Papers by Author: Xing Qian Ye

Abstract: Time-Temperature Indicator (TTI) is an intelligent or smart package. It is a simple device that can be attached to food packaging to indirectly reflect the full or partial temperature history and quality status of the food product. TTI is utilized widely throughout food processing and distribution of cold chain. An alkaline lipase TTI has been developed, which based on the reaction between alkaline lipase and glycerol tributyrate. Experiments under several isothermal conditions (1.3°C，6.1°C，10.9°C，15.5°C，20.6°C，25.4°C) were conducted and the Arrhenius parameters of the TTI were derived. The developed TTI chemical reaction system showed an Arrhenius behavior, the activation energy was 45.07±2.25 kJ/mol.

Abstract: A non-contact ultrasonic system to monitor the yogurt fermentation process through a stainless steel reactor wall is described. During the process, the acoustic impedance was determined by using multiple reflections of ultrasound within the stainless steel wall. Thus, the wall was part of the measurement system. By basing on measurement multiple reflections, the instrument sensitivity is increased by the power of the reflection coefficient. Experimental results show that the acoustic impedance changes continuously while pH declines. It is very useful, especially on production scale for yogurt that the acoustic impedance measurement does not demand a liquid transparent to ultrasound. Also, this noncontact sensing method can reduce the risk of food contamination from measuring instrument, and contribute to hygienization for food manufacture industries.

Abstract: The objective of this study was to evaluate the nutritional quality of reconstituted milk by determining concentrations of several important proteins. Difference in protein between raw milk and reconstituted milk was determined with spectrophotometer, HPLC, fluorometry, ELISA, photon correlation spectroscopy. Total undenatured whey protein, β-lactoglobulin, α-lactalbumin, chemically available lysine, insulin-like growth factor-Ⅰ (IGF-Ⅰ), epidermal growth factor (EGF), immunoglobulin G (IgG) contents and casein micelle size were analyzed for both raw milk and reconstituted milk. Results showed that reconstituted milk had a significant decrease (P<0.01) in total undenatured whey protein, β-lactoglobulin, α-lactalbumin, chemically available lysine, IGF-Ⅰ, EGF and IgG. The decrease of casein micelle particle size confirmed that most of the whey protein denatured and associated with the casein micelle occurred in the processing of milk powder manufacture. It is concluded that reconstituted milk has a lower nutritional value than that of raw milk.