Rowett Food Reports

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Figure 3: Schematic of how processing of tomatoes to form ketchup improves uptake of lycopene, a plant carotenoid. The Rowett Institute of ISSUE 03 SPRING 2012 Nutrition and Report author: Health Consumption of ketchup leads to a greater and more prolonged increase in plasma lycopene Professor Professor Garry Duthie concentrations than is observed when consuming tomatoes with a similar lycopene content (Fig 3). The Garry Duthie We undertake release of lycopene from the plant cells during ketchup manufacture improves availability and subsequent research to address absorbtion.8 Vitamin C is required to prevent scurvy and may play a role in preventing cardiovascular contemporary problems disease. Consequently fortification of processed foods with specific micronurients to compensate for such Nutritional Implications of Industrial Food in nutrition, which losses may be required. makes a significant Processing contribution to increased Conclusions Background scientific knowledge, Our consumption of industrially processed food is a recent event in relation to our evolutionary history Food processing converts primary animal and plant products into edible foods. The majority of food underpins Government Garry Duthie is Professor and the consequence for our health is a matter of contentious debate. However, food processing is a we consume in the UK has been industrially processed in some way. Processing techniques increase of Nutritional Science policies and informs fact of modern life and its continual innovations may be the only means of sustaining an ever expanding the stability of the product and permit the consumer to choose from a wide range of food items all at the University of innovation for industry. population on our planet. There are advantages (eg. improved availability, choice) and disadvantages year round. Some argue that without food processing methods it would be difficult for industrialised (eg toxic compounds, nutrient losses) of processed foods. The nutritional consequences of consuming Aberdeen. He is Head countries to sustain their populations.1 The main pressure on food processors is to return a profit. processed foods is arguably under-researched. There needs to be continual open dialogue between of Human Studies at Unsurprisingly, there is a tendency to focus on producing foods which appeal to the customer in terms academic scientists and the food industry to develop processing procedures which maximise the health the Rowett Institute of of taste, visual appeal and price. Such foods may be sub-optimum from a nutritional standpoint and properties of processed foods while still being profitable and attractive to the consumer. Please do not Nutrition and Health, may not be compatible with current health messages. This brief report summarises current industrial hesitate to contact us for further information. food processing procedures and discusses the consequences for the nutritional value of food. University of Aberdeen and is also leader of Methods of food processing the Natural Products Research Group. His Traditional methods of food processing such as sun drying, oven drying, smoking, salting, pickling References and fermenting require little equipment. Such procedures reduce microbiological activity and in the research focuses on pre-industrial era allowed foods to be stored against times of scarcity. Early technological innovations 1. Southgate DAT. Food processing. In Human Nutrition and Dietetics (eds Garrow JS, James WPT, Ralph A) the mechanisms by 2000, 397-409. Churchill Livingstone. to preserve food were canning (early 1800s), pasteurisation (1860s), freeze drying (early 1900s) and which dietary factors 2. Knorr D, Froehling A, Jaeger H, et al. Annu. Rev. Food Sci. Technol. 2011, 2, 203-205. deep freezing (1920). These methods are still in use today. However, there are now a whole range prevent or promote the 3. Somza V. Mol. Nutr. Food Res. 2009, 53, 1485-1486. of newer technologies employed by the food industry to provide palatable, safe food. These include development of diseases 4. Hooper L, Barlet C, Davey SG, Ebrahim S. Cochrane Datbase Syst Rev 2004, 1: CD003656 • the use of modified atmospheres such as heart disease 5. Lichtenstein AH, Kennedy E, Barrier P et al. Nutr. Rev. 1998, 56, S3-19. • the addition of preservatives (eg sulphites, benzoates, nitrites) and cancer. 6. Eaton SB, Konner M. New Eng. J. Med 1985, 283-289. • the control of microstructure (eg emulsions, matrices, extrusions) 7. Stender S, Dyerberg J, Bysted A. et al. Atherosclerosis Supplements 2006, 7, 46-52. • manothermosonication (combined ultrasonics, heat and pressure) 8. Shi J, Le Maguer M. Crtical Rev. Food Sci. Nutr. 2000, 40, 1-42 • irradiation CONTACT • the use of high magnetic field pulses

PROF. GARRY DUTHIE • electroporation (high voltage electric gradient pulses)

Email [email protected]

Rowett Institute of Nutrition and Health Rowett Institute of Nutrition and Health www.abdn.ac.uk/rowett www.abdn.ac.uk/rowett Tel: +44(0)1224 712751 Tel: +44(0)1224 438700 Fax: +44(0)1224 715349 Fax: +44(0)1224 715349 Supported by Scottish “The foremost beneficial Government “Enhancing health benefits from food effect of food processing is through production and the reduction or removal of processing” programme unwanted micro-organisms.”

