EFF对薄皮甜瓜采后相关生理因素的影响

研究不同体积分数EFF(促进保鲜配方)(enhanced freshness formulation,EFF)对薄皮甜瓜贮藏过程中部分采后生理因素的影响,为薄皮甜瓜的贮藏保鲜提供参考依据。以“金亨二号”薄皮甜瓜为试材,分别用1%和2%的EFF溶液浸泡后,以浸泡清水为对照(CK),测定了甜瓜在10℃贮藏期间果实品质和相关生理指标的变化。经EFF浸泡之后,减慢了果实贮藏期间质量、硬度、水分的降低速率,延缓了可溶性固形物的消耗;EFF处理延迟了乙烯高峰的出现,极显著地降低了乙烯的峰值(P＜0.01);显著提高了过氧化氢酶(catalase,CAT)和超氧化物歧化酶(superoxide dismutase,SOD)的活性(P＜0.05),极显著降低了过氧化物酶(peroxidase,POD)和多酚氧化酶(polyphenol oxidase,PPO)的活性(P＜0.01),延缓了果实的成熟和衰老,延长贮藏期。经EFF处理的果实,贮藏前期2%EFF醛类总量显著高于CK和1% EFF(P＜0.05);贮藏后期果肉中总芳香物质、总酯类、乙酸酯类和草酸酯类含量均显著升高,而且使芳香物质高峰延迟3d出现;减少了香气成分的缺失,较好地保持了甜瓜果实的品质。综合分析得出,体积分数2% EFF更有利于保持果实品质,延缓果实衰老。     

Effect of oxygen on aroma volatiles and quality of fresh-cut cantaloupe and honeydew melons

Cantaloupe and honeydew melon cultivars were processed and stored under a high oxygen passive modified atmosphere packaging (MAP) or reduced oxygen controlled atmosphere (CA; 5 kPa O₂ + 10 kPa CO₂ and balance N₂) for 14 days at 5 °C. Atmosphere did not affect softening rate or soluble solids content and had a negligible effect on colour. Volatile compounds known as flavour-important in melons were extracted using stir bar sorptive extraction (SBSE) and quantified via GC–MS. Acetate esters increased more in MAP than in CA. Non-acetate esters increased markedly in both cultivars and storage types. Alcohols were more abundant in honeydew than in cantaloupe. Aldehydes decreased during storage in both cultivars and storage types. Lower O₂ availability under CA conditions likely suppressed some of the esters relevant to the aroma of fresh-cut melon. Results suggest that package O₂ levels are more important in determining aroma than other quality attributes of fresh-cut melon, and high O₂ levels may be required to reveal desirable aroma compounds.     

EFF和硝酸钙混合液对薄皮甜瓜采后香气成分的影响

研究促进保鲜配方(EFF)和硝酸钙混合液对薄皮甜瓜采后香气成分的影响。以采后七成熟薄皮甜瓜‘玉美人’和‘日本甜宝’为试材,用EFF和硝酸钙混合液(EFF 2%和硝酸钙0.5%(V/V))浸泡,分别以浸泡清水和0.5%硝酸钙为对照(CK1和CK2),在15℃恒温培养箱中贮藏21d,测定贮藏期间果实香气成分的变化。结果表明,经混合液浸泡后,延缓了果实质量、硬度、水分的降低速率及可溶性固形物的消耗。果实贮藏前期,香气物质中醇类和醛类为主要成分,随着果实逐渐成熟衰老,两者含量逐渐减少,而酯类含量逐渐增加,且以乙酸酯类为主,其次是草酸酯类和其他酯类。处理果实中己醛含量和其他4种醛的总量均显著高于两个对照(P＜0.05),两个品种处理果实香气物质总含量均高于两个对照,而且香气物质出现高峰晚于两个对照,减少了香气成分的损失。两个品种比较,‘日本甜宝’更耐贮藏。综合分析得出,EFF和硝酸钙的混合液比单独使用硝酸钙更利于保持果实品质及香气成分,延缓采后果实的成熟与衰老。     

Effect of time before storage and storage temperature on survival of Salmonella inoculated on fresh-cut melons

