Physicochemistry of Lactose Crystallization (Turkish with English Abstract)

Abstract

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.

Keywords

• Lactose crystallization, physicochemistry of crystallization

Laktoz Kristalleşmesinin Fizikokimyası

Abstract

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.

Keywords

• Laktoz kristalleşesi, kristalleşenin fizikokimyası

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