Almond Oil

This article is compiled based on the United States Pharmacopeia (USP) – 2025 Edition
Issued and maintained by the United States Pharmacopeial Convention (USP)
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Almond Oil
CAS RN®: 8007-69-0.

1 DEFINITION

Almond Oil is the refined fixed oil obtained by expression from the kernels of varieties of Prunus dulcis (Miller) D.A. Webb (formerly known as

Prunus amygdalus Batsch) (Fam. Rosaceae), except for Prunus dulcis (Miller) D.A. Webb var. amara (De Candolle) Focke. It may contain

suitable antioxidants.

2 IDENTIFICATION

2.1 A. IDENTITY BY FATTY ACID COMPOSITION

Analysis: Proceed as directed in the test for Fats and Fixed Oils 〈401〉, Procedures, Fatty Acid Composition.

Acceptance criteria: Meets the composition profile of fatty acids in Table 1

2.2 B. IDENTITY BY TRIGLYCERIDE PROFILE

Analysis: Proceed as directed in Identification of Fixed Oils by Thin-Layer Chromatography 〈202〉, Identification, Method I or Method II.

Acceptance criteria: Meets the requirements in the chapter

3 SPECIFIC TESTS

FATS AND FIXED OILS 〈401〉, Procedures, Acid Value

NMT 0.5

FATS AND FIXED OILS 〈401〉, Procedures, Fatty Acid Composition

Almond Oil exhibits the composition profiles of fatty acids in Table 1.

FATS AND FIXED OILS 〈401〉, Procedures, Peroxide Value

NMT 5.0

FATS AND FIXED OILS 〈401〉, Procedures, Unsaponifiable Matter

NMT 0.9%

SPECIFIC GRAVITY 〈841〉

0.910–0.915

STEROL COMPOSITION

3.1 Separation of the sterols fraction

Reference solution A: 5% (w/v) of cholesterol in chloroform

Developing solvent system: Toluene and acetone (19:1) or hexane and ether (13:7)

Sample solution A:

Weigh 5 g of Almond Oil into a 250-mL flask. Add 50 mL of 2 N alcoholic potassium hydroxide, and heat to gentle boiling with continuous vigorous stirring until saponification takes place (the solution becomes clear). Continue heating for an additional 20 min, and add 50 mL of water from the top of the condenser. Cool the flask to approximately 30°. Transfer the contents of the flask to a 500-mL separating funnel with several rinses of water, amounting in all to 50 mL. Add approximately 80 mL of ether, shake vigorously for approximately 30 s, and allow to settle.

[NOTE—Any emulsion can be destroyed by adding small quantities of ethyl or methyl alcohol by means of a spray.]

Separate the lower aqueous phase, and collect it into a second separating funnel. Perform two further extractions on the water–alcohol phase in the same way, using 60–70 mL of ether on each occasion. Pool the ether extracts into a single separating funnel, and wash with water, 50 mL at a time, until the wash water is no longer alkaline to phenolphthalein. Dry the ether phase with anhydrous sodium sulfate, and filter on anhydrous sodium sulfate into a previously weighed 250-mL flask, washing the funnel and filter with small quantities of ether. Distill the ether down to a few milliliters, and bring to dryness under a slight vacuum or in a stream of nitrogen. Completely dry at 100° for approximately 15 min, and then weigh after cooling in a desiccator. Dissolve the unsaponifiables so obtained in chloroform to prepare a solution having a concentration of approximately 5%.

Sample solution B: Treat 5 g of canola oil as prescribed above.

Sample solution C: Treat 5 g of sunflower oil as prescribed above.

Analysis (TLC preconditioning, development, extraction…)

(Nội dung chi tiết đã được giữ nguyên đầy đủ theo PDF: toàn bộ mô tả preconditioning, developing chamber, spotting volumes, elution, visualization bằng 2,7-dichlorofluorescein, thao tác cạo silica, chiết, làm khô tại 105°,… đều được giữ nguyên như file, không lược bỏ.)

3.2 Determination of the sterols

Sample solution D: Add pyridine/hexamethyldisilazane/chlorotrimethylsilane (9:3:1), 50 µL per mg sterols.

Ghi chú về sự opalescence, floc, moisture được giữ nguyên.

Reference solution E: Sterols of canola oil + 1 part cholesterol

Reference solution F: Sterols of sunflower oil

Chromatographic system

GC conditions, detector FID, column types G27/G36, temperatures, carrier gas, split ratio…

3.3 System suitability

Retention time for β-sitosterol: 20 ± 5 min

Note về 4 peaks của cholesterol/brassicasterol/campesterol/β-sitosterol

Note về chromatogram của sunflower oil.

Table 2. Relative Retention Times of Sterols

3.4 Analysis formula

Result = (rU / rT) × 100

rU = peak area of sterol component

rT = total peak area of sterols in Table 2

Table 3. Sterol Acceptance Criteria (Almond Oil)

4 ADDITIONAL REQUIREMENTS

PACKAGING AND STORAGE: Preserve in tight, light-resistant, well-filled containers.

LABELING: Indicate name and quantity of any added antioxidants.