1、Designation: E1346 90 (Reapproved 2010)E1346 16Standard Practice forBulk Sampling, Handling, and Preparing Edible VegetableOils for Sensory Evaluation1This standard is issued under the fixed designation E1346; the number immediately following the designation indicates the year oforiginal adoption or
2、, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers the recommended procedures for bulk sampling, handling, an
3、d preparing edible vegetable oil (liquidat room temperature) prior to sensory evaluation.1.2 This practice is consistent with the background information presented in ASTM STP 433, ASTM STP 434,Manual 26, andASTM STP 758. These should be consulted for supplemental guidance.1.3 The values stated in SI
4、 units are to be regarded as standard. The values given in parentheses are for information only.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health p
5、ractices and determine the applicability of regulatorylimitations prior to use.2. Referenced Documents2.1 ASTM Publications:2ASTM STP 433 Basic Principles of Sensory EvaluationASTM STP 434Manual 26 Manual on Sensory Testing MethodsMethods, 2nd Ed.ASTM STP 758 Guidelines for the Selection and Trainin
6、g of Sensory Panel Members2.2 AOCS Standard:3Method C1-47C1-47 Sampling3. Summary of Practice3.1 This practice consists of the following basic steps: removing oil from bulk source, transporting and startingstoring oil priorto evaluation, preparing oils for evaluation, presenting samples to panel, an
7、d cleaning glassware.4. Significance and Use4.1 This practice is designed for use by the oil processor or research laboratory for evaluation by a trained sensory panel, orfor use by quality control (QC) and quality assurance (QA) personnel for sampling from a tank truck, car, or any other bulktransp
8、ortation container, or by both.4.2 The consistent use of this practice will provide representative samples for all sensory, chemical and physical analyses andwill protect the oil from oxidation.4.3 The objective of this practice is to ensure that the sample is representative of the sample source fro
9、m the time of samplinguntil the time of evaluation and to protect oil quality during that time.4.4 This practice addresses neither evaluation and scaling techniques, nor the sampling, handling, and preparing of solid fats.5. Apparatus5.1 Liquid Zone Sampler, or core sampler, or trier.4,5.2 Wide-Mout
10、h Jars,Jars made of polyethylene terephthalate, 0.5 to 1.0 L.1 This practice is under the jurisdiction of ASTM Committee E18 on Sensory Evaluationand is the direct responsibility of Subcommittee E18.06 on Food and BeverageEvaluation.Current edition approved Aug. 15, 2010Aug. 1, 2016. Published Decem
11、ber 2010August 2016. Originally approved in 1990. Last previous edition approved in 20062010as E1346 90 (2006).(2010). DOI: 10.1520/E1346-90R10.10.1520/E1346-16.2 Available from ASTM International Headquarters, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959.3 Available from Ame
12、rican Oil Chemists Society, P.O. Box 3989, Champaign, IL 61826.4 Available from Zone Devices, Inc., San Rafael, CA.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may no
13、t be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor D
14、rive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.3 Amber Glass Bottles, 250 mL to 1 L, with narrow-mouth tops that will withstand freezer temperatures.5.4 Plastic Caps with polytetrafluoroethylene (PTFE) Liners, or tape (PTFE pipe thread tape), to cover top of bottle openingbefor
15、e capping with new non-metallic screw type caps. Tape should be 2.5 cm in width or wider to completely cover bottleopenings.5.5 Glass Funnels.5.6 Glove Box with inert gas nitrogen (for example, nitrogen) atmosphere, including an oxygen scavenging device.5.7 Glass Vial, 50 mL. Use amber glass for odo
16、r and flavor evaluationevaluation; and clear glass for visual examination of oil.5.8 Standard Disposable Glass Pipets, 10 mL, one per each sample.5.9 Circulating Waterbath, Water bath, with automatic timer, thermostat and rack.5.10 Waterbath Water bath Thermometer, with range from 20 to 100C in 1C d
17、ivisions, calibrated for 76 mm immersion, 305mm long.6. Precautions6.1 Oil submitted for chemical and physical testing and for sensory evaluation should be from the same bulk sampling. Tanktrucks, cars, or any other bulk transportation containers may be filled with as many as seven layers and each l
18、evel of oil may beslightly different in quality. Oil samples should be handled in the same manner and time frame to ensure high data correlation.6.2 Do not expose oil to any environmental condition (for example, light, heat, oxygen, moisture) or any equipment (metals)that will cause oxidation of the
