#21 X-mas food science

I’m not sure how it happened, but all of a sudden Christmas is now waiting just around the corner yet again. As we all now, the most important parameter for any kind of celebration is the food! I mean the family of course… and the food! For those of you who have yet to experience a Swedish style Christmas table, the famous “Julbord”, it is filled with delicacies such as cured salmon, smoked salmon, pickled herring in a variety of flavors, herring salads, cold cuts of all kinds of meat and bread and cheese and eggs and more meats and… That´s for the first round. Second time around the warm food is put up and we feast on roast meat, ribs, sausages, chicken, more salmon (this time baked and warm), meatballs, potatoes, red cabbage, green kale, the traditional Christmas ham and “Janssons´ temptation” – a delicious potatoe gratin with anchovies eaten together with beetroot salad.

One of the most prominent features on the Christmas table as well as the table of almost any Swedish Holiday, is the array of pickled herring, or “sill”. It comes in all kinds of flavors, the most common being the “standard pickle”, onion and mustard. Pickling is an ancient and effective method of preserving food. The acidic environment created by the vinegar makes sure many unpleasant bacteria won’t be able to grow and spoil the food. The acid also denatures the protein in the fish, changing its appearance and texture to be perceived as cooked. Denaturing the proteins on the surface of the fish also opens up the fish so the meat can adsorb the other flavors included in the pickle brine to give the herring its special flavor, be it onion, mustard or something else.

Another ancient cooking method used to preserve food, of equal importance to the Christmas table, is curing. Cured salmon, or “gravlax”, accompanied by the classical gravlax-sauce, is an absolute must for a Swedish Christmas. By embedding the fish in a mixture of salt and sugar for a few days, the salmon is essentially “cooked” by moisture being drawn out of the meat by an osmotic effect.

The brown color of the meatballs and other meats on the Christmas table, is largely made up by melanoidins, large molecules polymerized from the products of what is known as the Maillard reaction – a complex reaction between sugars and proteins where the sugars reactive carbonyl group react with the nucleophilic amino group of the amino acid. Over 24 end products is the results of a Maillard reaction between the sugar glucose and the simple amino acid glycine and many foods contain many different kinds of sugar and an even larger variety of amino acids.

Accompanying all the meats and fish is always the potato. Starch in raw potatoes is very compact, but heating makes the starch granules adsorb water and swell, making the potatoes softer as the crystallized starch molecules changes into gels.

No matter if you are staying in Sweden for Christmas enjoying the Swedish “Julbord”, or if you are going abroad, I’m certain you will all enjoy lots of tasty foods over the Holidays. If you want to share what kind of delicious treats you will eat for Christmas, leave a comment below!



For more reading on science behind cooking and food preservation, read:

“Culinary reactions: The everyday chemistry of cooking” by Simon Quellen Field

and others..

(Photos from Pixabay.com)

2 thoughts on “#21 X-mas food science

  1. Great website. Plenty of useful info here. I’m sending it to a few buddies ans additionally sharing in delicious. And obviously, thank you for your effort!

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