Final answer:
Gel-free mass spectrometry (MS)-based methods are most useful in large-scale commercial protein harvesting.
Step-by-step explanation:
The technique that would be most useful in the large-scale commercial harvesting of proteins is gel-free mass spectrometry (MS)-based methods. Gel-based proteomic approaches and gel free-MS-based methods involving label-based and label-free protein quantification have been extensively used for characterization of stress-responsive proteins in soybean. These methods allow for the identification and characterization of proteins in a high-throughput manner, making them ideal for large-scale protein harvesting.