127: Particle Characterization of Spray-Dried Pulse Protein-Polyphenol Powders

Introduction

The development of pulse-fruit products is a strategic opportunity to broaden and diversify the application of both pulse proteins and fruit polyphenols. To accomplish this goal, it is necessary to establish scalable, industrially friendly production strategies to offer attractive pulse/fruit ingredients and products with desirable attributes and enhanced functionality for multiple culinary and formulation uses. Spray drying (SD) microencapsulation plays a pivotal role in the food industry by delivering commercially viable powdered forms that meet the demands of modern consumers for easy-to-use, long-lasting ingredients.

Although SD is one of the most popular drying techniques in the food industry, few scientific reports have demonstrated the scaled-up production of phenolic-rich food ingredients and their application in the formulation of food products. Therefore, the broader objective of this work was to use blackcurrant extract (BC) and pea protein concentrate (PP) to a) demonstrate the pilot scale production of spray-dried protein-polyphenol PP-BC complexed ingredients containing physiologically relevant phenolic concentration and b) evaluate their incorporation into protein bars, a highly sought product for the emerging wellness-oriented market.

Powder cohesion and flowability are vital to understand and control for processing of these spray dried ingredients (e.g., silo discharge, hopper design, fluidization, bagging). These parameters are themselves influenced by powder particle size, surface area, and morphology.

Methods

Spray dried BB, PP, and PP-BC powders were characterized by powder rheology techniques, dynamic imaging analysis, and Kr gas sorption using the Brunauer-Emmett-Teller (BET) method.

Results

Flow factor coefficients based on Jenike’s shear cell methodology and compressibility metrics as defined by Carr indices and Hausner ratios were determined for all three powders, allowing flowability to ranked. Specific surface area, particle size distribution, and shape factor distribution were also found for each powder. Smaller size and higher surface area correlated with higher cohesion and poorer flowability.

Significance

Powder rheology is a powerful tool to identify and quantify problems relating to powder processing with the ability to simulate environmental conditions (e.g., temperature, humidity). While powder rheology can identify the symptom of poor flowability, characterization of the particles' physical characteristics can help diagnose root cause (e.g., spray drying, milling, granulation, caking).

Authors: Roberta Targino Hoskin, Fabio Medeiros, Juan Ruano, Abhishek Shetty, Keith B. Rodenhausen, Mary Ann Lila, and Marvin Moncada