Essential oil extracted from peach (Prunus persica) kernel and its physicochemical and antioxidant properties

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Abstract

Peach kernel oil was extracted using Soxhlet extraction with different solvents (petroleum ether, ethyl ether, chloroform and hexane). The physicochemical properties (acid value, iodine value, peroxide value and saponification value), the fatty acid composition, phenolic constituents and contents, and antioxidant activities of peach kernel oil were examined. As per our results, oil extracted with hexane has better overall quality. Its acid, peroxide, iodine and saponification values were 0.895 mg KOH/g oil, 0.916 mg/g oil, 36.328 mg/100 g oil and 101.836 mg KOH/g oil, respectively. Large proportions of unsaturated fatty acid (91.27%) and high content of phenolic compounds (4.1593 mg GAE/g), which contribute to considerably strong antioxidant activity, were found in oil. The main fatty acids found in the peach kernel oil were oleic acid (61.87 g/100 g oil) and linoleic acid (29.07 g/100 g oil). The HPLC analysis of phenolic compounds showed that rutin, (-)-epicatechin gallate, hydrocinnamic acid, sinopinic acid, dithiothreitol and caffeic acid were major constituents. The results suggested that peach kernel oil is a good source of the unsaturated fatty acid, phenolic compounds with strong antioxidant activity, and has the potential to be used as nutrient rich food oil. The results also verified that peach kernel meals contained higher amounts of total phenolic and stronger antioxidant activities than oils, enabling their application as ingredients for functional or enriched foods.

Highlights

► Peach kernels can be considered as an important source of essential oil for the food and nutraceutical supplement industries.► Large proportions of unsaturated fatty acid (91.27%) and high content of phenolic compounds (4.1593 mgGAE/g), which contribute to considerably strong antioxidant activity, were found in the oil.► Peach kernel oil is a good source of the unsaturated fatty acids and of phenolic compounds, and has the potential to be used as nutrient rich food oil.► The results also verified that peach kernel meals contained higher amounts of total phenolic and stronger antioxidant activities than oils, enabling their application as ingredients for functional or enriched foods.

Introduction

Peach is the third most important deciduous tree fruits worldwide, ranking after apples and pears. A significant part of the harvested peaches is processed resulting in a substantial amount of waste stones. Peach kernel contain almost 50 wt% of oils (Yolanda, Albertina, Juan & Pando, 2009). The peach kernel has slightly toxic effects when used excessively due to its content of hydrogen cyanide (prussic acid). Hydrogen cyanide is a chemical compound with extremely poisonous, because it binds irreversibly to the iron atom in hemoglobin, making it unavailable to transport the vital O2 to the body’s cells and tissues. The dose should not be excessive and any excessive dose may cause headache, blurred vision, palpitations, or even death from respiratory failure. However, since the concentration of hydrogen cyanide in peach kernel is small (0.45–2.6 mg/g) and can be detected in the processed peach products (Barceloux, 2008, chap. 5).

Peach kernel oil has been widely used in the cosmetics industry as an ingredient in soaps, shampoos, lotions, creams, and shampoos because it is a light, penetrating oil, and absorbs easily and does not leave a greasy feeling. Peach kernel oil is nutritionally attractive and has an opportunity of producing high value products from the bio-waste in peach industry due to their unsaturated fatty acid and antioxidant constituents (Saadany, Kalaf, & Soliman, 2004). Therefore, peach kernel can be considered as an important source of essential oil for the food and nutraceutical supplement industries.

Fatty acids, especially, unsaturated fatty acids, are important as nutritional substances and metabolites in living organisms. Many kinds of fatty acids play an important role in the regulation of a variety of physiological and biological functions (Zhao, Wang, You, & Suo, 2007). The main fatty acids found in peach kernel oil are about 58% oleic acid and 32% linoleic acid (Kamel & Kakuda, 1992). Oleic acid is an 18-carbon monounsaturated fatty acid, essential in human nutrition and helps reducing triglycerides, LDL-cholesterol, total cholesterol and glycemic index (Eduardo, 2010). Also, the increase in stability over oxidation of vegetable oil is attributed to oleic acid (Abdulkarim, Long, Lai, Muhammad, & Ghazali, 2007). The linoleic acid is an essential fatty acid from omega-6 group (18:2(n-6).) and very important for development and maintenance of the nervous system and the physiological functions in humans, since it reduces total and LDL-cholesterol levels. Phenolic composition of food materials such as phenolic acids, flavonoids and tannins have been the scope of many studies lately due to their antioxidant effects.

