331: Development of a Freeze-Structured Meat Analogue Using Ultrasound-Modified Brewer’s Spent Grain Protein Isolate Stabilized Emulsion Gels

Introduction

BSG, a protein-rich by-product of the brewing industry, offers a sustainable alternative to animal proteins. However, its functional properties require modification for effective use in plant-based meat analogues. This study investigates the potential of ultrasound-modified BSGPI in developing emulsion gel-based meat analogs.

Methods

BSG was autoclaved, dried at 60°C, milled, and sieved using a 40-mesh screen. It was treated with 0.18% NaOH (w/v) at a 1:15 ratio, stirred, centrifuged, and the protein was precipitated at pH 4.8, neutralized, and freeze-dried. The BSG protein isolate (BSGPI) was analyzed for proximate composition. A 6% (w/v) dispersion of freeze-dried BSGPI was prepared and subjected to ultrasound treatment (20 kHz, 100 W, 4°C) for 5 minutes (BSGPIU-A), 15 minutes (BSGPIU-B), and 25 minutes (BSGPIU-C). The BSGPIU samples were freeze-dried and analyzed for FTIR, water retention capacity (WRC), oil retention capacity (ORC), emulsifying activity index (EAI), and emulsifying stability index (ESI). An emulsion slurry was prepared by mixing 6 g BSGPI, 2 g sodium alginate, 1 g salt, 0.1 g NaHCO₃, 0.2 g mustard, 82.5 g water, and 8.2 g flaxseed oil. The slurries were analyzed for rheological properties, frozen at -10°C for 8 hours, soaked in 3% calcium chloride (CaCl₂) at 4°C for 12 hours, refrozen, and thawed. The final product was evaluated for WHC, cooking loss, and microscopic structure. Data were analyzed statistically (α = 0.05).

Results

The BSGPI contained 76.6±1.08% protein. FTIR analysis showed that ultrasound treatment shifted O–H/N–H stretching (3232.34 to 3220–3225 cm⁻¹) and revealed hydrophobic regions (C–H stretching at 2885–2880 cm⁻¹). BSGPIU-2 demonstrated significantly higher (p<0.05) WRC (6.93±0.19 g water/g), ORC (3.14±0.32 g oil/g), EAI (82.33±0.43 m²/g), and ESI (13.41±0.84 min) compared to other samples. All emulsion slurries exhibited shear-thinning behavior (1.

Significance

This study highlights the potential of ultrasound-modified BSGPI as a plant-based protein source for developing meat analogues, presenting a promising pathway for creating future plant protein-based meat substitutes while valorizing BSG.

Authors: Kaushalya Wickramasinghe, Tharindu Trishan Dapana Durage, Mario Melendez, Mariel Benigno, Chien-I Hsu, Subramaniam Sathivel