Ingredients from tomato leaves: proteins or proteases?

Summary

Tomatoes, the world’s most popular vegetable, are cultivated globally with an annual production of 180 million tons. This leads to approximately 120 million tons of tomato leaves as by-products. Currently, these leaves are usually discarded, resulting in a significant loss of valuable components like proteins. This thesis explored the feasibility to extract proteins from tomato leaves. Although it is technically feasible to extract high purity proteins, the process is intensive and the yield is very low. One of the reasons for low yield is due to the endogenous proteases. These enzymes are present in the crude juice and can degrade proteins during extraction.

Alternatively, this thesis demonstrated the potential of using the crude juice for novel applications, due to its proteolytic activity. This route requires less processing and utilizes the juice as a whole product, rather than isolating a small fraction. With this finding, our research points out a new direction for valorizing agricultural waste-streams like tomato leaves.