The influence of ripening stage and cultivation system on the total antioxidant activity and total phenolic compounds of yellow passion fruit pulp

BACKGROUND: This work aimed to investigate the influence of both ripening stage and cultivation system on the total phenolic compounds (TPC) and total antioxidant activity (TAA) of passion fruit pulp. TPC extraction was optimized using a 2³ central composed design. The variables were fruit pulp volume, methanol volume and extraction solution volume. TPC was determined using the Folin–Ciocalteu reaction, and TAA using the ABTS radical reaction. RESULTS: The conditions to extract TPC were 2 mL passion fruit pulp and 9 mL extraction solution containing 40% methanol:water (v/v). TPC values increased in the passion fruit pulp during ripening for both cultivation systems, ranging from 281.8 to 361.9 mg gallic acid L^?1 (P?0.05) for the organic pulp and from 291.0 to 338.6 mg gallic acid L^?1 (P?0.05) for the conventional pulp. CONCLUSION: TPC values increased during ripening for both organic and conventional passion fruit. The same was true for TAA values for conventional passion fruit. For organic passion fruit, however, TAA values were highest at the initial ripening stages. These results suggest that antioxidant compounds exert strong influence on the initial ripening stages for organic passion fruit, when TPC still did not reach its maximum level. Copyright © 2012 Society of Chemical Industry     

百香果皮多糖的组成及其体外抗氧化活性分析

为探究百香果皮多糖(passion fruit shell polysaccharide,PFSP)的组成,以广西百香果为原料,从果皮中提取、分离纯化获得多糖,采用红外光谱等方法分析PFSP的结构特征,并通过体外抗氧化实验测定其抗氧化活性。结果显示,百香果皮多糖主要由6种单糖组成,分别是葡萄糖、木糖、半乳糖醛酸、鼠李糖、半乳糖和阿拉伯糖,分子摩尔比为14. 72∶1. 15∶17. 29∶1. 86∶1. 70∶1。体外抗氧化实验结果表明,百香果皮多糖组分对DPPH·、羟基自由基、超氧阴离子自由基及ABTS+自由基的最大清除率分别为82. 07%、81. 52%、22. 43%和64. 10%,显示出良好的抗氧化活性。该研究对于百香果的综合利用具有现实意义,可为百香果皮多糖在功能食品、药品领域中的开发利用提供参考依据。     

Effect of storage temperatures on antioxidant capacity and aroma compounds in strawberry fruit

The antioxidant capacity (measured as oxygen radical absorbance capacity, ORAC), total anthocyanins, total phenolics, aroma compounds, and postharvest quality of strawberry fruit (Fragaria x ananassa cv. Chandler) kept at 0°C, 5°C, and 10°C were investigated. Strawberry fruit stored at 10°C or 5°C showed higher antioxidant capacity, total phenolics, and anthocyanins than those stored at 0°C. However, the postharvest life based on overall quality was longer at 0°C than at 5°C or 10°C. The production of aroma compounds was markedly influenced by storage time and temperature. Individual aroma compounds were affected differently. For example, ethyl hexanoate, hexyl acetate, methyl acetate, and butyl acetate increased, while 3-hexenyl acetate and methyl hexanoate decreased during storage. In general, strawberries stored at 10°C or 5°C produced higher levels of these volatiles than those stored at 0°C. In conclusion, strawberries stored at 0°C retained an acceptable overall quality for the longest storage duration; however, berries stored at temperatures higher than 0°C showed higher content of aroma compounds and antioxidant capacity during the postharvest period.     

百香果果酒发酵工艺及香气成分分析

以百香果为材料,对酵母添加量、初始糖度、SO2添加量这三个发酵工艺参数进行优化,并采用高效液相色谱和气相色谱-质谱联用技术对百香果果酒有机酸组成和香气成分进行了分析。结果表明,百香果果酒最佳发酵工艺为SO2添加量90 mg/kg,初始糖度23%,酵母添加量0.4%。有机酸分析表明,百香果果酒有12种有机酸,其中甘露糖酸含量最高,为2 784.12 μg/mL,富马酸含量最低,为8.22 μg/mL。通过气相色谱-质谱对百香果果酒香气成分进行分析后,鉴定出10种香气成分,其中醇类物质相对含量约占60%,醛类约占15%,酯类约占12%,烷烃类物质的种类最多,判定醇类化合物为百香果果酒香气物质的主要成分。     

