Abstract
Two cocoa butters with differing physical properties originating from Malaysia (hard) and Mexico (soft) were mixed with with either anhydrous milk fat or anhydrous milk fat fractionated at a high melting point, and analysed using pulsed nuclear magnetic resonance (NMR) spectrometry. Iso-solid curves were drawn by measuring the solids content at different temperatures, immediately after solidification and after 1 month at 20C. Study of the kinetics of crystallization (variation in the solids content during solidification) was carried out on tempered mixtures at temperatures where crystals were still present. Each mixture was placed in the measuring cell of the thermostatic NMR spectrometer at 10C. The cocoa butters studied showed significant differences in physical properties, and these had a marked effect on the milk fat mixtures, necessitating changes in tempering conditions (pre-crystallization). A sample of milk chocolate was also examined during tempering for its crystallization kinetics. It is concluded that NMR spectrometry is a useful method of monitoring the tempering process during chocolate manufacture.Incluye 18 referencias bibliográficas.Two cocoa butters with differing physical properties originating from Malaysia (hard) and Mexico (soft) were mixed with with either anhydrous milk fat or anhydrous milk fat fractionated at a high melting point, and analysed using pulsed nuclear magnetic resonance (NMR) spectrometry. Iso-solid curves were drawn by measuring the solids content at different temperatures, immediately after solidification and after 1 month at 20C. Study of the kinetics of crystallization (variation in the solids content during solidification) was carried out on tempered mixtures at temperatures where crystals were still present. Each mixture was placed in the measuring cell of the thermostatic NMR spectrometer at 10C. The cocoa butters studied showed significant differences in physical properties, and these had a marked effect on the milk fat mixtures, necessitating changes in tempering conditions (pre-crystallization). A sample of milk chocolate was also examined during tempering for its crystallization kinetics. It is concluded that NMR spectrometry is a useful method of monitoring the tempering process during chocolate manufacture.