Pol. J. Food Nutr. Sci.
`
`2003, Vol. 12/53, No 2, pp. 57—61
`
`POLISH JOURNAL OF FOOD AND NUTRITION SCIENCES
`
`THE CONTENT OF NITRATES V AND III AND VITAMIN C IN JUICES OBTAINED FROM ORGANIC
`AND CONVENTIONAL RAW MATERIALS
`
`Maria (cid:229)miechowska
`
`Department of Commodity and Cargo Sciences, Gdynia Maritime University, Gdynia
`
`Key words: juices, nitrates V and III, vitamin C, organic food, conventional food
`
`The content of nitrates V and III, and vitamin C in vegetable, fruit and fruit-vegetable juices obtained from organic and conventional raw
`material was determined. A total of 189 juice samples were examined, including 63 juices with the expiry date of only one day and 48 juices
`obtained from organic raw material. The juices were purchased in the local food stores. The research covered the period of May—September of
`1999. The content of nitrates V and III in juices was different and dependent on the raw material origin and the producer. The lowest content of
`nitrates had apple juice (0.6—10.0 mg NaNO3/dm3) and orange juice (1.2—1.8 mg NaNO3/dm3), and the highest content of nitrates had fresh
`beetroot juice from the juice bar (718.7—1118.2 mg NaNO3/dm3). Juices obtained from organic raw material and juices of renowned brands had
`a similar content of nitrates V and III. The vitamin C content of juices was variable and fell in the range 2.8—38.9 mg/100 g. The highest content
`of vitamin C (26.6—42.6 mg/100g) was found in fermented vegetable juices obtained from organic raw material.
`
`INTRODUCTION
`
`Drinking juices are among the food products, the
`production and consumption of which is continuously
`growing. The reasons for this trend, as they might be
`concluded based on the marketing research, are the fashion
`for the consumption of juices (quickly spreading over
`Poland from the Western Europe) on the one hand, and the
`advertising campaign for changes in dietary habits on the
`other hand [Szponar et al., 1998]. Fruits and vegetables and
`their products play an important role in preventing
`civilisation diseases, particularly because of high content of
`vitamin C, b -carotene, polyphenols, catechins and fibre.
`A regular consumption of minimum 500 g of fruits, vegetables
`or their products per person per day has been suggested;
`they should be added to every single meal [Heimendinger &
`Chapelsky, 1996]. Apart from supplying the human
`organism with valuable nutrients and dietary components,
`the juices are above all the source of water, the main com-
`ponent of all beverages. The most common technique for
`producing juice is based on diluting juice concentrates with
`water, adjusting the taste and pasteurisation [Jarczyk, 1999].
`Water used for reconstituting concentrates may influence to
`a large degree the content of various pollutants (including
`nitrates V and III) in juices. No special regulations exist in
`Poland on the requirements for water intended for juice
`reconstitution. Drinking water is required to contain no
`more than 10 mg NaNO3/dm3, in the absence of nitrites
`[Jarczyk, 1999]. Basic requirements for water used for juice
`reconstitution in the European Union countries have been
`specified by AIJN (Association of the Industry of Juices and
`Nectars from Fruit and Vegetables). The suggested method
`of water treatment is the reverse osmosis [Code of Practice
`
`for evaluation of fruit and vegetable juices, Brussels, 1996].
`The enormous role played by juices requires their strict
`hygiene and health safety. The issue of safety is connected
`with the presence and level of nitrates V and III. The
`necessity to control them carefully results from the fact that
`juices are among the foodstuffs introduced the earliest into
`nutrition. The content of nitrates V and III in fruit and
`vegetable juices is determined mainly by the content of
`these compounds in raw material — fruit and vegetables.
`Introduction of nitrogen fertilisers in agriculture aims at
`increasing the crops yields. Unfortunately, the excess of
`nitrates in soil induces their accumulation in crops. Nitrates
`V, and particularly their reduction products nitrates III, are
`not neutral compounds to humans. Many papers report on
`the acute and chronic toxicity of nitrates V and III. Toxic
`efficacy of these compounds on the human organism are
`connected, among others, with nitrite methaemoglobinaemia,
`increased risk of stomach cancer and dysfunction of small
`intestine [Hill, 1991; Vittozzi, 1992]. Among the factors
`influencing the content of nitrates and nitrites in field crops,
`there are particularly: fertilising conditions, plant suscepti-
`bility, climate, soil, and activity of soil and root microflora
`[Vogtmann et al., 1984]. The content of nitrates in vegetables
`grown in Poland is variable, ranging from several mg to over
`20 g NaNO3/kg [Gajda & Kar‚owski, 1993]. Large quantities
`of nitrates have been mainly detected in early vegetables.
