Changes in the composition of aroma components in blue honeysuckle fruit at different developmental stages

Abstract:【Objective】The aim of the research was the identification and quantification of aroma components in blue honeysuckle berry in different periods of fruit development, which has not been reported previously. The current study might provide useful information about the potential utilization of the essential oils in this fruit especially monoterpenes in medications or as dietary supplements.【Methods】Gas chromatography(GC) separates different compounds in mixed gas because of their difference in partition coefficient in stationary phase and mobile phase. Mass spectrometry(MS) analyzes charge to mass ratio to identify different motions based on the various trajectories in specific magnetic field and detect the quality and intensity distribution of ions. Fruits of‘Berel'and‘Changbaishan 1'(‘C-1') at different growth periods(fruit set, color break and mature stage) were used in this study. 5 g fruit tissue from each sample was grinded into juice with 1.0 g Na Cl for headspace solid phase microextraction(HS-SPME) experiment. The above juice was analyzed qualitatively and quantitatively for aroma components using GC-MS with a chro-matographic column of DB-5MS(30 m×0.25 mm,0.25 μm), a gasification temperature of 250 ℃ and a temperature program of 40 ℃ for 3 min, heating to 160 ℃ at a rate of 5 ℃·min^-1, maintaining at 160 ℃ for 2 min, and heating to 220 ℃ at a rate of 10 ℃·min-1and maintaining this temperature for 2 min. The flow rate of chromatography was 1.0 mL·min^-1; quadrupole temperature 150 ℃; carrier gas helium gas; source temperature of ion 230 ℃;electron energy 70 e V; and scan range 35-625 amu. Obtained data were analyzed using an available computer library(NIST08.L) and relative contents of various compounds were identified using area normalization method. The analysis was conducted with two replicates.【Results】Hydrocarbons, alcohols and aldehydes were the major components through all developmental periods. A total of 78 aroma components were identified from the two cultivars. During fruit ripening, the total relative content of hydrocarbons rose, and aldehydes decreased first and then increased, while alcohol content displayed an opposite pattern with aldehydes. Butylated hydroxytoluene,(E)-2-hexenal, hexanal, alpha-4-trimethyl, 1-butanol, trimethylamine, compd with borane(1:1) and eucalyptol were the major aroma components in ripe fruit. Composition of aroma components differed in different periods of fruit developments.In‘Berel'fruit, a total of 20 species of compounds were detected at fruit setting stage, and aldehydes[(E)-2-hexenal and hexanal] and alcohols(3,7-dimethyl-1,6-octadien-3-ol) were prevailing compounds. 19 aroma components were identified at color break including alcohols such as 1-butanol,(E)-3-hexen-1-ol, 2-ethyl-1-hexanol, 3,7-dimethyl-1,6-octadien-3-ol, and 2-hexen-1-ol. A total of 24 aroma components were identified in the mature fruit, and aldehydes such as hexanal and(E)-2-hexenal)and hydrocarbons such as butylated hydroxytoluene were the dominant. In‘C-1'fruit, 25 aroma components were detected in fruit at setting period, and the main components were aldehydes such as(E)-2-hexenal and hexanal. A total of 25 aroma components, chiefly alcohols(1-Butanol,(Z)-3-hexen-1-ol, 3,7-dimethyl-1,6-octadien-3-ol, α-4-trimethyl, α-3-cyclohexene-1-methano) and hydrocarbons(butylated, hydroxytoluene, eucalyptol) were identified at color break stage. In ripe fruit, 25 aroma compounds were indentified including chiefly alcohols(3,7-dimethyl-1,6-octadien-3-ol, α-4-trimethyl, α-3-cyclohexene-1-methanol), aldehydes [(E)-2-hexenal and hexanal], hydrocarbons(butylated hydroxytoluene,eucalyptol) and others(1-methoxy-1-propene). There were 11 compounds detected in mature fruit of both cultivars. They were 1-butanol, 3-methylpenta-1,4-diene-3-ol, alpha-4-trimethyl, hexanal,(E)-2-hexenal, nonanal, eucalyptol, tridecane, tetradecane, butylated hydroxytoluene and 2-(1,1-dimethylethyl)-4-methyl-phenol. The contents of aroma components differed in the three growth periods. In‘Berel'fruit, the content of aldehydes was 70.98% of the total aroma components in fruit at setting period, and alcohols and hydrocarbons accounted for 44.64% and 22.93% of the total aroma components in the color break period, respectively, while in mature fruit, fruitalcohols, hydrocarbons and aldehydes accounted for13.71%, 30.89% and 32.26%, respectively. In the‘C-1', major compounds were aldehydes(65.62%) in fruit setting period, alcohols(53.54%) and hydrocarbons(26.5%) at color break, and alcohols(21.28%),hydrocarbons(37.29%) and aldehydes(17.76%) in maturation period【.Conclusion】There was great difference in composition of aroma compounds in different developmental periods of blue honeysuckle fruit and in different cultivars. Aroma components of blue honeysuckle fruit consisted mainly of hydrocarbons, alcohols and aldehydes in all periods of development. Alcohols were dominated in fruit setting period and hydrocarbons, alcohols and aldehydes were dominant in the mature fruit. The types of aroma components increased during fruit development and were more diversified in‘C-1'fruit than that in‘Berel'during the same period.