I have to agree with the others above, if you are pressed for time in the brining process, try injecting.
The only benefit of using a vac-sealer for brining or marinading is self containment of the liquid. Water would boil in the presence of a vacuum, so the removal of air in marinating is simply to prevent oxidation to promote bonding for flavors (it doesn't create a vacuum as implied).
But use caution, unless you have a chamber vac-sealer, liquids can damage your suction vac-sealer. That is why most suction sealers have a manual mode or marinating mode to help prevent liquids from being drawn into the machine.
Marinades are different from Brines:
Marinades are liquids that meat rests in for a short time before cooking. They usually contain water, salt, oil, flavoring, and some type of acid. Marinades are used for flavoring. Marinades do not tenderize meat (unless a tenderizing agent is added), they are strictly used for adding flavors.
Marinades usually do not contain sugar. If marinades contain sugar, they could burn and ruin the food when cooking too hot and too fast, like steaks and chops. Sugar is less of a problem in brines because the meat is slow roasting at lower temperatures when smoking.
While marinades do not burn because they contain no sugar, they can create other problems in cooking. Marinades keep the surface wet and can impede browning and crisping of the surface of the meat. We all know that browned meat has much more flavor. The moist surface somewhat changes the texture of the food when biting into it. Marinades do not penetrate the meat very far, usually less than a quarter of an inch. Because marinades do not penetrate the meat very far, the flavors and spices are usually concentrated on the surface. When you bite into the marinated food the concentrated flavors on the surface carries enough for the entire bite. What marinades do best is find their way into cracks and crevices on the surface of meats making a flavorful surface. The added oil of a marinade helps to facilitate surface browning while keeping the sub-surface moist and flavorful.
Brines are liquids that meat rests in for a given period of time before cooking. They usually contain water, salt, sugar, and sometimes flavoring. Brines penetrate deep into the meat over time and denature the protein bonds to help tenderize it. Brines can also be injected into the meat.
Brines are a solution of salt dissolved in liquid. Brines may also have added aromatics and herbs to impart flavors into foods/meats. Meat and fish are typically steeped in brine as a form of marinating to enhance tenderness and flavor.
Our own PATIO DADDIO (John Dawson) describes it best; The entire process of brining can be described that nature wants a balance. When you submerge the meat into the brine, you have created an imbalance that nature tries to remedy. The process of achieving this balance in is called equilibrium. You've created an imbalance where the concentration of the water, salt, and sugar outside the meat is much higher than inside the meat."
Given this situation, nature goes to work trying to reestablish its required equilibrium. The cells inside the meat are surrounded by a semi-permeable membrane. Small molecules like water, salt, and sugar can pass through this membrane, but larger molecules like proteins cannot. Through a process of osmosis by diffusion, the cell moves water, salt and sugar in and out of the cells trying to get things back into balance with the surrounding liquid. Also, since most brines contain flavorings in the solution, the cell unwittingly seasons itself, as it allows the brine into the cells. As the salt concentration in the cell increases it causes some of the tightly-wound proteins to unravel, or denature, and relax a bit. This allows the cell to take on even more of the solution. Some proteins in the cell actually denature completely and are liquefied. Denatured proteins will result in a more moist and tender product.
During the cooking process, the proteins will bind with one another and squeeze out moisture. However, the magic of brining continues during the cooking process; brining will add 10% or more moisture content to the weight of the meat and many proteins are denatured. So, even though normal cooking usually causes a 20% weight loss in moisture, we started with 10% or more added liquid. The denatured proteins can no longer bind in mass amounts, so the actual moisture loss is much less, resulting in a more tender and moist product.
Injections for meat are a quick method of distributing the brine deep in the tissue of the meat. Injections are usually made with diluted half strength brines using a syringe and a special needle. Injections are a common practice in BBQ competitions.