Apricot (Prunus armeniaca L.) is an important fruit species belonging to the Rosaceae family, widely cultivated in temperate climate zones. Due to its cultural heritage and economic significance, apricot cultivation is intensively practiced, particularly in Türkiye, as well as in Central Asia and Mediterranean countries. Türkiye holds a leading position in global apricot production, with the Malatya region standing out in both fruit production and the industrial utilization of apricot kernels. Apricot kernels, which are by-products of the fruit processing industry, are utilized in the food sector as well as in cosmetic and pharmaceutical applications.

Apricot kernels are rich in oil, protein, dietary fiber, and various bioactive compounds. In particular, the oil extracted from apricot kernels exhibits functional properties in terms of nutrition and health due to its high content of essential fatty acids, such as oleic and linoleic acids, as well as tocopherols and phytosterols. These biological properties have expanded both the traditional uses and industrial applications of apricot kernel oil. However, the presence of amygdalin, particularly in bitter apricot kernels, which has the potential to release cyanide, necessitates careful toxicological evaluation.

In recent years, numerous studies have been conducted on the chemical composition, biological activities, and health effects of apricot kernels and their oil. These studies support the antioxidant, anti-inflammatory, and anticancer effects of apricot kernel oil, while also highlighting the need for quality control and standardization to ensure safe usage. Furthermore, with the development of modern extraction techniques, there has been an increase in research aimed at improving both the yield and quality parameters of apricot kernel oil.

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Botanical Characteristics

Apricot (Prunus armeniaca L.) is a fruit species belonging to the Rosaceae family, cultivated under temperate climatic conditions, and holds significant economic importance as both a fresh and dried fruit. While its origin is considered to be Central Asia, apricot cultivation is currently widespread in many countries, particularly Türkiye, Iran, China, and Italy. Türkiye holds a prominent position in global apricot production and export. The Malatya region, in particular, stands out as one of the world-renowned centers for dried apricot production, recognized with a geographical indication registration.

The apricot tree is a deciduous species that can grow to a height of approximately 6 to 12 meters, with a broad canopy structure. Its leaves are ovate, pointed at the tip, and serrated along the edges. The flowers, which are white or pink in color, typically bloom in early spring before the appearance of the leaves. The fruits are round or oval in shape, covered with a thin, velvety epicarp (fruit skin), and display colors ranging from yellow to orange. The mesocarp (fruit flesh) is sweet, juicy, and possesses a high nutritional value.

Inside the apricot fruit lies a hard stone, known as the endocarp, which encloses the seed (commonly referred to as the kernel or almond). Apricot kernels are categorized into two main types: sweet and bitter. Sweet kernels are generally consumed directly or used as food additives, whereas bitter kernels are processed industrially for oil extraction and utilized in cosmetic products. Due to their amygdalin content, bitter kernels require careful processing to mitigate potential toxicity.

Apricot kernels are nutritionally rich. They contain approximately 40% to 50% fixed oil and are also valuable sources of protein (ranging from 14% to 45%), dietary fiber (around 35%), and essential minerals. Apricot kernel oil is obtained after the removal of the mesocarp and is further refined through various industrial processes.

The morphological characteristics of the apricot fruit and its kernel enhance the agricultural and industrial value of this plant. The oil derived from the kernels, in particular, serves as a valuable resource with potential applications in both the food and cosmetic industries.

Methods of Apricot Kernel Oil Extraction

Apricot kernel oil is a plant-based oil widely utilized in industrial applications, particularly within the food, cosmetic, and pharmaceutical sectors. The yield and quality of the oil vary depending on the type of kernel used, the processing method applied to the kernel, and the specific extraction technique employed. Both traditional and modern production methods are critical factors that determine not only the oil yield but also the preservation level of its bioactive compounds in the chemical composition.

