ti_gb15682-2008 inspection of grain and oils - method for sensory evaluation of paddy or rice...

8/11/2019 TI_GB15682-2008 Inspection of Grain and Oils - Method for Sensory Evaluation of Paddy or Rice Cooking and Eati

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Regional Economic Cooperation and Integration in Asia

Technical Inputs

National Standard of Peoples Republic of China

GB/T 15682-2008

Inspection of grain and oils Method for sensory evaluation of

paddy or rice cooking and eating quality


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Imprint

Published by theDeutsche Gesellschaft frInternationale Zusammenarbeit (GIZ) GmbH

Registered offices

Bonn and Eschborn, Germany


China OfficeTaYuan Diplomatic Office14 Liangmahe South Street, Chaoyang District10600 Beijing, PR ChinaT +86-10-8532-5344F +86-10-8532-5744

Office MongoliaNaiman Zovkhi Building

Seoul Street 21Ulaanbaatar 14251, Mongolia

[email protected]

As at

September 2014

Photo creditsCopyrights for all pictures: GIZCopyright for cover picture: GIZ/ Ursula Meissner

TextShenzhen Institute of Standards and Technology (SIST), Shenzhen, PR China

The findings and conclusions expressed in this documentation are entirely those of the authors. They do not necessarily repre-sent the view of the Deutsche Gesellschaft fr Internationale Zusammenarbeit (GIZ) or further organising parties. The informa-tion provided is without warranty of any kind.

On behalf of the German Federal Ministry for Economic Cooperation and Development (BMZ)


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ICS 67.060B 20

National Standard of the People's Republic of China

GB/T 15682-2008Replaces GB/T 15682-1995

Inspection of grain and oils Method for sensory evaluation of paddy or ricecooking and eating quality

Issue date: Nov 4 th , 2008 Implementation date: Feb 20 th , 2009

Issued by General Administration of Quality Supervision, Inspection and Quarantineof the People's Republic of China and Standardization Administration of thePeoples Repu li of China


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GB/T 15682-2008

Foreword

This standard replaces GB/T 15682-1995 (Rice-Determination of cooking test

quality).

There are main differences between this standard and GB/T 15682-1995:

--the a e of sta da d has ee ha ged i to I spe tio of g ai a d oils Method

fo se so e aluatio of padd o i e ooki g a d eati g ualit .

-- to add preparation method of rice with small sample and large sample.

-- to add procedure of rice Pretreatment with soaking.

--to modify the volume of water and cooking time.

--to revise scoring items and the weights of original evaluation system.

--to add a new evaluation system: Evaluation Method Two.

Annex A, Annex B and Annex C of this standard are normative, while Annex D is

informative.

This standard is proposed by the State Administration of Grain.

The standard is under jurisdiction of National Technical Committee on Grain and Oil

Standardization.The main organizations that participated in the drafting of this standard are: Henan

University of Technology, Hubei Monitoring Center of National Grains Quality, Testing

Center of Cereals and Cereal Products Quality Supervision of Ministry of Agriculture

(Haerbin), Chengdu Grain storage Research Institute State Administration of Grain

Reserve.

The main drafters: Xiangqing Zhou, Yurong Zhang, Ke Bian, Dunnian Yu, Ning Xiong,

Zhiming Wang, Lekai Wang, Xiahui Li, Aihua Cheng, Xuechao He, Lanlan Yang.

The published editions which are replaced are listed as follows:

------GB/T 15683-1995.


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GB/T 15682-2008

Inspection of grain and oils Method for sensory evaluation of paddy or rice

cooking and eating quality

1 Scope

This standard specifies terms, definitions, principle, apparatus, procedure of paddy

and rice cooking experiment, also contents, order, requirements and grading results

of rice tasting evaluation.

This standard applies to cooking evaluation and quality evaluation of paddy or rice.

2 Normative references

The following standards contain provisions which, referred by this standard,

constitute provisions of this standard. For dated references, only the edition cited

applies. For undated references, the latest edition of the referenced document

(including any amendments) applies. However, it is encouraged for each party

entering agreement according to this standard to decide whether to use the latest

versions of these documents. In addition, the latest versions of all reference

documents without dates are applicable to the standard.

