Exploring stingless bee honey from selected regions of Peninsular Malaysia through gas chromatography–mass spectrometry–based untargeted metabolomics

Volatile organic compounds in honey are known for their considerable impact on the organoleptic properties of honey, such as aroma, flavor, taste, and texture. The type and composition of volatile organic compounds are influenced by entomological, geographical, and botanical origins; thus, these compounds have the potential to be chemical markers. Sixty-two volatile compounds were identified using gas chromatography–mass spectrometry from 30 Heterotrigona itama (H. itama) honey samples from 3 different geographical origins. Hydrocarbons and benzene derivatives were the dominant classes of volatile organic compounds in the samples. Both clustering and discriminant analyses demonstrated a clear separation between samples from distant origins (Kedah and Perak), and the volcano plot supported it. The reliability and predictability of the partial least squares–discriminant analysis model from the discriminant analysis were validated using cross-validation (R²: 0.93; Q²: 0.83; accuracy: 0.97) and the permutation test (p < 0.001), and the output depicted that the model is legitimate. In combination with the variable importance of projection (VIP > 1.0) and the Kruskal–Wallis test (p < 0.01), 19 volatile organic compounds (encompassed aldehydes, benzene derivatives, esters, hydrocarbons, and terpenoids) were sorted and named potent chemical markers in classifying honey samples from three geographical origins. In brief, this study illustrated that volatile organic compounds of stingless honey originated from the same bee species, but different geographical origins could be applied as chemical markers.     

Influence of prefermentative maceration temperature on the colour and the phenolic and volatile composition of rosé wines

Prefermentative maceration for 8 h at 5, 10 and 15 °C was used to make rosé wines, and changes in their colour (colour intensity (CI), tone and CIELAB parameters), phenolic compounds (classic indices and individual compounds) and volatile compounds (major and minor) were monitored from the must stage to wines until 6 months after bottling. The 15 °C maceration temperature provided wines with the highest CI, a* and C* values, the greatest malvidin‐3‐glucoside content and the lowest alcohol and ethyl acetate levels. Only in these wines were terpenols released after 6 months in the bottle. The wines produced at 5 °C had the highest ester levels, which also remained more stable during storage. When using maceration temperature as the differentiating variable in a discriminant analysis, volatile compounds were important contributors. However, colour and phenolic compound parameters were important when sampling time was used as the differentiating variable. The best scoring wines in an informal sensory evaluation test were those subjected to 15 °C maceration, while the least appreciated were those macerated at 5 °C. Copyright © 2005 Society of Chemical Industry     

A systematic analysis on tomato powder quality prepared by four conductive drying technologies

Four pilot-scale conductive dryers, namely a vacuum drum dryer (VDD), a drum dryer (DD), an agitated thin film dryer (ATFD) and a refractance window dryer (RWD), were used to dry tomato puree. Drying induced colour differences between the reconstituted puree and the original puree and strongly affected the volatile and non-volatile profiles of the powders. Principal component analysis (PCA) identified four separated groups corresponding to the different drying methods, indicating that the drying methods caused significant variance in compound profiles. Subsequently, pairwise comparison of different dried powders was performed by partial least square discriminant analysis (PLS-DA). This resulted in a selection of discriminative volatile and non-volatile markers. RWD and VDD produced powders with high volatile markers that may be related to aroma retention. Conversely, DD dried products contained more non-volatile markers that can be related to taste perception. ATFD processed powders had a lower level of discriminant compounds.Industrial relevanceTomato products are frequently thermally processed and dehydrated. However, processing negatively affects the sensory quality of tomato products. In this study, four conductive drying processes, i.e. vacuum drum drying (VDD), drum drying (DD), agitated thin film drying (ATFD) and refractance window drying (RWD) were studied for being energy-efficient drying methods, while suitable for mild (e.g. due to the reduced pressure) drying of pastes and slurries, such as tomato puree. The pilot-scale drying experiments and subsequent statistical analyses of results on quality markers contributed to unravel the impact of the different conductive drying technologies on tomato powder quality. This study may be considered a starting point for selection of conductive drying technologies for the efficient production of high quality tomato powders and other vegetable powders.     

