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• The quality and flavor of Noni during ripening were analyzed by different methods. • The optimum stage of nutrient accumulation was 7M−8M. • The volatile odor changed markedly from 8M to 9M. • The sour, astringent and fresh tastes contributed to the dominant taste. • The shared and unique compounds can be used as references for ripeness markers. Different ripeness plays a key role in the final quality and flavor of Noni products, but the variations of quality and flavor during Noni ripening are still unclear. In this study, physicochemical analysis combined with electronic nose, electronic tongue and gas chromatography-mass spectrometry (GC–MS) were used to investigate the effect of different ripeness levels on Noni fruit quality and flavor chemistry. The results showed that the optimum stage of nutrient accumulation is 7–8 ripe (7M−8M), in which especially the higher contents were 144Mg/100 g vitamin C, 11.08 g/kg polyphenols, 15.32 g/kg flavonoids and 2420Mg/kg potassium. Octanoic acid and hexanoic acid with an unfriendly odor began to decrease significantly after 8 ripe (8M), the lowest contents were 256.76 and 231.26 ng/g at 9 ripe (9M). Sour, astringent and fresh tastes are the dominant tastes of Noni fruit. Therefore, the optimum harvesting time of Noni fruit is 8M. [ABSTRACT FROM AUTHOR]

The quality changes of RJ at different storage conditions are evaluated from various perspectives, including non-target volatile compound profiling, multi-index (physicochemical parameters and flavor characteristics), and multi-technology (HS-SPME-GC/MS, electronic nose, and electronic tongue) integration. [Display omitted] • A total of 37 volatile compounds in royal jelly are identified using HS-SPME-GC–MS. • Seven volatile compounds contribute largely to the overall flavor of royal jelly. • Electronic nose/tongue exhibit useful value in the quality control of royal jelly. • Combination of multiple methods enhance the evaluation of royal jelly quality. Royal jelly (RJ) is known for its unique flavor and nutritional value. However, the flavor changes of RJ during storage remain unclear. In this work, the flavor profiles of RJ during storage were evaluated by using headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) combined with both electronic nose and electronic tongue analyses. Results revealed that the moisture, water-soluble protein, and whiteness were changed significantly at 25 °C. The holistic variation of RJ flavor exhibited evident distinction based on principal component analysis with electronic nose and electronic tongue. Among the total of 37 volatile compounds identified in RJ, the octanoic acid showed the highest contents of 47.61 % at 25 °C in 21 d. Seven volatile compounds, i.e., 2(3H)-furanone,5-butyldihydro-, 2-heptanone, trans -β-ocimene, 2-nonen-4-one, 2-nonanone, methyl benzoate, and 2-octenoic acid (E), contributed largely to the typical overall flavor of RJ. This work provides an improved understanding of the flavor change of RJ during storage. [ABSTRACT FROM AUTHOR]

Eight kinds of commercial rice vinegars from Korea, China and Japan were selected to evaluate their flavour-related discriminative characteristics based on solid-phase microextraction and gas chromatography with mass spectrometry (SPME/GC-MS), an electronic nose (e-nose), electronic tongue (e-tongue) and subjective sensory evaluation. Principal component analysis patterns based on SPME/GC-MS provided a clear categorical discrimination among the vinegars of three origins. The distribution patterns of the samples were similar between SPME/GC-MS and e-nose analyses and Korean vinegars were clearly discriminated. A high correlation coefficient was determined between SPME/GC-MS and e-nose on acetaldehyde (0.948) and diacetyl (0.970). e-Tongue-based principal component analysis patterns were subdivided into three regions according to the origin, and Chinese vinegars were clearly discriminated. Sensory panelists recorded origin-specific scores on flavours for all the samples. In conclusion, SPME/GC-MS, e-nose and e-tongue analyses may be useful for discrimination of flavour profiles of rice vinegars of different producer origin. Copyright © 2017 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

In this study, electronic tongue (E-tongue), headspace solid-phase microextraction gas chromatography-mass spectrometer (GC-MS), electronic nose (E-nose), and quantitative describe analysis (QDA) were applied to describe the 2 types of citrus fruits (Satsuma mandarins [ Citrus unshiu Marc.] and sweet oranges [ Citrus sinensis {L.} Osbeck]) and their mixing juices systematically and comprehensively. As some aroma components or some flavor molecules interacted with the whole juice matrix, the changes of most components in the fruit juice were not in proportion to the mixing ratio of the 2 citrus fruits. The potential correlations among the signals of E-tongue and E-nose, volatile components, and sensory attributes were analyzed by using analysis of variance partial least squares regression. The result showed that the variables from the sensor signals (E-tongue system and E-nose system) had significant and positive (or negative) correlations to the most variables of volatile components (GC-MS) and sensory attributes (QDA). The simultaneous utilization of E-tongue and E-nose obtained a perfect classification result with 100% accuracy rate based on linear discriminant analysis and also attained a satisfying prediction with high coefficient association for the sensory attributes ( R2 > 0.994 for training sets and R2 > 0.983 for testing sets) and for the volatile components ( R2 > 0.992 for training sets and R2 > 0.990 for testing sets) based on random forest. Being easy-to-use, cost-effective, robust, and capable of providing a fast analysis procedure, E-nose and E-tongue could be used as an alternative detection system to traditional analysis methods, such as GC-MS and sensory evaluation by human panel in the fruit industry. [ABSTRACT FROM AUTHOR]

The importance of monitoring key aroma compounds as food characteristics to solve sample classification and authentication is increasing. The rhizome of Polygonatum sibiricum (PR, Huangjing in Chinese) has great potential to serve as an ingredient of functional foods owing to its tonic effect and flavor properties. In this study, we aimed to characterize and classify PR samples obtained from different processing levels through their volatile profiles and flavor properties by using electronic nose, electronic tongue, and headspace gas chromatography-mass spectrometry. Nine flavor indicators (four odor indicators and five taste indicators) had a strong influence on the classification ability, and a total of 54 volatile compounds were identified in all samples. The traditional Chinese processing method significantly decreased the contents of aldehydes and alkanes, while more ketones, nitrogen heterocycles, alcohols, terpenoids, sulfides, and furans/pyrans were generated in the processing cycle. The results confirmed the potential applicability of volatile profiles and flavor properties for classification of PR samples, and this study provided new insights for determining the processing level in food and pharmaceutical industries based on samples with specific flavor characteristics. [ABSTRACT FROM AUTHOR]