EUFIC:"Tea: Health and hydration"-"Food packaging u"

FOOD TODAY 08/2016

Tea: Health and hydration

 Tea has been used as a refreshing drink for centuries. Tea is said to have health benefits - does the latest scientific evidence support this? Is tea a healthy source of hydration?

History and types of tea 
Tea is a beverage, which has been consumed for centuries. It is the most-widely consumed drink in the world, after water.¹ Figure 1 shows tea consumption per capita in some European countries.



Figure 1: Tea consumption per capita in Europe²

Tea is produced by adding hot water to the leaves from the tea plant,Camellia sinensis. This process is called infusion. Herbal or fruit teas, despite their name, are not strictly teas as they come from other plant species (for example, lime tree or chamomile).

Different processing methods are used to produce the hundreds of varieties of tea: 

• Black teas, which are most common in Europe³, are produced when tea leaves are fermented (broken down by the enzymes in the tea leaves, in a temperature controlled room) and then dried. These processes release the specific polyphenols, which produce the distinctive colour and flavour.⁴
• Green (unfermented) tea is produced by steaming, before drying, to minimise oxidation by enzymes - keeping the colour of the leaf, and giving its flavour characteristics.
• Oolong tea is somewhere between green and black tea in terms of fermentation and taste – its leaves are only partially oxidised. 

Black and green (and oolong) teas contain different types of polyphenols, but the total polyphenol content is similar.⁵ 

Tea can be drunk as a simple infusion, or may have added milk or lemon, or sugar. However, more research is needed to understand to what degree and through which mechanisms this affects the bioavailability of the different polyphenols.

Is tea good for health? 

There is much more research published on green tea than black (and other) teas. A recent exhaustive review looking into associations between food and beverage groups and diet-related chronic diseases, reported that tea was the most protective of all of the commonly consumed beverages; people reporting the highest intake of tea was associated with significantly reduced risk of type 2 diabetes (by 16%), cardiovascular disease (by 28%) and cancers (by 34%), although other studies have not shown clear relationships between tea and cancers.⁶ Another large study reported each additional daily cup of tea resulted in an associated 9% lower all-cause mortality.⁷Many of the proposed benefits have been attributed to the presence of specific polyphenols called flavonoids having a beneficial effect on blood vessels, due to their antioxidant and anti-inflammatory properties, but caffeine and fluoride have also been suggested as important.^3,5

Major studies on tea and cardiovascular disease have reported that black and green tea consumption was associated with significantly lower levels in LDL-cholesterol, blood pressure and risk of stroke.⁸

Regarding weight management, two recent trials reported that increased black tea consumption produced a small but significant reduction in weight, when people followed their normal diet.^9,10 A previous review of 18 studies did not find a significant effect of drinking green tea on weight.¹¹ Thus, the relationship between weight management and tea consumption remains open to debate.

Tea flavonoids may be protective against dental caries, with suggested mechanisms including antiviral and antimicrobial effects.⁸ Furthermore, tea provides fluoride, which promotes dental health as it improves resistance to decay.¹² Nevertheless, good general dental care is the most important for proper dental health.

Caffeine in tea and how much to drink 
The brewing time largely dictates the amount of caffeine in tea, and it can vary from 1 to 90 mg per 100 ml.⁸ While herbal or fruit ‘teas’ do not normally contain caffeine. Studies have shown that a moderate intake of caffeine can be beneficial in physical endurance and alertness; on the other hand, excessive caffeine can affect sleep.^13,14 Another known effect of caffeine is its ability to act as a mild diuretic (causing the body to lose water), but studies show that this is only of concern with very high doses of caffeine. For example, drinking 6-8 cups of tea does not adversely affect hydration.¹⁵

A recent EFSA report¹⁶ concluded that healthy adults may safely consume single doses of caffeine up to 200 mg; the main guidelines are shown in Table 1, suggesting up to 8 cups of tea per day is safe for non-pregnant adults. Children over 24 months may safely drink 1-2 cups of unsweetened tea. Despite concerns over the impact of tea polyphenols on bioavailability of iron, reports have concluded that consumption of tea has little effect on iron status in adults or children.¹⁷ The British Dietetic Association recognises that tea helps towards fluid intake, and in some countries, such as Germany, tea is explicitly recommended for hydration.¹⁸

Table 1: Safe caffeine intakes and equivalent tea intake.¹⁶

	Safe daily caffeine intake	Equivalent cups of tea (based on 50 mg caffeine per 190 ml cup)
Adults	400 mg	8 cups
Pregnant and Breastfeeding women	200 mg	4 cups
Children	3 mg/kg of body weight	1-2 cups depending on age

Conclusion 
Tea is a beverage, which is enjoyed across Europe and up to eight cups of tea per day can be enjoyed within current caffeine guidelines for non-pregnant adults. Tea has unique health properties not found in other beverages owing to its high flavonoid content and is an excellent source of hydration.

