Physico-chemical characteristics of seed oils extracted from different apricot (Prunus armeniaca L.) varieties from Pakistan

Fatty acids profile in three cultivars of Tunisian apricot oilseeds (Prunus armeniaca L.): impact of maturity

Profiling's of oil yield and fatty acid were monitored during maturation of three different accession of Tunisian apricots (AprB, AprC and AprO) among different days after flowering (DAF) and grown in two different geographical regions of Tunisia. The first results show that a quick distribution started in immature oilseeds apricot and continued until their full maturity. Nine fatty acids were identified in apricot oilseeds such as palmitic, palmitoleic, stearic, oleic, linoleic, linolenic, arachidic, gadoleic and margaric acids. Palmitic, oleic and linoleic acids were determined as major fatty acids in apricot oil varieties. Interestingly, the content of each fatty acid in the three accessions of apricot varied significantly (p < 0.05) during seeds development and especially in wild apricot AprB. PCA analysis in AprB demonstrate that at the time-date of 41 DAF, the production of fatty acids is in its maximum and could have numerous future therapeutics applications.

Apricot kernel characterization, oil extraction, and its utilization: a review

Apricot (Prunus armeniaca L.) kernels, one of the economical stone fruit kernels, are utilized worldwide for edible, cosmetic, and medicinal purposes. Oil from the apricot kernel is valued by the richness of unsaturated fatty acids, the high proportion of oleic acids, phenols, and tocopherol content. Oil yield with quality from apricot kernel varies with region, variety, and adopted method of oil extraction. This review discusses apricot kernel characterization, different conventional and novel methods of oil extraction, their merits and demerits as reported in the literature. Novel technologies such as microwave-assisted oil extraction, ultrasound-assisted oil extraction, enzyme-assisted oil extraction, and supercritical fluid oil extraction have emerged as the most promising extraction methods that allow efficient oil recovery in very environment-friendly ways. Knowledge of the extraction technique aids in giving higher oil recovery with minimal nutritional losses while retaining the original organoleptic properties.

Graphical abstract

Apricot Kernel: Bioactivity, Characterization, Applications, and Health Attributes

Apricot kernel, a by-product of apricot fruit, is a rich source of proteins, vitamins, and carbohydrates. Moreover, it can be used for medicinal purposes and the formation of food ingredients. Several techniques have been adopted for the extraction of bioactive compounds from the apricot kernel such as solvent extraction, ultra-sonication, enzyme-assisted, microwave-assisted, and aqueous extraction. Apricot kernels may help to fight against various diseases such as cancer and cancer immunotherapy, as well as reduce blood pressure. Additionally, the kernel is famous due to its diverse industrial applications in various industries and fields of research such as thermal energy storage, the cosmetic industry, the pharmaceutical industry, and the food industry. Especially in the food industry, the apricot kernel can be used in the preparation of low-fat biscuits, cookies, cakes, and the fabrication of antimicrobial films. Therefore, in this review article, the bioactivity of the apricot kernel is discussed along with its chemical or nutritional composition, characterizations, and applications.

Accumulation Pattern of Amygdalin and Prunasin and Its Correlation with Fruit and Kernel Agronomic Characteristics during Apricot (Prunus armeniaca L.) Kernel Development

To reveal the accumulation pattern of cyanogenic glycosides (amygdalin and prunasin) in bitter apricot kernels to further understand the metabolic mechanisms underlying differential accumulation during kernel development and ripening and explore the association between cyanogenic glycoside accumulation and the physical, chemical and biochemical indexes of fruits and kernels during fruit and kernel development, dynamic changes in physical characteristics (weight, moisture content, linear dimensions, derived parameters) and chemical and biochemical parameters (oil, amygdalin and prunasin contents, β-glucosidase activity) of fruits and kernels from ten apricot (Prunus armeniaca L.) cultivars were systematically studied at 10 day intervals, from 20 days after flowering (DAF) until maturity. High variability in most of physical, chemical and biochemical parameters was found among the evaluated apricot cultivars and at different ripening stages. Kernel oil accumulation showed similar sigmoid patterns. Amygdalin and prunasin levels were undetectable in the sweet kernel cultivars throughout kernel development. During the early stages of apricot fruit development (before 50 DAF), the prunasin level in bitter kernels first increased, then decreased markedly; while the amygdalin level was present in quite small amounts and significantly lower than the prunasin level. From 50 to 70 DAF, prunasin further declined to zero; while amygdalin increased linearly and was significantly higher than the prunasin level, then decreased or increased slowly until full maturity. The cyanogenic glycoside accumulation pattern indicated a shift from a prunasin-dominated to an amygdalin-dominated state during bitter apricot kernel development and ripening. β-glucosidase catabolic enzyme activity was high during kernel development and ripening in all tested apricot cultivars, indicating that β-glucosidase was not important for amygdalin accumulation. Correlation analysis showed a positive correlation of kernel amygdalin content with fruit dimension parameters, kernel oil content and β-glucosidase activity, but no or a weak positive correlation with kernel dimension parameters. Principal component analysis (PCA) showed that the variance accumulation contribution rate of the first three principal components totaled 84.56%, and not only revealed differences in amygdalin and prunasin contents and β-glucosidase activity among cultivars, but also distinguished different developmental stages. The results can help us understand the metabolic mechanisms underlying differential cyanogenic glycoside accumulation in apricot kernels and provide a useful reference for breeding high- or low-amygdalin-content apricot cultivars and the agronomic management, intensive processing and exploitation of bitter apricot kernels.

