柚子精油提取、成分、贮藏及应用研究进展

柚子是柑橘属植物的重要成员之一,其果皮的油包层含有丰富的芳香类成分,可通过冷磨法、水蒸馏法、同时蒸馏萃取(SDE)法、溶剂辅助萃取法(SAFE)以及超临界二氧化碳萃取法(SFE-CO₂)等制备得到精油产品,其中冷磨法制备的精油香味最接近原柚皮香味。相关研究已经采用感官评价、气相色谱(GC)、气相色谱质谱联用(GC-MS)、气相色谱嗅闻仪联用(GC-O)、电子鼻 (E-Nose) 等方法分析了柚皮精油的成分,而高分辨率的质谱(HRMS)、气相色谱-飞行时间质谱(GC-TOF-MS)等方法在柚皮精油分析中较少。柚皮精油以萜烯类化合物为主,同时也存在着醇类、醛类、酯类等其他成分,其中月桂烯在柚皮精油中的含量显著高于其他柑橘类水果。不同品种柚子精油的香味特征及香气成分具有一定的差异,琯溪蜜柚精油以清香、柠檬和果香为主,梁平柚精油以花香为主,沙田柚精油以薄荷味为主。贮藏温度、光照及氧气会引起精油中挥发性成分的变化,其中紫外线对精油风味影响最大,是精油香味和成分不可逆变质的重要原因。柚皮精油在医药、食品添加剂以及化妆品行业应用非常广泛,对柚皮精油的进一步研究具有重要意义。

Pummelo Essential Oil:Extraction, Volatiles, Storage, and Application

Pummelo (Citrus maxima) is one of the major native species of citrus, of which the skin peel contains a rich amount of essential oil (EO) in its flavedo part. EO could be extracted by using cold pressing, water distillation, simultaneously distillation and extraction (SDE), solvent-assisted fluid extraction (SAFE), and super critical fluid extraction of carbon dioxide (SFE-CO₂). Among these extraction methods, EO, prepared by the cold pressing, possesses the best aroma close to the natural pummelo aroma. Sensory evaluation, gas chromatograph (GC), GC-mass spectrometer (MS), GC-olfactory (O), and electronic nose have been used to analyze the pummelo EO. Albeit high resolution mass spectrometer and time of flight mass spectrometry have not been applied yet. Pummelo EO is mainly composed of terpenes and terpenoids, plus a small amount of aldehydes, alcohols, and esters. Particularly, the beta-myrcene content in the pummelo EO is higher than that in other citrus EOs. In addition, EO from different pummelo species has different aromatic profiles. The aroma profile of GuanXi pummelo EO is dominated by green, lemon,and fruit notes while LiangPing pummelo EO has a strong aroma of citrus and sweet note. Meanwhile, Shatian pummelo EO has a strong minty note. It is known that environmental factors, including sunlight, storage temperature, and oxygen have significant effects on the composition of EO and remarkable impact on its aroma profile. In particular, UV-irradiation is the major factor causing the irreversible deterioration to the pummelo quality. Pummelo EO has shown many valuable applications in pharmaceutical, food, and cosmetics industries. Thus, pummelo EO is worthy to be studied in more depth.