`Alternative production of early vegetables with organic
`methods allowed significant reduction of the nitrate content
`[(cid:229)miechowska & Przyby‚owski, 2000]. Vegetables originating
`from organic cultivation contain less nitrates V and III
`[Evers, 1989; Rembia‚kowska, 1998; (cid:229)miechowska, 2001;
`Vogtmann et al., 1984]. The content of nitrates V and III in
`vegetables stored in cellars and clamps and later used for
`
`Author(cid:213)s address for correspondence: Maria (cid:229)miechowska, Katedra Towaroznawstwa i (cid:252)adunkoznawstwa, Akademia Morska, ul. Morska 81—87,
`98-225 Gdynia; tel.: (48 58) 690 15 62; fax: (48 58) 620 67 01; e-mail: smiemari@am.gdynia.pl
`
`Human Power of N Company
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`Page 1 of 5
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`58
`
`M. (cid:229)miechowska
`
`processing is influenced mainly by: storage temperature,
`ventilation, access to daylight and microbiological quality of
`stored vegetables [Hiller et al., 1987]. The content of nitrates
`V and III in vegetable juices may be also influenced by
`pretreatment and technological or thermal process
`[Markowska et al., 1995]. Recently, successful attempts have
`been made to reduce nitrates in vegetable products by
`biotechnological methods using the denitrifying bacteria
`and nitrates V and III reductase [Walkowiak-Tomczak et al.,
`1996]. In search of alternative methods for food production,
`limiting a widespread chemicalisation of agriculture and
`food processing, attention was paid to organic agriculture
`and processing. Organic production excludes the possibility
`of reconstitution for juice production, because the conditioned
`water never has the quality and properties of the intracellular
`water. Product marked as a natural juice should refer only
`to a juice that is a squeeze of fruit or vegetables. In the EU
`countries, natural juices are marked as NFC (not from
`concentrate).
`The publications on the quality of processed organic
`food are lacking in Poland. Therefore, this research was
`carried out in an attempt to answer the question about the
`quality of processed organic products, on the example of
`juices. The objective of this work was to determine the
`content of nitrates V and III, and vitamin C in vegetable,
`fruit and fruit-vegetable juices obtained from organic and
`conventional raw material.
`
`MATERIALS AND METHODS
`
`Material. The research material was the following
`vegetable, fruit and fruit-vegetable juices manufactured
`from conventional material by Polish leading producers:
`orange, apple, black currant (producer FX); tomato, apple,
`carrot, carrot-apple, multi-vegetable, black currant (producer
`FA); and carrot, carrot-apple (producer PZ). The juices
`were pasteurised products and were packed in 1 L Tetra Pak
`packages. The material included also fresh carrot juice from
`the producers DC and MA and multi-vegetable, beetroot,
`cabbage, beetroot-apple, and apple juices from a juice bar.
`The juices manufactured by DC and MA firms were packed
`in glass bottles with a volume of 330 mL and had only one
`day expiry date, valid in the day of the purchase of the juice.
`The juices from the juice bar were sampled into sterile glass
`bottles and were taken immediately to the laboratory for
`analysis. The organic juices (EKO) examined included
`tomato, sour beetroot, multi-vegetable sour and carrot-
`-apple juice. These were manufactured by the firm having
`an Ekoland (Polish Federation of Organic Food Producers)
`attestation. They were pasteurised and packed in glass
`
`bottles with a volume of 250 mL. All examined juices were
`purchased in the Tri-City (Gda˜sk—Sopot—Gdynia) food
`stores and in a local juice bar. The assortment of juices was
`selected on the basis of marketing research, indicating these
`juices as the most preferred by consumers [Kubiak &
`Rembowski, 1999]. The research was conducted in the
`period of May—September 1999.