GB 1354-- Rice

GB5491--Inspection of Grain and Oilseeds Methods for Sampling and Sample

Reduction

GB/T 10220-- Sensory Analysis Methodology General Guidance

GB/T 13868--Sensory Analysis General Guidance for the Design of Test Rooms

3 Terms and definitionsThe following terms and definitions are applicable to this standard.

3.1 Sensory evaluation of rice eating quality

When rice is cooked under specified conditions, assessors evaluate rice by color, odor,

taste, viscosity and hardness palatability by eyes, nose, mouth, etc., and then have a

comprehensive evaluation.

3.2 Primary assessorThe person who is selected and trained and has certain ability and experience of


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GB/T 15682-2008

sensory analysis.

3.3 Selected assessorThe person who is selected and trained and has high ability and experience ofsensory analysis.

4 Principles

The paddies which have been hulled and whiten in to Grade 3 rice of national

standard are chosen to be test sample. Commercial rice is chosen as test sample

directly. Take a certain amount of test sample and cook rice under specified

conditions, then, assessors evaluate the rice by odor, appearance, palatability, taste,

texture of cool rice, etc. Take the average value of comprehensive scores carried out

by participators as the final test result.

5 Apparatus

5.1 Laboratory rice huller .

5.2 Laboratory rice polisher .

5.3 Balance, accurate to 0.0 1 g.

5.4 Single-drawer aluminum (or stainless steel) steamer , diameter of 26~28cm.

5.5 Electric stove 220 V, 2kW, or electromagnetic oven with the same capacity factor.

5.6 Steaming rice dish , aluminum (or stainless steel) box, volume more than 60 ml.

5.7 Directly-heated electronic rice cooker , 3L, 500 W.

5.8 Rice washing basin , 500 ml (for small sample preparation) or 3000 ml (for large

sample preparation).

5.9 Dewatering screen , sieve, QC 16.

5.10 Bowl , capability of about 50 g test sample.5.11 Round white porcelain plate , diameter of about 20 cm, the edge of the plate

are equally stuck on a red, yellow, blue, green colors of plastic adhesive tape.

6 Procedures

6.1 Preparation of test sample

6.1.1 Sampling

See GB 5491.

6.1.2 Preparation of rice sample


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GB/T 15682-2008

Weigh 1500g~2000g paddy, shell to brown rice by rice huller (5.1), then milled by rice

polisher to polished rice of third level of national standard. Follow the procedure

described in GB 1354. Take commercial rice as test sample directly.

6.1.3 Numbering and registration of the samplesRandomly arrange the number of samples, box (5.6) and cooker (5.4 or 5.7). Record

necessary information, e.g. sample varieties, origins, dates of harvest or production,

methods of storage and processing.

6.1.4 Selection of reference sample

6.1.4.1 Reference sample of paddy

Select 3~5 paddy samples with fatty acid value (with KOH) less than 20 mg/100 g (dry

basis). The assessors taste and evaluate twice or thrice after the samples have been

prepared and steamed (see 8.3.1). Then select one sample which is normal in color,

odour, taste and gets 75 scores as reference sample.

6.1.4.2 Reference sample of rice

Select 3-5 fresh rice samples, which are compliant to the requirements of Grade 3

rice of national standard. The assessors taste and evaluate twice or thrice after the

samples are steamed (see 8.3.1). Then select one sample which is normal in color,odour, taste and gets 75 scores as reference sample.

6.2 Preparation of rice

6.2.1 Preparation of small sample

6.2.1.1 Sample weight

Weigh 10 g of each sample in steaming rice dish (5.6). Number of samples is

consistent with that of assessors.

6.2.1.2 Rice washing

Pour weighed sample into dewatering screen (5.9), then take the dewatering screen

into Rice washing basin (5.8). Add 300 ml water quickly. Stir clockwise for 10 round,

then anti-clockwise for 10 round. Exchange the water quickly and repeat the above

operation. Rinse with 200 ml distilled water, dewater the rice and pour it into

steaming rise dish. The washing time should be controlled in 3~5 min.