The effects of a waiting period at room temperature ( approximately 22 degrees C) before refrigerating fresh-cut watermelon, cantaloupe and honeydew pieces contaminated with Salmonella on survival of the inoculated pathogen were investigated. Whole cantaloupes, honeydew melons and watermelons were washed with water, and fresh-cut pieces from individual melons were prepared and inoculated with a five strain cocktail of Salmonella at 10(5)cfu/ml. Populations of aerobic mesophilic bacteria, yeast and mold and Pseudomonas spp. were higher for fresh-cut cantaloupe than for fresh-cut watermelon and honeydew immediately after preparation. Populations of Salmonella, aerobic mesophilic bacteria, yeast and mold and Pseudomonas ssp. in fresh-cut melons left at room temperature for up to 5h before refrigeration were significantly (P<0.05) higher than populations in fresh-cut melons stored at 5 degrees C immediately after preparation. Populations of Salmonella recovered in fresh-cut melon after inoculation with the cocktail of Salmonella strains averaged 2 log(10)cfu/g for all three types of melons. Populations in fresh-cut watermelon and honeydew pieces declined by 1 log when stored immediately at 5 degrees C for 12 days, while the populations in fresh-cut cantaloupe did not show significant (P>0.05) changes. Populations of Salmonella in fresh-cut melons stored immediately at 10 degrees C for 12 days increased significantly (P<0.05) from 2.0 to 3.0 log(10)cfu/g in watermelon, 1.9 to 3.0 log(10)cfu/g in honeydew and 2.0 to 3.6 log(10)cfu/g in cantaloupe pieces. Holding freshly prepared, contaminated fresh-cut melon pieces at 22 degrees C for 3h or more prior to refrigerated storage would increase the chances of Salmonella proliferation, especially if the fresh-cut melons were subsequently stored at an abusive temperature.     

同时蒸馏萃取、溶剂萃取和顶空固相微萃取与GC-MS联用分析甜面酱的挥发性成分

利用气质联用技术对同时蒸馏萃取、溶剂萃取和顶空-固相微萃取三种方法的萃取成分进行分析鉴定比较.通过研究发现,利用GC-MS共鉴定出化合物60种, 挥发性的酯、醛以及含氮、含硫化合物构成了甜面酱风味的主体.并且同时蒸馏萃取法对甜面酱中高沸点化合物,如醛类有较好的萃取效果;溶剂萃取法则对酸类的提取效果较好;顶空固相微萃取法有利于提取易挥发性化合物,特别是对挥发性酯和烯烃类的提取更加有效.     

ATP bioluminescence assay for estimation of microbial populations of fresh-cut melon

Estimation of microbial numbers in foods by conventional microbiological techniques takes days, so there is a need for faster methods that can give results in minutes. Research was undertaken to investigate the use of bioluminescent ATP determination and a firefly luciferase assay to estimate the initial population of aerobic mesophilic bacteria on fresh-cut melons immediately after preparation and during storage at 5 or 15 degrees C for up to 12 days. Populations of aerobic mesophilic bacteria on fresh-cut cantaloupe prepared immediately from unsanitized whole melons averaged 3.42 log CFU/g, corresponding to an ATP value of 5.40 log fg/g. Populations for fresh-cut honeydew prepared from unsanitized whole melon averaged 1.97 log CFU/g, corresponding an ATP value of 3.94 log fg/g. Fresh-cut pieces prepared from cantaloupe or honeydew melons sanitized with either chlorine (200 ppm free chlorine) or hydrogen peroxide (2.5%) had similar ATP values: 3.1 log fg/g (corresponding to bacterial counts 1.7 log CFU/g) for cantaloupes and 2.6 log fg/g (corresponding to bacterial counts of 0.48 CFU/g) for fresh-cut honeydew. Positive linear correlations for ATP concentrations and microbial populations were found for fresh-cut cantaloupe (R2 = 0.99) and honeydew R2 = 0.95) during storage at 5 degrees C for up to 12 days. ATP values in fresh-cut melons inoculated with either aerobic mesophilic bacteria or yeast and mold were significantly higher (P < 0.05) than control values and parallel total plate counts on plate count agar. Results of this study indicate that the bioluminescent ATP assay can be used to monitor total microbial populations on fresh-cut melon after preparation and during storage for quality control purposes to establish specific sell-by or consume-by dates.     