采摘时期对菊花茶汤感官及理化属性的影响

选取市面上常见的8种茶用菊花,探究不同采摘时期对其茶汤感官属性及挥发性、非挥发性物质的影响。通过定量描述性分析、气相色谱质谱联用、高效液相色谱以及紫外分光光度法对感官及理化属性进行测定。结果表明,采摘时期主要影响菊花茶汤的滋味和口感,利用偏最小二乘回归分析,确定总酚、游离氨基酸质量浓度与感官滋味正相关。此外,采摘时期也会对菊花茶汤的挥发性物质产生影响,但远不及品种和生长种植条件的差异,进一步利用气味活度值推测正壬醛和桉叶油醇为传统菊花香气的主要物质来源,该研究为菊花茶产业的市场推广以及定向调控菊花品质满足消费者需求提供依据。     

Composition of volatile compounds in bovine milk heat treated by instant infusion pasteurisation and their correlation to sensory analysis

Volatile compounds in skim milk and nonstandardised milk subjected to instant infusion pasteurisation at 80°C, 100°C and 120°C were compared with raw milk, high temperature short time pasteurised milk and milk pasteurised at 85°C/30 s. The composition of volatile compounds differed between infusion pasteurisation treated samples and the reference pasteurisations. The sensory properties of skim milk subjected to instant infusion pasteurisation were described by negative attributes, such as cardboard sour and plastic flavours, which are not associated normally with fresh milk. Partial least squares modelling showed good correlation between the volatile compounds and the sensory properties, indicating the predictive and possible causal importance of the volatile compounds for the sensory characteristics.     

Study on the potential contribution of bacterial community on the volatile flavour of Yongfeng chilli paste

The study aimed to explore the contribution of the microbial community on flavour formation by measuring physicochemical properties, volatile compounds composition and bacterial community of Yongfeng chilli paste. A similar amino acid nitrogen level and different pH, total acid and salt content were observed in five brands of Yongfeng chilli paste. A total of 106 volatile compounds were identified, wherein, ethyl palmitate, ethyl trans-4-decenoate, phenylethyl alcohol were the common volatile compounds with high content in all samples. Additionally, Oxyphotobacteria-unclassified, Mitochondria-unclassified, Pediococcus, Bacillus, Lactobacillus and Weissella were the dominant genera. Lactobacillus was related to the production of some alcohols and terpenes. Whereas, Bacillus, Pediococcus and Weissella, which showed higher salt tolerance, could affect the formation of esters, such as ethyl salicylate, ethyl lactate. Thus, this study provided a basis for further research on the mechanism of flavour formation and some guidance for the improvements of the quality of traditional fermented chilli paste.     

Predication of Japanese green tea (Sen-cha) ranking by volatile profiling using gas chromatography mass spectrometry and multivariate analysis

The sensory quality ranking of Japanese green tea (Sen-cha) was evaluated and predicted using volatile profiling and multivariate data analyses. The volatile constituents were extracted from tea infusion using vacuum hydrodistillation and analyzed using GC/MS. A quality of green tea could be discriminated to a high or low grade regarding the volatile profile by partial least squares discriminant analysis (PLS–DA). A quality ranking predictive model was developed from the relationship between subjective attributes (sensory quality ranking) and objective attributes (volatile profile) using partial least squares projections to latent structures together with the preprocessing filtering technique, orthogonal signal correction (OSC). Several volatile compounds highly contributed to model prediction were identified as various odor-active compounds, including geraniol, indole, linalool, cis-jasmone, dihydroactinidiolide, 6-chloroindole, methyl jasmonate, coumarin, trans-geranylacetone, linalool oxides, 5,6-epoxy-β-ionone, phytol, and phenylethyl alcohol. The whole fingerprints of these volatile compounds could be possible markers for the overall quality evaluation of green tea beverage.     

Biometric,nutritional and sensory changes in intensively farmed Murray cod (Maccullochella peelii peelii, Mitchell) following different purging times

A period of purging before harvesting is common practice in intensive aquaculture to eliminate any possible off flavours from the fish. The present study was conducted to evaluate the biometrical, nutritional and sensory changes in intensively farmed Murray cod (Maccullochella peelii peelii) after 0, 2 and 4 weeks of purging. After the main biometric parameters were recorded, fish were analysed for proximate, fatty acid composition and flavour volatile compounds. A consumer preference test (triangle test) was also conducted to identify sensorial differences that may affect the consumer acceptability of the product.     

