Polyphenolics: the latest must-have food additives
Red wine, purple fruits and dark chocolate back in fashion amongst the health conscious due the their “rich in polyphenolics” label. Food S&Ts are keen on their colourant and preservative properties. I am fairly sure I know what they are, however a little revision and research would not go amiss. Care to join me? Everyone is talking about the power of Polyphenols as natural health boosters, capable of turning back your body’s clock and protecting your heart.
First, a review of phenolic compounds’ structure.
The Aromatic ring Phenols are a group of organic compounds that have an -OH group attached directly to an aromatic ring, according to my chemistry lecture notes. An aromatic ring is a compound that actually has a sweet scent. The basic aromatic ring structure of all phenols is a benzene which has 6 Carbon atoms and 6 Hydrogen atoms, with double bonds between the Carbon and Hydrogen represented by the ring.
Double bonds can be represented by internal lines
Polyphenols are compounds made of more than one phenol with an array of interesting and useful side chains coming off the Carbons. The are soluble in water which means they aren’t shy of travelling around food matrices or the body.
Polyphenols and colour
The chromophore is the portion of a molecule that is responsilble for its colour. The structure of a molecule provides spaces in which visible light can be absorbed or reflected. When visible light hits a molecule’s chromophore an electron is excited and reacts. Depending on how energetic that reaction is light of a certain wavelength is absorbed. In the case of phenols their chromophores are in the conjugated double of which they have plenty in the aromatic ring itself and usually some back ups in their side chains.
The human eye sees what is not absorbed of the visible light spectrum and that is the complimentary colour. If you a violet object that means the object has absorbed yellow light with wavelengths of around 550 nanometers leaving you the violet rays to process.
- This PP is Delphinidin, found in bilberries. It gives a strong blue colour. Look at all those double bonds – just the right kind of space for orange light absorbing chromaphores
Polyphenols as antioxidants
The definition of an antioxidant is “a compound which reduces the peroxide value by quenching singlet oxygen.”
Unleashed, unpredictable and unhelpful these single oxygen molecules also known as free radicals and cause things to go off.
Lipid peroxidation is in involved in arterial disease in the human body* and destabilises fats in foods causing rancidity. We will get in to the mechanisms of antioxidants elsewhere, but basically antioxidants block oxidation. This means they stop something giving away its electrons and changing in to something else, usually something undesirable such as rust on iron.
Oxidative stress is associated with aging and cell damage so it is easy to see why a foods that can send in the clean-up squad are highly valued.
There is a lot to look at with polyphenols, so l’m going to
- start calling them PPs, if that’s all right with you
- focus on the red, blue and violet ones, colorimetrically speaking
- break it all down to PPs in terms their of properties and applications in food colouring, flavour and health benefits.
- look at their applications in the food industry
I like to take my own photos as much as possible for Crackling. This means I need to go shopping for good chocolate, red wine, berries and black and purple foods. This means I am going to cook with them, and this means recipes. I feel Mexican black beans coming on as part of a meal of slow cooked pork shoulder, dirty rice, salsa and a dish of yam plant tops I had in the Yucatan many years ago. I may have to settle for silverbeet.
Here’s a recipe to get you started, PPs in the chocolate and cherries of Black Forest Gateau