6.2.1.3 Soaking


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GB/T 15682-2008

The amount of water in long-shaped rice soaking is 1.6 times as the sample, while it

is 1.3 times in polished round-grained rice soaking. Amount of soaking water is based

on hardness of rice. Soak the rice for 30 min in the water of 25 .

6.2.1.4 Steaming

Add appropriate amount of water into steamer (5.4) and heat the water to boiling by

electric stove (or electromagnetic oven). Remove the lid, and then take covered

steaming rice dishes containing samples on the steamer tray, cover the lid, continue

heating and timing. 40 min later, stop heating and keep still for 20 min.

6.2.1.5 The prepared samples of different rice dish on the white porcelain plate

(5.11), 1 disc/person, 4 samples/disc.6.2.2 Preparation of large sample

6.2.2.1 Rice washing

Weigh 500 g sample in dewatering screen (5.9), then take the dewatering screen into

rice washing basin (5.8). Add 1500 ml tap water quickly. Stir clockwise for 10 round,

then anti-clockwise for 10 round. Exchange the water quickly and repeat the above

operation. Rinse with 1500 ml distilled water. Dewater the rice and pour it into

corresponding electronic rice cooker (5.7). The washing time should be controlled in

3~5 min.

6.2.2.2 Soaking

The amount of water in long-shaped rice soaking is 1.6 times as the sample, while it

is 1.3 times in polished round-grained rice soaking. Amount of soaking water is on

the basic of the rice hardness. Soak the rice for 30 min in the water of 25 .

6.2.2.3 Steaming

Rice sample is steamed by electronic rice cooker. It is not allowed to open the lid of

cooker in the cooking process. Keep still for 20 min after the switch tripped out.

6.2.2.4 Mixture of steamed rice

Mix cooked steamed rice with spoon, loosen the around of cooker to separate

steamed rice from cooker wall, then glide breadthwise and lengthwise respectively

for twice. Mix with chopsticks up and down for 4 times, the excess moisture canevaporate in this way. Cover the lip and keep still for 10 min.


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GB/T 15682-2008

6.2.2.5 Fill bowls (5.10) with about 50 g steamed rice, 1 bowl / person (peripheral

steamed rice is not recommended). Upside down bowls of steamed rice cone on the

white porcelain plate (5.11) in positions with different colors (red, yellow, blue,

green).

7 Requirement of evaluation

7.1 Environment

See GB/T 10220.

7.2 Evaluation Laboratory

See GB/T 13868.

7.3 Assessor

Choose 5~10 selected assessors or 18~24 primary assessors according to Annex A.

Number the assessors and then randomly divide them into several groups. They are

not allowed to smoke or eat anything except water an hour before tasting. Assessor

should maintain normal physiological state and not wear cosmetics and other

smelling products.

7.4 Review copies and taste time of steamed rice

Evaluate only 4 samples (including 1 reference sample and 3 test samples) in each

test. When there are 5 or more samples, they should be tested in 2 groups. When the

samples are less than 4, one of the test samples should be evaluated repeatedly.

However, the assessors should not be informed of. One assessor should not

participate in the evaluation two times a day. Taste time should be 1 h before or 2

hours after meal.7.5 Numbering and ordering of evaluation samples

Number all the samples with No.1, No.2, No.3, No.4, and the reference sample is

No.1, other samples are numbered randomly. Taste and evaluate samples along with

the same order in one group. The number of test samples and sequence for

evaluation should be consistent among different groups.

8 Evaluation of sample

8.1 Content of evaluation


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GB/T 15682-2008

Taste and evaluate the smell, appearance of structure, palatability (including viscosity,

elasticity and hardness), taste and texture of cool rice.

8.2 Order and requirement of evaluation

8.2.1 Preparation before evaluation

The assessor should rinse the mouth with warm boiled water before each evaluation.