Chemical Composition and Antioxidant Properties of Oils from the Seeds of Five Apricot (Prunus armeniaca L.) Cultivars

Oils from five cultivars of apricot (Prunus armeniaca L.) grown in Poland were analysed for characteristics of chemical and biological activity. The extracted oils had an average iodine value (g of I/100 g of oil) of 99.2; a refractive index of (40°C) 1.4675; a saponification value of 189 mg of KOH/g of oil; and 0.68% unsaponifiable matter. As regards the oxidation state, the specific extinction values of the oils at 232 and 268 nm were 2.55 and 0.94, respectively, while the peroxide value was 1.40 meq O₂/kg and the p-anisidine value was 1.42. Oleic acid (70.70%) was the predominant fatty acid found in the oils, followed by linoleic (22.41%), palmitic (3.14%), stearic (1.4%), linolenic (0.90%), and palmitoleic (0.70%) acid. The content of α-, γ-, and δ- tocopherols in the oils from the five apricot cultivars was 19.6-40.0, 315.4-502.3, and 28.3-58.5 mg/kg, respectively. The antioxidant capacity of the apricot kernel oils, measured using the FRAP assay, ranged from 1.07 to 1.38 mM Fe²⁺/L, while total polyphenols and β-carotene content were 0.85-1.22 mM gallic acid/L and 42.3-66.8 μg/g, respectively. The results indicate that among the cultivars tested, the 'Somo' cultivar grown in Poland provides the most oil, with the highest antioxidant activity. The results of our study demonstrate that apricot seeds are a potential source of oil that can have both dietary and cosmetic applications.

Mango Seed Kernel Fat as a Cocoa Butter Substitute Suitable for the Tropics

Cocoa butter is a key ingredient in many chocolate products but its partial substitution with mango (Mangifera indica L.) seed kernel fat (MSKF) has the potential to reduce chocolate production costs and improve shelf-life. Here, MSKF was extracted from three cultivars of mango grown in Pakistan: Lal Badshah, Anwar Retual, and Chaunsa. Physicochemical and antioxidant properties of the MSKF samples were studied at 0, 30, and 60 days of storage at 30 °C, a temperature reflecting typical storage conditions in the tropics. Overall, the Lal Badshah MSKF had the most favorable physicochemical properties, including the highest DPPH antioxidant activity among the three cultivars. Thus, Lal Badshah MSKF was used to formulate cocoa butter substitute chocolate (CBSC), substituting the cocoa butter at 20 to 80 g/100 g. CBSC had a lower value for hardness (3.80 N) compared with the control chocolate (4.42 N). Color values L^* , a^* , and b^* were not significantly affected by the different rates of substitution or by length of storage. Oxidative stability and antioxidant potential of CBSC increased with both higher substitution levels of MSKF and length of storage. The results suggest that MSKF can be utilized as a cocoa butter substitute at levels up to 60 g/100 g. This potential for substitution is particularly valuable for tropical regions where refrigerated storage may not be available or financially viable. PRACTICAL APPLICATION: Mango seed kernel fat (MSKF) has potential to be used as a cocoa butter substitute in confectionery products, particularly chocolate. The mango industry could utilize fat extraction from mango seeds, which are normally a waste product, for value adding.

Selection of reference genes for gene expression studies in Siberian Apricot (Prunus sibirica L.) Germplasm using quantitative real-time PCR

Quantitative real time reverse transcription polymerase chain reaction has been applied in a vast range of studies of gene expression analysis. However, real-time PCR data must be normalized with one or more reference genes. In this study, eleven putative consistently expressed genes (ACT, TUA, TUB, CYP, DNAj, ELFA, F-box27, RPL12, GAPDH, UBC and UBQ) in nine Siberian Apricot Germplasms (including much variability) were evaluated for their potential as references for the normalization of gene expression by NormFinder and geNorm programs. From our studies, ACT, UBC, CYP, UBQ and RPL12 as suitable for normalization were identified by geNorm, while UBC and CYP as the best pair by NormFinder. Moreover, UBC was selected as the most stably expressed gene by both algorithms in different Siberian Apricot seed samples. We also detected that a set of three genes (ACT, CYP and UBC) by geNorm as control for normalization could lead to accurate results. Furthermore, the expression levels of oleosin gene were analyzed to validate the suitability of the selected reference genes. These obtained experimental results could make an important contribution to normalize real-time PCR data for gene expression analysis in Siberian Apricot Germplasm.