Analysis Of Nanguo Pear Aroma Components And Its Variation During Storage

As one fine variety of Pyrus ussriensis Maxim in China, Nanguo pear has bright color, delicious tasty, very juicy and rich nutrition, deeply favored by consumers in market. As special fruit in Liaoning province,Nanguo pear cultivated area has been nearly 6×102 million m2 and production nearly 0.2 million ton in the province.Full rich aroma is an important character of fruit quality, it also has deeply influence on juice, fruit wine, fruit vinegar et al. There are many research on post harvest physiology and pathology. However, the research on flavor especially on aroma components of Nanguo pear has not be reported as yet. Thus, research on aroma components on one hand could help to understand the basic chemical information of Nanguo pear, on the other hand could provide basic scientific message of breeding processing,storage and fruit essential oil, which would lay a foundation of research on the mechanism and technique of Nanguo pear.The present research on aroma components of Nanguo pear by analysis several aspects of Nanguo pear included:(1) Analysis of Nanguo pear aroma components by solid phase micro extraction (SPME) and conditions optimize.(2) Analysis of the fruit aroma constituents of Nanguo pear different parts.(3)Research on Nanguo pear aroma components changes after 1-MCP treatment at normal temperature by analysis firmness, content total solubility solid, ethylene production and aroma components of fruit on 20℃storage.(4) Research on Nanguo pear aroma components changes after 1-MCP treatment at low temperature by analysis firmness, content total solubility solid, ethylene production and aroma components of fruit onThere were some conclusions by preliminary research of the experiment:(1)The fruit aroma component of Nanguo pear juice were determined by SPME and Gas Chromatography Mass Spectrometry(GC-MS).Through single factor experiment, make sure extraction time, extraction temperature, extraction salinity. The result shows that:the best extraction condition, time 30min,temperature 40℃,NaCl 0.32g/mL.On the best extraction condition, Nanguo pear juice was identified 8 kinds of aroma components, were ethyl acetate(3.8%), butanoic acid ethyl ester(14.49%), hexanoic acid methyl ester(4.86%), acetic acid hexyl ester(48.9%), acetic acid hexyl ester(4.93%), alpha.-farnesene(13.9%),ethanol(1.6%),2,6-dimethyl-6-(4-methyl-3-pentenyl)bicyclo[3.1.1]hept-2-ene(7.21 %).(2)The fruit aroma components of Nanguo pear different parts were determined by SPME, including full and cracked pear, the fruit peel and pulp. The results showed that the kinds of volatile aroma compounds were more than the cracked ones.18 fruit aroma compounds of Nanguo pear were identified, and the major components were ethyl acetate (1.49%),butanoic acid ethyl ester (7.48%),acetic acid,2-methylpropyl ester (1.43%), hexanoic acid methyl ester (1.46%), hexanoic acid ethyl ester (41.76%),acetic acid hexyl ester (11.78%),2-octenoic acid,ethyl ester (1.07%),octanoic acid ethyl ester (6.73%) and a-farnesene (21.6%).There are lots of common fruit aroma components in fruit peel and pulp, but different in quantity. The relative percentage content of hexanoic acid ethyl ester in fruit peel and pulp were 46.89%,35.2% respectively.(3)The results showed that Nanguo pear treated by 1-MCP decrease the quantity of aroma during the normal temperature storage. On 1-MCP (0.25mg/kg) group, the quantity of total fruit aroma and esters aroma reduced 27.8% and 31.3%,respectively compared to the same comparison.1-MCP treatment slowed down the decrease harness, keep content total solubility solid, inhibited ethylene production and delayed the ethylene peak, prolong the shelf-life of Nanguo pear, while inhibited the production of fruit aroma.(4)The results showed that combine 1-MCP treatment with cold storage technology played conjunction preservation effects, keep fruits harness, inhibited ethylene production, but the aroma of the fruit has also been inhibited.