Traditional Extraction Methods

Traditionally, apricot kernel oil is obtained by mechanically breaking the kernels, followed by grinding the inner parts and pressing them to extract the oil. This method is commonly employed in small-scale production and traditional practices. Mechanical pressing may generate high temperatures, which can lead to the oxidation of certain bioactive compounds, such as tocopherols and phenolic compounds. Generally, oil yield through traditional methods is lower compared to modern extraction techniques.

Cold Pressing Method

Cold pressing is a method in which kernels are mechanically processed at low temperatures (typically below 40-50°C). The oil obtained through this method retains a substantial portion of its natural antioxidant compounds. Cold-pressed apricot kernel oil is particularly preferred in cosmetic products and functional food formulations. Since this method is solvent-free, it is considered environmentally friendly and regarded as a safe extraction technique for human health.

Solvent-Based Extraction

Solvent-based extraction, frequently utilized on an industrial scale, is applied to enhance the oil yield from apricot kernels. Organic solvents such as hexane are typically used to penetrate cell structures more effectively, facilitating a higher oil release. While this method results in greater yields, the presence of solvent residues and potentially toxic compounds formed during the extraction process necessitate caution, especially in food applications. The obtained oil typically undergoes refining to eliminate these residues.

Enzyme-Assisted Extraction Methods

Enzyme-assisted extraction, one of the modern methods, facilitates the breakdown of kernel cell walls using enzymes, thereby allowing for a more efficient release of oil. Enzymes such as pectinase, cellulase, and protease are employed to degrade the cellular structure, increasing oil extraction efficiency. In a study conducted by Kevser Nehir Demir, the extraction efficiency was reported to reach up to 86.5%, although the direct oil yield was noted as 48.8% due to emulsion formation. Additionally, the use of surfactants and salt solutions was found to further enhance oil recovery.

Impact of Extraction Methods on Oil Quality

The extraction method applied significantly influences the quality parameters of apricot kernel oil. Cold pressing and enzyme-assisted techniques help maintain a low free fatty acid content, thereby improving oxidative stability. In contrast, solvent-based methods offer high yields but necessitate further refining processes. Moreover, the extraction technique directly affects the concentration of tocopherols, phytosterols, and phenolic compounds present in the oil. Therefore, the choice of extraction method should be carefully aligned with the intended end-use of the product. This comprehensive approach ensures the production of high-quality apricot kernel oil, suitable for various applications in both food and cosmetic industries.

Chemical Composition of Apricot Kernel Oil

Apricot kernel oil possesses a remarkable chemical composition among vegetable fixed oils. Rich in fatty acids and unsaponifiable matter, it exhibits properties suitable for both nutritional and cosmetic applications. Although the composition may vary slightly depending on the extraction method and the geographical origin of the kernels, its high proportion of unsaturated fatty acids and the presence of biologically active compounds are the primary factors defining the functional attributes of apricot kernel oil.

Fatty Acid Profile

The most significant chemical components of apricot kernel oil are its fatty acids. The oil typically contains approximately 40-50% fixed oils, the majority of which are monounsaturated and polyunsaturated fatty acids. The principal fatty acids are as follows:

• Oleic Acid (C18:1, n-9): Present at levels ranging from 58% to 74%. This monounsaturated fatty acid (MUFA) is known for its beneficial effects on lipid metabolism. It also contributes to the oxidative stability of apricot kernel oil.
• Linoleic Acid (C18:2, n-6): Found in concentrations of 20% to 30%. As an essential polyunsaturated fatty acid (PUFA), linoleic acid cannot be synthesized by the human body and must be obtained through dietary intake.
• Palmitic Acid (C16:0) and Stearic Acid (C18:0): These saturated fatty acids are present in lower amounts, typically between 2% and 6%.

The balanced distribution of these fatty acids makes apricot kernel oil a valuable nutritional oil with considerable resistance to oxidation.

Unsaponifiable Components

The unsaponifiable fraction of apricot kernel oil, comprising approximately 1-2% of its composition, is crucial for its functional and biological activities.

