Reduced and Low-lactose Powdered Milk Production and Determination of its Physicochemical and Microstructural Properties During Storage

Resumo

The lactose hydrolysis-based production of powdered dairy products is a challenge faced by the food
industry due to difficulty in drying these products, as well as in powder storage stages. Therefore, the
aim of the current study is to feature lactose-free fat-reduced powdered milk during storage, based on
using samples produced through spray drying and lyophilization processes. Samples of powdered milk
produced through the two aforementioned drying methods were subjected to different storage conditions
(temperatures at 21 °C and 50 °C). Subsequently, the following sample features were determined: spectral
profiles (based on Raman spectroscopy), microstructure (based on scanning electron microscopy), particle
size in solution (based on laser diffraction), and sorption isotherms; in addition, a Maillard reaction
(5-hydroxymethylfurfural) indicator was measured. The powders obtained by freeze-drying had worse
characteristics compared to the products dried via spray dryer, in addition, as the hydrolysis content of
lactose increased, a worsening in the characteristics of the powders was again observed. Finally, it is
possible to conclude that drying via spray-drying is the best alternative compared to freeze-drying, for
products with and without lactose hydrolysis.