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Spray drying is the gold standard for manufacturing dairy powders, due to its ability to maintain nutritional and functional properties and operate at high capacities. It is, however, extremely energy intensive, accounting for the largest share of total energy consumption in the powder manufacturing process. Therefore, spray dryer optimization, along with other water removal steps such as reverse osmosis and vacuum evaporation, is essential from a sustainability perspective. The objective of this paper is to review recent technological advances relating to product and process (reformulation, pretreatments and emerging technologies) which contribute to improved efficiency and reduced energy consumption in conventional spray drying based processes. Additionally, disruptive technologies that substantially reduce environmental footprint of powder manufacturing process by completely replacing spray drying are discussed. [ABSTRACT FROM AUTHOR]

Granulation of whey permeate (WP) and demineralised whey (DW) superconcentrates was evaluated by addition of powder using a high-shear mixer during which consumption of electrical current was monitored. Granulation of DW required 50% more energy than that of WP and the resulting DW granules were larger (∼2×) indicating greater resistance to fragmentation. Furthermore, addition of whey protein isolate (WPI) into the back-mix powder resulted in more efficient granulation (reduced energy, finer granules etc.) of superconcentrated WP. This was linked to the higher water-holding capacity of WPI and a simple model based on protein content was proposed to predict occurrence of granulation. This study sheds light on granulation behaviour under these conditions. Interestingly, while high cohesiveness of superconcentrates, which is related to protein content, has been previously shown to negatively impact granulation, increasing the protein content of the granulating powder was shown here to have positive effects, which offers great potential for design of formulated products. [Display omitted] • Protein content plays a key role in determining granulation efficiency. • High protein content in superconcentrates negatively affects granulation. • High protein content in the back-mixed powder improves granulation efficiency. [ABSTRACT FROM AUTHOR]

Breakthrough energy savings were recently projected by a spray-dryer free dairy powder manufacturing process based on superconcentration and granulation. The extent of superconcentration and the recirculation rate of powder for granulation, determines process performance. In this study, the evolution of physical properties during superconcentration and granulation was investigated for a model system (skim milk microfiltrate) using rheological and shear-cell based techniques. Results demonstrated that superconcentration leads to the development of a cohesive non-flowing state. The transition from concentrate to cohesive wet powder regime, manifested as a sharp increase in cohesiveness, occurring at around 82% w/w dry matter (DM). Powder addition for successful granulation was related to DM at the end of the cohesive phase (∼89% w/w DM). Interestingly, laboratory-based rheological and shear cell measurements were well correlated with the amperage of the mixer used; similar measurements could be applied in-process providing a better understanding and control of the product behavior within the system. • Flow behavior of dairy superconcentrates was successfully modelled. • Onset of a highly cohesive phase restricts superconcentration processes. • Shear-cell based tests provide critical information about cohesive phase. • Agitator power consumption reliably reflects evolution in product flow behavior. [ABSTRACT FROM AUTHOR]

An innovative approach based on superconcentration and granulation was investigated to manufacture dairy ingredients at lab-scale. A wet mass characterization technique, which measured agitator current consumption, was developed to study cohesiveness of super-concentrated products at various dry matter (DM) contents. For all ingredients, a composition-dependent cohesive phase was observed as DM increased, which was typified by a sharp rise and subsequent fall in power consumption. The effect of powder back-mixing on granulation was studied using three superconcentrate:powder (w / w) ratios (1:0.8, 1:1 and 1:1.2, respectively). Minimum powder addition rate for successful granulation was related to DM content at the end of the cohesive phase. Granulated powders had larger particle size, higher densities, lower porosities and enhanced flow properties compared to commercial spray-dried powders. The lab-scale model provided useful information on physical properties and limits during superconcentration and granulation, which increases the scientific knowledge relating to this novel powder production approach. Spray drying is the most widely utilized powder manufacturing technology in the dairy industry, especially for producing ingredients and nutritional products. It is, however, extremely energy intense and therefore spray drying of high-volume, low-value dairy streams such as permeate represents a poor use of resources for industry. An alternative spray dryer-free process has been developed for such streams, with significant savings. This process is based on superconcentration of streams to DM content in excess of what is typically seen in a spray-drying process (up to 80% w / w DM) followed by granulation achieved by back-mixing of finished product and, finally, drying of granules. However, little information is available on how various dairy ingredients behave in this system. Therefore, a novel lab-scale production model was produced to determine limits of superconcentration and granulation behavior of various ingredients. This work provides vital information and represents the first step in a larger program which will culminate in demonstration of the industrial applicability of the new approach for drying of various dairy streams. [Display omitted] • Lab scale model developed to mimic 'superconcentration-granulation' based process. • Tracking electrical current as a function of dry matter identified key parameters. • A highly cohesive phase limited superconcentration beyond a particular dry matter. • Composition of dairy ingredients highly influenced the onset of the cohesive phase. [ABSTRACT FROM AUTHOR]