Effect of processing method on chemical composition, physicochemical property, antioxidant activity and volatile compound of Cinnamomum camphora seed kernel oil
Introduction
Cinnamomum camphora (L.) Presl tree is an evergreen broad-leaved tree of Camphor family and widely distributed in the south of the Yangtze River in China (Yan, Zhang et al., 2021). Cinnamomum camphora seeds fall off in large quantities in winter, which may seriously pollute the environment. However, the seeds have not yet been rationally developed and utilized. The Cinnamomum camphora seed kernel (CCSK) contains 55%− 65% oil, and the CCSK oil (CCSKO) contains more than 95% medium chain fatty acids, including 61.18% capric acid and 35.94% lauric acid, which is regarded as a natural medium chain oils (Fu et al., 2015). Our previous study has found that CCSKO ameliorated glucose and lipid metabolism disorders in SD rats (Fu et al., 2016). Moreover, it was found that CCSK contained high levels of polyphenols and tocopherols, showing high antioxidant activity and strong anti-inflammatory activity (Hu et al., 2011, Zhang et al., 2021). As many countries have a severe shortage of edible vegetable oils, the development and application of CCSKO has a broad prospect.
To a certain extent, the physicochemical properties and active components of oils are influenced by processing methods. In general, pressing and solvent extraction (SE) are the two most important extraction methods of vegetable oils. The pressing method can be divided into hot pressing (HP) and cold pressing (CP). Although it has a simple operation procedure and low processing cost, the main disadvantage of this method is the high residual oil rate (Lv and Wu, 2019). The extraction efficiency of solvent extraction (SE) is high, however, this method has some shortcomings, such as solvent residue and long extraction time (Zhang, Zhu et al., 2022). Aqueous extraction (AE), as a potential alternative to SE, is faced with the problem of oil emulsification (Yang et al., 2019). Although sub-critical fluid extraction (SCFE) and supercritical fluid extraction (SFE) are limited by the expensive investment in equipment and operation, which makes it difficult to achieve large-scale industrial applications, they are more in line with the concept of safe, efficient and environmentally friendly processing (Gao et al., 2021). Previous studies have shown that the different processing methods had significant effects on the physicochemical properties, chemical composition, antioxidant activity and volatile components of vegetable oils, such as peanut oil, Paeonia lactiflora Pall seed oil and macadamia oil (Dun et al., 2019, Nie et al., 2020, Shuai et al., 2022). However, to our knowledge, no study on CCSKO has been reported in this regard.
In this study, six processing methods were used to prepare CCSKO, and the extraction efficiency, chemical composition, physicochemical properties, antioxidant activity and thermal behaviors of different samples were measured. Meanwhile, solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS), combined with principal component analysis (PCA) and clustering heat map, was used to analyze the volatile compounds of CCSKO obtained by different processing methods. The results provide a theoretical basis for evaluating the quality and nutritional value of CCSKO and guiding its production, processing and quality control.
Section snippets
Materials and chemicals
The fresh mature Cinnamomum camphora fruits were collected from Nanchang University (Jiangxi, China) in November 2021. Then the pulps of the fruits were completely removed, and the seeds were dried in the sun, followed by shelling to obtain CCSK with oil content of 58.04 ± 0.32% (w/w), and then stored at 4 °C for further use.
Standards of fatty acid methyl esters, triacylglycerols, tocopherols, squalance, 5α-cholestane and 2-methyl-3-heptanone were from Beijing Solarbio Science & Technology Co.,
Extraction efficiency and physicochemical properties
As shown in Table 1, the extraction efficiency of SCFE was the highest (97.93%), which was mainly due to the enhancement of molecular diffusion performance and the acceleration of mass transfer in sub-critical state, thus significantly improving the permeability and solubility of oil during extraction (Zhang, Zhu et al., 2022). However, the extraction efficiency of CP was the lowest (44.48%), mainly because the cold pressing only released oil molecules from CCSK by physical extrusion, and the
Conclusions
The results showed that the extraction efficiency of SCFE was the highest. The AV and PV values of all the CCSKO were below the standards of Codex Alimentarius Commission for crude oil, indicating good initial quality and long storage life. CCSKO was rich in medium-chain saturated fatty acids, mainly including capric acid and lauric acid, while triacylglycerol was mainly capric acid-capric acid-lauric acid. There was no significant difference in the thermal behaviors and FTIR spectra of CCSKO
CRediT authorship contribution statement
Qingwen Zhu: Conceptualization, Methodology, Investigation, Writing − original draft preparation. Yujing Yang: Investigation, Formal analysis, Software. Zheling Zeng: Project administration, Supervision, Funding acquisition, Writing − review & editing. Ting Peng, Xianghui Yan: Data curation, Software, Validation. Junxin Zhao, Jiaheng Xia: Software, Validation. Ping Yu: Validation, Supervision, Writing − review & editing. Xuefang Wen: Investigation, Writing − review & editing. Deming Gong:
Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Acknowledgements
This work was supported by the International Science and Technology Cooperation Program of China, (Project No. 2011DFA32770); the National Natural Science Foundation of China (Project No. 31701651, 32060516); the Science and Technology Program of Jiangxi Province, China (Project No. 20143ACG70015); the Central Government Guide Local Special Fund Project for Scientific and Technological Development of Jiangxi Province, China (Project No. 20212ZDD02008, 20221ZDD02001); the Research Program of
References (46)
- et al.
Identification and quantification of essential oil content and composition, total polyphenols and antioxidant capacity of Perilla frutescens (L.) Britt
Food Chem.
(2019) - et al.
). Total and individual carotenoids and phenolic acids content in fresh, refrigerated and processed spinach (Spinacia oleracea L.)
Food Chem.
(2008) - et al.
Evaluation of ultrasound assisted and conventional methods for production of olive pomace oil enriched in sterols and squalene
LWT
(2019) - et al.
Development of a headspace solid-phase microextraction gas chromatography mass spectrometry method for the quantification of volatiles associated with lipid oxidation in whole milk powder using response surface methodology
Food Chem.
(2019) - et al.
Effects of hot and cold-pressed processes on volatile compounds of peanut oil and corresponding analysis of characteristic flavor components
LWT
(2019) - et al.
Crystallization and melting properties studied by DSC and FTIR spectroscopy of goldenberry (Physalis peruviana) oil
Food Chem.
(2022) - et al.
Effects of processing methods on the chemical composition and antioxidant capacity of walnut (Juglans regia L.) oil
LWT
(2021) - et al.
Flavoromics approach in monitoring changes in volatile compounds of virgin rapeseed oil caused by seed roasting
J. Chromatogr. A
(2016) - et al.
Comparative study on the extraction of Xanthoceras sorbifolia Bunge (yellow horn) seed oil using subcritical n-butane, supercritical CO2, and the soxhlet method
LWT
(2019) - et al.
Comparison of antioxidant activities of selected phenolic compounds in O/W emulsions and bulk oil
Food Chem.
(2021)