• Tocopherols (Vitamin E): Primarily consisting of α-tocopherol, but also including β- and γ-tocopherols. Tocopherols are potent antioxidants that protect cell membranes from free radical damage. The total tocopherol content in apricot kernel oil ranges from 40 mg/kg to 80 mg/kg.
• Phytosterols: Notably high in β-sitosterol, with total phytosterol content reaching up to 76%. Phytosterols inhibit cholesterol absorption, exert hypocholesterolemic effects, and exhibit anti-inflammatory properties.
• Squalene: Recognized for its moisturizing and antioxidant properties, squalene is also present in the unsaponifiable fraction and is beneficial for skin health in cosmetic applications.

Phenolic Compounds and Antioxidant Capacity

Apricot kernel oil is also rich in phenolic compounds. Among them, vanillic acid, sinapic acid, and protocatechuic acid are particularly noteworthy. These phenolic constituents enhance the antioxidant capacity of the oil, improving its oxidative stability. They play a crucial role in scavenging free radicals, preventing lipid peroxidation, and reducing oxidative damage at the cellular level.

Nutritional and Health Implications of the Chemical Composition

The chemical composition of apricot kernel oil, characterized by high concentrations of unsaturated fatty acids and antioxidant compounds, provides several health benefits. Dietary intake of oleic and linoleic acids is associated with reduced cardiovascular disease risk, while tocopherols and phenolic compounds offer protection against free radical-induced damage.

However, it is important to note the presence of amygdalin in bitter apricot kernels, which poses a risk of cyanide poisoning. Therefore, oils intended for food use must be refined to eliminate toxic compounds, ensuring their safety for consumption. This comprehensive chemical profile underscores the value of apricot kernel oil in both nutritional and cosmetic applications, while also highlighting the importance of quality control and proper processing to maximize its benefits and ensure consumer safety.

Quality Control Criteria and Purity Assessment of Apricot Kernel Oil

The quality control of apricot kernel oil holds critical importance for both protecting human health and enhancing the commercial value of the product. The physicochemical properties, biological efficacy, and safety of the oil are directly dependent on its quality parameters. To ensure product quality and prevent adulteration, various analytical methods are applied in accordance with national and international standards.

Physicochemical Parameters

In the evaluation of apricot kernel oil quality, key physicochemical parameters such as free fatty acid content (FFA), peroxide value, refractive index, specific gravity, and saponification value are considered.

• Free Fatty Acid Content (FFA): This parameter indicates the level of hydrolytic degradation in the oil. In high-quality apricot kernel oil, the FFA value should be below 1.5%. Elevated FFA levels typically reflect poor storage conditions or deterioration during processing.
• Peroxide Value (PV): A crucial indicator of oxidative deterioration and shelf life. Fresh oils are expected to exhibit low peroxide values, generally below 10 meq O₂/kg. An increase in PV signifies the initiation of oxidation processes and a decline in product quality.
• Refractive Index and Specific Gravity: These parameters are employed to determine the purity and authenticity of the oil. For apricot kernel oil, the refractive index typically ranges between 1.463 and 1.476, while specific gravity falls within 0.910 to 0.917 g/cm³.
• Saponification Value: Provides information on the triglyceride structure of the oil. In apricot kernel oil, the saponification value is measured between 188 and 198 mg KOH/g.

Authenticity Determination and Adulteration Detection

To verify the purity and authenticity of apricot kernel oil, comprehensive compositional analyses are conducted. Adulteration, often motivated by economic factors, involves the addition of cheaper vegetable oils to apricot kernel oil. Detection of such practices involves the following methods:

• Fatty Acid Profile Analysis: The specific ratios of oleic and linoleic acids reflect the characteristic composition of apricot kernel oil. Deviations from this profile may indicate adulteration.
• Sterol Profile Analysis: Apricot kernel oil is naturally rich in β-sitosterol. Significant variations in the levels of campesterol, stigmasterol, or other sterols may suggest contamination with foreign oils.
• Unsaponifiable Matter Analysis: This fraction contains phytosterols and tocopherols. The composition and quantity of the unsaponifiable matter serve as important indicators of product purity.
• Evaluation of Characteristic Physicochemical Parameters: Deviations in parameters such as refractive index and specific gravity can also signal adulteration.

