Lactose hydrolyzed milk powder: Thermodynamic characterization of the drying process

ABSTRACT

Industrial production of lactose hydrolyzed milk powder (LHMP) remains challenging. Due to the presence of the monosaccharides glucose and galactose, lactose-free powders tend to suffer stickiness, caking, and browning during drying and storage. We sought to find ideal conditions spray dryer inlet air temperature (θ_air,in) and concentrated milk flow rate (m_CM) for LHMP production. We tested θ_air,in settings of 115–160°C and m_CM of 0.3–1.5 kg · h⁻¹, and also applied mass and energetic balances. LHMP generally exhibited higher mass and energetic losses than the control (milk powder containing lactose), as a consequence of the relatively low dryability of LHMP. For a lab scale spray dryer, the ideal conditions settings for LHMP production were θ_air,in = 145 ± 2°C and m_CM = 1.0 kg · h⁻¹, taking into account the mass yield and energetic cost (kJ · kg⁻¹ of powder) of the process. These ideal conditions are a potential tool for the industrial development of lactose-free dairy powders.

KEYWORDS:

• Lactose hydrolyzed milk powder
• mass and energetic balances
• spray drying

Additional information

Funding

This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [Grant Number 308223/2015-2], Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [Grant Number 5477-15-8], and Fundação de Amparo à Pesquisa do Estado de Minas Gerais [Grant Number APQ-02382-16]