Chemické složení kávy
Akrylamid
- 2016- ve vzorcích pražené kávy obsah akrylamidu
- Od 151 do 274 µg.kg-1
- Směrná hodnota pro praženou kávu nebyla překročena
Informace
- Cause cancer
- Reproductive toxicity
- Council for Education and Research on Toxics (CERT)
- Vydal pokyn, že prodejci musí varovat své zákazníky, že káva obsahuje kancerogen
- Forms from naturally present free asparagine (amino acid) and sugars
- During high temperature processing
- Frying
- Roasting
- Baking [11]
- Particularly in
- Potato-based products
- Cereal-based products
- Coffee
- Coffee substitutes [11]
- Initially detected in 2002
- European Food Safety Authority (EFSA)
- Confirmed in 2015 that acrylamide is a carcinogenic substance
- That current levels of dietary exposure to acrylamide indicate a concern with respect to the carcinogenic effects [11]
- Commission started discussions with Member States' authorities to determine appropriate regulatory measures to reduce the presence of acrylamide in food. [11]
Arsenic
- Main sources of exposure for the general population in Europe
- The main adverse effects of with long term ingestion of inorganic arsenic in humans
- Skin lesions
- Cancer
- Developmental toxicity
- Reduced birth weight
- Neurotoxicity
- Cardiovascular diseases
- Abnormal glucose metabolism
- Diabetes [12]
- Can exceed their tolerable weekly intake for inorganic arsenic
- Children under three years of age
- The most exposed to inorganic arsenic
- High consumers of rice in Europe
- High consumers of algae-based products [12]
- Maximum levels for arsenic
- Rice and derived products [12]
Cafestol
- Diterpen z nefiltrované kávy
- Implicated in the cholesterol-raising effects of coffee [13]
Draslík
- 1 cup of coffee contributes only 1–2% of the adequate intake (AI) for potassium (4700 mg/d) in adults [12]
Furan
- Toxic and carcinogenic effects on animals
- Cancer research agency lists it as a “possible” carcinogen in humans [17]
- Determination of furan in coffee and coffee products
- By headspace gas chromatography and mass spectrometry (HS GC-MS) [14]
- Highly volatile compound present in many foods and drinks
- Result of thermal treatment during processing
- Coffee consumption may be the highest contributor to furan exposure from dietary sources among adults
- Furan is present in coffee as part of the volatile aroma components
- Generated during roasting of green coffee beans
- Furan levels decrease because of its
- High volatility
- Low water solubility [16]
- Levels of furan decrease through
- Grinding
- Packaging
- Storage
- Brewing procedures [16]
- Varies in amount depending on the mode of brewing
- Capsule preparations had the highest level
- Capsules are sealed
- During the extracting process they don’t allow exposure to air
- Furan cannot escape when created by the hot water passing through the beans [17]
- Drip machines contained the least [17]
- Drip process, the pot is open to the air
- Furan can escape [17]
- Lower in instant and decaf than in espresso
- Reach unsafe levels, the consumer would have to drink
- 200 instant coffees
- 30 espressos
- 20 cups of capsule coffee per day of the highest furan-content brands [17]
- 20 to 200 cups of coffee per day
- Will have problems of other kinds in health for sure [18]
- Formation of furan during roasting
- Dependent on roasting conditions
- Directly linked to achieving targeted flavour profiles
- Modifications to reduce furan levels
- May have the opposite effect on other undesired reaction products of the roasting chemistry such as acrylamide [18]
- Only cca 10% of the initially generated furan during roasting gets into the cup of coffee for consumption [18]
Hořčík
- 240 ml of brewed coffee provide 7 mg of magnesium
- 30 ml of espresso provides 24 mg of magnesium http://www.nal.usda.gov/fnic/foodcomp
- 1 cup of coffee could contribute 1–5% of the recommended dietary allowance (RDA) for magnesium (420 mg/d) in adult men [12]
Kadmium
Kahweol
- Diterpen nefitrované kávy
- Implicated in the cholesterol-raising effects of coffee [13]
- In ileostomy patients
- About 70% of the cafestol and kahweol in unfiltered coffee is absorbed intestinally
- Consumption of cafestol and kahweol in French press coffee
- Result in persistent increases in cholesterol ester transfer protein (CETP) activity in humans
- May contribute to increases in LDL cholesterol
- CETP transfers cholesteryl esters from HDL to the apolipoprotein B-containing lipoproteins, LDL and VLDL
Takže snižuje efektivitu přenosu cholesterolu cestou HDL do jater
Ten samý enzym je ale důležitý i pro transport cholesterolu z VLDL na HDL a pro lepší transport cholesterolu do jater ??? Proto jeho blokáda nebyla účinnou cestou snížení LDL cholesterolu v krvi ?
Kofein
- 0,5–2,6 %
- Dusíkatá heterocyklická sloucenina
- Derivát xanthinu (1,3,7-trimethylxanthin)
- Nejen v káve, ale i v dalších více než 60-ti rostlinných produktech
- I cajové lístky
- Cistý kofein
- Bílý hebký prášek
- Tvoří lesklé jehličky
- Hořké chuti [2]
Množství kofeinu v bežném šálku kávy
- 0,5 až 1,5 dl kávy
- Od 0,05 g do 0,2 g kofeinu [1]
- 100 mg kofeinu je asi 1 šálek kávy [1]
Kyselina chinová
- 10 %
Kyselina chlorogenová - Chlorogenic acid
- 4–6 % [1]
- Mitigating oxidative stress
- Anti-inflammatory activities by modulating a number of important metabolic pathways
- Glutamate-induced neuronal cell death was inhibited by treatment with CGA
- CGA prevented the increase in intracellular concentrations of Ca(2+) caused by the addition of glutamate to cultured neurons.