National and International Standards

In Türkiye, the standards established by the Ministry of Agriculture and Forestry, as well as the Turkish Food Codex, form the regulatory framework for apricot kernel oil. Additionally, general quality standards for vegetable oils have been defined by the European Union and Codex Alimentarius. Although there is no specific international standard solely for apricot kernel oil, general guidelines for cold-pressed oils and edible vegetable oils are applied. Compliance with these quality criteria is also significant in processes such as organic certification and geographical indication labeling.

Quality control and authenticity verification of apricot kernel oil are essential for ensuring consumer safety, maintaining product integrity, and sustaining competitiveness in the global market. Regular monitoring of quality parameters and adherence to established standards are fundamental components of reliable and sustainable production practices.

Biological Activities and Pharmacological Effects of Apricot Kernel Oil

Apricot kernel oil possesses various biological activities and pharmacological effects attributed to its rich chemical composition and is utilized in both traditional and modern applications. Its content of monounsaturated and polyunsaturated fatty acids, tocopherols, phytosterols, and phenolic compounds contributes to its antioxidant, anti-inflammatory, anticancer, and hypocholesterolemic properties. These biological activities have been supported by both in vitro and in vivo studies.

Antioxidant Effects

Apricot kernel oil exhibits a high antioxidant capacity, primarily due to its tocopherol and phenolic compound content. These bioactive components play a critical role in reducing oxidative stress induced by free radicals. The antioxidant properties of the oil help prevent lipid peroxidation at the cellular level, thereby contributing to the preservation of cell membrane integrity. Additionally, the presence of phenolic compounds may offer protection against degenerative diseases associated with oxidative stress by preventing DNA damage.

Anti-inflammatory Properties

The anti-inflammatory effects of apricot kernel oil are largely attributed to its phytosterols and linoleic acid, which are known to modulate inflammatory responses. The oil reduces the production of pro-inflammatory cytokines and regulates the release of inflammatory mediators, thereby alleviating inflammatory reactions. In traditional medicine, apricot kernel oil has been reported to provide supportive treatment for respiratory tract diseases and inflammatory conditions such as arthritis.

Effects on Cardiovascular Health

The high levels of oleic and linoleic acids in apricot kernel oil have shown beneficial effects on serum lipid profiles. The oil helps lower low-density lipoprotein (LDL) cholesterol levels while increasing high-density lipoprotein (HDL) cholesterol levels. Furthermore, the phytosterols in the oil inhibit cholesterol absorption in the intestine, contributing to its hypocholesterolemic effect. These properties make apricot kernel oil a potential supportive agent in the prevention of cardiovascular diseases.

Anticancer Potential

Amygdalin, a component found in apricot kernel oil, has gained attention in traditional alternative medicine for its alleged anticancer properties. Although the metabolism of amygdalin releases cyanide, posing a potential toxicity risk, some controlled studies have demonstrated inhibitory effects on tumor cell growth. However, the anticancer effects of amygdalin remain controversial, and further clinical research is necessary to validate its therapeutic potential.

Antimicrobial and Antiparasitic Effects

Apricot kernel oil exhibits antimicrobial activity against various bacterial and fungal species. It has shown inhibitory effects, particularly against Gram-positive bacteria. In addition, certain studies have reported antiparasitic activity. These antimicrobial properties support the use of apricot kernel oil as a preservative component in cosmetic formulations.

Applications in Traditional Medicine

In traditional medicine, apricot kernel oil has been used to alleviate respiratory disorders, including asthma and bronchitis. It has also been employed as a supportive agent in the treatment of constipation due to its mild laxative effect. When applied topically, apricot kernel oil is reported to have emollient and moisturizing effects, promoting wound healing and skin regeneration.

Apricot kernel oil’s wide range of biological activities and pharmacological effects, supported by its complex chemical composition, make it a valuable functional ingredient in both nutraceutical and dermocosmetic applications. However, its use—particularly in formulations containing amygdalin—requires careful consideration regarding safety and standardization.