`
`Methods. The content of nitrates V and III was
`determined by spectro-photometrical method based on a
`Griess reaction [ISO Standard, 1984]. The reduction of
`nitrates V to nitrates III was carried out on a cadmium
`column, according to the modifications by Przyby‚owski
`et al. [1983]. The content of vitamin C was determined as
`L-ascorbic acid according to the ISO standard [1984] using
`2,6-dichlorophenylindophenol for titration.
`
`RESULTS AND DISCUSSION
`
`The content of nitrates V and III in juices was different
`and dependent on the raw material (organic or conventional)
`and the producer. The lowest content of nitrates V and III
`was found in fruit juices (Table 1). Fruit is generally a mode-
`rate source of nitrates. Their content of domestic fruit is
`1.2—65.1 mg NaNO3/kg [Markiewicz et al., 1998]. According
`to the research of Nabrzyski and Gajewska [1994], the lowest
`content of nitrates V was found in apples: 1.32—9.67 mg
`KNO3/kg (1.11—8.13 mg NaNO3/kg). Occasionally, however,
`apples can contain significant amounts of these compounds.
`Bary‚ko-Pikielna and Tyszkiewicz [1991] quote after
`Mi«dzobrodzka et al. that the content of nitrates in apples
`may reach 285.5 mg KNO3/kg, what corresponds to
`239.8 mg NaNO3/kg.
`Among the fruit juices examined there were no products
`obtained from organic raw materials. This results from the
`difficulties in supplying of organic fruit in quantities
`sufficient to maintain continuous production of juices. The
`Polish fruit-farmers are dominated by the producers using
`conventional methods or an integrated method, for which
`the use of small, necessary amounts of pesticides and crop-
`-protection chemicals is characteristic [Horuba‚a, 1999].
`Organic farms tend to balance the matter and energy flows,
`therefore specialised fruit orchards are basically lacking.
`The feature of organic agriculture is the existence of
`orchard or garden within a farm, along with cultivation of
`cereals and roots and breeding of animals. Fermented juices
`prevailed among the organic vegetable juices (Table 2 and
`3). The research works have evidenced that upon fermentation
`nitrates are decomposed and that fermented vegetable
`products are wholesome [Mi(cid:230)kiewicz et al., 1988].
`
`TABLE 1. The content of nitrates V and III in fruit juices manufactured by various producers.
`
`Juice
`
`Apple
`
`Black currant
`
`Orange
`
`Producer
`
`HX
`FA
`Juice bar
`HX
`FA
`HX
`
`n
`
`19
`12
`12
`12
`12
`6
`
`—x–SD
`3.1–2.3
`2.3–0.8
`7.7–0.9
`54.6–24.8
`81.9–31.4
`1.4–0.3
`
`NaNO3 [mg/dm3]
`Range
`0.6—10.0
`0.6—3.6
`5.5—8.5
`26.4—117.4
`62.2—176.3
`1.2—1.8
`
`V [%]
`72.85
`34.88
`12.16
`45.50
`38.33
`22.13
`
`—x–SD
`0.07–0.12
`0.00
`0.44–0.15
`0.36–0.32
`0.77–0.11
`0.00
`
`NaNO2 [mg/dm3]
`Range
`0.00—0.38
`0.00
`0.00—0.51
`0.28—0.61
`0.66—0.84
`0.00
`
`V [%]
`83.21
`-
`33.36
`28.73
`6.71
`-
`
`Page 2 of 5
`
`

`

`Juices from organic and conventional materials
`
`TABLE 2. The content of nitrates V and III in organic and conventional vegetable juices.
