Comparison on chemical compositions and antioxidant capacities of the green, oolong, and red tea from blueberry leaves

Abstract

Blueberry leaves, by‐products of the blueberry industry, could be explored as source of functional foods, such as teas. Three different types of tea, including nonfermented green tea, semifermented oolong tea, and fully fermented red tea from blueberry leaves, were investigated on their chemical compositions and antioxidant capacities here. The contents of individual amino acids in three types varied, while the total amounts retained constant. A total of 167 volatiles were detected with alcohols, alkenes, and aldehydes as the dominant. More volatiles produced in the fermented teas. The total phenolic/flavonoid contents were highest in the green tea and decreased significantly in the oolong and red teas, correlating inversely with the fermentation degree. The highest levels of representative phenolics, that is, phenolic acids and flavonol glycosides, contributed to the strongest antioxidant capacity in the green tea. These indicated that blueberry leaves provided promising and prospective potential to develop new teas beneficial for health.

Comparison of Nutritional and Nutraceutical Properties of Burdock Roots Cultivated in Fengxian and Peixian of China

“…The method described by Chai et al [ 19 ] was used for the separation and identification of volatile compounds of F-BRP sample. A 5 g of sample was placed in an extraction bottle and was put in a water bath at 60 °C for 30 min with magnetic stirring (300 rpm).…”

Ribes himalense as potential source of natural bioactive compounds: Nutritional, phytochemical, and antioxidant properties

“…The results in vitro showed that the R. himalense fruits could be effective sources of antioxidants. In addition, previous investigators had reported that the antioxidant capacity cannot be correlated just with the total polyphenol content of extracts, which is owing to the complex activity of various compounds, such as flavonoids and anthocyanins (Chai et al., 2020; Laczkó‐Zöld et al., 2018; Lin et al., 2016). Moreover, previous findings on Ribes species fruits, including Ribes nigrum L. (black currant), Ribes rubrum L. (red currant), currant cultivars, Ribes uva‐crispa L. (gooseberry), and R. biebersteinii Berl., indicated that these berries are the richest in polyphenols, such as anthocyanins, flavonoids, and phenolic acids, which play a vital role in the prevention and control of various illnesses through equilibriuming the oxidative and antioxidation factors in the human body (Carole et al., 2019; Delazar et al., 2010; Hurst et al., 2020; Laczkó‐Zöld et al., 2018).…”

Antioxidant, α-amylase and α-glucosidase inhibitory activities of Cedrela sinensis (A. Juss) leaf with ethanol extract concentration

“…The ORAC assay is a reliable technique that combines the inhibition percentage of several varieties of reactive oxygen species of biologically relevant sources over time (Prior & Cao, 1999). Therefore, ORAC is largely utilized to assess the total antioxidant capacity, and it could also account for the ORAC values being much higher than the DPPH/ABTS + values (Chai et al, 2020).…”