长波紫外造成货架椪柑汁挥发性风味组分的变化

Changes in Volatile Flavor Components of On-shelf Ponkan Juice Resulting from Ultraviolet A Irradiation

研究了长波紫外线(ultraviolet-A,UVA)对非浓缩还原椪柑汁货架风味品质影响。PET瓶装椪柑汁于25℃货架上施以UVA照射30 d,同时以避光存放椪柑汁为对照。分别对0 d、避光30 d和UVA照射30 d椪柑汁,采用顶空固相微萃取-气相色谱-质谱/脉冲火焰光度检测联用法分析其挥发性物质的组成和含量差异,通过气味活性值(odor active value,OAV)筛选受UVA显著影响的风味组分,确定UVA照射对货架果汁整体风味的作用。结果显示,0 d、避光和UVA照射椪柑汁中分别检出43、51和53种挥发物。对避光和UVA照射终了样品中浓度存在显著差异的物质,筛选出OAV≥1的关键风味成分共22种,包括芳樟醇、苯乙醛、甲硫醚等6个醇、6个醛、4个烃、3个挥发性硫化物、2个酯及1个酮类物质;其中花香气味强度(以OAV计)0 d(583)>避光(456)>UVA(400)照射,不良风味强度反之(83、135和284),并得到感官评价基本验证。此外,UVA还加速异味物质甲硫醚的生成。综上所述,UVA影响椪柑汁风味组分浓度变化,加速风味品质劣变。

Herein,the effects of ultraviolet A(UVA)irradiation on the flavor proprieties of on-shelf not-from-concentrate(NFC)Ponkan juice were evaluated and compared with those under dark storage.Polyethylene terephthalate-bottled NFC Ponkan juice was stored at 25℃and subjected to UVA irradiation for 30 days.Bottles of Ponkan juice stored in the dark were used as controls.Volatile compound composition and contents of Ponkan juice were analyzed by headspace solid-phase microextraction with gas chromatography-mass spectrometry/pulsed flame photometric detection at day 0 and 30 days after storage in the dark or exposure to UVA.The odor active value(OAV)was used to screen flavor components significantly affected by the UVA irradiation,and the overall flavor of the on-shelf juice was evaluated.Overall,43,51 and 53 volatile compounds were detected in juice samples collected on day 0,day 30 after storage in the dark,and day 30 after UVA exposure,respectively.Among the components showing significant concentration differences after dark storage and UVA irradiation,a total of 22 key flavor components with OAV≥1 were identified,which included six alcohols(such as linalool),six aldehydes(such as phenylacetaldehyde),four hydrocarbons,three volatile sulfur compounds(such as dimethyl sulfide),two esters,and one ketone.Moreover,the odor intensities(in terms of OAVs)of floral flavor components from the three samples were as follow:day 0(583)>day 30 in the dark(456)>day 30 of UVA irradiation(400),whereas those of off-flavor components showed the opposite order(83,135,and 284,respectively).Sensory evaluation further verified the detected changes in the odor attributes of on-shelf juice,including enhanced dimethyl sulfide production rate upon UVA exposure.In conclusion,UVA irradiation speeds up flavor deterioration of Ponkan juice by modifying the compositions and concentrations of flavor components.