8.2.2 Evaluation of rice smell

Hold the steamed rice under the nose, breathe in deeply and distinguish odor of

steamed rice.

8.2.3 Observation of appearance

Observe apparent color, sheen and rice integrality of rice.8.2.4 Palatability distinguishing

Put a little of rice into mouth with chopsticks, chew for 3-5s, taste the viscosity,

hardness, elasticity and savour.

8.2.5 Texture of cooling rice

Keep rice sample at room temperature for 1 h, taste and evaluate the viscosity,

cohesiveness and hardness of cooling rice.

8.3 Score

8.3.1 Scoring Method One

8.3.1.1 Score the rice sample by odor, appearance, palatability, taste and cool rice

texture, contrasting with reference sample (6.1.4), take sum of scores as a

comprehensive score. For score rules and record table format, see Annex B.

8.3.1.2

Calculate the average value of comprehensive scores given by the assessors.

Individuals with a big deviation (10 scores over the mean) should be discarded before

mean calculation. The mean of comprehensive score (integer) is sensory evaluation

result of rice eating quality. Summarize a statistical table (for format, see Annex D).

8.3.1.3 Sample with a score less than 50 is identified as e Bad , ~ Bad ,

~ Co o , ~ lightl Good , ~ Good , o e tha E elle e .

8.3.2 Score Method TwoEvaluate rice sample with odor, appearance, palatability, taste and cool rice texture,


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GB/T 15682-2008

contrasting to reference sample (6.1.4). The results are divided into 7 grades

e p essed as slight, inferior , ost , the sa e as efe e e sa ple et c. (for

score record table format, see Annex C).

See Ta le Co te ts a d des iptio s of i e ualit se so e aluatio du i g the

grading.

Table 1 Contents and descriptions of rice quality sensory evaluationContents of evaluation Description

odor Characteristicaroma

full aroma; slight aroma; no aroma

Peculiar smell stale rice smell; unpleasant smellAppearance Color normal color, white; abnormal color, yellow or

graySheen intensity of surface light reflex: sheen; no sheenIntegrality maintaining integrality: compact structure; part

compact structure; part popcornPalatability Viscosity teeth adhesive: smooth; viscous; non- viscous

Hardness pressure of steamed rice by molars: moderate;hard; soft

Elasticity chewy; non-chewy; loose; dry and residualTaste Purity &

Constancytaste of chew: purity, strength and constancy ofsweet and spiciness

Texture of coolrice

Cohesiveness mouthfeel of cooling steamed rice: andretrogradation (cohesiveness, hardness, etc. .)Viscoelasticity

Hardness

8.3.2.2 Fi ishi g s o e e o d, ead the alue sig ed , the same as reference

sa ple if the e is o sig .

8.3.2.2.3 Calculate a mean of scores which given by assessors. Individuals with a big

deviation (positive or negative inconsistent between comprehensive scores and

mean or grading result deviation is above 2 levels) should be discarded before mean

calculation. The mean of comprehensive scores (two bit decimal) is sensory

evaluation result of rice eating quality. Summarize a statistical table (format see

Annex D).


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GB/T 15682-2008

Annex A

(Normative)Method of assessor selection

A.1 General requirements

The assessors should be of different genders and ages. Select persons with high

sensory sensitivity trough identification test.

A.2 Method of selection

Steam 4 helpings (2 helpings made by the same specimen) of rice according to the

prescribed standards. Then taste and evaluate according to relative standard. The

taste person is required to identify the 2 helpings rice made by the same specimensig ed ehi d the u e s ith . Re o d fo a d e a ple a e sho i Ta le

A.1.

Table A.1 Identification test and exampleAssessing person: Date:

Sample number Identification result1 2

34

Identification tests should be repeated twice. The record form and example are

shown in table A.2. Person with the right answer sig ed ith " ", while person with

the wrong answer signed with "". 2 wrong answers mean that the person has low

sensitivity and should not be chosen.