UPGRADING SPENT LAYER MEAT BY MECHANICAL DEBONING AND FURTHER PROCESSING

Spent layer chickens, an underutilized, inexpensive source of animal protein in the United States, were used to produce an acceptable all chicken frank following mechanical deboning of the chicken parts without pregrinding. The franks were subjected to shear tests and compared to two well-known commercial brands of chicken franks for overall acceptability by an untrained 59 member panel. The franks produced from mechanically deboned spent layer chickens (Lab franks) had greater resistance to shear than the two commercial brands and the panelists showed significantly greater preference for one of the commercial brands. Comments of the panelists indicated the texture of the lab-prepared franks was tougher than the two commercial brands. However, 12 members of the panel stated the lab-frank texture was tender. Collagen content of the spent layer franks was no higher than for the commercial brands. It is therefore concluded that the toughness could have been due to the nature of the myofibrillar proteins. Such toughness could be modified by tenderizing enzyme treatment of the raw material to produce varying degrees of frank softness or firmness depending on consumer preference.     

Sugars, organic acid and phenolic compounds of Ziziphus mauritiana Fruit

This study was conducted to identify soluble sugars, non-volatile acids and phenolic compounds in Ziziphus mauritiana fruit. Soluble sugars in Ziziphus mauritiana fruit were qualitatively determined by TLC. The sugars identified to be present in Ziziphus mauritiana were galactose, fructose and glucose. TLC was also used for qualitative analysis of phenolic compounds; five spots of phenolic compounds were observed. Only two of the observed spots were identified using the R_f values of the standards that were available. The two phenolic compounds identified by TLC were caffeic acid and p-coumaric acid. Phenolic compounds were also quantified using HPLC. Twelve peaks of phenolic compounds were detected. Among these, p-hydroxybenzoic acid, caffeic, ferulic acid and p-coumaric acid were the most abundant with concentrations of 365.94, 30.76, 19.64 and 19.28 mg/kg dry mass respectively, whereas vanillic acid was the least abundant with a concentration of 2.52 mg/kg. The organic acids were qualitatively analysed by PC and citric acid, malonic acid and malic acid were identified in the Ziziphus mauritiana fruit.     

Chemical composition and volatile constituents of canned mango juice

The chemical composition of mango (Mangifera indica L.) pulp and canned mango juice were evaluated. Canned mango juice was characterized by a lower content of ascorbic acid, free amino nitrogen, reducing sugars and carotenoids than the mango pulp, while the latter was characterized by lower natural total soluble solids, higher pH, lower total sugars and lighter color. The volatile composition of canned mango juice was investigated by means of standard-controlled distillation-extraction, liquid-solid chromatography and gas chromatography-mass spectrometry. This combination led to the characterization of 64 volatiles, of them 21 hydrocarbons, 25 alcohols, 12 esters, 2 aldehydes, 2 lactons and 2 other compounds. The volatile components of canned mango juice were quantitatively determined in range of 2260 ppb to 10 ppb. Limonene, myrcene, cis and trans-ocimene, β-caryophellene and α-terpinolene were the major hydrocarbons of canned juice; meanwhile, methyl butanoate + ethyl 2-methyl butanoate, furfural, α-terpineol and γ-octalacton were the abundant oxygenated compounds.     

乳酸菌协同发酵对饼干风味的影响及应用

本文基于消费者喜好酸度的探究,考察乳酸菌协同发酵对饼干风味特性的影响。经消费者对不同pH值面团制备的乳酸菌协同发酵饼干的喜好度评价显示,当发酵面团p H值为4.35~4.20时具有较高的消费者喜好度评分。采用21株乳酸菌发酵制备饼干,观察其对产品风味的影响。经感官描述性分析发现,坚果味、水果味(气味和滋味)、乳品酸味和甜味的强度与消费者喜好度呈正相关;而丁酸味、苦味和酵母味风味强度则与喜好度呈负相关。不同乳酸菌制备的发酵饼干中风味物质的种类和含量均具有差异。酯类、羰基类及烃类化合物的含量与消费者喜好度呈正相关;而有机酸及醚类物质种类及含量的不同是决定产品风味差异及喜好度评分不同的主要因素之一。结果表明,乳酸乳球菌XX3发酵制得的饼干具有较好的感官风味品质,其果香风味强度及酯类物质含量显著高于其他组饼干。     

