Study of extraction conditions for oat and chickpea in plant-based drink preparation

Abstract

Plant-based drinks require suitable processing methods to improve extraction efficiency, liquid recovery and functional quality. Enzymatic treatment and ultrasound-assisted processing can help solid–liquid separation by modifying the structure of the raw material during slurry preparation. In this thesis, oat- and chickpea-based products were prepared using α-amylase hydrolysis and ultrasound treatment. The slurries were prepared using a 1:8 solid-to-liquid ratio. Different levels of α-amylase activity, ranging from 60–240 U/g raw material (corresponding to 0.2%-0.8% dosages), were tested at 65 °C for 60 min, followed by ultrasound treatment. The study compared how enzyme concentration and ultrasound treatment affected liquid recovery, separation and the functional properties of the extracted liquids. Rapeseed oil was added at 2%, 5% and 10% levels to observe the emulsion behaviour of the extracts.

Descriptive Mean ± SD analysis revealed that the highest liquid recovery was obtained with 0.80% α-amylase (240 U/g raw material)- US of 37kHz of power 70% at 45 mins for both oat and chickpea. Thus, the condition of 0.80% α-amylase and 45 min ultrasound treatment at 37 kHz and 70% power (406 W) was chosen for scale up experiments and emulsion stability tests.

Chickpea showed higher soluble protein content than oat, while oat was more affected by starch hydrolysis. Residual starch test showed that α-amylase treatment reduced the amount of starch remaining in the pellet. Later emulsions of oat and chickpea were found to be visually stabilised at 10% and 5% of rapeseed oil. Future work should focus on optimization studies on ultrasound treatments, detailed analysis of viscosity, size of particles, colour, storage stability and sensory properties, and pilot-scale testing to evaluate the process for plant-based beverage production.