Use of hydrogen peroxide in combination with nisin, sodium lactate and citric acid for reducing transfer of bacterial pathogens from whole melon surfaces to fresh-cut pieces

Hydrogen peroxide (2.5%) alone or hydrogen peroxide (1%) in combination with nisin (25 microg/ml), sodium lactate (1%), and citric acid (0.5%) (HPLNC) were investigated as potential sanitizers for reducing Escherichia coli O157:H7 or Listeria monocytogenes populations on whole cantaloupe and honeydew melons. Whole cantaloupes inoculated with E. coli O157:H7 and L. monocytogenes at 5.27 and 4.07 log10 CFU/cm2, respectively, and whole honeydew melons inoculated with E. coli O157:H7 and L. monocytogenes at 3.45 and 3.05 log10 CFU/cm2, respectively, were stored at 5 degrees C for 7 days. Antimicrobial washing treatments were applied to inoculated whole melons on days 0 or 7 of storage and surviving bacterial populations and the numbers transferred to fresh-cut pieces were determined. At days 0 and 7 treatment with HPLNC significantly (p<0.05) reduced the numbers of both pathogens, by 3 to 4 log CFU/cm2 on both types of whole melon. Treatment with HPLNC was significantly (p<0.05) more effective than treatment with 2.5% hydrogen peroxide. While fresh-cut pieces prepared from stored whole melons were negative for the pathogens by both direct plating and by enrichment, fresh-cut pieces from cantaloupe melons treated with 2.5% hydrogen peroxide were positive for both pathogens and pieces from honeydew melons were positive for E. coli 0157:H7. The native microflora on fresh-cut melons were also substantially reduced by HPLNC treatment of whole melons. The results suggest that HPLNC could be used to decontaminate whole melon surfaces and so improve the microbial safety and quality of fresh-cut melons.     

Volatile Compounds and Sensory Properties in Various Melons,Which were Chosen from Different Species and Different Locations,Grown in Turkey

Gas chromatography coupled to mass spectrometry using a static head space technique was applied to analyze the volatile aromatic compounds of various melons collected from different locations in Turkey. Some physicochemical and sensory analyses were also made. A total of 33 volatile compounds were identified. Differences in the physicochemical and sensory properties of various Turkish melon samples were observed. The multivariate analyses by the volatile compounds separated the three varieties into groups successfully. The most abundant volatile compounds as mean value in all melon varieties were ethyl acetate (22.10%), acetaldehyde (13.65%), and ethanol (23.25%). The results showed that Cantaloupe melons were more preferred by panelists, which had relatively high levels of esters being responsible for strong fruit flavor, like melon, as well as high total soluble solid content and low titratable acidity compared with Inodorus and Simama.     

基于电子鼻与电子舌技术评价氯吡脲对甜瓜品质的影响

为了评价施用氯吡脲对甜瓜风味品质的影响,本实验以薄皮甜瓜为研究对象,采用电子鼻和电子舌技术结合主成分分析(PCA)和判别式分析方法,并结合甜瓜的生理指标进行分析对甜瓜风味品质进行评价。结果发现使用氯吡脲后的甜瓜与人工授粉的甜瓜相比,甜瓜的纵径和单果重显著提高(p<0.05),而横径和甜瓜中的可溶性固形物没有显著性差异;通过对电子鼻检测发现高浓度氯吡脲(20 mg/L)的使用使成熟期甜瓜中部分挥发性成分减少,电子舌数据显示氯吡脲的使用增加了成熟期甜瓜中的呈酸物质。通过主成分分析,发现氯吡脲对其它风味也造成一定影响,处理组与对照组的品质组成存在显著差异(p<0.05),且与氯吡脲的施用浓度存在一定的相关性,本实验为评价氯吡脲对甜瓜等农产品品质影响提供了科学依据,也为制定氯吡脲的合理使用规范提供了重要的数据支撑。     

A contribution to the differentiation between nectar honey and honeydew honey

Thirty genuine honey samples were analyzed for pH, acidity, water, ash, net absorbance, total polyphenols (Folin–Ciocalteau method) and glucose, fructose, melezitose and erlose (as their trimethylsilyl oximes and trimethylsilyl ethers) by capillary gas chromatography. The resulting data were used, along with palynological analysis, to characterize the samples in relation to their possible source (nectar, honeydew and mixture honeys).Some minor components (carboxylic acids and cyclitols), eluting before monosaccharides, were also determined. One of these compounds was quercitol (1,3,4/2,5-cyclohexane-pentol), a deoxyinositol which has been previously determined in Quercus sp. samples. Quercitol was present in a broad concentration range (0.01–1.50 g/100 g) in honeys whose major source was honeydew but it was never higher than 0.01 g/100 g in samples characterized as nectar honeys. Quercitol concentrations appear to be related to the presence and amount of Quercus sp. honeydew as honey source, although further research is required to confirm this.     