Related references
Science Brief (2015). EFSA opinion on the safety of caffeine.
Food Today (2015). Polyphenols.

References

1. Hodgson JM & Croft KD (2010). Tea flavonoids and cardiovascular health. Molecular Aspects of Medicine 31:495–502.
2. Europmonitor, World Bank. (Cited by Quartz, 2014)
3. Siddiqui IA, et al. (2004). Antioxidants of the beverage tea in promotion of human health. Antioxidants &Redox Signaling 6:571–582.
4. British Nutrition Foundation (2003). Plants: Diet and Health. (ed G. Goldberg) Oxford: Blackwell Publishing.
5. Stangl V, et al. (2006). The role of tea and tea flavonoids in cardiovascular health. Molecular Nutrition & Food Research 50:218–28.
6. Fardet A & Boirie Y (2014). Associations between food and beverage groups and major diet-related chronic diseases: an exhaustive review of pooled/meta-analyses and systematic reviews. Nutrition Reviews 72(12):741–762.
7. Gardener H, et al. (2013). Coffee and tea consumption are inversely associated with mortality in a multiethnic urban population. Journal of Nutrition 143:1299-1308.
8. Ruxton C, Phillips F & Bond T (2015). Is tea a healthy source of hydration? Nutrition Bulletin 40(3):166-176.
9. Bohn SK, et al. (2014). Effects of black tea on body composition and metabolic outcomes related to cardiovascular disease risk: A randomised controlled trial. Food Function 5:1613-1620.
10. Li Y, et al. (2015). Effects of tea or tea extracts on metabolic profile in patients with type 2 diabetes mellitus: a meta-analysis of ten randomised controlled trials. Diabetes Metabolism Research and Reviews. Doi 10.1002/dmrr2641.epub.
11. Jurgens TM et al. (2012). Green tea for weight loss and weight maintenance in overweight or obese adults. Cochrane Database of Systematic Reviews 12:CD008650.
12. European Food Safety Agency (EFSA) (2013). Scientific Opinion on Dietary Reference Values for Fluoride. EFSA Journal 11(8):3332.
13. Einöther SJ & Martens VE (2013). Acute effects of tea consumption on attention and mood. American Journal of Clinical Nutrition 98(6):1700S–1708S.
14. Killer S, Blannin AK & Jeukendrup AE (2014). No evidence of dehydration with moderate daily coffee intake: a counterbalanced cross-over study in a free-living population. PLoS One 9(1):e84154.
15. Ruxton CH & Hart VA (2011). Black tea is not significantly different from water in the maintenance of normal hydration in human subjects: results from a randomised controlled trial. British Journal of Nutrition 106(4):588-595.
16. European Food Safety Agency (EFSA) (2015). Scientific Opinion on the safety of caffeine.
17. Scientific Advisory Committee on Nutrition (SACN) (2010). Iron and health. London: The Stationery Office.
18. Blumberg JB (2013). Introduction to the proceedings of the Fifth International Scientific Symposium on Tea and Human Health. American Journal of Clinical Nutrition. 98(6):1607S-1610S.

FOOD TODAY 09/2016

Food packaging unwrapped

Food packaging plays an important role in protecting and delaying chemical, physical, and biological deterioration. In this way, even simple packaging (such as glass, metal, plastics and paper) can extend product shelf-life, improve quality and safety, reduce food waste and promote widespread availability.

An important purpose of food packaging materials is to serve as a physical barrier to protect their contents from exposure to microorganisms, pests and the absorption of external odours.They prevent mechanical damage, vibration, shock, and protect from possible contamination or tampering during transport and storage.¹

In addition, most foods are susceptible to moisture (e.g. biscuits go soft, bread dries out), and require protection using appropriate packaging. Oxygen and light on the other hand are involved in oxidation, a process which results in off-flavours or discolouration in meat, and lower vitamin C in fruit juice. The technique of modified atmosphere packaging (MAP) replaces the air inside the packaging with a single gas or mixture of gases that extends the product shelf life for these foods. For example, lowering the level of oxygen inside the packaging can slow down bacterial growth. Combining this technology with packaging materials that limit the transfer of gases from the outside air (e.g. to stop oxygen entering) and low-temperature storage further prevents spoilage and keeps foods safe for longer.² Often packaging is made up of multiple layers of different materials each offering a functional benefit. For example, a paperboard/cardboard container to maintain shape can be combined with a resin-coated foil liner to protect the freshness of the product by acting as a barrier to moisture or air.
Food packaging and technology 
Over the last 50 years there have been many significant technological breakthroughs in this field such as: sterile (free from bacteria and other microorganisms) processing and packaging, flexible and reusable containers, gas absorbers, microwaveable materials, tamper-evident closure, and active, intelligent, and recyclable packaging systems.¹ Over this time, there has also been a reduction in the number of food manufacturers, which has resulted in longer food distribution chains, often spanning multiple European countries.² With this comes a need for longer product shelf lives, particularly for fresh and chilled foods.

