Evaluation of the effect of Torulaspora delbrueckii on important volatile compounds in navel orange original brandy using E-nose combined with HS-SPME-GC-MS

Simultaneous inoculation of non-Saccharomyces cerevisiae during the alcoholic fermentation process has been found to be an effective strategy for enhancing wine flavor. This study aimed to investigate the effect of Torulaspora delbrueckii NCUF305.2 on the flavor of navel orange original brandy (NOOB) using E-nose combined with HS-SPME-GC-MS. The results showed a significant increase (p < 0.05) in the sensitivity of NOOB to W5C, W3C, W1S, and W3S sensors by mixed fermentation (MF). Esters in NOOB increased by 4.13%, while higher alcohols increased by 21.93% (p < 0.001), terpenes and others increased by 52.07% and 40.99% (p < 0.01), respectively. Notably, several important volatile compounds with relative odor activity values above 10 showed an increase. Sensory analysis revealed that a more pronounced citrus-like flavor and higher overall appearance scores were found in MF than in pure fermentation (PF). These findings offer valuable theoretical guidance for enhancing the quality of fruit brandies.

Analysis and application evaluation of the flavour-precursor and volatile-aroma-component differences between waste tobacco stems

The development and utilization of waste resources have important scientific significance and social value. As a renewable and clean resource, the flavour components of waste tobacco stems (WTS) make a significant contribution to the development of waste resources. To evaluate the industrial applicability of the different WTS as raw materials, the present study systematically examined the differences in flavour precursors and volatile aroma components in tobacco stems (TS) from typical tobacco (Nicotiana tabacum L.) growing areas in Yunnan Province through HPLC and GC‒MS analysis. Meanwhile, the contribution to improving the quality of cigarette products is discussed accordingly. The results showed that the contents of flavour precursors, carotenoid and hexane degradation products, neophydiene and total volatile aroma substances in TS were the highest in the Dianxi area, Yun 87 variety and the upper part of Yunnan Province, while the contents of Maillard reaction products and phenylalanine degradation products were the highest in the Diandong area and middle part. The aroma components and sensory quality of TS have obvious regional characteristics in Yunnan. Accordingly, the higher flavour components improve cigarette quality. Most importantly, the middle and upper TS should be preferred to use and classified to process according to the tobacco growing areas, which is beneficial for promoting industrial applicability in cigarette preparation. This study provides a theoretical reference for the industrial value-added applicability of TS in the aspects of flavour extraction and cigarette preparation.

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Differences in flavour precursors and aroma components in tobacco stems were systematically studied.

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Flavour precursors and total volatile substances were the highest in the Dianxi area, Yun 87 variety and upper parts.

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The aroma components and sensory quality of tobacco stems have obvious regional characteristics.

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Higher flavour components in tobacco stems provide a better contribution to improving cigarette quality.

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The use of middle and upper tobacco stems are preferred and classify to process to promote industrial applicability.

Volatile aroma components and MS-based electronic nose profiles of dogfruit (Pithecellobium jiringa) and stink bean (Parkia speciosa)

Dogfruit (Pithecellobium jiringa) and stink bean (Parkia speciosa) are two typical smelly legumes from Southeast Asia that are widely used in the cuisines of this region. Headspace/gas chromatography/flame ionization detection analysis and mass spectrometry (MS)-based electronic nose techniques were applied to monitor ripening changes in the volatile flavor profiles of dogfruit and stink bean. Compositional analysis showed that the ripening process greatly influenced the composition and content of the volatile aroma profiles of these two smelly food materials, particularly their alcohol, aldehyde, and sulfur components. The quantity of predominant hexanal in stink bean significantly declined (P < 0.05) during the ripening process, whereas the major volatile components of dogfruit changed from 3-methylbutanal and methanol in the unripe state to acetaldehyde and ethanol in the ripe bean. Moreover, the amount of the typical volatile flavor compound 1,2,4-trithiolane significantly increased (P < 0.05) in both ripened dogfruit and stink bean from 1.70 and 0.93%, to relative amounts of 19.97 and 13.66%, respectively. MS-based nose profiling gave further detailed differentiation of the volatile profiles of dogfruit and stink bean of various ripening stages through multivariate statistical analysis, and provided discriminant ion masses, such as m/z 41, 43, 58, 78, and 124, as valuable “digital fingerprint” dataset that can be used for fast flavor monitoring of smelly food resources.

Physico-chemical properties, wax composition, aroma profiles, and antioxidant activity of granulated non-centrifugal sugars from sugarcane cultivars of Thailand

Non-centrifugal cane sugar (NCS) is globally consumed and has various health benefits. It is mostly produced in hardened block form, which is less convenient than in granulated form for food applications. In terms of the traditional processing of NCS, preparation of granulated products is difficult due to the impurities found in the cane juice extracted from the whole stalk. Therefore, the aim of this study was to characterize and determine the physico-chemical properties, wax composition (policosanols and long-chain aldehydes), volatile aroma profiles, and antioxidant activity of traditional NCS in granular form made from four different cane cultivars of Thailand. The total soluble solid, pH, color, and mineral content varied among the sugarcane cultivars, whereas there was no significant difference in the total sugar, phenolic and flavonoid content. The total policosanol, a cholesterol-lowering nutraceutical wax component, and long-chain aldehyde contents were similar in the NCS products amongst three cultivars, and ranged from 2.63 to 3.69 mg/100 g. The granulated NCS products, in which acetaldehyde and dimethyl sulfide were the main volatile compounds, gave less aroma components than traditional NCS. The use of different sugarcane cultivars thus influenced the quality attributes of granulated non-centrifugal sugar products.