`
`Juice
`
`Producer
`
`Multivegetable
`
`Multiveg. sour
`Carrot
`
`Tomato
`
`Fresh cabbage
`Fresh beetroot
`Sour cabbage
`Sour beetroot
`
`FA
`Juice bar
`EKO
`FA
`PZ
`DC
`MA
`Juice bar
`EKO
`FA
`EKO
`Juice bar
`Juice bar
`EKO
`EKO
`
`n
`
`3
`12
`16
`10
`4
`11
`16
`12
`16
`10
`16
`9
`12
`12
`12
`
`—x–SD
`67.1–3.7
`389.3–109.3
`142.3–19.7
`32.9–6.2
`87.4–9.2
`419.5–37.0
`330.1–74.4
`73.6–11.8
`7.4–1.1
`21.2–4.2
`16.9–2.7
`232.2–99.5
`938.9–158.8
`94.6–5.5
`7.4–1.8
`
`NaNO3 [mg/dm3]
`Range
`63.3—70.8
`151.5—491.7
`99.3—164.9
`25.7—47.0
`78.9—97.1
`375.7—498.7
`293.6—604.7
`61.3—95.6
`6.1—10.1
`15.9—28.6
`12.3—21.6
`68.9—307.6
`718.7—1118.2
`83.2—103.0
`3.1—8.6
`
`V [%]
`5.60
`28.08
`13.88
`18.94
`10.58
`8.81
`70.50
`16.04
`15.30
`20.01
`15.84
`42.84
`16.91
`5.78
`24.71
`
`—x–SD
`0.30–0.07
`0.73–0.12
`3.33–1.56
`0.02–0.05
`0.19–0.07
`0.97–0.22
`0.60–0.13
`0.20–0.20
`0.29–0.24
`0.04–0.06
`0.29–0.13
`1.06–0.54
`1.06–0.54
`0.85–0.24
`0.90–0.17
`
`NaNO2 [mg/dm3]
`Range
`0.25—0.38
`0.38—0.89
`1.27—5.08
`0.00—0.13
`0.13—0.25
`0.63—1.14
`0.38—0.76
`0.00—0.51
`0.00—0.76
`0.00—0.13
`0.00—0.38
`0.25—1.52
`0.25—1.52
`0.13—1.01
`0.51—1.01
`
`TABLE 3. The content of nitrates V and III in organic and conventional fruit-vegetable juices.
`
`Juice
`
`Carrot-apple
`
`Beetroot-apple
`
`Producer
`
`PZ
`EKO
`Juice bar
`
`n
`
`14
`14
`12
`
`—x–SD
`40.4–6.1
`7.4–1.1
`547.8–124.2
`
`NaNO3 [mg/dm3]
`Range
`29.4—47.6
`5.5—8.5
`356.5—577.9
`
`V [%]
`15.07
`15.30
`22.67
`
`—x–SD
`0.04–0.06
`0.29–0.24
`1.07–0.44
`
`NaNO2 [mg/dm3]
`Range
`0.00—0.13
`0.00—0.76
`0.63—1.65
`
`59
`
`V [%]
`24.74
`16.79
`48.14
`10.82
`38.49
`22.89
`21.05
`98.80
`81.62
`61.01
`44.44
`51.26
`51.26
`28.84
`18.51
`
`V [%]
`39.23
`81.62
`41.61
`
`One of the factors strongly influencing the nutritional
`value of juices is the content of vitamin C. Vitamin C
`participates in the reduction of nitrates V and III and, in
`addition, it is an efficient inhibitor of nitrosation [Sobala
`et al., 1991]. The content of vitamin C in the examined juices
`was found to be different. Among fruit juices, the apple
`juice contained the least amount of vitamin C. The average
`content of vitamin C in the examined fruit juices was con-
`sistent with other authors(cid:213) results [Cicho˜, 2000]. The con-
`tent of vitamin C in vegetable juices was different and
`dependent on juice production method (Tables 4 and 5).
`The vitamin C content of carrot juices might suggest their
`fortification, the fact not always declared by the producer
`on a packaging. It arises from earlier studies that the
`vitamin C content of carrots is influenced not only by the
`type of farming (organic or conventional), but also by the
`carrot cultivar [(cid:229)miechowska & Przyby‚owski, 1996]. The
`Regulation of Polish Ministry of Health [DzU 2001 r. Nr 9,
`
`poz. 72] does not specify the permissible content of
`ascorbic acid in juices. Ascorbic acid, acidity regulator and
`antioxidant used in drinking juices, should be added
`according to good practice, i.e. in the lowest dose necessary
`to achieve a desired technological effect. The regulation
`specifies, however, the amount of vitamin C added to juices
`intended for children younger than 3 years old at the level
`of 0.3 g/L. Ascorbic acid is also on the list of positive
`additives and improving substances allowed in the processing
`of crops from organic farming [EEC Council Regulation
`No. 2092/91]. The juices from fermented vegetables were
`
`TABLE 5. The content of vitamin C (mg/100 g) in organic and
`conventional vegetable juices.
