Suppressive Interaction Approach for Masking Stale Note of Instant Ripened Pu-Erh Tea Products

Abstract

The unpleasant stale note is a negative factor hindering the consumption of instant ripened Pu-erh tea products. This study focused on investigating volatile chemicals in instant ripened Pu-erh tea that could mask the stale note via sensory evaluation, gas chromatography-mass spectrometry (GC-MS), and gas chromatography-olfactometry (GC-O) analyses. GC-MS and GC-O analyses showed that linalool, linalool oxides, trans-β-ionone, benzeneacetaldehyde, and methoxybenzenes were the major aroma contributors to the simultaneous distillation and extraction (SDE) extract of instant ripened Pu-erh tea. Sensory evaluation showed that the SDE extract had a strong stale note, which was due to methoxybenzenes. By investigating suppressive interaction among flavour components, the stale note from methoxybenzenes was shown to have reciprocal masking interactions with sweet, floral, and green notes. Moreover, the validation experiment showed that the addition of 40 μg/mL of trans-β-ionone in the instant ripened Pu-erh tea completely masked the stale note and improved the overall aromatic acceptance. These results elucidate the volatile chemicals that could mask the stale note of instant ripened Pu-erh tea products, which might help to develop high quality products made from instant ripened Pu-erh tea.

Characterization of the Aroma of an Instant White Tea Dried by Freeze Drying

“…Compounds with different structures frequently demonstrated masking effects [32]. For instance, (E)-2-hexenal (green and grassy note) could reduce the intensities of roasted and sulfur notes in the oolong tea [32]; Zhang et al showed that trans-β-ionone can significantly eliminate stale note and improved the overall aromatic acceptance of instant ripened Pu-erh tea infusion [36]. By comparison, it is the first time to reveal the synergistic interaction of trans-β-damascenone and camphene could reciprocally reduce the notes of both trans-β-damascenone (sweet) and camphene (green).…”

“…Volatile compounds in IWT were extracted according to the methods reported in the literature [36]. An SDE apparatus similar to the design of Lickens-Nickerson apparatus was purchased from Beijing Glass Instrument Factory (Beijing, China).…”

“…Because linalool, trans-β-damascenone and camphene had the highest FD factors (FD = 64) among all the detected volatiles possessing different notes, these three compounds were chosen to explore the interaction between different notes. To study the interactions among the major aroma contributors, seven interaction models were prepared with linalool, trans-β-damascenone, camphene and n-hexane to a final volume of 1.5 mL, according to a previous method [36]. The samples were: (1) the pure floral note model was the pure solution of linalool (128.7 mg/L); (2) the pure sweet note model was the pure solution of trans-β-damascenone (5.9 mg/L); (3) the pure green note model was the pure solution of camphene (42.1 mg/L); (4) the interaction model of floral and sweet notes was the mixed solution of linalool (128.7 mg/L) and trans-β-damascenone (5.9 mg/L); (5) the interaction model of floral and green notes was made of linalool (128.7 mg/L) and camphene (42.1 mg/L); (6) the interaction model of sweet and green notes was made of trans-β-damascenone (5.9 mg/L) and camphene (42.1 mg/L); and (7) the interaction model of floral, sweet and green notes was made of linalool (128.7 mg/L), trans-β-damascenone (5.9 mg/L) and camphene (42.1 mg/L).…”

Analysis of the Volatile Components in Selaginella doederleinii by Headspace Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry

“…The preliminary identification of the volatiles was done by comparing the mass spectra with National Institute of Standards and Technology (NIST) 14.0 MS database and Wiley National Institute of Standards and Technology (Wiley NIST) 14.0 MS database. These volatiles were further confirmed by matching the reference literature records and retention time of authentic standards, as well as contrasting the calculated RI with that which was recorded in the NIST network database (http://webbook.nist.gov/chemistry/) [44]. Identified volatile oils were semi-quantified by comparing the peak areas of each volatile with total peak areas.…”

“…Variable important plot (VIP) score is an indicator of the correlation of variables. When the volatile oil has a VIP value greater than 1, it indicates that they have an above-average effect [41] and can be used to distinguish S. doederleinii in Zhejiang and Guizhou, namely anethol (19), zingerone(49), 2,4-di-tert-butylphenol(40), ledene(42), hexyl hexanoate(25), α-cadinol(52), phytone(58), hinesol(48), decanal(13), octadecene(56), cedren(30), 7-tetradecene(26), copaene(28), beta-humulene(37), 2-butyl-2-octenal(24), tetradecane (27), cedrol(47), calacorene(43), 6-dodecanone(23), β-caryophyllene(31), 4-oxoisophorone(9), γ-nonanolactone(22), 2-pentylfuran(5), 1,2-epoxyhexadecane(55), carvacrol(21), n-pentadecane (38), diisobutyl phthalate, (53) farnesene(29), n-heptadecane(54), linalool(8), 1-octen-3-ol(2), phytane(57), and β-asarone (44). Therefore, these substances were important markers for the identification and quality control of S. doederleinii.…”