Such processes can have both beneficial and undesirable consequences. For example, use of electric fields and high pressures may limit formation of undesirable compounds and retain freshness to the food Table 2: product. On the other, microbiological spores may not be destroyed and flavour characteristics may be Some potentially harmful compounds arising from food negatively altered. Nowadays, several processing approaches may be combined (hurdle technology) to processing procedures increase shelf life and ensure the food item is safe for consumption.2

Beneficial aspects of food processing Compounds Description Possible adverse effects The foremost beneficial effect of food processing is the reduction or removal of unwanted micro- 3-chloro-propane-1,2-diol (3MCPD) By-product of the manufacture of Carcinogenic, antifertility agent organisms. However, there are several other economic and societal benefits which appeal to hydrolysed vegetable protein. Also found manufacturers and consumers (Table 1). in soya products and a range of cereal products. Table 1: Trans fatty acids Formed during the partial hydrogenation of Promote coronary heart Beneficial aspects of food Beneficial aspects Action Consequence vegetable oils to a semi-solid state for use disease processing in manufacturing processes. Food safety Inactivation of pathogens and natural Improved product shelf-life. toxins and prevention of formation of Acrylamide Formed from the condensation of the Carcinogenic oxidised compounds. amino acid asparagine with reducing sugars such as fructose or glucose upon Sensory quality Formation or inclusion of compounds Improve consumer acceptability heating. which enhance texture, flavour and taste. and demand. Heterocyclic amines Formed from free amino acids, creatine, Carcinogenic, neurological Diversity Independence from seasonal availability Widening of consumer choice. and glucose under variety of conditions disorders and access to wide range of products. including processing time and temperature. Cost Bulk buying of primary products and Economy of scale leading to lower Polycyclic aromatic hydrocarbons Produced by pyrolysis of fats and wood Carcinogenic, mutagenic, ingredients. cost to consumer. smoke curing and preservation. Convenience Increase supply of ready-to-eat and semi- Less preparation time for Acrolein Formed during different stages of Carcinogenic prepared foods. consumer. processing from frying of vegetable and animal fats.

Potentially undesirable effects of food processing In addition to the formation of undesirable compounds, processed foods can have high levels of salt Food processing can lead to undesirable reactions and the formation of compounds which are and fat. A high salt intake raises blood pressure and increases risk of stroke and cardiovascular events. potentially toxic (Table 2). Many are formed during Maillard reactions which are a complex series of Historically, salt was used as a preservative but it is now also widely used by the food industry to enhance chemical interactions that occur when proteins are heated in the presence of carbohydrates. Laboratory the palatability of processed foods. Only 5% of salt consumed is naturally present in foods and 15% is 4 studies potentially implicate compounds arising from food processing methods in the development added at the table or in domestic cooking. The remainder (80%) is added by the food industry. Similarly, of several clinical conditions such as cancer and heart disease although this does not necessarily the fat content of processed foods can exceed dietary recommendations as it favourably enhances taste mean that they produce a health risk to humans in the quantities found in certain processed foods.3 and hence consumer preference. Excessive intake of fat is associated with cardiovascular disease, 5 Nevertheless, regulatory authorities impose stringent limitations on the amount permissible in foods. diabetes and obesity. Supported by Scottish “The foremost beneficial Government “Enhancing health benefits from food effect of food processing is through production and the reduction or removal of processing” programme unwanted micro-organisms.”

Potentially undesirable effects of food processing In addition to the formation of undesirable compounds, processed foods can have high levels of salt Food processing can lead to undesirable reactions and the formation of compounds which are and fat. A high salt intake raises blood pressure and increases risk of stroke and cardiovascular events. potentially toxic (Table 2). Many are formed during Maillard reactions which are a complex series of Historically, salt was used as a preservative but it is now also widely used by the food industry to enhance chemical interactions that occur when proteins are heated in the presence of carbohydrates. Laboratory the palatability of processed foods. Only 5% of salt consumed is naturally present in foods and 15% is 4 studies potentially implicate compounds arising from food processing methods in the development added at the table or in domestic cooking. The remainder (80%) is added by the food industry. Similarly, of several clinical conditions such as cancer and heart disease although this does not necessarily the fat content of processed foods can exceed dietary recommendations as it favourably enhances taste mean that they produce a health risk to humans in the quantities found in certain processed foods.3 and hence consumer preference. Excessive intake of fat is associated with cardiovascular disease, 5 Nevertheless, regulatory authorities impose stringent limitations on the amount permissible in foods. diabetes and obesity. Supported by Scottish “Consumption of processed Government “Enhancing health benefits from food foods is a very recent event in through production and processing” programme our evolutionary lifespan”