`
`Juice
`Multivegetable
`
`Multiveg. sour
`Carrot
`
`Tomato
`
`Fresh cabbage
`Fresh beetroot
`Sour cabbage
`Sour beetroot
`
`Producer
`FA
`Juice bar
`EKO
`FA
`PZ
`DC
`MA
`Juice bar
`EKO
`FA
`EKO
`Juice bar
`Juice bar
`EKO
`EKO
`
`n
`3
`12
`16
`10
`4
`11
`16
`12
`16
`10
`16
`9
`12
`12
`12
`
`x–SD
`9.5–0.2
`8.3–0.7
`38.9–2.4
`12.2–3.0
`18.7–1.8
`19.5–7.5
`20.9–7.0
`16.5–5.2
`33.9–2.7
`12.2–3.0
`15.9–2.5
`23.7–6.9
`14.9–0.5
`31.7–1.6
`29.7–3.6
`
`Range
`9.3—9.8
`6.9—9.1
`35.0—42.6
`6.8—16.3
`16.0—20.0
`9.6—29.6
`10.6—31.0
`10.3—23.6
`29.6—38.8
`6.8—16.3
`11.6—18.6
`17.0—36.0
`14.0—15.2
`29.5—35.2
`25.6—39.9
`
`V [%]
`2.64
`9.10
`6.13
`24.82
`9.90
`38.33
`33.52
`79.91
`7.89
`24.82
`15.86
`28.95
`3.11
`4.96
`12.15
`
`n
`19
`12
`12
`12
`12
`6
`14
`14
`12
`
`Range
`1.2—4.9
`1.5—6.1
`5.0—9.1
`16.0—20.3
`21.3—26.8
`25.6—31.9
`10.6—21.0
`29.6—38.8
`15.0—15.9
`
`V [%]
`40.76
`43.72
`15.87
`9.10
`9.10
`9.73
`22.81
`7.89
`15.13
`
`TABLE 4. The content of vitamin C (mg/100 g) in organic and con-
`ventional fruit and fruit-vegetable juices.
`—x–SD
`2.9–1.2
`2.8–1.2
`8.0–1.3
`18.2–1.6
`25.4–1.6
`28.0–2.7
`15.9–3.6
`33.9–2.7
`13.5–2.0
`
`Juice
`Apple
`
`Producer
`HX
`FA
`Juice bar
`HX
`FA
`HX
`PZ
`EKO
`Beetroot — apple Juice bar
`
`Black currant
`
`Orange
`Carrot — apple
`
`Page 3 of 5
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`

`

`60
`
`M. (cid:229)miechowska
`
`found to contain more vitamin C than juices from fresh
`vegetables, which corresponds with results reported by other
`authors [Wieczorek & Traczyk, 1995]. It was impossible to
`make the variance analysis for the influence of farming type
`(organic or conventional) on the vitamin C content of
`juices, because of different juice production methods. The
`juices from organic raw materials are not produced by
`reconstitution from concentrates and they are often
`fermented. A considerable influence of farming type on the
`content of nutrients and pollutants in vegetables has been
`earlier evidenced [Evers, 1989; Rembia‚kowska, 1998;
`(cid:229)miechowska & Przyby‚owski, 1996; Vogtmann et al., 1984].
`The level of nitrates V and III in juices must be controlled,
`since these compounds are toxic, impair the B vitamins
`utilisation and oxidise vitamin A and carotenes [Livissier
`et al., 1976]. The research on the quality of juices, including
`nitrate V, nitrate III and vitamin C content, should be
`continued also because of the changes in dietary habits,
`especially among young people. Many people are on
`vegetarian or slimming diets that include juice drinking.
`The products polluted to a significant degree with nitrates
`V and III would pose a serious health threat.
`It seems that the changes observed in the manner of
`nutrition and in dietary habits result from dietary education
`on the one hand, and evolution of new consumer attitudes as
`influenced by fashion and advertisement(cid:213) on the other hand.
