Changes produced in the aroma compounds and structural integrity of basil (Ocimum basilicum L) during drying

The influence of drying on the aroma compounds, from a chemical and sensory standpoint, and on the structural integrity of basil (Ocimum basilicum L) was evaluated. The drying methods tested were oven drying at 45 °C, air drying at room temperature and freeze‐drying. The volatile compounds of fresh and dried basil were extracted and concentrated by simultaneous distillation/extraction and analysed by gas chromatography/mass spectrometry. In all, 27 volatile components were identified, linalool being the major component, followed by eugenol. The total quantity of volatiles of fresh basil decreased considerably during oven drying and freeze‐drying, whereas air drying of basil at room temperature brought about only small losses of volatile components. The cell damage produced on basil leaves during drying was evaluated by scanning electron microscopy. From a sensory standpoint, fresh basil was described as having a fresh, herbaceous and floral odour, while the dried samples had a mentholated, spicy, hay‐like and earthy odour. Copyright © 2004 Society of Chemical Industry     

大型罗勒和柚子精油的成分分析及其抗氧化性

采用气相色谱-质谱(GC-MS)联用法对大型罗勒精油和柚子精油的化学成分进行分析,并采用DPPH自由基(DPPH·)清除法、ABTS自由基阳离子(ABTS⁺·)清除法对精油及其主要单体的抗氧化性能进行了研究。大型罗勒精油鉴定出46个化学成分,占总含量的84.07%,其主要成分为香叶醛(14.20%)、β-石竹烯氧化物(10.97%)、香橙醛(10.38%)和β-石竹烯(4.09%);柚子精油鉴定出48个化学成分,占总含量的92.24%,其主要成分为柠檬烯(43.88%)、石竹烯(22.09%)、葎草烯(4.57%)和γ-松油烯(4.41%)。结果表明,大型罗勒精油和柚子精油对DPPH·和ABTS⁺·均具有清除活性,其中大型罗勒精油和柚子精油清除DPPH·的IC₅₀值分别为3.96 mg/mL和23.22 mg/mL;清除ABTS⁺·的IC₅₀值分别为1.61 mg/mL和2.30 mg/mL。由此可知,大型罗勒精油和柚子精油可以作为一种较为安全的天然抗氧化物来源。     

Chemical composition and antioxidant capacity of free volatile aglycones from basil (Ocimum basilicum L.) compared with its essential oil

The present paper examines the chemical composition and antioxidant capacity of free volatile aglycones from basil compared to their essential oil. The comparison of chemical composition of volatile aglycones with the chemical composition of essential oil reveals four common compounds: eugenol, chavicol, linalool and α-terpineol. For the evaluation of the mentioned antioxidant capacities, two different methods were performed: the 2,2′-diphenyl-1-picrylhydrazyl radical scavenging method (DPPH) and ferric reducing/antioxidant power assay (FRAP). DPPH method shows that free volatile aglycones possess good antioxidant properties comparable with that of the essential oil and well-known antioxidant butylated hydroxytoluene (BHT), but less than pure eugenol. The results obtained by FRAP method show that these compounds are some less effective antioxidants than essential oil and BHT.