Nutrition Meets Food Science

Chemicals in My Plate

There is a lot of news about processed foods containing chemicals. Some are telling us that we should only eat home-cooked food and others are telling us that use only organic grains and fruits and vegetables as others contain chemicals.

What we forget is that food itself consists of chemicals. Nutrients are chemicals; water is a chemical and what we add to food like sugar, salt, butter or ghee etc. are all chemicals. Each one has a chemical formula so let us not unnecessarily get confused and scared.

There are chemicals that are essential for us and we call them nutrients, although these also should be consumed in the recommended quantities as their excess is undesirable or even can be unsafe.

Then there are others that do no harm or good physiologically but may add colour, flavour or other aesthetic value to food. These in small proportion may not be harmful but in larger quantities, they may not be safe.

Then there are chemicals that are harmful even in small amounts. These include poisons that may be naturally present in some plants, fish, mushrooms etc. and we avoid these. Some poisons are formed by pathogenic microbes like Clostridium botulinum or Staphylococcus aureus which may cause spoilage in some foods if not properly processed. There may be some chemicals produced for non-food uses that may be unsafe if used in foods. Such chemicals are not permitted in foods. Metanil yellow, for example is used in printing industry and long ago was used for colouring jalebis and mithais. After it was found to be unsafe, it was banned from use in food products.

Our grandmothers used sour fruits like lime and lemon to give sourness to foods. Even today some paneer may be made by souring the milk by lime juice with heat. Later people started purifying citric acid from limes so rather than fruit for use to give sourness. So, the ingredient lime juice became additive or chemical citric acid which may have been prepared from fruit or by fermenting sugar or by chemical process. Or acetic acid an essential component in brewed vinegar made from sugarcane juice or apple cider. The nature of the substance has not changed but our perception has changed.

Earlier honey, palm sap or sugar/beet juice was used to provide sweetness but now we use purified sugar. Similarly, we used whole spices and herbs to provide desirable taste and flavour to foods, we now have spice oils, oleoresins and purified substances like capsaicin etc. that could be added to give the desired effect with much fewer quantities and also getting the desired textural effects and eating qualities.

Many such examples could be found in food preparation. We used eggs for emulsion formation for making cakes etc. Now we can use lecithin that was earlier purified from eggs but now available from soya. The substance is same but now we call it additive or chemical. Cakes and bread while baking becomes brown due to caramelisation due to browning of sugar. However, if we add caramel prepared from sugar by heating, it is additive or chemical being added. Riboflavin is vitamin B2 – a nutrient – but is also a colouring food additive. Vitamin C also known as ascorbic acid is an additive functioning as an acidity regulator and tocopherols (δ,γ) used as antioxidants.

There are many such additives that are present in nature as such and we consume without any problem but when these are added in making food products people say chemicals are added to food.

Some of the additives used in food processing are new and synthetic. Such additives like stabilisers, emulsifiers, sweeteners and colours etc. are thoroughly tested for both efficacy and safety, by JECFA (FAO/WHO) following scientific risk assessment. After making sure that they are safe, the acceptable daily intake (ADI) is determined which represents the amount that a person may consume every day over a lifetime with no adverse effect.

Maximum limits are set by Codex for various food categories/sub-categories, which several countries including India adopt with minor variations, if any. The maximum limit allocated to food is the legal limit. Every country does an exposure assessment to assess whether the total additive intake through consumption of foods in which it is permitted, is below, near or exceeds the ADI. Since we now consume foods produced domestically and imported, it is necessary for a harmonized allocation of additives which is what the Codex Food Category System ensures and countries follow. Theoretical exposure assessments can be done using the allocated limits and the quantity of food consumed. Where there is concern of exceeding ADI, actual usage and consumption data is required. Safety is predictive.

In agriculture also, when plant grows it absorbs chemicals from soil and makes its own chemical by photosynthesis using sunlight and we have no problem with that. However, some protest the use of fertilisers to provide additional food to crops. As our population is large and we need huge quantities of food, we had green revolution to produce hybrid varieties that not just required fertilisers but also pesticides as these crops were prone to pest attacks and spoilage. Government has allowed use of pesticides and when used with proper procedure within proper amounts would not cause any safety issues for consuming these grains. Many pesticides like ethylene oxide would evaporate during harvesting, threshing and storing of grains to levels below acceptable levels. However, some protesters want only organically grown crops that do not use chemical fertilisers or pesticides. That would take us back to when there were shortages of food and the possibility of famine.

These additives are used for a technological purpose to make the food more enjoyable, as we love the food that gives us pleasure. They keep bread soft and biscuits crisp or crumbly. The preservatives also ensure that food does not spoil easily and cause wastage. They keep the food safe. Additives are essential for us today and they are safe.

For more information:

Dr Jagadish Pai

Editor, PFNDAI

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