Maillard反应对加曲发酵鳀制鱼露风味的影响

用气相色谱-质谱联用(GC-MS)分析Maillard反应前后的加曲发酵1年的鱼露中挥发性风味物质.结果表明,Maillard反应可以有效改善加曲发酵鱼露的风味,其含氮、含硫以及醛、酮类化合物相对含量增加,二甲基硫、二甲基三硫、吡啶、吡嗪、2-甲基丁醛和3-甲基丁醛等对鱼露主体风味有积极贡献的化合物含量有显著增加,而自然发酵1年的鱼露中挥发性特征风味物质的含量不高.     

Influence of cultivation parameters on the composition of volatile compounds and physico‐chemical characteristics of kiwi fruit

BACKGROUND: The effect of four cultivation parameters (post‐maturity harvest date, storage period at 0 °C and input of nitrogen or potassium fertilisers) on the physico‐chemical characteristics and composition of volatile compounds in kiwi fruit (Actinidia deliciosa) were evaluated. Five physico‐chemical parameters were selected, namely, pH, total acidity, dry matter, conductivity and refractive index. To our knowledge, no published data are available concerning the influence of nitrogen or potassium fertilisers on the volatile compounds and physico‐chemical parameters in kiwi fruit. RESULTS: Except for total acidity, these parameters were only weakly influenced by cultivation parameters. The concentrations of five main volatile compounds [hexanal, (E)‐hex‐2‐enal, hexan‐2‐ol, ethyl butyrate and hexanol] were also measured using gas chromatography and gas chromatography‐mass spectrometry. This work showed that the total content of volatile compounds decreased with post‐maturity harvest date and storage period of 3 months. In contrast, the input levels of nitrogen and potassium had little effect on the concentrations of volatile components CONCLUSION: This study demonstrates a high degree of difference in the physiochemical parameters and volatile composition of kiwi fruit, depending on the harvest date, the time of storage and the input of fertilisers. © 2012 Society of Chemical Industry     

百香果全果与果汁发酵酒滋味成分及香气成分对比

目的：提升百香果酒品质。方法：以百香果全果和果汁为原料酿制百香果酒,分别测定其有机酸、氨基酸和挥发性化合物含量,并结合电子舌试验结果评价百香果酒风味成分。结果：2种百香果发酵酒中主要有机酸为酒石酸、柠檬酸、乳酸和苹果酸,但全果酒的前3种有机酸含量均显著高于果汁酒中的（P<0.05）,全果酒和果汁酒中含量最多的有机酸分别为酒石酸（27.20 mg/mL）和柠檬酸（12.49 mg/mL）;除半胱氨酸未检出外,全果酒和果汁酒中16种游离氨基酸总含量分别为88.16,68.88 mg/100 g,且全果酒中4类呈味氨基酸含量高于果汁酒;电子舌测试发现,2种百香果发酵酒中咸味信号强度差异性最大,且全果酒中的鲜味、咸味最强,酸味、涩味和甜味最弱;HS-SPME-GC-MS共检出179种香气成分,全果酒中挥发性风味化合物种类比果汁酒多4种,但其萜烯类物质含量和种类分别比果汁酒的多1,3倍。结论：相比于果汁酒,新型百香果全果酒整体风味（鲜味、咸味、萜烯类物质等）较突出,提升了百香果资源的综合利用度。     

Key aroma volatile compounds of gulupa (Passiflora edulis Sims fo edulis) fruit

By application of the aroma extract dilution analysis of gulupa (Passiflora edulis Sims fo edulis), fruit pulp extract obtained by solvent-assisted flavour extraction, and also comparison of chromatographic, spectroscopic (mass spectrum), and odour properties with standards, β-ionone, γ-nonalactone, ethyl butanoate, and ethyl cinnamate were identified as volatiles exhibiting the highest flavour dilution (FD) factor. Among the nineteen odour-active compounds of gulupa, only those showing the highest FD factors were quantified by stable isotope dilution assay. After calculation of odour activity values (OAVs; ratio of concentration to odour threshold in water), ethyl butanoate, ethyl hexanoate, and β-ionone were identified as key aroma compounds in gulupa, responsible for the fruity and floral odour notes.     

