I am trying to make vegan mayonnaise. In my first attempt I used soy milk and corn oil as the major ingredients. I tried adding lemon juice instead of vinegar as the emulsifying agent and used the immersion blender to blend. However I could not get the creamy texture. The resultant product tasted like mayonnaise (at least in my imagination) and was white in color (due to soy milk?) but was watery in consistency. The volume did not expand.

Most of the recipes online calls for avacado oil or soy bean oil. I am wondering about the relation between length/saturation of the fatty chain and the ease of emulsification.

  1. Are long chain fatty acids difficult to emulsify as compared to medium chain and short chain fatty acids?

  2. How does the degree of saturation affect emulsification?

  • 1
    First, read ralph's chemistry lesson below. Then, whatever you end up doing, consider adding some mustard and/or garlic to the sauce, because both of those enhance emulsifyers
    – FuzzyChef
    Commented Dec 28, 2019 at 5:54
  • 1
    Hi, as all Stack Exchange sites, we work best with small, focused questions, not with a bunch of questions in the same post. So I reverted your edit. If you want to know these things, please post them as separate questions. As a side effect, you'll also get more rep from upvotes on more questions.
    – rumtscho
    Commented Dec 30, 2019 at 10:01

2 Answers 2


Fatty acids are not the emulsifiers here. Long chain fatty acids are excellent for emulsification, if they are deprotonated. But then they would be called “fatty acid salts”, and their flavor would be soapy - bitter. If they're neutral fatty acids, they're not ionized enough to retain a sphere of water around the micelle, and block aggregation of the droplets of fat in an emulsion.

Note that the term “fatty acid” is often misused. It is used to describe structural components of triglyceride fats, but in that form they are esterified, and not in their acid forms. They only become free fatty acids after the saponification (breakdown) of a fat, which can happen when cooking fats at high temperature. It's convenient to talk about them as fatty acids when they're still inside triglycerides because of their roles in nutrition (saturated vs. unsaturated vs. polyunsaturated, etc.).

An emulsifying agent like lecithin has two non-polar (electrically neutral), lipophilic (fat soluble) “fatty acid” (but still esterified) hydrocarbon chains, and a polar head consisting of a phosphate/choline (-/+) ionic structure that is very hydrophilic (soluble in water) due to having both positive and negative standing charges. Because of its net electrically neutral structure, the flavor is mild and fatty, not soapy. Phospholipids like lecithin are available in all cells, since they form the lipid bilayer that defines each cell.

Neither vinegar nor lemon juice would act as an effective emulsifying agent. Acetic acid, citric acid, etc., are all too water soluble, and wouldn't stick to the surface of the fat droplets in an emulsion. Rather, components of the soy milk, particularly soy lecithin, would fill that role in this recipe for vegan mayonnaise. In traditional mayonnaise, of course, egg yolks are a rich source of lecithin. The vinegar has little effect other than flavor.

The degree of unsaturation in the non-polar tails of a phospholipid would not significantly affect the stability of an emulsion once formed. Unsaturation of fatty acid esters in triglycerides does affect the texture of a fat, and how it varies with temperature.

  • 2
    I am super impressed by the chemistry lesson here. Thanks for your answer!
    – FuzzyChef
    Commented Dec 28, 2019 at 5:52

One factor not mentioned yet is when emulsifying make sure all the ingredients have sat at the same temperature for a few hours first as it enables all the chemical reactions to occur more evenly.

  • 2
    Emulsification does not involve chemical reactions.
    – Sneftel
    Commented Dec 28, 2019 at 11:16
  • 1
    When physical reactions are affected by temperatures though
    – One Face
    Commented Dec 30, 2019 at 4:15
  • Under mechanisms of emulsion in wiki A number of different chemical and physical processes and mechanisms can be involved in the process of emulsification Commented Jan 1, 2020 at 1:01

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