Table A.2 Score summary of assessorNumber of

assessing person:Results of identification test Score

1 2P1 GoodP2 ExcellentP3 GoodP4 BadP5 ExcellentP6 Excellent

Train the selected persons according to relative provisions of GB/T 10220, then,select assessors.


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GB/T 15682-2008

Annex B(Normative)

Rules & record form of sensory evaluation of riceMethod one

Number of assessing group: Name: Gender: Age: Place of birth:Assessing time: Y M D H M

One classindexScore

Two classindexScore

Specific characterizationScore

Scores of sampleNo.2 No.3 No.4

Smell20

Purity &Richness

20

Characteristic aroma, full:18~20Characteristic aroma,light:15~17Characteristic aroma, weak:12~14No aroma, no Peculiar smell:7~12Peculiar smell: 0~6

Appearance20

Color7

White color: 6~7Normal color: 4~5Yellow or gray: 0~3

Sheen8

Obvious sheen: 7~8Light sheen: 5~6

No sheen: 0~4Integrality

5compact structure andintegrality: 4~5Most with compact structureand integrality: 3Part popcorn: 0~2

Palatability30

Viscosity10

Smooth, viscous, no teethadhesive: 8~10Viscous, almost no teeth

adhesive: 6~7Viscous, teeth adhesive or noviscosity: 0~5

Elasticity10

Chewy:8~10Lightly chewy: 6~7Loose, hard, residual: 0~5

Hardness10

Moderate: 8~10

Hard or soft 6~7Too hard or too soft 0~5

Taste25

Purity &Constancy

Taste of chew: strong sweetand spiciness 22~25


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25 Taste of chew: weak sweetand spiciness 18~21Taste of chew: no sweet andspiciness, also no peculiar

taste 16~17Taste of chew: no sweet andspiciness, but peculiartaste 0~15

Texture ofcool rice

5

Cohesiveness&

Viscoelasticity& Hardness

5

Loose, good Viscoelasticity,modest hardness: 4~5Cohesive, light Viscoelasticity,lightly hard: 2~3Compact, bad Viscoelasticity,hard: 0~1

comprehensive ScoreRemark


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GB/T 15682-2008

Annex C(Normative)

Rules & record form of sensory evaluation of riceMethod Two

Number of assessing group: Name: Gender: Age: Place of birth:Assessing time: Y M D H MReference sample: red test sample number: No. yellow

Program Compare with reference sampleBad Reference

sampleGood

most inferior

slight most inferior

slight

Score -3 -2 -1 0 +1 +2 +3odour

AppearancePalatability

TasteTexture of cool

ricecomprehensive

ScoreRemark

Reference sample: red test sample number: No. blueProgram Compare with reference sample

Bad Referencesample

Goodmost inferior slight most inferior slight

Score -3 -2 -1 0 +1 +2 +3odour

Appearance

PalatabilityTasteTexture of cool

ricecomprehensive

ScoreRemark

Reference sample: red test sample number: No. green


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GB/T 15682-2008

Program Compare with reference sampleBad Reference

sampleGood

most inferior slight most inferior slightScore -3 -2 -1 0 +1 +2 +3

odourAppearancePalatability

TasteTexture of cool

ricecomprehensive

ScoreRemark

NOTE : Co pa e ith efe e e sa ple, sig ith i the o espo di g olu . NOTE 2: comprehensive o e is a o p ehe si e e aluatio a o di g to assesso s

feeling, addiction after compare with the reference sample.

NOTE 3: W ite spe ial e aluatio i the Re a k olu o ot .


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GB/T 15682-2008

Annex D(Informative)

Statistical list of sensory evaluation of rice

Numberof

assessor

Group Name Age Sex Comprehensive ScoreNo.2

(yellow)No 3blue

No.4green

1234

5678 n

X(Mean)


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E [email protected] www.giz.de


Office ChinaTa Yuan Diplomatic Office14 Liangmahe South Street, Chaoyang District100600 Beijing, PR China

Office MongoliaNaiman Zovkhis BuildingSeoul Street 21,Ulaanbaatar 14251, Mongoli

E [email protected]

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