`
`CONCLUSIONS
`
`1. Considering the content of nitrates and vitamin C, the
`quality of drinking juices is different. The quality of conven-
`tional juices produced by renowned brands is similar to the
`quality of organic juices.
`2. Fruit juices obtained from conventional raw material
`contained diversified quantities of nitrates V. The lowest
`content of nitrates was determined in apple juice (0.6—10.0 mg
`NaNO3/dm3), while the highest in black currant juice
`(26.4—176.3 mg NaNO3/dm3). The content of nitrates III
`ranged from 0.00 to 0.84 mg NaNO2/dm3.
`3. The vegetable juices obtained from conventional raw
`materials by renowned producers and the juices obtained
`from organic raw materials were characterised by low nitrate
`V and III content, amounting 3.1—103.0 mg NaNO3/dm3 and
`0.00—5.08 mg NaNO2/dm3, respectively. The content of
`nitrates V in conventional juices of other producers and
`juices from juice bar is significantly higher and amounts
`232.2—938.9 NaNO3/dm3. Juices containing beetroot were cha-
`racterised by the highest quantities of nitrates, independent of
`production method and material origin. This is consistent with
`the well-known tendency for nitrate accumulation in beetroot.
`4. In the case of nearly 50% of fresh juices produced in
`juice bar and the juice from small manufacturers declaring
`only one day expiry date, an increased content of nitrates V
`was detected, more than 500 mg NaNO3/dm3. Poor quality
`of raw material was most likely the possible reason for this.
`5. Fermented (sour) juices from cabbage and beetroot
`contained ten times less nitrates than juices from fresh
`vegetables.
`6. The content of vitamin C in fruit juices from conven-
`tionally-cultivated fruit was different. Apple juice contained
`the least amount (1.2—9.1 mg ascorbic acid /100 g) and orange
`juice — the highest amount (25.6—31.9 mg /100 g) of vitamin C.
`
`7. Fermented (sour) juices from cabbage and beetroot
`originating from organic cultivation contained 2 times more
`vitamin C than juices from fresh vegetables.
`
`REFERENCES
`
`1. Bary‚ko-Pikielna N., Tyszkiewicz S., Chemiczne ska(cid:253)enia
`(cid:253)ywno(cid:230)ci. Stan i (cid:144)r(cid:151)d‚a. PAS Report. Warszawa 1991,
`157—202 (in Polish).
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`rynkowych. Przem. Ferment. Owoc.-Warzyw., 2000, 9,
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`3. Code of practice for evaluation of fruit and vegetable
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`from Fruits and Vegetables of the European Union,
`Brussels 1996.
`4. EEC Council Regulation No. 2092/91 of June, 24th 1991
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`identification. OJL 1991,198, 22, 7.
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`wach i ziemniakach 1987—1991. Roczn. PZH, 1993, 44,
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`7. Heimendinger J., Chapelsky D., The national 5 a day for
`better health program. Adv. Exp. Med. Biol., 1996, 401,
`199—206.
`8. Hill M.J., Nitrates and nitrites from food and water in
`relation to human disease, 1991. In: Nitrates and nitrites
`in food and water (ed. Ellis Horwood), London 1991.
`9. Hiller A., Skolimowska U., Grzelka M., Stan mikrobio-
`logiczny a zawarto(cid:230)(cid:141) azotan(cid:151)w i azotyn(cid:151)w w warzywach
`korzeniowych przechowywanych w okresie jesienno-
`-zimowym i nara(cid:253)onych na przemarzni«cie. Bromat.
`Chem. Toksykol., 1987, 1, 1—7 (English abstract).
`10. Horuba‚a A., (cid:229)wiatowe tendencje w technice i techno-
`logii sok(cid:151)w i napoj(cid:151)w. Przem. Ferment. i Owoc.-
`-Warzyw., 1999, 11, 29—36 (English abstract).
`11. International Standard ISO 6557.2, 1984(E). Fruits,
`vegetables and derived products. Determination of
`ascorbic acid content. Part 2: Routine methods.
`12. International Standard ISO 6635.2, 1984(E). Fruits,
`vegetables and derived products. Determination of
`nitrite and nitrate content. Photometric method.
