Assessment of radio frequency heating on composition, microstructure, flowability and rehydration characteristics of milk powder

Abstract

Radio frequency heating (RFH) provides higher efficiency and more uniform heating zone compared with conventional method. The aim of present work is to evaluate the effect of RFH (at 90 °C for 5 or 10 min) on the changes in composition (protein oxidation and fat distribution), microstructure, flow characteristic and rehydration property of infant milk powder. The results indicate that the concentration of protein dityrosine was slightly enhanced, more free fat appeared on powder surfaces (> 50% increase), and porosity in powder matrix as tested by SEM was increased after RFH treatment. For powder flowability, raw sample had low cohesiveness (specific energy = 4.39 mJ/g), and RFH provided better flowability and decreased compressibility. Moreover, RFH had some negative impacts on wettability and solubility of powder particles with contact angle increase at least 5% and solubility decrease of 2%~4%, indicating worse rehydration abilities. Guggenheim-Anderson-de Boer (GAB) model was applied to fit moisture vapor sorption isotherms, and longer RFH duration leading to higher c values (about 63% increase at 10 min). In addition, the RFH initiated browning reaction as CIE a* values increased from -1.8 to -1.3.Keywords: radio frequency heating; infant milk powder; microstructure; powder flowability; powder rehydration.Practical Application: RFH is potentially used in post-process lethality of milk powder, thus making it critical to evaluate the influence of RFH treatment temperature and duration on bulk characteristics of milk powder when applied in post sterilization in dairy industry.

Caracterização da superfície de partículas de produtos lácteos desidratados

“…Em tecnologias mais avançadas, Zhong et al (2017) demonstraram que a intensidade do tratamento térmico para produção do leite em pó pode afetar sua composição, microestrutura, estado de aglomeração e suas propriedades em geral, como comportamento de fluxo e característica de reidratação. Portanto, o controle de qualidade desses produtos é de grande importância.…”

Radio Frequency Heating of Milk–Effects on Quality, Safety, and Shelf Life Assessed Using Artificial Senses and Chemometric Tools

“…Therefore, the aim of this work was to study the impact of different RF heating protocols on quality and safety aspects of raw bovine milk, using artificial senses coupled with chemometric tools. Other authors have investigated the effect of RF heating on dairy products, such as yogurt [20,21] and powder milk [22]; however, this is the first study using electronic senses to achieve this task. Consisting of an array of sensors, exhibiting various selectivity and pattern recognition systems that analyze the sensor responses, this process is inspired by the neurophysiology of the smell and taste [23].…”