Cooking Chemistry: Why Blueberries Turn Green When Cooked

Keep your blueberries blue and cabbage red with chemistry

Cooking Chemistry: Why Blueberries Turn Green When Cooked

Have you had blueberries turn green during cooking? Cabbage go funky? This may be the reason why.

I was experimenting in the kitchen, hardcore, when disaster struck. As I was folding in egg whites into the candied gelatin mixture that would shortly become blueberry marshmallows - the last step before putting them in the pan - the beautiful purple began to turn... green? Flummoxed, I tasted it. Tasted fine. I tried stirring it up. No luck. So as I went looking on the internet for the answer, a Google book provided me a little tidbit I never knew or thought about before:

Blueberries have anthocyanins. Suddenly, everything became clear to me.

But maybe it's not clear to you yet. What, you might be asking, the Sam Hill is an anthocyanin? Anthocyanins are color-changing pigments that react to the acidity or alkalinity of substances. Indeed, back on my home blog about 18 months ago, I did some winter fun experiments with kidlet and red cabbage - another abundant source of the pigments. You chop up the cabbage, you boil it in water, the pigments make the tap water a pretty blue purpley color... and then you put other stuff in it. Lemon juice makes it a brilliant, almost-neon pink. Baking soda turns it green, and stronger substances (like bleach) can make the colors range from yellow to nearly colorless.

I don't actually get to cook with blueberries all that much, which is possibly why I've never noticed this before. Kidlet prefers his blueberries fresh. And in his mouth. And my eggs...

Well, apparently my eggs have seen better days. You see, when fresh, egg whites are nearly neutral in pH. But as they age, they become more alkaline, swinging from about 7 to sometimes over 9--roughly the same pH as washing soda, which, oddly enough, turns cabbage water a pretty shade of green.

So my marshmallows were technicolored, though the taste wasn't affected any. But this same process could affect pancakes, muffins, and other things where blueberry (or cabbage) pigment hits something that is a few steps removed on the pH scale.

If you have a problem with your foods turning color when they shouldn't be, a little acid might help--this is why you should add vinegar to cooking red cabbage. Sometimes the culprit is actually what you're cooking your food in. Iron, tin, and aluminum can react with anthocyanins too (you shouldn't be using aluminum or tin cookware anyway, so throw it out).

And of course, always make sure that your eggs are fresh.

Or at least, fresher than mine were.

Have you had blueberries turn green during cooking? Cabbage go funky? This may be the reason why.

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No Bake Mars Bar Rice Krispies Treats

Marshmallows are passe

No Bake Mars Bar Rice Krispies Treats

You won't believe how quickly you can whip these Mars Bars Rice Krispies squares up, and how amazing they taste!

I inherited the original Mars Bars Rice Krispies recipe from a friend years ago. I believe there's recipes floating around on the internet too, cause she was a follow-the-recipe kind of gal. The taste was delicious, but they were really dense, kind of greasy, tough to chew, and kind of overkill on the chocolate... and the calories.  With a few tweaks, I got a really light square that was more economical, easy to eat, produced more than 16 tiny (impossible to cut) little squares, and was not death-by-chocolate.

'Cause things like that matter. Who needs 300+ calories in a single bite? Nobody, that's who.

While I don't make this recipe as often as I used to, it's always a crowd pleaser at potlucks and BBQs! And it doesn't use any gooey melted marshmallows to make it, which makes it a total win when it comes to cleaning the kitchen afterwards.

Mars Bars Rice Krispies Squares



4 heaping cups Rice Krispies
7 tbsp butter (1 stick minus 1 tbsp)
4 regular-size Mars Bars candy bars
1 cup milk chocolate chips (optional - if you like death by chocolate)


 Chunk cut the butter and the Mars Bars (if you don't want to wait all day for it to melt), and melt them in a large pot over low heat, stirring occasionally. 

 Lightly grease an 8 x 11" pyrex casserole dish (or nearest equivalent metal pan - 9x9" - but bars will be thicker) while waiting for the candy to melt.

 Once the bars are melted (don't worry if the caramel persists a little), stir in the Rice Krispies and mix thoroughly. Pour into casserole dish, and compress lightly into the bottom. 

**IF you want to use the optional chocolate topping, melt the chocolate chips in a cup in the microwave and spread over the top at this point**

 Chill the bars for at least 1 hour in the freezer, then cut and serve.

You won't believe how quickly you can whip these Mars Bars Rice Krispies squares up, and how amazing they taste!

 RELATED: Homemade Caramel Squares


How to Grill Fruit, Like a Boss

(AKA How To Make Friends & Influence People - Grilled Fruit Edition)

How to Grill Fruit, Like a Boss

10 Tips for getting the best results when experimenting with grilled fruit this summer! | BBQ | Paleo

If you're bored with the traditional summer offerings of hotdogs, potato salad, and corn, then clearly it's past time to try grilled fruit in your diet. High heat caramelizes the sugars in the fruit - it's everyone's favourite chemical reaction, the Maillard, and the grill can impart a complex smoky and uber-sweet flavour that will make you say wow! 

Grilling fruit isn't nearly as difficult as one might suppose, although there are a few tips and tricks to keep in mind for best results!

Here are 10 things to help you make grilled fruit your favourite summer treat too!

1 - For parties, grill fruit the colors of rainbow. For the best dazzle, mix it up with an array of colours and flavour, and serve it as a warm fruit salad.

2 - Use soaked bamboo skewers to keep little pieces of fruit in line or easier to grab with tongs and flip. You can also make grilled fruit kabobs for appetizers.

3 - Always use oil. A light coating of oil will keep the fruit from making a sticky mess. You can use a flavourless oil like light olive or canola, but a touch of EVOO can actually add an extra dimension to the smoky caramelized sweetness of fruit. Feel free to experiment.

4 - Stick to the firm stuff. You don't want a mushy overripe peach; you want a barely-ripe one that will be able to take a little rough handling between flame and tongs. 

5 - Don't peel or hull. Better nutrition; less likely to kerplode and make a huge mess.  Obviously there will be a few exceptions. *cough, pineapple*

6 - Experiment with thickness. The thicker the fruit, the less likely the inside will be affected as much as the outside, making for an interesting tastebud experience! Try thick-cut pineapple and watermelon wedges, and treat them like pieces of steak as you experiment with added flavourings.

7 - Watch the sugar. If you want to sweeten fruit with maple syrup, honey, or brown sugar, add it towards the end of cooking to keep it from burning.

8 - Play with liquors. Alcohol and fruit together aren't just for sangrias! Soak fruit in liqueurs. 

9 - Short and sweet (and possibly indirect). Unless very thickly cut, most fruit only needs 2-3 minutes per side. Most places recommend that you use indirect heat to grill fruit, however I have no problems with direct heat on my grill.

10 - Pair it. Don't just grill your peaches and dump them on a plate; serve them with grilled pork tenderloin. Grill your bananas before offering to make people banana splits instead of handing them a lump of ice cream. Serve your grilled watermelon with feta. Toss a whole mess of grilled fruit with salad greens and serve with white wine. Possibilities are endless.

Have fun!

10 Tips for getting the best results when experimenting with grilled fruit this summer! | BBQ | Paleo

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