Effect of ammonium nitrogen supplementation of grape juice on wine volatiles and non-volatiles composition of the aromatic grape variety Albariño

Vitis vinifera cv. Albariño is an aromatic variety characterised by terpenes present largely as glycosidic flavour precursor compounds, which depends on fermentation to reveal its aromatic varietal potential. Clarified Albariño must containing 250 mg N/L (control) was supplemented with diammonium phosphate to 350 and 450 mg N/L before fermentation with a high-nitrogen-demand wine strain of Saccharomyces cerevisiae (M05). Ammonium supplementation had a significant effect on the chemical composition (titratable acidity and ethanol) and volatile profile of Albariño wines. Varietal compounds in the free fraction (limonene, linalool, α-terpineol, α-ionone and β-damascenone) and bound (limonene, linalool and α-terpineol), as well as most yeast-derived fermentation products (including esters, higher alcohols and volatile acids) were associated with moderate nitrogen concentrations. Free β-ionone, bound geraniol, bound α-ionone, bound β-damascenone and 1-hexanol were associated with high nitrogen concentrations. OAV wines made with moderate nitrogen exhibited a higher total odorant activity, driven by ethyl esters, terpenes and C₁₃-norisoprenoids, resulting in fruity and floral aroma attributes.     

Volatile Compounds in Red Wines Processed on an Industrial Scale by Short Pre-fermentative Cold Maceration

Nero d’Avola and Shiraz grapes were subjected to pre-fermentative cold maceration at 4°C for about 24 h in industrial winemaking, in order to evaluate the effects of the pre-treatment on aroma profile. The volatile compounds were identified by gas chromatography-mass spectrometry and grouped into 14 chemical families 4 and 9 months after bottling. Principal components analysis (PCA) plots of the volatile compounds showed clear separation among wines from the Shiraz and Nero d’Avola varieties. For instance, Shiraz wines were characterized along the PC1 axe by esters of organic acids, norisoprenoids and C₆ alcohols, while Nero d’Avola wines were characterized by acetates and monoterpenic oxides and diols. Moreover, pre-treated samples showed significant (p?<?0.05) changes in volatile compounds belonging mainly to ethyl esters of straight chain fatty acids, acetates and norisoprenoids. The sensorial analysis showed that cold maceration contributed to development of a different aroma profile during bottle maturation if applied on Nero d’Avola or Shiraz variety.     

Development of pectin–eugenol emulsion coatings for inhibition of Listeria on webbed-rind melons: a comparative study with fig and citrus pectins

The objective of this study was to employ pectin-based antimicrobial coatings for inhibition of Listeria on surfaces of whole webbed-rind melons that cause frequent outbreaks of listeriosis. For this purpose, emulsion-based coatings were developed using citrus pectin (CPEC) or pectin extracted from processing wastes of sun-dried figs (FPEC) and eugenol (EUG). The emulsions of FPEC and CPEC with EUG (droplet size range: 1.99–11.22 µm) were highly stable for minimum 10 days at 10 °C. The FPEC-EUG films showed higher flexibility and degree of wettability than CPEC-EUG films. In contrast, CPEC-EUG films had a higher gas barrier performance against oxygen at 50% relative humidity than FPEC-EUG films. The zone inhibition tests showed that FPEC-EUG films are more effective against Listeria innocua than CPEC-EUG films. However, FPEC and CPEC coatings with 2% EUG caused 2.2 and 2.7 decimal inactivation of Listeria on Galia melons within 1 week, respectively. The pectin coatings with EUG could reduce the risk of listeriosis from webbed-rind melons.     