`13. Jarczyk A., Woda jako sk‚adnik sok(cid:151)w owocowych.
`Przem. Ferment. i Owoc.-Warzyw., 1999, 1, 41—43
`(English abstract).
`14. Kubiak K., Rembowski E., Badania marketingowe
`popytu na soki i napoje owocowe i warzywne. Przem.
`Ferment. i Owoc.-Warzyw., 1998, 2, 50—51 (English
`abstract).
`15. Livissier M., Suschetet H., Causert J., Influence des
`nitrites et des nitrates certains aspects de l(cid:213)etat de
`nutrition vitaminique. Ann. Nutr. Alim., 1976, 30,
`847—857 (in French).
`16. Markiewicz R., Borawska M., Sikorski A., Zawarto(cid:230)(cid:141)
`azotan(cid:151)w i azotyn(cid:151)w w wybranych owocach krajowych.
`Bromat. Chem. Toksykol., 1998, 31, 197—198 (English
`abstract).
`17. Markowska A., Kotkowska A., Furmanek W.,
`Gackowska L., Siwek B., Kacprzak-Strza‚kowska E.,
`
`Page 4 of 5
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`

`Juices from organic and conventional materials
`
`6611
`
`B‚o˜ska A., Badania zawarto(cid:230)ci azotan(cid:151)w i azotyn(cid:151)w
`w wybranych warzywach surowych oraz poddanych
`obr(cid:151)bce termicznej. Roczn. PZH, 1995, 46, 349—355
`(English abstract).
`18. Mi(cid:230)kiewicz W., Ol«dzka R., Chojak F., Nowotko M.,
`Pokorska-Lis G., Skrobisz B., Wp‚yw proces(cid:151)w fermen-
`tacyjnych stosowanych w przetw(cid:151)rstwie domowym na
`rozpad azotan(cid:151)w. Roczn. PZH, 1988, 39, 35—41 (English
`abstract).
`19. Nabrzyski M., Gajewska R., Zawarto(cid:230)(cid:141) azotan(cid:151)w i azo-
`tyn(cid:151)w w owocach i warzywach oraz niekt(cid:151)rych innych
`(cid:230)rodkach spo(cid:253)ywczych. Roczn. PZH, 1994, 45, 167—180
`(English abstract).
`20. Przyby‚owski P., Kisza J., Nowicka B., Ocena precyzji
`i dok‚adno(cid:230)ci zmodyfikowanej metody oznaczania
`azotan(cid:151)w i azotyn(cid:151)w w mleku. Roczn. PZH, 1983, 34,
`487—494 (English abstract).
`21. Rembia‚kowska E., Badania por(cid:151)wnawcze jako(cid:230)ci
`zdrowotnej i od(cid:253)ywczej marchwi i bia‚ej kapusty
`z gospodarstw ekologicznych i konwencjonalnych
`Roczn. AR Pozna˜ CCCIV, 1998, 27, 257—266 (English
`abstract).
`22. Sobala G.M., Pignatelli B., Schorah C.J., Bartsch H.,
`Sanderson M., Dixon M.F., King R.F.G., Axon A.T.R.,
`Levels of nitrate, nitrite, N-nitroso-compounds, ascorbic
`acid and total bile acids in gastric juice of patients with
`and without precancerous conditions of the stomach.
`Carcinogenesis, 1991, 12, 193—198.
`23. Szponar L., Rychlik E., Koz‚owska-Wojciechowska M.,
`Bezpia˜ska-Ogl«cka A., Anio‚a J., Health quality of
`food, dietary habits, nutritional education as important
`public problems in Poland. ßyw. Cz‚ow. Metab., 1998, 2,
`176—185.
`
`24. (cid:229)miechowska M., Przyby‚owski P., Nitrates, nitrites and
`vitamin C in vegetables from ecological and conven-
`tional plants. 1996, In: Proceedings of the 5th
`International Commodity Science Conference (cid:210)Quality
`for European Integration(cid:211), Pozna˜ University of
`Economics, 481—484.
`25. (cid:229)miechowska M., Przyby‚owski P., Zawarto(cid:230)(cid:141) azotan(cid:151)w
`(V) oraz azotan(cid:151)w (III) we wczesnych warzywach
`z uprawy ekologicznej. Roczn. AR Pozna˜ CCCXXIII,
`2000, 31, 521—525 (English abstract).
