I understand that some Asian coffees, like those from Vietnam and Cambodia, are roasted in butter oil. Does anybody know how much of the saturated fat and cholesterol in the butter is absorbed by the coffee and finds its way into the cup?
To answer your question, it all depends on what oil is used during the process, which can be found by just flipping the label over. Sugar is also used; it is very similar to searing something on a pan so there is no exact way to measure what % of the ingredients you used will be "absorbed" into the beans. The oil here is used to glaze the beans, which would then mix consistently when ground and brewed. I would refer to this answer similarly asked under Cooking-Exchange
....The... beans are generally roasted in what is referred to as "butter oil", which may or may not be actual clarified butter oil. Occasionally vegetable oils are used, and historically, traditional "home-grown" coffee roasting style involves creating almost a caramel-like coating effect with the use of a small amount of sugar, oil, and generally a touch of vanilla or cocoa. This coating blackens in the roast and the beans wind up with almost a thin, hard shell. Why is this done? Robusta beans are uniquely slow to ripen on the bush, and often pickers pick unripe beans along with ripe beans. The traditional coating gives all the beans a similar color. The presence of a few unripe beans does not hurt the overall taste effect of the blend. However, modern growers pick only ripe beans despite the extra labor, and do not feature this coating in their roasting, opting simple for a little oil to keep the beans easy to turn in the slow roasting process.
Here you will find more information on how the technique for the beans are roasted.
I hope helps answer your question