Estimation of volatile onion aroma and flavour compounds

Summary. The Chemical Oxygen Demand (COD) method was used for the evaluation of onion aroma components. the method was found to be reliable and to correlate well with odour threshold values for raw onions and with taste scores for dehydrated onion products. Odour threshold values could not be used for the latter products due to the development of undesirable off-odour after exposure to high temperature or prolonged storage.     

景芝芝麻香型白酒重要挥发性香气成分研究

芝麻香型白酒是1949年后新发展起来的一种新香型白酒,一直以来对其重要香气成分认识不清。应用顶空固相微萃取（HS-SPME）、液液微萃取（LLME）结合气相色谱-质谱（GC-MS）及气相色谱-氢火焰离子化（GC-FID）检测技术,共分析定量出86种香气成分。其中α-雪松烯和α-萜品醇首次在芝麻香型白酒中被定量,平均浓度分别为45.34μg/L和15.77μg/L。结合香气活力值（OAV）分析,发现景芝酒中重要的香气成分为辛酸乙酯、己酸乙酯、丁酸乙酯、3-甲基丁醛、二甲基三硫、3-甲基丁酸乙酯、2-甲基丙酸乙酯和戊酸乙酯（OAV>1000）。剖析芝麻香型白酒的重要挥发性香气成分,将为芝麻香型白酒的生产质量控制提供理论依据与实践指导作用。      

百香果全果酒发酵工艺优化及体外抗氧化性比较分析

以紫皮百香果（Passiflora edulis）为原料发酵百香果全果酒,通过单因素试验结合响应面法,确定百香果全果酒的最适发酵工艺,并通过四个抗氧化体系（DPPH·、ABTS+·、·OH、还原能力）来评价其与百香果果汁酒和原汁的抗氧化活性。结果表明,百香果全果酒最适发酵工艺条件为初始糖度21%、酵母接种量0.04%、发酵温度29 ℃、发酵时间5 d。在此优化工艺条件下,百香果全果酒酒精度为11.9%vol;在四种抗氧化体系中,自由基清除率和还原能力均随样品体积的增加而增大,抗氧化活性的大小顺序为全果酒＞果汁酒＞原汁。     

The aroma volatile repertoire in strawberry fruit: a review

Aroma significantly contributes to flavor, which directly affects the commercial quality of strawberries. The strawberry aroma is complex as many kinds of volatile compounds are found in strawberries. In this review, we describe the current knowledge of the constituents and of the biosynthesis of strawberry volatile compounds, and the effect of postharvest treatments on aroma profiles. The characteristic strawberry volatile compounds consist of furanones, such as 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone and 4‐methoxy‐2,5‐dimethyl‐3(2H)‐furanone; esters, including ethyl butanoate, ethyl hexanoate, methyl butanoate, and methyl hexanoate; sulfur compounds such as methanethiol, and terpenoids including linalool and nerolidol. As for postharvest treatment, the present review discusses the overview of aroma volatiles in response to temperature, atmosphere, and exogenous hormones, as well as other treatments including ozone, edible coating, and ultraviolet radiation. The future prospects for strawberry volatile biosynthesis and metabolism are also presented. © 2018 Society of Chemical Industry     

茶叶中挥发性香气物质研究进展

茶是3大非酒精饮料之一,具有降血糖、抗氧化和抗炎等健康功能。近年来,大量研究报道了茶叶的生物活性和健康功能,而作为感官审评的重要指标,茶叶的香气同样值得深入研究。按照香气物质的生源途径分类,茶叶中香气物质可以分为类胡萝卜素、脂肪酸、糖苷类源香气前体物质以及加工过程中产生的美拉德反应产物。本综述对茶叶中香气物质的研究进展进行了归纳总结,以期为茶叶风味品质化学的研究提供借鉴。     

多轮增香发酵对传统榨菜风味成分影响研究

以四川传统特色发酵食品榨菜为研究对象,分析鉴定普通榨菜、多轮增香发酵榨菜发酵前后的物质成分变化。采用气相色谱-质谱连用技术对普通榨菜与多轮增香榨菜的风味成分进行鉴定和分析,探讨多轮增香发酵工艺对榨菜发酵风味物质的影响。结果表明,普通榨菜共识别出24种化合物,多轮增香发酵榨菜共识别出30种化合物,主要是醇类、醛类、酮类和酸类等,它们的协同作用构成了榨菜特有的香味成分,而且多轮增香发酵榨菜的风味更好。     

