Valorisation of theanine from decaffeinated tea dust in bakery functional food

Abstract

Nowadays, consumers appreciate the positive properties of decaffeinated tea for their well-being. During decaffeination process, a very fine tea dust powder is obtained as by-product, which contains the same quantity of bioactives as decaffeinated tea: the antioxidant polyphenols and the amino acid theanine. The aim was to add value to theanine gained from black tea powder dust and to develop theanine-enriched bread. A theanine containing powder was obtained by column separation of decaffeinated tea dust extract and spray-drying using carrier supports. This powder contains also the very polar compounds from decaffeinated tea such as amino acids, sugars and minerals. Breads with 110, 220 and 330 ppm of theanine, respectively, were prepared with the theanine powder. Physical properties, theanine and total polyphenolic content in bread were analysed. Bread and other bakery food serve as good products to add value to bioactive tea dust ingredients.

Influence of black tea fractions addition on dough characteristics, textural properties and shelf life of wheat bread

“…Wang and Zhou [36] reported that around 84% of the green tea catechins were retained in bread after baking. Also, theanine fortified breads lost up to 30% of theanine content after baking [16]. In this study, after baking, breads contained around 34% lower level of TPC than the corresponding dough.…”

“…Aqueous tea fractions, theanine (T) and polyphenols (P) enriched fraction, respectively, were prepared from decaffeinated black tea dust, by fractionation on a XAD-16 resin, as reported in previous studies [16,17]. T fraction contained all free amino acids present in tea (among them, theanine with a content of 1.6 mg/mL), sugars (sucrose 1.4 mg/mL, glucose 5.3 mg/mL, fructose 4.7 mg/mL) and very polar phenolic compounds such as gallic acid (1 mg/mL).…”

“…Recently, tea polyphenols have been incorporated in various bakery products for nutritional benefits and the potential to prolong shelf life [12][13][14][15]. Black tea dust, a by-product from the black tea decaffeination process, is a very fine powder (particle size lower than 1 mm) that was shown to represent a source of valuable components [16]. In a previous work, the effect of theanine and polyphenols enriched fractions from decaffeinated black tea dust on the formation of Maillard reaction products and sensory attributes of breads was investigated [17].…”

High‐theabrownins instant dark tea product by Aspergillus niger via submerged fermentation: α‐glucosidase and pancreatic lipase inhibition and antioxidant activity

“…In recent years, the use of instant tea (i.e. both to make tea and as a food ingredient) has become more accepted by consumers and has been widely applied in the food industry . Instant dark teas are made by drying the infusions of dark tea that had been processed via solid‐state fermentation.…”

“…both to make tea and as a food ingredient) has become more accepted by consumers and has been widely applied in the food industry. 16,17 Instant dark teas are made by drying the infusions of dark tea that had been processed via solid-state fermentation. Lu et al 11 reported a new method of producing instant dark tea (Fu-brick) from green tea leaves processed by the fungus Eurotium cristatum using SF.…”