云南芒果中酵母菌分离鉴定及在芒果酒发酵中的应用

本实验以从云南省采集的4 个品种的芒果果皮作为分离源,经分离、纯化及三级筛选得到6 株在芒果汁基质中具有良好发酵力的酵母菌。利用WL营养培养基对所筛得酵母菌进行初步分类,结合26S rDNA测序鉴定,除1 株为Hanseniaspora opuntiae,另外5 株均为Wickerhamomyces anomalus。其中DTM9（W. anomalu）和DKT11（H. opuntiae）发酵芒果酒的气相色谱-质谱联用（gas chromatography-mass spectrometry,GC-MS）分析结果表明,与芒果清汁相比,DTM9发酵的芒果酒中,酯类物质含量增加了51.63%,种类增加了400%;醇类物质含量增加28.37%,种类增加了27.27%;DKT11发酵的芒果酒中酯类物质含量增加了44.27%,种类增加了433%;醇类物质含量增加了34.17%。综合比较理化指标和感官分析结果,DTM9具有更高的糖利用率,且发酵的芒果酒感官品质更优良,对提高芒果酒的香气质量有重要意义。     

Characterisation of volatile compounds in Maotai flavour liquor during fermentation and distillation

Volatile constituents in raw liquor and zaopei during fermentation and distillation were investigated by gas chromatography. Zaopei (steamed grains mixed with Daqu [FG1], stacking fermented grains [FG2], anaerobic fermented grains [FG3] and steamed grains [FG4]) presented changes in physicochemical properties. In all, 72 volatile compounds were identified in zaopei and raw liquor with similarity across 12 zaopei preparations. Principal component analysis and partial least squares discriminant analysis differentiated FG3 from other samples based on content of aroma compounds. FG3 had the highest level of aroma compounds, which increased from the fourth to sixth batches, and was characterised by the presence of 1, 2‐propanediol, acetic acid and linoleic acid, while the others were portrayed by phenylpropionate, ethyl laurate and 4‐ethyl guaiacol. The volatile compounds of raw liquor were dominated by ethyl acetate and ethyl lactate. Correlation analysis illustrated a lack of correlation of volatile compound content between the raw liquors and the zaopei distillation variants. © 2019 The Institute of Brewing & Distilling     

Identification of odour-active compounds in ewes' raw milk commercial cheeses with sensory defects

The aim of this work was to identify key odorant compounds associated with main off-flavours (acid, rancid and faecal) and one defect related to the internal appearance (big irregular eyes) in ewes' raw milk commercial cheeses. Cheese samples were submitted to solvent assisted flavour evaporation (SAFE) and odorant compounds were detected by gas chromatography–olfactometry (GC–O). Odour-active compounds detected by GC–O were identified and quantified by gas chromatography–mass spectrometry (GC–MS). Partial least square regression was performed to determine relationships between relative abundances of the odour-active compounds and sensory defects of commercial cheeses. An imbalance in the concentration of short-chain free fatty acids, predominant compounds in all cheese samples, was associated with acid and rancid off-flavour, whereas faecal off-flavour was related to minor compounds such as 4-methylphenol and 3-methyl-1-butanol. No volatile compound could be related to the defect of big irregular eyes.     

Effect of controlled atmospheres and shelf life period on concentrations of volatile substances released by ‘Pink Lady®’ apples and on consumer acceptance

BACKGROUND: ‘Pink Lady^®’ (Malus × domestica Borkh.) apples were harvested at commercial maturity and stored at 1 °C under either air or controlled atmosphere (CA) conditions (2.5 kPa O₂: 3 kPa CO₂ and 1 kPa O₂: 2 kPa CO₂) for 15 or 28 weeks. Standard quality parameters, consumer acceptance and volatile compound emission were evaluated after cold storage plus shelf life period at 20 °C. RESULTS: A shelf life period of 17 days after long‐term storage in controlled atmosphere allowed the regeneration of the characteristic esters associated to the aroma of this variety. Sixty‐five per cent of consumers preferred apples with higher emissions of aroma‐active volatile compounds, despite the fact that these apples displayed lower values for standard quality attributes. The most accepted samples corresponded to fruit stored in air for 15 weeks regardless of post‐storage period, in air for 28 weeks plus 1 day at 20 °C, and in 2.5 kPa O₂: 3 kPa CO₂ for 15 weeks plus 7 days at 20 °C. CONCLUSIONS: Concentrations of specific aroma volatile compounds are suggested to be more important than total aroma emission for consumer acceptance of ‘Pink Lady^®’ apples. Copyright © 2009 Society of Chemical Industry     

