Does addition of tomato puree make the oil component of sauce less lubricating?

Question

I believe the oil component of a sauce of a pasta sauce, for example is the critical lubricating factor. It is here that herbs and spices will get infused. Wherever the oil goes thereafter so will the flavor from herbs and spices.

When you add tomato puree, the puree itself cannot get absorbed by the oil so significant bits of non oil mixed puree will exist in the final sauce. This will not absorb the flavors of the herbs and spices, so there isn't an equal distribution of herbs and spices throughout the sauce.

Is this correct, or would you say a sauce such as dolmio, or homemade has the oil mixed with and well distributed in the tomato? Put another way I don't think herbs/spices are soluble in pureed tomatoes, so I don't expect a good distribution of the flavour throughout the puree.

Answer 1

I think you're getting a little caught up on minutiae.

True, oil & water [or tomato purée] don't mix - however, oils & water can be emulsified. In other words you can create a mixture that appears to be a single liquid - like a solution - even though one is actually suspended in the other rather than being permanently intermixed.

You can 'fix' this emulation in a pasta sauce by adding a little cornflour [or any starch] a couple of minutes before the end. It effectively binds the two together, certainly for longer than it takes to eat it; and in fact semi-permanently in food terms.
Some people [including me] don't like to do this because it removes the glossy sheen that the oil imparts to the sauce, & though it certainly helps adhesion to the pasta, makes for a slightly more homogeneous look to the sauce itself.

Whether you use any type of starch binder at the end or not, so long as you have your actual water quantity low enough by the time it's served that it doesn't drain through to the plate [allowing for a little last-minute absorption by the pasta itself] then your sauce to all intents & purposes will be 'a single entity', with the oil & water sufficiently mixed that no-one is going to spot it isn't actually a solution, but an emulsion.

The flavours will balance, no matter which component each herb or spice is technically dissolved in.

Answer 2

You're right - a sauce of fried tomato concentrate or other water-based ingredients floating about in oil would not be very appetizing, taste of much, or adhere to the pasta very well. But tomato purée is often 'fried out' at a higher temperature than would be possible after adding water-based ingredients, to caramelize it, giving it a deeper, more complex flavor, sweeter and less acidic.

Most classic Italian recipes calling for a flavorful sauce clinging to pasta are very particular about forming a cream, an emulsion between the oil-based and and water-based ingredients. As often as not that's achieved by finishing the cooking of the pasta in the sauce in the sauce's wide, open pan, tossing it about, releasing some starch from the pasta, which aids emulsification, and slackening the sauce to the desired consistency by adding a splash or two of the pasta cooking-water, which helps form the cream as well.

It suits some pasta dishes, especially tomato-based, to be dressed lightly with a good olive oil after cooking, on the plate, to get a gloss, a little lubrication, as you put it, and a fragrance that would be lost if the oil was cooked.

Answer 3

I understand what you're asking. You see, the trick with tomato based gravies is to fry it long enough. If you do not Fry it completely then the answer to your question would simply be yes, but if you fry it long enough on low heat and take it off a few seconds before the oil separates then you will not face this issue and it will also release the natural MSG from the tomatoes in your sauce.

[Tomato paste is the basis of most curries in Indian cooking. We usually temper very little quantity of hot oil with a combination of ginger/garlic/onion/chilli paste and then add the tomato paste. Physically and chemically at this stage it is not much different from pasta sauce. However tomato paste is cooked way longer in Indian cooking than it is done for pasta. Sometimes when we dont habe enough time we do not fry it long enough and the difference in flavor is very noticeable, viz. it is way less umami. Ideally, we keep it frying untill the oil separates from the paste which happens once all the water is evaporated and there are only tomato solids left in the oil base. You can see this effect in any tomato or onion paste based Indian curry reciepe video for eg. Gravy Paneer.

For the purpose of pasta it is not desirable to fry it completly till the oil separates in the aforementioned manner but to take it off just before it is about to separate.]

In simple terms, the more you fry tomato paste the more flavorfull it will become.