Toxin removal during protein extraction from tomato leaves

Protein production from agricultural side streams aids in global crop valorisation. This study aimed to isolate protein from tomato leaves (Solanum lycopersicum) with simultaneous toxin removal for use as a food ingredient. Protein was isolated through three methods; pH precipitation, ethanol precipitation, and a combination of heat coagulation and filtration. Protein yield and purity were determined and protein isolates were tested for presence of the toxins, tomatine and dehydrotomatine. Protein recovery was 6–10% of the original total protein content. The pH precipitation method yielded a powder with the highest purity of 76%, but was least effective at removing toxins. Ethanol precipitation removed toxins most effectively, but gave a low protein purity of 40%. The combination of heat coagulation and filtration gave the optimal result, yielding a high purity protein powder of 71% with 99.7% of toxins removed. However, absolute toxin levels might still be too high and safety assessment of toxin removal will be necessary.