建宁莲子挥发性风味化合物分析

目的 分析建宁莲子中的挥发性风味化合物。 方法 采用顶空固相微萃取-气相色谱-质谱联用技术(headspace solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS),结合热图分析和偏最小二乘-判别分析(Partial least squares Discriminant Analysis,PLS-DA)对莲子挥发性风味化合物进行鉴定及产品差异化分析。 结果 8款建宁莲子中一共鉴定出 93 种挥发性化合物,共有挥发性化合物23种。其中53 种为风味化合物,共有风味化合物17种,主要为醇类、酸类、烃类和杂环类。热图分析结果显示风味化合物被聚类成上、中、下3个区域,8款莲子可以被分为4类。基于 PLS-DA 模型的变量投影重要性(variable important in the projection,VIP)得分对 8款莲子风味化合物进行了判别分析,筛选出 13 种(VIP?1)标志风味化合物,其中双戊烯、己醇、异戊醇和苯乙醇是主要的差异化合物。 结论 研究表明,建宁莲子中风味化合物种类丰富,主要包括醇类、烃类、杂环类和醛类等。风味化合物结合热图与PLS-DA分析可用于莲子产品差异化分析,并为莲子工艺改进、产地区分和育种提供理论支撑和思路。     

Effect of γ-irradiaton on the volatile compounds of licorice (Glycyrrhiza uralensis Fischer)

The volatile compounds of non-irradiated and 1, 3, 5, 10 and 20 kGy γ-irradiated roots of licorice (Glycyrrhiza uralensis Fischer) were isolated by simultaneous distillation–extraction (SDE) technique and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 61 volatile compounds belonging to the chemical classes of acid (2), alcohol (16), aldehyde (8), ester (6), furan (2), hydrocarbon (14), ketone (10) and N-containing compounds (3) were identified in non-irradiated licorice. The prime volatile compound of licorice was 2-ethoxy-1-propanol, which makes up to 22.82% of the total composition. Over a dose of 1 kGy, another compound, benzaldehyde appeared, whereas other compounds, 3,5-dimethyl octane and phenethyl alcohol, disappeared at the dose of 20 kGy. Though the content of several volatile compounds increased after γ-irradiation, the content of major volatile compounds such as 4-terpineol, myrtenal, tetramethylpyrazine, hexanoic acid, azulene and p-cymene decreased. In comparison to non-irradiated licorice, 10 kGy dose of irradiation induced the maximum level of total yield of volatile compounds by 12%, but slightly decreased at 20 kGy. Therefore, the application of γ-irradiation is feasible without major qualitative and quantitative loss of volatile compounds when exposed at 10 kGy.     

Evaluation of processed green and ripe mango peel and pulp flours (Mangifera indica var. Chokanan) in terms of chemical composition,antioxidant compounds and functional properties

BACKGROUND: Mango is a highly perishable seasonal fruit and large quantities are wasted during the peak season as a result of poor postharvest handling procedures. Processing surplus mango fruits into flour to be used as a functional ingredient appears to be a good preservation method to ensure its extended consumption. RESULTS: In the present study, the chemical composition, bioactive/antioxidant compounds and functional properties of green and ripe mango (Mangifera indica var. Chokanan) peel and pulp flours were evaluated. Compared to commercial wheat flour, mango flours were significantly low in moisture and protein, but were high in crude fiber, fat and ash content. Mango flour showed a balance between soluble and insoluble dietary fiber proportions, with total dietary fiber content ranging from 3.2 to 5.94 g kg^?1. Mango flours exhibited high values for bioactive/antioxidant compounds compared to wheat flour. The water absorption capacity and oil absorption capacity of mango flours ranged from 0.36 to 0.87 g kg^?1 and from 0.18 to 0.22 g kg^?1, respectively. CONCLUSION: Results of this study showed mango peel flour to be a rich source of dietary fiber with good antioxidant and functional properties, which could be a useful ingredient for new functional food formulations. Copyright © 2011 Society of Chemical Industry