What word describes someone who has expert knowledge in gastronomy?

The term that best describes an individual with expert knowledge in gastronomy is "connoisseur." This word is often used to refer to someone who has a deep understanding and appreciation of food, beverages, and the culinary arts. A connoisseur typically possesses refined taste and the ability to discern the subtleties in flavors, presentation, and quality of dishes and culinary experiences.

In the context of gastronomy, a connoisseur is not just a casual consumer of food; rather, they actively engage in the exploration of various cuisines, often educating themselves on sourcing, preparation techniques, and the cultural significance of dishes. This expertise allows them to offer informed opinions and preferences, making their insights valuable in culinary discussions.

The other options do not adequately pertain to the realm of expert knowledge in gastronomy. For instance, "commingle" refers to the act of mixing or blending things together, while "consummate" describes a state of perfection or completeness but does not specifically relate to gastronomic expertise. Lastly, "diaphragm" is an anatomical term that pertains to a muscle structure in the body and has no relevance to culinary knowledge.