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Effects of Food Processing, Storage, and Cooking on Nutrients in Plant-Based Foods
Published in Nicole M. Farmer, Andres Victor Ardisson Korat, Cooking for Health and Disease Prevention, 2022
Blanching is mild heat treatment used in most vegetables and cut fruits prior to freezing. Its main purpose is the inactivation of enzymes that cause flavor or texture degradation during frozen storage. Examples of these enzymes include polyphenol oxidase, responsible for the development of undesirable colors through enzymatic browning (text box 1), and lipoxygenase that promotes the production of peroxides, which are responsible for undesirable flavors and odors. Of note, peroxidase activity is used as a proxy for lipoxygenase activity as a maker of the effectiveness of blanching because the activity of the latter is difficult to assess.
Anti-Inflammatory Activity of Wild Medicinal Plants of Piauí State-Brazil
Published in Mahendra Rai, Shandesh Bhattarai, Chistiane M. Feitosa, Ethnopharmacology of Wild Plants, 2021
Valdiléia Teixeira Uchôa, Mahendra Rai, Gilmânia Francisca Sousa Carvalho, Herbert Gonzaga Sousa, Patrícia e Silva Alves, Renata da Silva Carneiro, Ariane Maria da Silva Santos Nascimento, Felipe Pereira da Silva Santos, Gabriel e Silva Sales
In this species, bioactive compounds and secondary metabolites, such as steroids, saponins, alkaloids and glycosides of pharmacological importance are considered a good source of polyphenol oxidase (Antunes et al. 2018). Phytochemical screening performed of S. paniculatum L. extract revealed the presence of alkaloids, lactones, as well as a high content of phenols (flavonoids and tannins). Qualitative analysis of phenols by TLC showed a suggestive point of isovitexin (flavonoid) and the presence of tannic acid (tannin) in the extract (Garcia et al. 2008).
Health Benefits of Green Tea
Published in Robert E.C. Wildman, Richard S. Bruno, Handbook of Nutraceuticals and Functional Foods, 2019
Priyankar Dey, Geoffrey Y. Sasaki, Richard S. Bruno
Green, black, and oolong teas are all derived from the leaves and buds of Camellia sinensis. Although each is prepared from the same plant, they differ in post-harvest processing. The leaves intended for green tea are unfermented, whereas those for black and oolong tea are fully and partially fermented, respectively. Tea leaves used for the manufacture of green tea are processed rapidly upon harvesting including high temperature exposure by steaming or pan frying prior to being rolled and dried.2,18 This inactivates polyphenol oxidase and peroxidases that otherwise cause oxidation (i.e., fermentation) of the catechins (Table 7.1).23,24
Development and characterization of gamma ray and EMS induced mutants for powdery mildew resistance in blackgram
Published in International Journal of Radiation Biology, 2023
Murugesan Tamilzharasi, Dharmalingam Kumaresan, Venkatesan Thiruvengadam, Jegadeesan Souframanien, T. K. S. Latha, N. Manikanda Boopathi, Palaniappan Jayamani
The phytic acid (mg/g) and total phenols (mg/g) were estimated using the Folin-Ciocalteau reagent; total sugars (mg/g) using anthrone method as described by Sadasivam and Manickam (1996). Silicon content (µg/g of a leaf) in leaves was quantified following the methodology of Prasad et al. (2010). Catalase (Enzyme Unit (EU) g−1 of fresh weight) was determined according to the method of Aebi (1983). Peroxidase activity (changes in absorbance (in units) g−1 of fw) was determined according to Hammerschmidt et al. (1982). Polyphenol oxidase activity (changes in absorbance (in units g−1 of fw) was determined as per Mayer and Harel (1979). Superoxide dismutase (SOD) (EU g−1 of fw) assay was performed adopting the protocol of Dhindsa et al. (1981).
Effects of green tea extract epigallocatechin-3-gallate (EGCG) on oral disease-associated microbes: a review
Published in Journal of Oral Microbiology, 2022
Chen Kong, Huili Zhang, Lingfeng Li, Zhihui Liu
Tea is one of the most commonly consumed beverages in the world, second only to water. According to the manufacturing process, especially the drying and fermentation methods, tea can be divided into four major varieties: white tea made from young leaves or buds, green tea made from mature unfermented leaves, oolong tea made from partially fermented leaves, and black tea made from fully fermented leaves [1,2]. In recent years, green tea has become more and more popular due to its health benefits, including anti-inflammatory, antioxidant, anti-cancer, antibacterial and promotion of cardiovascular and oral health. It has been used for daily health care in many countries, and its output accounts for about 20% of the total amount of tea in the world [3]. Because the initial cooking process in green tea production destroyed polyphenol oxidase, the polyphenol content was protected [4]. Catechins in polyphenols are considered to be the source of many biological properties of green tea, which include free catechins such as catechin (C), gallocatechin (GC), epicatechin (EC) and epigallocatechin (EGC), and gallocatechins such as epicatechin gallate (ECG), epigallocatechin gallate (EGCG), catechin gallate (CG) and gallocatechin gallate (GCG) [5,6]. In green tea, EGCG and EGC are the most abundant, accounting for about 59% and 19% of the total catechins, respectively. The former constitutes the most effective antibacterial component in catechins and has now become the subject of most studies [7].
Optimisation of umbu juice spray drying, and physicochemical, microbiological and sensory evaluation of atomised powder
Published in Journal of Microencapsulation, 2020
Michelle M. B. de Souza, Andrelina M. P. Santos, Attilio Converti, Maria Inês S. Maciel
There was no statistically significant difference (p > 0.05) in colour, aroma and appearance of nectars prepared from formulations A and B, but rather between them and the standard (p < 0.05), while taste did not differ significantly (p > 0.05) among the three formulations. Considering that heat not only vaporises water but also causes enzymatic and non-enzymatic darkening reactions as well as loss of volatile and thermosensitive components such as aromatic and phenolic compounds, the decrease of more than one point of the hedonic scale in the average score for colour and 0.7–0.8 points for aroma compared with the standard may be ascribed to drying-induced changes of product reflectivity and colour. In addition, residual polyphenol oxidase activity may have led to fruit browning during storage. Volatile components are in fact lost in the initial stages of drying generating an open porous structure in dehydrated foods that allows oxygen to enter; therefore, the oxidation of some remaining volatiles may have been a second important cause of aroma loss (Jittanit et al.2010).