 2006. Modelling of lactose crystallization and color changes in model infant foods. J Dairy Sci, 89(7):2365-2373.
11. Ross YH. 2002. Importance of glass transition and water activity to spray drying and stability of dairy powders. Lait, 82: 475-484.
12. Jouppila K, Kansikas J, Roos YH. 1997. Glass transition, water plasticization, and lactose crystallization in skim milk powder. J Dairy Sci, 80(12):3152-3160.
13. Karel M, Anglea S, Buera P, Karmas R, Levi G, Ross Y. 1994. Stability-related transitions of amorphous foods. Thermochim Acta, 246: 249- 269.
14. Chiou D, Langrish TAG. 2008. A comparison of crystallisation approaches in spray drying. J Food Eng, 88(2): 177-185.
15. Langrish TAG. 2008. Assessing the rate of solidphase crystallization for lactose: The effect of the difference between material and glass-transition temperatures. Food Res Int, 41(6): 630-636.
16. Noel TR, Ring SG, Whittam MA. 1990. Glass transitions in low-moisture foods. Trends Food Sci Tech, 1:62.
17. Vua TTL, Durhama RJ, Hourigan JA, Sleigh RW. 2005. Dynamic modelling optimisation and control of lactose crystallisations: Comparison of process alternatives. Sep Purif Technol, In Press.
18. Barham AS, Haque MK, Ross YH, Hodnett BK. 2006. Crystallization of spray-dried lactose/ protein mixtures in humid air. J Cryst Growth, 295(2): 231-240.
19. Yılmaz R, Temiz A. 1997. Deproteinize peyniraltı suyundan bir etil alkol-su karışım sisteminden yararlanarak peyniraltı suyu kristalize laktozu elde edilmesi. Gıda Mühendisliği III. Ulusal Sempozyumu, Hacettepe Üniversitesi Mühendislik Fakültesi. http://eskisite.gidadernegi.org/dokgoster.asp?dosya=/d10/f240931012.htm (Erişim tarihi 17.05.2009).
20. Mimouni A, Schuck P, Bouhallab S. 2005. Kinetics of lactose crystallization and crystal size as monitored by refractometry and laser light scattering: Effect of proteins. Lait, 85:253-260.
21. Mazzobrea F, Sotob G, Aguilerab M, Bueraa P. 2001. Crystallization kinetics of lactose in systems co-lyofilized with trehalose. Analysis by Differential Scanning Calorimetry. Food Res Int, 34: 903-911.
22. Pala M, Saygı YB. 1983. Su aktivitesi ve gıda işlemedeki önemi. GIDA, 8(1): 33-39.
23. Kedward CJ, MacNaughtan W, Mitchell JR. 2000. Isothermal and non-isothermal crystallisation in amorphous sucrose and lactose at low moisture contents. Carbohydr Res, 329: 423- 430.
24. Twieg WC, Nickerson TA. 1968. Kinetics of lactose crystallization. J Dairy Sci, 51(11):1720-1724.
25. Ross YR, Karel MA. 2006. Crystallization of amorphous lactose. J Food Sci, 57(3): 775-777.
26. Certel M, Ertugay Z. 1992. Mikrokalorimetrinin Hububat teknolojisinde kullanım imkânları II. Differential Scanning Calorimetry (DSC)’nin hububat teknolojisinde kullanımı. GIDA, 17(2): 93-100.
27. Mimouni A, Schuck P, Bouhallab. 2009. Isothermal batch crystallization of alpha-lactose: A kinetic model combining mutarotation, nucleation and growth steps. Int Dairy J, 19(3): 129-136.
28. Lebail A, Boillereaux L, Davenel A, Hayert M, Lucas T, Monteau JY. 2003. Phase transition in foods: Effect of pressure and methods to assess or control phase transition. Innov Food Sci Emerg Tech, 4: 15-24.
29. Ottenhof M-A, MacNaughtan W, Farhat IA. 2003. FTIR study of state and phase transitions of low moisture sucrose and lactose. Carbohydr Res, 338: 2195-2202.