Dados do Trabalho

Título

PULSE SPRAY DRYING FOR THE PRODUCTION OF POWDERED VEGETABLE DRINKS

Introdução

Pulse spray drying (PSD) is an emerging technology in the food sector, claimed to be energetically more economical than traditional drying. Oat has been employed in preparing plant-based milk analogs due to its traits such as flavor, texture, and nutritional properties. Moreover, the food industry is currently interested in plant proteins, including those derived from faba bean. Therefore, this work aims to evaluate PSD's feasibility in producing vegetable drink powder.

Material e Métodos

For that, two formulations were prepared: (1) a liquid drink named “OAT”, produced from oat flour using an enzymatic pre-treatment and centrifugation; (2) a liquid drink named “OAT-PRO”, produced as (1) and subsequently added with faba bean protein isolate (FBPI) in the proportion of 2.91% (m/m). The final formulations contained approximately 2.7% and 5.4% (m/m) of total protein, respectively. Both drinks were dried in a Pulsed Spray Dryer (PCD-70, Ekonek, Spain) operating at an outlet air temperature of 83±1 ºC, with a feed flow rate of 71 L/h. Measures of moisture, aw, water solubility, lipid peroxidation (TBARS), and particle size were determined.

Resultados e Discussão

The powders’ moisture and aw were 2.64±0.08% and 0.150±0.004, and 4.37±0.11% and 0.290±0.004 for OAT and OAT-PRO, respectively. These results suggest that OAT-PRO presented strong inter-particle liquid bridges and interlocking forces between particles. FBPI slightly decreased the solubility of powders (67.95±0.45% vs 75.09±0.18%), which was expected and derived from its compact protein structure and lower solubility (around 11%). Also, the literature reports solubility peaks occurring at pH 10–11 in FBPI, and we worked with feed solutions at neutral pH. On the other hand, FBPI seemed to protect the samples against lipid oxidation: 2.78±0.23 mg MDA kg−1 for OAT powder vs 1.70±0.27 mg MDA kg−1 for OAT-PRO. This finding can be associated with the natural antioxidant capacity that many food proteins possess (through different mechanisms). Furthermore, under some circumstances, proteins may oxidize faster than unsaturated fatty acids, thereby delaying lipid oxidation and rancidity. Finally, OAT-PRO showed higher particle sizes than OAT (values of D50: 74.3±0.7 μm vs 41.3±0.2 μm).

Conclusão

Our work evidenced that PSD could produce a vegetable protein-enriched drink, having features consistent with those found in the bibliography.