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Cosmetic and Dermocosmetic Applications of Apricot Kernel Oil

Apricot kernel oil is among the widely utilized plant-based oils in cosmetic and dermocosmetic products due to its chemical composition and biological properties. It is particularly incorporated into skin and hair care formulations, either as a carrier oil or as an active ingredient. The high content of monounsaturated fatty acids, tocopherols, and phytosterols in apricot kernel oil contributes to its effectiveness in dermal applications.

Skin Moisturization and Anti-Aging Effects

Due to its richness in oleic and linoleic acids, apricot kernel oil supports the skin's lipid barrier, thereby reducing transepidermal water loss. This characteristic helps maintain the skin's moisture balance and exerts an emollient effect, particularly beneficial for dry and sensitive skin types.

Tocopherols neutralize free radicals, reducing oxidative stress and alleviating the effects of photoaging on the skin. Consequently, apricot kernel oil is commonly included in anti-aging formulations aimed at diminishing the appearance of wrinkles and fine lines.

Wound Healing and Reparative Properties

Apricot kernel oil is incorporated into wound healing creams and ointments due to its anti-inflammatory effects and emollient properties. It assists in reducing skin irritation and inflammation while promoting the regeneration of epithelial tissue, thus accelerating the healing process. These effects make it a valuable supportive treatment in managing skin disorders such as atopic dermatitis and eczema.

Applications in Hair Care Products

Widely used in hair care, apricot kernel oil helps maintain moisture balance within hair strands and nourishes the scalp. Its linoleic acid content is believed to provide protective effects against hair loss and support hair growth. Moreover, it is favored in hair oils and shampoo formulations to enhance natural shine and prevent hair breakage.

Carrier Systems in Formulations and Stability

Apricot kernel oil serves as an effective carrier oil for the delivery of essential oils and active ingredients to the skin. When combined with liposomal and nanoemulsion systems, it enhances bioavailability and facilitates deeper penetration of actives. Its high oxidative stability extends the shelf life of formulations and supports product stability.

Allergic Reactions and Side Effects

Although generally well-tolerated, apricot kernel oil may, in rare cases, cause skin sensitivity or contact dermatitis. Special caution is advised when using oils derived from bitter kernels and unrefined forms due to their amygdalin content. The use of refined apricot kernel oil in cosmetic formulations minimizes such adverse effects. It is recommended that individuals with sensitive skin perform a patch test prior to product application.

Apricot kernel oil’s emollient, anti-inflammatory, and antioxidant properties make it a valuable ingredient in cosmetic and dermocosmetic products aimed at improving skin and hair health. However, considerations regarding oil purity, refinement, and potential allergens are essential to ensure product safety and efficacy.

Applications of Apricot Kernel Oil in the Food Industry

Apricot kernel oil is utilized in various sectors of the food industry due to its nutritional content and functional properties. Rich in essential fatty acids such as oleic and linoleic acids, as well as tocopherols and phytosterols, this oil is incorporated into functional food products and edible oil formulations. In addition, apricot kernel processing by-products and kernel flours are employed as food additives, contributing to product quality and nutritional value.

Use in Functional Foods and Dietary Supplements

Apricot kernel oil is included in functional food compositions due to its content of essential fatty acids and natural antioxidants. Its high proportion of unsaturated fatty acids makes it suitable for diets designed to support cardiovascular health. Furthermore, its vitamin E content has been reported to enhance immune function and help mitigate oxidative stress. As a result, apricot kernel oil is considered a valuable component in dietary supplements and functional food formulations aimed at promoting overall health.

Use in Baked Goods and Snack Products

Apricot kernel oil serves as an alternative to margarine and other fat-based ingredients in the production of baked goods. It is commonly used as a fat substitute in cookies, biscuits, cakes, and other bakery products, thereby improving shelf life and sensory properties. Additionally, apricot kernel flour is incorporated into bakery formulations to enhance fiber and protein content, contributing to the nutritional profile of these products.

