标准搜索结果: 'GB 5009.227-2016英文版'
| 标准号码 | 内文 | 价格(元) | 第2步 | 交付天数[PDF] | 标准名称 | 相关标准 |
| GB 5009.227-2016 |
英文版
| 300 |
购买全文
|
现货, 9秒内下载
|
食品安全国家标准 食品中过氧化值的测定
|
GB 5009.227-2016
|
标准编号: GB 5009.227-2016 (GB5009.227-2016)
中文名称: 食品安全国家标准 食品中过氧化值的测定
英文名称: Method for analysis of hygienic standard of edible oils
行业: 国家标准
中标分类: X09
字数估计: 8,863
发布日期: 2016-08-31
实施日期: 2017-03-01
旧标准 (被替代): SN/T 0801.3-2011; GB/T 5538-2005; GB/T 5009.37-2003部分
标准依据: 国家卫生和计划生育委员会公告2016年第11号
GB 5009.227-2016: 食品安全国家标准 食品中过氧化值的测定
GB 5009.227-2016 英文名称: Method for analysis of hygienic standard of edible oils
中华人民共和国国家标准
1 范围
本标准规定了食品中过氧化值的两种测定方法:滴定法和电位滴定法。
本标准第一法适用于食用动植物油脂、食用油脂制品,以小麦粉、谷物、坚果等植物性食品为原料经
油炸、膨化、烘烤、调制、炒制等加工工艺而制成的食品,以及以动物性食品为原料经速冻、干制、腌制等
加工工艺而制成的食品;第二法适用于动植物油脂和人造奶油,测量范围是0g/100g~0.38g/100g。
本标准不适用于植脂末等包埋类油脂制品的测定。
第一法 滴定法
5 分析步骤
5.1 试样制备
样品制备过程应避免强光,并尽可能避免带入空气。
5.1.1 动植物油脂
对液态样品,振摇装有试样的密闭容器,充分均匀后直接取样;对固态样品,选取有代表性的试样置于密闭容器中混匀后取样。
5.1.2 油脂制品
5.1.2.1 食用氢化油、起酥油、代可可脂
对液态样品,振摇装有试样的密闭容器,充分混匀后直接取样;对固态样品,选取有代表性的试样置
于密闭容器中混匀后取样。如有必要,将盛有固态试样的密闭容器置于恒温干燥箱中,缓慢加温到刚好
可以融化,振摇混匀,趁试样为液态时立即取样测定。
5.1.2.2 人造奶油
将样品置于密闭容器中,于60℃~70℃的恒温干燥箱中加热至融化,振摇混匀后,继续加热至破
乳分层并将油层通过快速定性滤纸过滤到烧杯中,烧杯中滤液为待测试样。制备的待测试样应澄清。
趁待测试样为液态时立即取样测定。
5.1.3 以小麦粉、谷物、坚果等植物性食品为原料,经油炸、膨化、烘烤、调制、炒制等加工工艺而制成的食品
从所取全部样品中取出有代表性样品的可食部分,在玻璃研钵中研碎,将粉碎的样品置于广口瓶
中,加入2~3倍样品体积的石油醚(3.2.4),摇匀,充分混合后静置浸提12h以上,经装有无水硫酸钠的
漏斗过滤,取滤液,在低于40℃的水浴中,用旋转蒸发仪减压蒸干石油醚,残留物即为待测试样。
5.1.4 以动物性食品为原料经速冻、干制、腌制等加工工艺而制成的食品
从所取全部样品中取出有代表性样品的可食部分,将其破碎并充分混匀后置于广口瓶中,加入2~
3倍样品体积的石油醚(3.2.4),摇匀,充分混合后静置浸提12h以上,经装有无水硫酸钠的漏斗过滤,
取滤液,在低于40℃的水浴中,用旋转蒸发仪减压蒸干石油醚,残留物即为待测试样。
5.2 试样的测定
应避免在阳光直射下进行试样测定。称取“5.1.1~5.1.4”中制备的试样2g~3g(精确至0.001g),
置于250mL碘量瓶中,加入30mL三氯甲烷-冰乙酸混合液,轻轻振摇使试样完全溶解。准确加入
1.00mL饱和碘化钾溶液,塞紧瓶盖,并轻轻振摇0.5min,在暗处放置3min。取出加100mL水,摇匀
后立即用硫代硫酸钠标准溶液(过氧化值估计值在0.15g/100g及以下时,用0.002mol/L标准溶液;
过氧化值估计值大于0.15g/100g时,用0.01mol/L标准溶液)滴定析出的碘,滴定至淡黄色时,加1
mL淀粉指示剂,继续滴定并强烈振摇至溶液蓝色消失为终点。同时进行空白试验
7 精密度
在重复性条件下获得的两次独立测定结果的绝对差值不得超过算术平均值的10%。
第二法 电位滴定法
8 原理
制备的油脂试样溶解在异辛烷和冰乙酸中,试样中过氧化物与碘化钾反应生成碘,反应后用硫代硫
酸钠标准溶液滴定析出的碘,用电位滴定仪确定滴定终点。用过氧化物相当于碘的质量分数或1kg样
品中活性氧的毫摩尔数表示过氧化值的量。
9 试剂和材料除非另有说明,本方法所用试剂均为分析纯。水为GB/T 6682规定的三级水。
9.1 试剂
9.1.1 冰乙酸(CH3COOH)。
9.1.2 异辛烷(C8H18)。
9.1.3 碘化钾(KI)。
9.1.4 硫代硫酸钠(Na2S2O3·5H2O)。
9.1.5 重铬酸钾(K2Cr2O7):工作基准试剂。
9.2 试剂配制
9.2.1 异辛烷-冰乙酸混合液(40+60):量取40mL异辛烷,加60mL冰乙酸,混匀。
9.2.2 碘化钾饱和溶液:称取20g碘化钾,加入10mL新煮沸冷却的水,摇匀后贮于棕色瓶中,存放于
避光处备用。要确保溶液中有饱和碘化钾结晶存在。使用前检查:在30mL异辛烷-冰乙酸混合液
(9.2.1)中添加0.5mL碘化钾饱和溶液和2滴1%淀粉指示剂,若出现蓝色,并需用0.01mo1/L硫代
硫酸钠溶液超过1滴以上才能消除的,此溶液应重新配制。