Recovery of volatile fruit juice aroma compounds by membrane technology: Sweeping gas versus vacuum membrane distillation

The influence of temperature (10–45 °C), feed flow rate (300–500 L/h) and sweeping gas flow rate (1.2–2 m³/h) on the recovery of berry fruit juice aroma compounds by sweeping gas membrane distillation (SGMD) was examined on an aroma model solution and on black currant juice in a lab scale membrane distillation set up. The data were compared to recovery of the aroma compounds by vacuum membrane distillation (VMD). The flux of SGMD increased with an increase in temperature, feed flow rate or sweeping gas flow rate. Increased temperature and feed flow rate also increased the concentration factors (C_permeate/C_feed) of the aroma compounds. At 45 °C the most volatile and hydrophobic aroma compounds obtained the highest concentration factors: 12.1–9.3 (black currant juice) and 17.2–12.8 (model solution). With black currant juice a volume reduction of 13.7% (vol.%) at 45 °C, 400 L/h, resulted in an aroma recovery of 73–84 vol.% for the most volatile compounds. Compared to VMD, the aroma recovery with SGMD was less influenced by the feed flow rate but more influenced by the temperature. Higher fluxes were achieved during concentration by VMD and this reduced the operation time, which in turn reduced the degradation of anthocyanins and polyphenolic compounds in the juice.

Industrial relevance

High temperature evaporation is the most widely used industrial technique for aroma recovery and concentration of juices, but membrane distillation (MD) may provide for gentler aroma stripping and lower energy consumption. This study gives important clues about the fate of berry juice aroma compounds and polyphenols during concentration by MD, and identifies the main factors influencing the aroma recovery efficiency with MD. Both SGMD and VMD are promising techniques for gentle stripping of berry juice aroma compounds and deserve further consideration as alternative techniques for gentle aroma stripping in industrial fruit juice processing.     

Distribution of aroma volatile compounds in tangerine hybrids and proposed inheritance

BACKGROUND: With the desirable combination of sugars and acids, volatile compounds contribute to the essential organoleptic attributes of citrus. This study evaluated the aroma volatiles of 20 tangerine hybrids of the University of Florida breeding program. Volatiles were sampled from hand‐squeezed juice by headspace solid‐phase microextraction (SPME), and analyzed by gas chromatography–mass spectrometry. Principal component analysis (PCA) and cluster analysis (CA) were used to find similarities among samples due to volatile composition with effect of genetic background. RESULTS: In total, 203 volatiles were detected in all samples. Volatiles in lower amounts were widely distributed among samples and were classified mainly as terpene hydrocarbons and oxygenated compounds, such as aldehydes, esters, alcohols and ketones. PCA, based on relative peak areas (content) clearly separated the samples higher in volatile content, mainly those with sweet orange genetic contributions in their background. CA, based on volatile presence/absence, grouped samples into five clusters, each showing distinctive volatile profiles. CONCLUSION: The genetic background of tangerine hybrids affected volatile composition and content of samples. In general, tangerines were characterized by fewer volatiles (in both quality and quantity) and more aldehydes, and hybrids with sweet orange in their background had more sesquiterpenes and esters, which would likely affect their aroma. Published 2010 by John Wiley & Sons, Ltd.     

Ultrasound‐assisted extraction kinetics,fatty acid profile,total phenolic content and antioxidant activity of green solvents' extracted passion fruit oil

The main objective of this current work was to evaluate the feasibility of green solvent's application on passion fruit oil extraction. In this study, the effects of green solvent on oil yield, fatty acid profile, oil physicochemical properties, total phenolic content and antioxidant activity associated with extracted oil were compared to those of conventional solvent, hexane application. Therefore, this study may provide supplementary information on previous studies that focused on oil recovery. Oilseeds' proximate composition and the influence of oilseeds‐to‐solvent (w/v) ratio on oil yield were investigated. The oilseeds contained high fibre, fat and protein. Oilseeds‐to‐solvent (w/v) ratio (1:8) provided the highest oil yield. Overall, acetone was suggested as a suitable hexane replacer due to its higher oil recovery, similar fatty acid profile and oil physicochemical properties with higher antioxidant activity. Ethanol‐extracted oil contained higher amounts of omega‐9 MUFA, which may indicate the influence of extraction solvent on final fatty acid composition and thus final oil application.