Compositional, Nutritional, and Functional Characteristics of Instant Teas Produced from Low- and High-Quality Black Teas

Abstract

Two types of instant teas produced from low- and high-quality black teas were examined for their proximate composition, dietary fiber, minerals, water-soluble vitamins, total phenolic content, various antioxidant assays, phenolics (flavanols, condensed phenolics, and phenolic acids), alkaloids, and carotenoids as well as taste-active compounds (sugars, organic acids, and free amino acids). Some variations, albeit to different extents, were observed (p < 0.05) among these parameters between instant teas produced from low- and high-quality black teas. With respect to proximate composition, carbohydrate was the predominant component (56.68-59.84 g/100 g), followed by protein (19.31-19.86 g/100 g). Ash, moisture, and, to a lesser extent, dietary fiber and fat were also present in both instant teas. Thirteen minerals, four water-soluble vitamins, six flavanols, two alkaloids, three condensed phenolics, one phenolic acid, and one carotenoid were identified. Total phenolic content varied between 17.35 and 17.82 g of gallic acid equivalents (GAE)/100 g instant tea. With regard to antioxidant activities, three different assays such as oxygen radical absorbance capacity (ORAC), trolox equivalent antioxidant capacity (TEAC), and cupric ion reducing antioxidant capacity (CUPRAC) were measured. No significant differences (p > 0.05) in total phenolic, ORAC, TEAC, and CUPRAC contents between low- and high-quality instant teas were observed. With regard to taste-active compounds, 3 sugars, 5 organic acids, and 18 free amino acids were positively identified, of which fructose, tannic acid, and theanine predominated, respectively. The present work suggests that despite some differences, instant teas produced from low- and high-quality black teas should not be distinguished on the basis of their compositional, nutritional, and functional characteristics as well as taste-active compounds.

Volatile compounds and sensory characteristics of various instant teas produced from black tea

“…The extraction of black tea for subsequent preparation of instant teas was performed according to Alasalvar et al (2013). Scheme of the process used to produce instant teas is presented in Figure 1.…”

“…Scheme of the process used to produce instant teas is presented in Figure 1. Spray-drying of tea extract was performed according Alasalvar et al (2013). Freeze-drying was performed in a pilot scale freeze dryer (Telstar LyoBeta 35, Barcelona, Spain), which was programmed from -40 to 25 °C for 48 h. Decaffeination of black tea leaves was performed according to Bahar, Pelvan, Hasbay and Alasalvar (2013), with a slight modification.…”

Determination of phenolic compounds by ultra high liquid chromatography-tandem mass spectrometry: Applications in nuts

“…Reversed-phase liquid chromatography coupled with electrospray mass spectrometry detection is the most powerful analytical technique for the analysis of polyphenols (Boros et al, 2010) among the others such as high-performance liquid chromatography (HPLC) coupled with negative atmospheric pressure chemical ionization mass spectrometry (APCI-MS) (Caruso, Colombo, Patelli, Giavarini, & Galli, 2000;Sang et al, 2002), HPLC with UV detector (Hakkinen, Karenlampi, Heinonen, Mykkanen, & Torronen, 1998), diode array detector (Andrade, Seabra, Valentiio, & Areias, 1998;Alasalvar et al, 2013), fluorescence detector (Gurbuz et al, 2007;Rodriguez-Delgado, Malovana, Perez, Borges, & Montelongo, 2001), capillary electrophoresis (CE) (Arce, Rios, & Valcarcel, 1998;Ehala, Vaher, & Kaljurand, 2005), and highperformance thin layer chromatographic (HPTLC)-densitometric technique (Sharma, Sharma, Kumar, & Sinha, 2007).…”

Voltammetric determination of tannic acid in beverages using pencil graphite electrode

“…The content of TA in fruits, tea, and beer can strongly influence their taste, and hence, it is an important parameter to evaluate and control the quality of these products (Alasalvar et al 2013). TA is also used as an additive in the medicinal industry, including those used for the treatment of burns and diarrhoea (Wan et al 2007).…”