9.3 标准溶液配制
9.3.1 0.1mo1/L硫代硫酸钠标准溶液:称取26g硫代硫酸钠(Na2S2O3·5H2O),加0.2g无水碳酸
钠,溶于1000mL水中,缓缓煮沸10min,冷却。放置两周后过滤、标定。
9.3.2 0.01mo1/L硫代硫酸钠标准溶液:由9.3.1以新煮沸冷却的水稀释而成。临用前配制。
10 仪器和设备
10.1 分析天平:感量为1mg、0.01mg。
10.2 电热恒温干燥箱。
10.3 电位滴定仪:精度为±2mV;能实时显示滴定过程的电位值-滴定体积变化曲线;配备复合铂环
电极或其他具有类似指示功能的氧化还原电极以及10mL、20mL的带防扩散滴定头的滴定管。
10.4 磁力搅拌器。
注:使用的所有器皿不得含有还原性或氧化性物质。磨砂玻璃表面不得涂油。
11 分析步骤
11.1 试样制备试样制备同“5.1.1~5.1.2”。
注:应避免在阳光直射下进行试样制备。
11.2 试样的测定
称取“5.1.1~5.1.2”中制备的油脂试样5g(精确至0.001g)于电位滴定仪的滴定杯中,加入50mL
异辛烷-冰乙酸混合液,轻轻振摇使试样完全溶解。如果试样溶解性较差(如硬脂或动物脂肪),可先向
滴定杯中加入20mL异辛烷,轻轻振摇使样品溶解,再加30mL冰乙酸后混匀。
向滴定杯中准确加入0.5mL饱和碘化钾溶液,开动磁力搅拌器,在合适的搅拌速度下反应60s±
1s。立即向滴定杯中加入30mL~100mL水,插入电极和滴定头,设置好滴定参数,运行滴定程序,采
用动态滴定模式进行滴定并观察滴定曲线和电位变化,硫代硫酸钠标准溶液加液量一般控制在
滴定后,须将搅拌器或搅拌磁子、滴定头和电极浸入异辛烷中清洗表面的油脂。
同时进行空白试验。采用等量滴定模式进行滴定并观察滴定曲线和电位变化,硫代硫酸钠标准溶
液加液量一般控制在0.005mL/滴。到达滴定终点后,记录滴定终点消耗的标准溶液体积V0。空白试
验所消耗0.01mo1/L硫代硫酸钠溶液体积V0 不得超过0.1mL。
注1:要保证样品混合均匀又不会产生气泡影响电极响应。可根据仪器说明书的指导,选择一个合适的搅拌速度。
注2:可根据仪器进行加水量的调整,加水量会影响起始电位,但不影响测定结果。被滴定相位于下层,更大量的
水有利于相转化,加水量越大,滴定起点和滴定终点间的电位差异越大,滴定曲线上的拐点更明显。
GB 5009.227-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National Food Safety Standard -
Determination of Peroxide Value in Foods
ISSUED ON. AUGUST 31, 2016
IMPLEMENTED ON. MARCH 1, 2017
Issued by. National Health and Family Planning Commission of the
People’s Republic of China
Table of Contents
Foreword ... 3
1 Scope ... 4
Method I Titration ... 4
2 Principle ... 4
3 Reagents and Materials ... 4
4 Instruments and Equipment ... 6
5 Analytical Procedures ... 6
6 Expression of Analysis Results ... 8
7 Precision ... 9
Method II Potentiometric titration ... 9
8 Principle ... 9
9 Reagents and Materials ... 9
10 Instruments and Equipment ... 10
11 Analytical Procedures ... 10
12 Expression of Analysis Results ... 11
13 Precision ... 13
National Food Safety Standard -
Determination of Peroxide Value in Foods
1 Scope
This Standard specifies two methods of determining peroxide value in foods. titration
and potentiometric titration.
In this Standard, Method I is applicable to edible animal and vegetable fats and oils,
and edible oil products, as well as food processed through deep-frying, puffing, baking,
modulating and frying from plant-based food as the raw material, such as wheat flour,
cereal and nut, etc.; food processed through quick freezing, dry-cure and pickling from
animal-based food as the raw material. Method II is applicable to animal and
