固封精油熏蒸对油桃采后保鲜效果的影响

为开发一种新的植物精油保鲜方法,本试验用琼脂平板固封百里香精油和薄荷精油,制成精油香膏,使精油缓慢释放,用于熏蒸油桃,并采用固相微萃取-气质联用(SPME-GCMS)分析精油香膏熏蒸时盒内空气中精油活性成分的变化,同时比较不同精油香膏熏蒸对油桃果实腐烂指数、失重率、硬度、抑菌能力以及可溶性固形物、可滴定酸、抗坏血酸和类胡萝卜素含量的影响。结果表明,33 d贮藏期结束后,对照组油桃腐烂指数为23.3%,试验组油桃腐烂指数降低至10.8%以下,并且试验组能较好地保持果实失重率和硬度。SPME-GCMS分析发现,百里香酚和香芹酚作为主要的抑菌功能成分,其含量随着贮藏时间缓慢增加后趋于平衡,但相对百分含量较低。低浓度下,2种精油对褐腐病菌均有较高的抑菌活性,10%薄荷精油熏蒸几乎能完全抑制褐腐病菌的萌芽,1%和10%百里香精油能将褐腐病菌的萌芽率分别降低35.4和49.1个百分点,但灰葡萄球菌对精油挥发性成分敏感性较低。精油熏蒸能够减少抗坏血酸和类胡萝卜素的氧化,延缓可溶性固形物和可滴定酸含量的降低。综上所述,精油香膏熏蒸能减少油桃果实的腐烂,延缓后熟衰老,较好地保持果实品质,具有进一步开发成商品化果蔬保鲜剂的潜力。本研究结果为固封精油熏蒸在油桃采后保鲜上的应用提供了一定的参考。

Effect of Fumigation With Fixed Essential Oil Method on the Storage and Preservation of Postharvest Nectarine Fruits

To develop a new method for Nectarine preservation by using plant essential oils, the thyme and savory essential oil(EO) were sealed with agar plate, which made the EO fumigation slowly, persistently and stably through slow-release diffusors. Solid phase microextraction coupled with gas chromatography and mass spectrometry (SPME-GCMS) was used to analyze the variations of volatile bioactive components in sealed storage cabinets during fumigation with different EO. The effects of fumigation on the decay index, weight loss rate, hardness, antimicrobial activity, soluble solids, titratable acid, ascorbic acid and carotenoid content in nectarine fruits were studied. The results showed that compared with the control group, the decay index of the nectarine decreased from 23.3% in the control group to lower than 10.8% after funigation, and the fruit weight loss rate and hardness of the fumigated nectarine were well maintained at the end of storage. SPME-GCMS analysis showed that thymol and carvacrol, as major antimicrobial components, increased slowly and then tends to equilibrium, but the relative percentage was low. However, both two essential oils had high antibacterial activity against M. fructicola even at lower concentrations, and 10% savory essential oil could almost completely inhibited the germination of M. fructicola. 1% and 10% thyme essential oil could also reduce the germination rate of M. fructicola by 35.4 and 49.1 percent points respectively. However, B. cinerea was less sensitive to EO vapors than M. fructicola. In addition, EO fumigation could reduce the oxidation of ascorbic acid and carotenoids, and delay the decrease of soluble solids and titratable acids in fruits. In summary, the slow-release fumigation by sealed EO could prevent the decline of postharvest nectarine quality, which has the potential to be further developed into a commercial fruit and vegetable preservatives and provide a reference for the application of the sealed EO fumigation in post-harvest preservation of nectarine.