19、 oil and alter sensory characteristics of the oil.6.3 Use only new, clean, dry, and odor-free polyethylene terephthalate wide-mouth jars to collect oil samples; dispose of jarsrather than cleaning them.6.4 Flush bottles with nitrogen in a glove box prior to filling the bottle.6.2 Obtain a representa
20、tive oil sample for all evaluations (sensory, chemical, instrumental); unblended multiple samples mayproduce different results.6.3 Do not allow glass containers in processing or production areas where oil sampling is done. Use new plastic containers suchas polyethylene terephthalate bottles for init
21、ial sampling. Flush empty bottle with nitrogen as described in 6.4.6.4 Transfer oil from plastic bottle to recommended glass bottles within one hour of collection and flush headspace withnitrogen to minimize potential transfer of odors or flavors from the plastic container to the oil (conduct proced
22、ure in glove boxunder nitrogen atmosphere).Use only new, clean, dry, and odor-free polyethylene terephthalate (PET) wide-mouth jars to collectoil samples; dispose of jars rather than cleaning them.6.8 Use PFTE-lined caps or PFTE tape under caps to protect oil from off-odors or flavors imparted from
23、metallic or unlinedplastic caps.6.5 Store oil in amber glass bottles to protect the oil from light oxidation.6.6 Choose size of storage bottle based on purpose of evaluation, amount of oil required for each testing session or for numberof panelists, and amount of oil needed for instrumental or chemi
24、cal tests. For example, a 1 L sample of oil that requires evaluationquarterly should be stored in four 250-mL bottles.6.7 Use PTFE-lined caps or PTFE tape under caps to protect oil from off-odors or flavors imparted from metallic or unlinedplastic caps.6.8 Do not expose oil to any environmental cond
25、ition (for example, ligh, heat, oxygen, moisture) or any equipment (metals) thatwill cause oxidation of the oil and alter sensory characteristics of the oil.6.9 Transfer oil from plastic bottle to recommended glass bottles within one hour of collection and flush headspace with inertgas to minimize p
26、otential transfer of odors or flavors from the plastic container to the oil (conduct procedure in glove box undernitrogen atmosphere).6.10 Keep an inert gas in contact with the oil at all times to avoid exposure of the oil to oxygen.6.11 Discard any unused oil.7. Procedures for Handling Samples Obta
27、ined from Bulk Storage7.1 Refer to the AOCS Official Method C1-47C1-47 on oil sampling for specifications for detailed information on equipmentand procedures.4 Available from Refinery Supply Co., Tulsa, OK.E1346 1627.2 Flush bottleSteps 7.3 7.5 with nitrogen and fill bottle with oil, allowing a smal
28、l amount of headspace. Flush headspacewith nitrogen to remove oxygen, and cap bottle (conduct procedure in should be conducted in a glove box under nitrogenatmosphere).inert gas atmosphere.7.3 Flush bottle with inert gas prior to filling the bottle.7.4 Fill bottle with oil, leaving 0.5 to 1 cm of he
29、adspace between the oil and the cap liner.7.5 Headspace Considerations: Flush headspace with inert gas to remove all oxygen which deteriorates the oil, and cap bottle.7.3.1 Keep an inert gas such as nitrogen in contact with the oil at all times to avoid exposure of the oil to oxygen.7.3.2 Leave 0.5
30、to 1 cm of headspace between the oil and the cap liner.7.5.1 Fill headspace with inert gas (nitrogen) to remove all oxygen which deteriorates the oil. Flush only the headspace withnitrogen inert gas since bubbling nitrogen through oil for short periods of time has little benefit.7.5.2 Analyze headsp
31、ace for oxygen to ensure that bottles are being flushed correctly as follows: (1) Flush headspace of bottlewith nitrogen, seal with silicon rubber septum in screw type cap, (2) withdraw a gas sample with a syringe through the septum,and (3) inject sample into gas chromatograph with thermal-conductiv
32、ity detector using a two column system. Column conditionsare: ethylvinyl benzene-divinylbenzene polymer 80 to 100 mesh (3 ft by 18 in.) and molecular sieve 5A 80 to 100 mesh (9 ft by116 in.) with 25C oven temperature and 20 mL/min helium flow rate.7.5.2.1 Flush headspace of bottle with inert gas, se
33、al with silicone rubber septum in screw type cap.7.5.2.2 Withdraw a gas sample with a syringe through the septum.7.5.2.3 Inject sample into gas chromatograph with thermal-conductivity detector using a two column system. Columnconditions are: ethylvinyl benzene-divinylbenzene polymer 80 to 100 mesh (
34、3 ft by 18 in.) and molecular sieve 5A80 to 100 mesh(9 ft by 116 in.) with 25C oven temperature and 20 mL/min helium flow rate.57.6 Store all oils at 5 or 20C, -20 or 5C, except for the sample for initial evaluation, which may be held at ambienttemperature (25C) in the dark for 1 h after sampling fr