vegetable fats, and margarine, and the range of measurement is 0 g/100 g ~ 0.38
g/100 g.
This Standard is not applicable to the determination of embedded oil and fat products,
for example, non-dairy creamer.
Method I -- Titration
2 Principle
The prepared oil and fat sample dissolves in chloroform and glacial acetic acid, the
contained peroxide reacts with potassium iodide and generates iodine. Use sodium
thiosulfate standard solution to titrate the precipitated iodine. Use an equivalent mass
fraction of iodine in peroxide or the mmol number of reactive oxygen in 1 kg of sample
to represent the peroxide value.
3 Reagents and Materials
Unless otherwise indicated, the reagents adopted under this method are of analytical
purity. The water is third-grade water as specified in GB/T 6682.
3.1 Reagents
3.1.1 Glacial acetic acid (CH3COOH).
3.1.2 Chloroform (CHCl3).
3.1.3 Potassium iodide (KI).
and layering. Use quick qualitative filter paper to filter the oil layer to beaker. The
filtrate in the beaker is the sample to be tested. The prepared sample shall be clarified
for testing. Immediately take the sample and determine it while the sample is still
liquid.
5.1.3 Food processed through deep-frying, puffing, baking, modulating and
frying from plant-based food as the raw material, such as wheat flour, cereal
and nut
Take edible part of representative sample from all the samples, grind it in a glass
mortar; place the grinded sample in a wide-mouth bottle, add petroleum ether (3.2.4)
at two to three times the volume of the sample; shake it and mix it up thoroughly, place
it evenly; start extraction for over 12 h. Use a funnel that holds anhydrous sodium
sulfate to filter it, and take the filtrate. Adopt rotary evaporator to decompress and dry
petroleum ether in water bath at below 40 °C. The remaining becomes the sample to
be tested.
5.1.4 Food processed through quick freezing, dry-cure and pickling from
Take edible part of representative sample from all the samples, grind it and thoroughly
mix it up; place the grinded sample in a wide-mouth bottle, add petroleum ether (3.2.4)
at two to three times the volume of the sample; shake it and mix it up thoroughly, place
it evenly; start extraction for over 12 h. Use a funnel that holds anhydrous sodium
sulfate to filter it, and take the filtrate. Adopt rotary evaporator to decompress and dry
petroleum ether in water bath at below 40 °C. The remaining becomes the sample to
be tested.