- On the other hand, there was little effect of CGA on
- Cell death induced by nitric oxide
- Is downstream of the ischemic neuronal cell death [3]
- Are a family of esters
- Formed between quinic and trans-cinnamic acids
- Important group of dietary phenols
- Most common individual chlorogenic acid is 5-O-caffeoylquinic acid
- Still often called chlorogenic acid
- Coffee is the richest dietary source of chlorogenic acids and cinnamic acids (caffeic acid)
- 70–350 mg / 200 ml (7-oz) cup of coffee
- Cca 35–175 mg of caffeic acid
- Absorbed intestinally
- Cca 33% of ingested chlorogenic acid
- Cca 2/3 in colon may be metabolized by microflora
- Likely hydrolyzed to caffeic acid and quinic acid
- Presence of bacterial metabolites of chlorogenic acid in the urine
- Cca 95% of caffeic acid
Kyselina kávová
Kyselina nikotinová
- Cca 1–3 mg of nicotinic acid per cup
- Cup of coffee could contribute 6–18% of the RDA for niacin (16 mg/d) in adult men [12]
Ochratoxin A (OCHA) or (OTA)
- A mycotoxin, which can be found in food such as
- Coffee, wine, cereals, meat, nuts [4]
- Grain-based products, confectionery, meat products and fruit juice [5]
- Tea, bear
- Nephrotoxic and renal carcinogenic [5]
- Even after roasting and brewing coffee beans
- Ochratoxin a can still remain intact [8]
- The initial contamination of coffee with OTA
- Spores in the air and in the ground [10]
- Spores may produce a mould
- Only if the right circumstances
- Humidity
- Temperature [10]
Proper moisture management
- Throughout the entire processing
- Supply chain
- Farmers
- Middlemen
- Exporters
- Shipment of coffee
- Careful inspection
- May be very localized
- Making sampling extremely complex [10]
- Visual appearance
- Any mouldy or earthy smells
- Can be a useful tool for checking [10]
Pesticide residues in coffee beans
- Endosulfan alpha
- Endosulfan beta
- Cypermethrin
- Permethrin
- Deltamethrin
- Chlorpyrifos ethyl
- Heptachlor epoxide
- Hexachlorobenzene
- P'p-DDE
- P'p-DDD
- O'p-DDT
- P'p-DDT [4]
Washing of coffee beans
- Showed 14.63-57.69 percent reduction [4]
Roasting process
- Reduced up to 99.8 percent
- Chlorpyrifos ethyl, permethrin, cypermethrin, endosulfan ? and ß in roasting
- All of the 12 pesticides in the coffee brewing processes were not detected [4]
- Only very rarely exceed the limit values
- Monitoring is a vital aspect of an HACCP system
- Absolutely essential that coffee growers maintain chemical registers
- Chronological order
- Type and quantities of all chemicals used
- Timing of their application
- Only chemicals that have been approved for use on coffee may be used
- Only within the withholding limits specified by the manufacturers [10]
Polysacharidy
- 25–30 %
Příchutě přimíchávané do kávy (např. Starbucks)
Konzervanty příchutí
Potassium sorbate
- The main preservative found in Starbucks flavor shots
- Suspected of damaging the white blood cells [8]
Emulsifier soy lecithin
- Used in Starbucks flavor syrups
- From soybean oil
- Often genetically modified
- Common food allergen [8]
High fructose corn syrup
- Largest portion of ingredients in flavored syrup [8]
- Consuming beverages with high fructose corn syrup for just 2 weeks
- Raised the risk of cardiovascular disease even more so than regular fructose or glucose [8]
- Consumption is connected with dangerous high blood pressure, obesity, and insulin resistance [8]
Proteiny
- 13 %
Tuky a vosky
- 0,1–0,8 %
Hydrocarbon contamination
- Usually caused by jute coffee bags
- 'batching oil' used to soften the jute fibres before spinning
- Instances of contaminated oil being used
- Old engine oil for example
- International Jute Organization
- Established specifications (IJO Standard 98/01) for the manufacture of jute bags to be used in the food industry
- Ingredients used as batching oils:
- Must be non-toxic
- Approved for use in packaging materials that will come into contact with food
- Must not contain compounds that could produce off-flavours or off-tastes in food
- Chemical criteria:
- The amount of unsaponifiable compounds (which cannot be converted into soap by boiling with alkali)
- Shall be less than 1250 mg/kg [10]
- Organoleptic criteria
- Jute bags shall be analysed for their olfactory qualities
- No undesirable odours, or odour untypical of jute, shall be present
- No unacceptable odours shall develop after artificial ageing of the sacks
- The ageing procedure to be followed - European Standard EN 766 for use on sacks for the transport of food [10]
- Hydrocarbon-free lubricant, based on vegetable oil, to soften the jute fibre
- Non-toxic, biodegradable oil
- Bags made with it can be classified as food grade bags
- The oil used must be stable and may not turn rancid [10]
Vitamín E
- About 0.1% of the adult RDA for vitamin E (15 mg/d of RRR-alpha -tocopherol)/1 šálek kávy [12]
Voda
- 10–13 %