Phenolic compounds make important contributions to the nutritional properties, sensory characteristics and the shelf life of peach kernel oil. However, the fate of individual phenolic compounds in the course of peach kernel oil extraction as well as their contribution to the overall antioxidant properties of oils has not yet been investigated.

The extraction technique used to obtain high aggregate value compounds from natural products is crucial for product quality. Soxhlet extraction is a standard technique and is the main reference to which other extraction methods are compared. The advantage of conventional Soxhlet is that the sample is repeatedly brought into contact with the fresh portions of the solvent, thereby helping to displace the transfer equilibrium. There is a wide variety of official methods involving a sample preparation step based on Soxhlet extraction (US EPA, 1995, AOAC, 1990, British Standard, 1994, 8 p.). In short, Soxhlet extraction is a general, well-established technique which clearly surpasses in performance other conventional extraction techniques.

However, there are only few studies on the extraction of peach kernel oil (Yolanda, Albertina, Juan & Pando, 2009), and the fatty acid profile, polyphenolic compound, physicochemical properties and antioxidative properties of peach kernel oil were not well established yet. Therefore, the objectives of this study were to compare the efficiency of the extraction solvents; evaluate the quality of peach kernel oil through the physicochemical properties, fatty acid composition, profile of phenolic compounds and antioxidant activity; and at last define the most effective solvent that can be used in the extraction of peach kernel oil with Soxhlet.

Section snippets

Materials

Peaches (Prunus persica) were harvested from orchard of Vineland Research Centre (Ontario, Canada). Peach pits were collected and cracked to obtain the kernel. The kernel were then ground in a food grinder (Waring commercial Co. Ltd., USA) to reduce the particle size to a maximum diameter of 500 μm as measured by a sieve (The W.S. Tyler Company of Canada Ltd., Canada), sealed in a plastic container and stored in a refrigerator until extraction. The storage conditions assured eliminating effects

Physicochemical properties of oils

The total oil yields are shown in Table 1. Among soxhlet extraction, the solvent of ethyl ether provided significantly highest total oil yield (0.38 ± 0.07 g/g d.b), follow by chloroform extraction (0.35 ± 0.06 g/g d.b). There no significant difference was observed on the total oil yields that extracted by petroleamether (0.25 ± 0.04 g/g d.b) and hexane (0.26 ± 0.04 g/g d.b). The results indicated that peach oil has many intermediate to high polarity compounds result in the obtained high oil

Conclusions

Peach kernel oils were extracted by organic solvents (petroleum ether, ethyl ether, chloroform and hexane) and evaluated for their characterization and quality analysis. According to the analysis of physicochemical properties, fatty acid profile, total phenols and antioxidant capacity based on DPPH radical-scavenging and TEAC, the results showed that these oils are rich in oleic acid and linoleic acid, indicating that they are stable and tolerant to rancidity. The effects of different

Acknowledgements

Authors gratefully acknowledge the contribution of the MOE/AAFC Program and Guelph Food Research Center, Agriculture and Agri-Food Canada.

References (32)

  • R.C. Blinn et al.

    Colorimetric determination of residues of the dithiolane insecticides in cotton kernel and cotton foliage

    Journal of American Oil Association Chemistry

    (1964)
  • BS 4267: Part 10

    (1994)
  • M.L. Bengoechea et al.

    Phenolic composition of industrially manufactured purees and concentrates from peach and apple fruits

    Journal of Agriculture and Food Chemistry

    (1997)
  • T. Bahorun et al.

    Total phenol, flavonoid, proanthocyanidin and vitamin C levels and antioxidant activities of Mauritian vegetables

    Journal of the Science of Food and Agriculture

    (2004)
  • L.M.A.S. Campos et al.

    Free radical scavenging of grape pomace extracts from Cabernet sauvingnon (Vitis vinifera)

    Bioresource Technology

    (2008)
  • O.D. Ekpa et al.

    The effects of coconut oil concentration and air exposure to the total acidity of palm oil

    Global Journal of Pure and Applied Sciences

    (1995)
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