Production of High‐Aroma Instant Tea Powder Using Various Novel Technologies

Abstract

Various nonthermal processing technologies were applied, including pulsed electric field (PEF) technology, freeze concentration and vacuum freeze‐drying. The black tea was extracted with hot water extraction, cold extraction and PEF extraction. Results indicated that PEF‐assisted extraction had the best extraction efficiency for the main chemical components from tea at lower temperatures. Optimal PEF extraction conditions were achieved (tea leaves/water ratio of 1:16, electric field strengths of 20 kV/cm and pulse frequency of 125 Hz). The effects of PEF‐assisted extraction on the chemical component contents and sensory qualities of the tea infusion were investigated. Results showed that extraction yield (22.7%) of black tea powder could be enhanced over PEF‐assisted extraction, whereas its original flavor could be retained by freeze concentration and vacuum freeze‐drying. It also turned out that a total of 61 major aromatic compounds were identified in the tea powder. Floral and sweet flavor components were high and pure. Practical Applications Instant black tea is presently manufactured through hot water extraction or cold‐water extraction from the tea infusion and by spray/freeze‐drying of the concentrated brew of extracted tea leaves; the drawback of this method is inferior quality. The product obtained from the new method had an excellent quality and good aromatic characteristics to the other ordinary instant black tea powder manufacturing methods. The process developed in this study could be suitable for black tea manufacturers to produce high‐aroma instant black tea powder.

Effect of Ultrasonic-assisted and Microwave-assisted Technology on Bioactive Compounds and Aroma Quality of Instant Green Tea

“…Studies have reported that the color and aroma of tea improves following ultrasonic and microwave treatments [29][30][31][32][33][34]. However, in this study, the aroma of tea after ultrasonic and microwave treatments increased and decreased, respectively.…”

Processing Technologies for the Extraction of Value-Added Bioactive Compounds from Tea

“…By using PEF for extraction, tea’s aromatic compounds, polyphenols are protected from damage [ 34 , 35 , 188 ], and its color, taste, and aroma remain unchanged [ 34 , 35 , 39 , 179 , 186 , 188 ]. Traditionally, PEF has been used in the extraction and retention of polyphenols from green tea [ 179 , 187 ], black tea [ 186 ], Puer tea [ 174 ], and green tea infusions [ 33 – 35 ]. PEF retained more bioactive compounds and color than conventional heat treatment [ 34 , 35 ].…”

Extraction and preparation of high-aroma and low-caffeine instant green teas by the novel column chromatographic extraction method with gradient elution

“…Most of the aroma compounds are low-polar volatile substances which were not effectively extracted by the traditional extraction methods using hot water or ethanol aqueous solution, or lost during the concentration of tea extracts at high temperatures (Zhu et al 2008;Huo et al 2014;Katsuno et al 2014). Some efforts have been made to extract or recover the tea aroma compounds in the production of instant tea, such as vacuum-distillation, simultaneous distillation and extraction, resin adsorption, supercritical extraction, microwave assisted extraction and freeze drying (Lv et al 2012;Ye et al 2014). These methods are ineffective or uneconomic for industrial production of instant green teas.…”