Edible Films and Coating Systems

In food packaging technologies, apricot kernel oil is utilized in the development of biodegradable edible films and coating systems. Lipid-based film systems reduce oxygen permeability, prolong shelf life, and prevent moisture loss in packaged foods. When combined with antimicrobial agents, these films contribute to enhanced food safety by inhibiting microbial growth. Such applications are particularly valuable in extending the shelf life of fresh produce and processed foods.

Industrial Oils and Flavor Products

Due to its mild aroma and neutral flavor, apricot kernel oil functions as a carrier in aromatic oil blends. It is incorporated into salad dressings, infant formulas, and functional beverages, providing desirable flavor and texture attributes. Its thermal stability allows its use in certain cooking processes; however, unrefined oils are generally recommended for raw consumption to preserve their nutritional and sensory qualities.

Utilization of Food Processing By-Products and Sustainability

The by-products generated during apricot kernel processing are repurposed in sustainable production practices. Kernel shells and fiber fractions are used in animal feed and biocomposite manufacturing, supporting waste management and environmental sustainability. Additionally, the residual meal from oil production can be incorporated into food products as a functional fiber source, contributing to the development of health-oriented and eco-friendly food solutions.

Apricot kernel oil offers versatile applications in the food industry, both as a functional ingredient and within sustainable production frameworks. Its nutritional profile and multifunctionality make it a valuable component in modern food technology and product development.

Adverse Effects, Toxicological Evaluation, and Safety of Apricot Kernel Oil

Although apricot kernel oil is widely used in both the food and cosmetic industries, products derived from bitter apricot kernels carry certain toxicological risks. These risks primarily stem from the presence of amygdalin, a naturally occurring compound found in the kernels. Therefore, safety assessments and toxicity evaluations play a crucial role in the responsible use of apricot kernel oil.

Amygdalin and Cyanide Poisoning Risk

Bitter apricot kernels contain high levels of amygdalin, which can be enzymatically hydrolyzed to release cyanide. Cyanide is a highly toxic compound that inhibits the cellular respiratory chain, leading to hypoxia and potentially severe poisoning. While amygdalin has been explored in traditional medicine for its alleged anticancer properties, its uncontrolled use significantly increases the risk of cyanide intoxication. As a result, oils intended for use in food and cosmetic products must undergo refining processes to remove amygdalin and its derivatives.

The consumption of large quantities of bitter apricot kernels or their derivative oils can lead to symptoms such as nausea, dizziness, headache, respiratory distress, and in severe cases, convulsions or coma. The World Health Organization (WHO) and various health authorities have issued warnings regarding the consumption of products with high amygdalin content, emphasizing the need for caution.

Safe Consumption Doses and Usage Recommendations

Oils derived from sweet apricot kernels, which contain significantly lower levels of amygdalin, are considered safer and are permitted for use in the food industry. However, dosage limits and daily intake recommendations should still be observed. The consumption of unrefined oils for dietary purposes is generally limited, with such products typically recommended for external use.

For dietary applications, it is advised that daily intake of refined apricot kernel oils does not exceed 15-20 mL. This quantity is deemed sufficient to confer the benefits of essential fatty acids and other bioactive compounds. In cosmetic applications, it is recommended that a patch test be conducted prior to use, particularly in individuals with sensitive skin types.

Safety of Refined Products

Refined apricot kernel oils, which have been processed to eliminate amygdalin and cyanogenic derivatives, offer enhanced safety profiles. These oils undergo quality control testing to ensure compliance with established safety standards prior to their release on the market for use in food and cosmetic formulations. Oils obtained through cold pressing and subsequently refined processes are capable of retaining their biological value while minimizing potential health risks.

In summary, while apricot kernel oil presents several health-promoting properties, its safe use depends on appropriate processing techniques and adherence to recommended dosages, particularly when derived from bitter kernels. Rigorous quality control and toxicological assessments are essential to ensure consumer safety.