Sensory evaluation in food

GC-O-MS technique and its applications in food flavor analysis.

In this research, effect of the thermal treatment on the flavor generation from Maillard reaction of xylose and chicken peptide was studied. In summary, high temperature (>100 °C) could remarkably increase the formation of meaty aroma generated by xylose and chicken peptide through a Maillard reaction system, while lower temperature and longer heating tended to generate a broth-like taste (i.e., umami and kokumi). Pyrazines were the major contributors to the nutty/roast and basic meaty aroma in the Maillard reaction products (MRP), while the Glu released under the low temperature heating was considered an important contributor to the umami taste of MRPs. The low molecular weight peptide ( 1000 Da formed from peptides 3000 Da were very likely responsible for the bitter taste.

Effect of thermal treatment on the flavor generation from Maillard reaction of xylose and chicken peptide

Production of ethyl levulinate by direct conversion of wheat straw in ethanol media.

This paper is a review of the recent studies on Maillard reaction products, the formation mechanism for these compounds and melanoidin structure, the undesirable consequences in food especially in fruit juice processing, the desirable effects and the biological properties related to the beneficial health. Melanoidins are compounds generated in the late stages of the Maillard reaction from reducing sugars and proteins or amino acids during food processing and preservation. Recently, the effects of melanoidins on human health and the chemical characterization of the beneficial components have gained a lot of attention, and their implications on several levels, sensory, nutritional, toxicological and technological were investigated. Food melanoidins have been reported to be anionic, coloured compounds, and some of their key chromophores have been elucidated. The antioxidant activity and other biological effects of melanoidins from real foods and model systems have been widely studied. Despite this, very few different melanoidin structures have actually been described, and specific health effects have yet to be linked with chemically distinct melanoidins. The variety of Maillard reaction products formed during the reaction, in conjunction with the difficulty in purifying and identifying them, makes a thorough analysis of melanoidins challenging.

Melanoidins Formed by Maillard Reaction in Food and Their Biological Activity

Previously, the aroma compounds in watermelon juice were analyzed by either GC-MS or GC-O. These methods could not extract and analyze the volatile compounds comprehensively. Compared to the previous studies, for accurately identifying the aroma profile, the volatile compounds in fresh watermelon juice (FW) and thermally treated watermelon juice (TW) were analyzed using HS-GC-IMS and GC × GC-O-MS. Twenty-three compounds were detected by HS-GC-IMS, among them, allyl methyl sulfide, acetoin, and pentanal were identified for the first time in TW. Through GC × GC-O-MS analysis, 130 and 140 compounds were detected in FW and TW, respectively, and 36 and 38 of these compounds were smelled. In this study, 2,6-dimethyl-5-heptenal was identified for the first time in FW as an odor-contributing compound. These two kinds of juices could be differentiated by heat-mapping. The concentrations of (E)-2-decenal, decanal, 2-hexenal, 2-pentylfuran, and 6-methyl-5-hepten-2-one increased greatly by Volcano plot, and they contributed to the off-flavor in TW. For aroma analysis of watermelon juice, HS-GC-IMS can rapidly analyze the samples with low detection limits without pretreatment, while GC × GC-O-MS can precisely identify the compounds with sniffing. The results of this study suggest that HS-GC-IMS and GC × GC-O-MS can analyze the aroma profile more comprehensively and discriminate FW and TW more efficiently.

Screening of the volatile compounds in fresh and thermally treated watermelon juice via headspace-gas chromatography-ion mobility spectrometry and comprehensive two-dimensional gas chromatography-olfactory-mass spectrometry analysis

Formation mechanism of volatile and non-volatile compounds in peptide–xylose Maillard reaction

The aroma-active compounds in Jinhua ham processed and stored for 9, 12, 15 and 18 months were extracted by dynamic headspace sampling (DHS) and solvent-assisted flavor evaporation (SAFE) and analyzed by gas chromatography-olfactometry-mass spectrometry (GC-O-MS). In GC-O-MS, volatile compounds were identified based on their mass spectrum, linear retention index (LRI), odor properties, or reference compound comparisons. The results showed that a total number of 81 aroma-active compounds were identified by GC-O-MS. Among them, acids (such as acetic acid, butanoic acid and 3-methylbutanoic acid), saturated aldehydes (such as hexanal, heptanal, octanal and 3-methylbutanal), benzene derivatives (such as benzeneacetic acid), ester and lactone (such as γ-nonalactone and γ-decalactone) were identified as critical compounds in Jinhua ham aroma. The results also indicated that the type and content of the odorants increased significantly with the duration of the fermentation period.

https://www.mdpi.com/1420-3049/19/11/19097/pdf

Aroma-Active Compounds in Jinhua Ham Produced With Different Fermentation Periods

Aroma-active compounds and non-volatile substances determine the characteristic aroma and taste of yeast extract (YE). Changes in the characteristic aroma and taste of YE due to thermal reaction are rarely studied, and the relationship between aroma-active compounds and non-volatile compounds is not yet clear.; Results: Non-volatile compounds identified by HPLC and LC/MS/MS were reduced by a rise in temperature, except for some amino acids. Peptides underwent degradation. In addition, a further rise in temperature above 120 °C resulted in a bitter and sour taste. Furans, pyrazines, thiophenes, thiazoles and some branched chain sulfur compounds were derived from GC/O/MS (SPME and SAFE). Sensory results revealed that the concentration of volatile compounds increased with an increase in temperature. The overall aroma profiles of YE at 25, 100 and 110 °C were buttery, green, nutty and meaty, while YE at 140 °C had a strong sour and sulfur odour.; Conclusion: The non-volatile compounds of YE were reduced and different volatile compounds were produced under different thermal treatments. There was a negative correlation between these two types of compounds. The different taste sensors and all precursors were correlated with each other. There are significant relationships between different odorants and aroma-active compounds of YE after thermal treatment. © 2018 Society of Chemical Industry.; © 2018 Society of Chemical Industry.

Tingting Zou

Papers

Screening of the volatile compounds in fresh and thermally treated watermelon juice via headspace-gas chromatography-ion mobility spectrometry and comprehensive two-dimensional gas chromatography-olfactory-mass spectrometry analysis

Formation mechanism of volatile and non-volatile compounds in peptide–xylose Maillard reaction

Aroma-Active Compounds in Jinhua Ham Produced With Different Fermentation Periods

Flavour-active compounds in thermally treated yeast extracts.

The behavior of umami components in thermally treated yeast extract