Nutritional consequences of food processing Changes in the structure of fats during processing For example, canning can decrease vitamin C also can be problematical. For example, trans fatty content by 70% compared with the amount in Modern human beings appeared about 40,000 years acids (Fig 2) formed during the partial hydrogenation the original ingredients. Vitamin C is required to ago and our genetic constitution and nutritional of vegetable oils to a semi-solid state for use in prevent scurvy and may play a role in preventing requirements have changed relatively little since manufacturing processes have been associated with cardiovascular disease. Consequently fortification then. The diverse range of macronutrients and heart disease, Alzheimer’s, diabetes and cancer. of processed foods with specific micronurients to micronutrients we require to maintain health was Their use is banned in Denmark, and there is compensate for such losses may be required. originally obtained from primary animal and plant pressure on the UK food industry to minimise the use products. Consumption of processed foods is a of trans fats the food chain.7 In contrast, processing can release nutrients and very recent event in our evolutionary lifespan. bioactive compounds from the food matrix where they Figure 2: Consequently we may be poorly adapted in relation are bound. As a result digestibility and bioavailability Structures of a “normal” and trans fatty to the chemical and physical changes to nutrients may be improved compared with that achieved when 6 acid produced during processing. during some food processing procedures. For consuming the non-processed primary products. example, native proteins may be denatured or form A classical example is lycopene, a carotenoid aggregates and starches may undergo crystallisation found in tomatoes which may have health benefits. (Fig.1). This may alter digestibility compared with consuming the nutrients in a non-processed primary Table 3: product. Effects of processing procedures on some vitamins Figure 1: Schematic of changes in structures of starch and proteins that can arise from food processing Nutrient Causative processes Vitamin C Water leaching,heat,oxygen Biotin Alkaline conditions Carotenoids Heat,light

Vitamin B12 Alkaline,acid conditions Folic acid Heat,light Niacin Water leaching Pantothenic acid Heat,alkaline,acid Adequate intakes of vitamins are essential to Riboflavin Heat,light,alkali maintain health. Many of these micronutrients Thiamine Water leaching,oxygen,heat, light,alkaline conditions are sensitive to heat, oxygen and pH (Table 3). Vitamin K Light,alkaline conditions Generally processing can lead to a decrease Vitamin A Heat,light,oxygen in the amount of these micronutrients in foods. Vitamin D Light,oxygen, alkaline conditions Supported by Scottish “Consumption of processed Government “Enhancing health benefits from food foods is a very recent event in through production and processing” programme our evolutionary lifespan”

1. Southgate DAT. Food processing. In Human Nutrition and Dietetics (eds Garrow JS, James WPT, Ralph A) Research Group. His Traditional methods of food processing such as sun drying, oven drying, smoking, salting, pickling 2000, 397-409. Churchill Livingstone. and fermenting require little equipment. Such procedures reduce microbiological activity and in the research focuses on 2. Knorr D, Froehling A, Jaeger H, et al. Annu. Rev. Food Sci. Technol. 2011, 2, 203-205. pre-industrial era allowed foods to be stored against times of scarcity. Early technological innovations the mechanisms by 3. Somza V. Mol. Nutr. Food Res. 2009, 53, 1485-1486. to preserve food were canning (early 1800s), pasteurisation (1860s), freeze drying (early 1900s) and which dietary factors deep freezing (1920). These methods are still in use today. However, there are now a whole range 4. Hooper L, Barlet C, Davey SG, Ebrahim S. Cochrane Datbase Syst Rev 2004, 1: CD003656 prevent or promote the of newer technologies employed by the food industry to provide palatable, safe food. These include 5. Lichtenstein AH, Kennedy E, Barrier P et al. Nutr. Rev. 1998, 56, S3-19. development of diseases 6. Eaton SB, Konner M. New Eng. J. Med 1985, 283-289. • the use of modified atmospheres such as heart disease • the addition of preservatives (eg sulphites, benzoates, nitrites) 7. Stender S, Dyerberg J, Bysted A. et al. Atherosclerosis Supplements 2006, 7, 46-52. and cancer. • the control of microstructure (eg emulsions, matrices, extrusions) 8. Shi J, Le Maguer M. Crtical Rev. Food Sci. Nutr. 2000, 40, 1-42 • manothermosonication (combined ultrasonics, heat and pressure) • irradiation CONTACT • the use of high magnetic field pulses

PROF. GARRY DUTHIE • electroporation (high voltage electric gradient pulses)

Email [email protected]

Rowett Institute of Nutrition and Health Rowett Institute of Nutrition and Health www.abdn.ac.uk/rowett www.abdn.ac.uk/rowett Tel: +44(0)1224 438700 Tel: +44(0)1224 438700 Fax: +44(0)1224 715349 Fax: +44(0)1224 715349