Binding capacity of brown pigments present in special Spanish sweet wines

Some special Spanish sweet wines are obtained by addition of a sweetening and coloring agent called grape syrup, which is obtained by heating must to give a dark and highly caramelised liquid, with similar consistency than other syrups. The aim of this work was to establish the influence of the addition of boiled must or “grape syrup” on the aroma and colour of sweet wines focussing specially on the possible binding effect on volatile compounds. The influence of must polyphenols was also studied, so, a wine sweetened with a “grape syrup” free of polyphenols was also elaborated. As it was expected, the addition of grape syrups gave an increase in the levels of furfural related compounds, and sweet wines showed lower concentrations of terpenes, ethyl esters, organic acids and acetates of alcohols than the control wine. The capacity of brown polymers present in grape syrups to bind these volatile compounds is discussed. Furthermore, colour parameters were also studied and significant differences were found for all of them between sweet wines and control wine.     

Evaluation of botulinal toxin production in packaged fresh-cut cantaloupe and honeydew melons.

The ability of Clostridium botulinum to produce toxin on cubed, packaged melons was investigated relative to microbial spoilage at various incubation temperatures and in different packaging systems. Freshly cut cubes (approximately 2.5 cm3) of cantaloupe and honeydew melons were surface inoculated with a 10 strain mixture of proteolytic and nonproteolytic spores of C. botulinum (10 to 15 cubes per package; approximately 100 total spores per package). To initially evaluate toxin production and spoilage in a passively modified atmosphere, melon cubes were loosely packaged in air in polyethylene pouches, sealed, and incubated at 7 or 15 degrees C for up to 21 days. At various sampling intervals, samples were tested for headspace oxygen and carbon dioxide levels, pH, presence of botulinal toxin, aerobic and anaerobic plate counts, and counts of yeasts and molds. During incubation, headspace oxygen levels decreased, headspace carbon dioxide levels increased, aerobic and anaerobic plate counts increased, and the pH remained constant or decreased slightly. Botulinal toxin was not detected in any cantaloupe samples or in honeydew samples incubated at 7 degrees C. Botulinal toxin was detected in some honeydew samples at 15 degrees C after 9 days of incubation, but the toxic honeydews were severely spoiled and considered organoleptically unacceptable. A similar second experiment was performed in which half of the melon cubes were treated with UV light to inactivate vegetative organisms before packaging, and these were incubated at 7, 15, or 27 degrees C. In this second experiment, toxin production occurred in the UV-treated samples at 15 degrees C with gross spoilage and at 27 degrees C with only marginal spoilage. These data indicate that inhibition of spoilage organisms with UV light could result in botulinal toxin formation in packaged melons before overt spoilage.     

Optimizing concentration and timing of a phage spray application to reduce Listeria monocytogenes on honeydew melon tissue

A phage cocktail was applied to honeydew melon pieces 1, 0.5, and 0 h before contamination with Listeria monocytogenes strain LCDC 81-861 and 0.5, 1, 2, and 4 h after contamination. The phage application was most effective when applied 1, 0.5, or 0 h before contamination with L. monocytogenes, reducing pathogen populations by up to 6.8 log units after 7 days of storage. This indicates that under commercial conditions, if contamination occurs at the time of cutting, phage would have to be applied as soon as possible after cutting the produce. However, all phage applications from 1 h before to 4 h after contamination and all phage concentrations ranging from 10(4) to 10(8) PFU/ml reduced bacterial populations on honeydew melon pieces. Higher phage concentrations were more effective in reducing pathogen populations. A phage concentration of approximately 10(8) PFU/ml was necessary to reduce the pathogen populations to nondetectable levels immediately after treatment, and pathogen growth was suppressed by phage concentrations of 10(6) through 10(8) throughout the storage period of 7 days at 10 degrees C. In an attempt to enhance the effectiveness of the phage cocktail on low pH fruit, such as apples, the phage was applied in combination with MnCl2. This combination, however, did not enhance the effectiveness of the phage on apple tissue. The results from this study indicate that the effectiveness of the phage application on honeydew melon pieces can be optimized by using a phage concentration of at least 10(8) PFU/ml applied up to 1 h after processing of the honeydew melons.     

Evaluation of an analytical methodology using QuEChERS and GC-SQ/MS for the investigation of the level of pesticide residues in Brazilian melons

A multiresidue method based on the sample preparation by modified QuEChERS and detection by gas chromatography coupled to single quadruple mass spectrometers (GC-SQ/MS) was used for the analysis of 35 multiclass pesticides in melons (Cucumis melo inodorus) produced in Ceara-Brazil. The rates of recovery for pesticides studied were satisfactory (except for the etridiazole), ranging from 85% to 117% with a relative standard deviation (RSD) of less than 15%, at concentrations between 0.05 and 0.20 mg kg⁻¹. The limit of quantification (LOQ) for most compounds was below the MRLs established in Brazil. The combined relative uncertainty (Uc) and expanded uncertainty (Ue) was determined using repeatability, recovery and calibration curves data for each pesticide. Analysis of commercial melons samples revealed the presence of pesticides bifenthrin and imazalil at levels below the MRLs established by ANVISA, EU and USEPA.     