Moreover, the importance of prolonging the shelf life of food products and reducing waste has been gaining momentum in recent times; the European Commission has set a target to reduce food waste by 50%,³ and recycle 75% of packaging,⁴ by 2030. Sustainable alternatives to petrochemical-based (plastic) packaging can help protect the environment; materials made from by-products from food processing are easily recyclable or biodegradable and can help to reduce waste and landfill from food packaging.⁵ Some current innovations in sustainable food packaging include potato- and whey-coated cartons⁵, a biodegradable replacement for polystyrene made from mushroom material,⁶ and sugarcane-based bottles.⁷ Research is being carried out to develop packaging additives that can control or speed up composting time or biodegradation of packaging materials. Edible coatings and films (made from ingredients like casein, whey, collagen, egg, or corn) which can be applied directly to the food products thereby removing the need for packaging are also being developed.⁸ In the long term sustainable packaging materials should lower costs and increase competitiveness for packaging producers and the agro-food sector.
Nanotechnology is also considered an important area for the development of innovative food packaging. This applied science involves the control of matter on the atomic scale, with nanoparticles typically having an average size of 100 nanometres or less.⁹ These new materials have unique physical and chemical properties such as: improved strength, reduced weight, antimicrobial properties, or increased resistance to heat, gases, UV radiation, and moisture.¹⁰ Exciting areas of research include the design of colour-changing nanosensors to instantly detect leaks in vacuum or gas-packed foodstuffs, temperature variations over time, and microbial growth (e.g. the presence and growth of bacteria, viruses or moulds that can lead to food spoilage). In addition, active packaging has been developed that contains preservatives that are released in a controlled way only when a food starts to spoil.¹¹ 
So-called intelligent packaging materials are also increasingly being used to monitor and communicate the condition of a packaged food to the consumer or supply chain actors. For example, indicators in packaging can change colour to let consumers know whether the product has been heated or cooled above a critical temperature that affects the quality or safety of the product (e.g. freeze–thaw–refreezing).¹²
Regulation of food packaging 
In the EU, a food contact material (FCM) is defined as any material that is intended to, or that can reasonably be expected to, come into contact with food during production, transport, storage or consumption e.g. packaging, cutlery, containers, machinery etc. European regulations ensure that FCMs produced and used in the EU are safe for their intended uses.¹³,¹⁴ For example, packaging materials should not affect the composition, taste or odour of the food inside in an unacceptable way. Manufacturers must also ensure that chemicals and particles from packaging materials do not migrate into food at levels that could cause harm. In addition, there are specific measures (with more detailed restrictions) in place to regulate certain materials such as recycled plastics, active and intelligent FCMs, regenerated cellulose and ceramics.¹⁵
References

1. Trinetta V (2016). Definition and Function of Food Packaging. Reference Module in Food Science Published online 1 Dec 2015.http://www.sciencedirect.com/science/article/pii/B9780081005965033199  
2. Dixon J (2011). Packaging Materials: 9. Multilayer Packaging for Food and Beverages. ILSI Europe Report Series. Brussels. Retrieved 5th August 2016.
3. European Commission. EU Actions on Food Waste.
4. European Commission. Press release on Circular Economy Package: Questions & Answers
5. European Commission. Sustainable food packaging from food waste
6. European Commission. Sustainable packaging from “mushroom materials”.
7. Chief Packaging Officer, USDA Program Promotes Sustainable Packaging Including Plant-based Bottles.
8. Robinson DKR & Propp T (2011). Innovation-Chain Approach to prospecting technology embedment in society: An illustration for potential nano-enabled agrifood sector transformations. Fourth International Seville Conference on Future-Oriented Technology Analysis (FTA), Seville, 12-13 May 2011.
9. Food Safety Authority of Ireland Nanotechnology and Food
10. RIKILT and Joint Research Centre (2014). Inventory of Nanotechnology Applications in the Agricultural, Feed and Food Sector. EFSA Supporting Publication: EN-621, 125pp.
11. FAO (2010) Report from FAO/WHO expert meeting on the application of nanotechnologies in the food and agriculture sectors: potential food safety implications
12. Ghaani M et al. (2016). An overview of the intelligent packaging technologies in the food sector. Trends in Food Science & Technology 51:1-11.
13. Regulation (EC) No 1935/2004 of the European Parliament and of the Council of 27 October 2004 on materials and articles intended to come into contact with food and repealing Directives 80/590/EEC and 89/109/EEC
14. Commission Regulation (EC) No 2023/2006 of 22 December 2006 on good manufacturing practice for materials and articles intended to come into contact with food
15. Food Safety Authority of Ireland (2014) Food Contact Materials