`26. (cid:229)miechowska M., The nitrate intake with food of animal
`and plant origin. Acta Pol. Toxicol., 2001, 1, 115—123.
`27. Vittozzi L., Toxicology of nitrates and nitrites. Food
`Contam., 1992, 9, 579—585.
`28. Vogtmann H., Temperli A.T., Kuensch V., Eichenberger
`H., Ott P., Accumulation of nitrates in leafy vegetables
`grown under contrasting agricultural systems. Biol.
`Agric. Hortic., 1984, 2, 51—68.
`29. Walkowiak-Tomczak D., Grajek W., Nowak A., Czapski
`J., Akumulacja azotan(cid:151)w w warzywach i metody ich
`usuwania. Przem. Ferment. Owocow.-Warzyw., 1996, 1,
`25—27 (in Polish).
`30. Wieczorek C., Traczyk I., Wp‚yw przechowywania i nie-
`kt(cid:151)rych proces(cid:151)w technologicznych na zawarto(cid:230)(cid:141)
`azotan(cid:151)w, azotyn(cid:151)w i witaminy C w kapu(cid:230)cie bia‚ej.
`ßyw. Cz‚ow. Metab., 1995, 22, 165—173 (English
`abstract).
`
`Received July 2001. Revision received December 2001 and
`accepted February 2003.
`
`ZAWARTO(cid:229)(cid:140) AZOTAN(cid:238)W (V) I (III) ORAZ WITAMINY C
`W SOKACH PITNYCH OTRZYMANYCH Z SUROWC(cid:238)W EKOLOGICZNYCH I KONWENCJONALNYCH
`
`Maria (cid:229)miechowska
`
`Katedra Towaroznawstwa i (cid:252)adunkoznawstwa, Akademia Morska, Gdynia
`
`Oznaczono zawarto(cid:230)(cid:141) azotan(cid:151)w V i III oraz witaminy C w sokach pitnych owocowych, warzywnych i owocowo-warzyw-
`nych otrzymanych z surowc(cid:151)w ekologicznych i konwencjonalnych. Og(cid:151)‚em przebadano 189 pr(cid:151)bek sok(cid:151)w zakupionych
`w sklepach na terenie Tr(cid:151)jmiasta (Gda˜sk—Sopot—Gdynia), w tym 63 pr(cid:151)bki sok(cid:151)w o jednodniowym terminie przydatno(cid:230)ci
`do spo(cid:253)ycia i 48 pr(cid:151)bek sok(cid:151)w otrzymanych z surowc(cid:151)w ekologicznych. Badania przeprowadzono w okresie maj—wrzesie˜
`1999 roku. Zawarto(cid:230)(cid:141) azotan(cid:151)w V i III w sokach pitnych by‚a zr(cid:151)(cid:253)nicowana i zale(cid:253)a‚a nie tylko od pochodzenia surowca,
`ale tak(cid:253)e od producenta. Najmniej azotan(cid:151)w V zawiera‚ sok jab‚kowy 0.6—10.0 mg NaNO3/dm3 i sok pomara˜czowy 1.2—1.8
`mg NaNO3/dm3, a najwi«cej sok ze (cid:230)wie(cid:253)ych burak(cid:151)w pochodz(cid:136)cy z pijalni sok(cid:151)w 718.7—1118.2 mg NaNO3/dm3 (tab. 1 i 2).
`Soki otrzymane z surowc(cid:151)w ekologicznych oraz soki wyprodukowane przez renomowane zak‚ady posiada‚y zbli(cid:253)on(cid:136)
`zawarto(cid:230)(cid:141) azotan(cid:151)w V i III. Zawarto(cid:230)(cid:141) witaminy C w sokach pitnych by‚a zr(cid:151)(cid:253)nicowana i kszta‚towa‚a si« (cid:230)rednio w zakresie
`2.8—38.9 mg/100 g. Najwi«cej witaminy C zawiera‚y soki warzywne fermentowane otrzymane z surowc(cid:151)w ekologicznych
`26.6—42.6 mg/100 g.
`
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