5.2 Determination of Samples
The determination of samples shall avoid direct sunlight. Weigh-take 2 g~3 g
volumetric flask, add 30 mL of trichloroethane-glacial acetic acid mixed solution;
slightly shake it to thoroughly dissolve the sample. Accurately add 1.00 mL of
saturated potassium iodide solution and tightly plug it, then, slightly shake it for 0.5
min; place it in the dark for 3 min. Take it out and add 100 mL of water, shake it up;
immediately use sodium thiosulfate standard solution (when the estimated peroxide
value is ≤ 0.15 g/100 g, use 0.002 mol/L standard solution; when the estimated
peroxide value is >0.15 g/100 g, use 0.01 mol/L standard solution) to titrate the
precipitated iodine, till it turns yellowish; add 1 mL of starch indicator, continue the
titration and strongly shake the solution till blue vanishes. Meanwhile, conduct a blank
test shall be ≤ 0.1 mL.
c - The concentration of sodium thiosulfate standard solution, expressed in (mol/L);
m - The mass of sample, expressed in (g);
1,000 - Conversion factor.
The calculation result shall be expressed as the arithmetic mean value of the result of
two independent determinations obtained under repeatability conditions. The result
shall retain two significant figures.
7 Precision
The absolute difference between the two independent determination results obtained
Method II -- Potentiometric titration
8 Principle
The prepared oil and fat sample dissolves in isooctane and glacial acetic acid, the
contained peroxide reacts with potassium iodide and generates iodine. Use sodium
thiosulfate standard solution to titrate the precipitated iodine; use potentiometric
titrator to determine the terminal of titration. Use an equivalent mass fraction of iodine
in peroxide or the mmol number of reactive oxygen in 1 kg of sample to represent the
peroxide value.
9 Reagents and Materials
purity. The water is third-grade water as specified in GB/T 6682.
9.1 Reagents
9.1.1 Glacial acetic acid (CH3COOH).
9.1.2 Isooctane (C8H18).
9.1.3 Potassium iodide (KI).
9.1.4 Sodium thiosulfate (Na2S2O3.5H2O).
9.1.5 Potassium dichromate (K2Cr2O7). working reference reagent.
9.2 Preparation of Reagents
Weigh-take 5 g (accurate to 0.001 g) of oil and fat sample that’s prepared in
isooctane-glacial acetic acid mixed solution, slightly shake the sample to thoroughly
dissolve it. If the sample manifests relatively poor solubility (for example, stearin or
animal fat), add 20 mL of isooctane to the titration cup first; slightly shake the sample
to dissolve it; add 30 mL of glacial acetic acid, then, mix it up.
Accurately add 0.5 mL of saturated potassium iodide solution to the titration cup, then,
activate magnetic stirrer; react for 60 s ± 1 s at an appropriate stirring speed.
Immediately add 30 mL~100 mL of water to the titration cup, insert electrode and
titration head, set titration parameter, start the procedure of titration; adopt the mode
of dynamic titration to titrate, and observe titration curve and potential change; the
0.05 mL/drop~0.2 mL/drop. After reaching the terminal of titration, record the volume
V of consumed standard solution at the terminal. After completing the titration of a
sample, soak the stirrer or stirring magnet, titration head and electrode in isooctane to
rinse grease on the surface.
Meanwhile, conduct a blank test. Adopt the mode of monotonic titration for titration,
and observe titration curve and potential change; the amount of added sodium
thiosulfate standard solution shall be controlled at 0.005 mL/drop. After reaching the
terminal of titration, record the volume V0 of consumed standard solution at the
terminal. The volume V0 of 0.01 mol/L sodium thiosulfate standard solution consumed
Note 1. guarantee that the sample is thoroughly mixed and no bubble is generated to
affect electrode response. Select an appropriate stirring speed in accordance with the
guidance by instrument manual.
Note 2. adjust the amount of added water in accordance with the instrument; this amount
will affect starting potential, but will not affect the result of determination. The titrated
phase is on the bottom layer, and a great deal of water is conducive to phase conversion.
More added water signifies a more significant potential difference between the starting
titration point and terminal titration point, and more obvious inflection point on the titration
curve.
12 Expression of Analysis Results
12.1 When an equivalent mass fraction of iodine in peroxide is adopted to signify
peroxide value, it shall be calculated in accordance with Formula (3).
|