不同甜香风味特征的酱香型白酒中挥发性物质分析

为探究不同甜香风味特征酱香型白酒的主要挥发性物质组成及香气物质差异,本研究运用感官品评方法选取酱香型酒样,采用顶空固相微萃取（headspace solid phase microextraction,HS-SPME）结合气相色谱-质谱法剖析其中的挥发性成分,通过偏最小二乘判别分析法（partial least squares discriminant analysis,PLS-DA）解析不同酒样及其风味差异物质。结果表明:样品被分为三组,每组的甜香强度值分别为4.0～5.0、3.0～4.0和0.0～3.0;共鉴定出68种风味物质,包括酯类27种、醇类12种、醛酮类10种、酸类3种、芳香族化合物10种和萜烯类物质6种。其中,具有甜香和水果香的酯类、芳香族类和醇类物质是酒样中含量最为丰富的三类化合物,且在甜香强度大于3.0的酒样中含量最高,说明这三类物质对甜香风味特征有重要影响;影响三组酒样的潜在差异物质有25个,与之相关的甜香风味标志性物质主要为3-甲基丁醇、辛酸乙酯、乳酸异丁酯和苯乙酸乙酯,说明这些物质是造成不同甜香酒样之间差异的重要香气物质。     

Structure-taste relationship of some sweet-tasting dipeptide esters.

The sweetness of dipeptide esters, structurally related to L-aspartyl-L-phenylalanine methyl ester (Aspartame), depends among other things on molecular size. This paper describes a method for predicting whether a dipeptide ester is sweet or not with the aid of atomic models. The method is based on the determination of the size, length and shape of the side chain (R) of the amino-acid ester attached to L-aspartic acid. We measured the side chains of 28 dipeptide esters, 13 of which were synthesized and evaluated for sweetness in our laboratory. Data of the other esters were taken from the literature. Twentyone dipeptide esters were sweet; the size and length of the side chains could be correlated with the degree of sweetness. An ester is sweet provided the length of the side chain (R) is between 4.8 and 8.8 A, and its size greater than or equal to 29 A; as for shape of R in sweet esters, there were two maxima in space filling at about 2 and 4 A or about 3 and 5 A from the asymmetric carbon atom.     

Thermal Isomerization and Degradation Behaviours of Carotenoids in Simulated Sweet Corn Juice

The thermal behaviour of carotenoids may affect the nutritional value and flavour quality of sweet corn juice. In this study, carotenoid compositions and volatile components in simulated sweet corn juice at elevated temperatures from 100 to 130 °C were identified and compared by C₃₀-HPLC-DAD-APCI-MS and HS-SPME-GC-MS methods. The result showed that with the increase of temperature, concentrations of total and trans carotenoids in sweet corn juice model decreased gradually, as compared with all-trans α-carotene and all-trans β-carotene, oxy carotenoids (such as all-trans lutein, all-trans zeaxanthin and all-trans β-cryptoxanthin degraded faster), especially for carotenoid epoxides (such as neoxanthin). Meanwhile, the concentration of total cis carotenoids was related with the formation of some oxidative products and volatile compounds. Levels of major volatile components derived from carotenoids in sweet corn juice model including 4-ethyltoluene, p-cymene, 2-ethyl-1, 4-dimethylbenzene, 1, 2, 3, 4-tetramethylbenzene, dodecane, BHT, 1,7-dimethyl naphthalene, hexanal, 2-nonenal, undecanal, benzaldehyde, geranyl acetone, etc. increased with temperature. Some new volatiles such as 1, 2, 4-trimethylbenzene, naphthalene, pentadecane, acetaldehyde, β-ionone, limonene, tridecanone, etc. were also formed under higher temperatures. It is suggested that the aromatic compounds containing benzene ring and alkane are produced by degradation of carotenoids, which affect the overall flavour of sweet corn juice.