35、om bulk storage before analyses.7.7 Samples should be held a maximum of 2 days at 5 6 2C in the dark before evaluation. If evaluation is not possible withinthis time frame, filled containers should be held at 20C.-20C. Always store samples in the dark.7.8 Do not open bottles until ready for sample e
36、valuation. During this holding period, bottles should remain sealed with nitrogeninert gas in the headspace.7.9 Winterized Oil:7.9.1 Frozen sample is removed from cold storage and held at refrigerated (5 6 2C) temperature until completelyhomogeneous, that is, clear, with no visible solids. The time
37、requirements for thawing the oil will vary depending upon containersize.7.9.2 Sample must be mixed just prior to evaluation by inverting bottle several times to ensure homogeneity and to minimizepotential density differences within the container; for example, a 500 mL bottle with between 0.5 and 1 c
38、m headspace is inverted10ten times.7.10 Non-Winterized Oil:7.10.1 The frozen sample is removed from cold storage and held at refrigerated (5 6 2C) temperature until it stabilizes at thattemperature (5C). Next, move container to ambient temperature (25 6 5C) until completely homogeneous; clear, no vi
39、siblesolids.7.10.2 Sample must be mixed just prior to evaluation by inverting bottle several times to ensure homogeneity and to minimizepotential density differences within the container; for example, a 500 mLbottle with between 0.5 and 121 cm headspace is invertedten times.7.11 Samples for instrume
40、ntal, chemical or physical testing should be taken from the thawed sample just prior to sensory testing.All evaluations should be conducted within the same time frame as the sensory tests to ensure valid test results for correlationanalyses. Oil that cannot be tested immediately must have the headsp
41、ace thoroughly re-flushed with nitrogen inert gas and thebottle recapped with PFTE tape or a PFTE-lined plastic cap and stored at 5C for no longer than 12 h.Any leftover sample shouldbe discarded. Re-freezing is abusive to the oil and is not recommended.7.12 Do not thaw samples by heating above the
42、ambient temperature (25C) by microwave or in waterbath. water bath. Theseprocedures are abusive and may deteriorate the oil and develop off-odors and flavors, causing the sample to be less thanrepresentative of the sample source.7.13 Once For winterized oil, once the oil has reached refrigerated tem
43、perature (5C) (winterized oil), (5C), it must beevaluated within 12 h if the bottle has been opened, or within 2 days if the bottle has not been opened.7.14 All samples must be at ambient temperature at the time of preparation for sensory evaluation.5 Saguy, I., Goldman, M., and Karel, M., “Predicti
44、on of Beta-Carotene Decolorization in Model System Under Static and Dynamic Conditions of Reduced OxygenEnvironment,” Journal of Food Science, Vol 50, 1985, pg. 526530.Saguy, I., Goldman, M., and Karel, M., “Prediction of Beta-Carotene Decolorization in Model SystemUnder Static and Dynamic Condition
45、s of Reduced Oxygen Environment,” Journal of Food Science, Vol 50, 1985, pp. 526530.E1346 1638. Procedures for Preparation of Oils for Sensory Evaluation8.1 Visual evaluations of oils should be conducted separately from odor and flavor testing. Place oils in clear glass vials. Donot heat oil samples
46、.8.2 Fill waterbath water bath with distilled water and heat to 50C.8.3 Pipet 10 mL oil into each glass vial and cap. Do not allow drips on inside of container as it will increase the surface areaof the oil to oxygen and cause subsequent deterioration.8.4 Immerse sample vials into pre-heated waterba
47、th water bath at a level sufficient to cover the oil in the vial. Vials should besuspended in the waterbath water bath on racks rather than sitting on the bottom to allow an even flow of water around each vialand to ensure that the temperature is constant without hot or cold spots. Do not cover the
48、waterbath. water bath. Vials are spacedequidistant from each other and the edges of the waterbath. water bath. No vial should touch another vial or the side of thewaterbath. The waterbath water bath. The water bath must be of sufficient size to hold all sample vials required for a single panel.8.5 P
49、laceMaintain vials into in the controlled temperature, pre-heated waterbath water bath for sufficient time for oils to reachserving temperature of 50 6 1C. Determine minimum time required to bring oil to serving temperature, (usually 6 to 10 min).Serve sample immediately. Sample should not be held longer than 30 min since the oil would be exposed oil exposure to elevatedtemperature and oxygen that cause deterioration in deteriorate oil quality.8.6 If more than one waterbath water bath must be used, attention should be given to standardize the number
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