Effects of Food Processing, Storage, and Cooking on Nutrients in Plant-Based Foods
Nicole M. Farmer, Andres Victor Ardisson Korat in 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.
Health Benefits of Green Tea
Robert E.C. Wildman, Richard S. Bruno in Handbook of Nutraceuticals and Functional Foods, 2019
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
Vinca rosea (Madagascar Periwinkle) and Adhatoda vesica (Malabar Nut)
Azamal Husen in Herbs, Shrubs, and Trees of Potential Medicinal Benefits, 2022
The antioxidant potential is mostly associated with the roots of white and pink blooms that contain extracts, as determined by several assays, such as hydroxyl radical, peroxide radical, DPPH radical, and nitric oxide radical suppression (Alba and Bhise, 2011). 2,3-dihydroxybenzoic acid demonstrated significant radical-scavenging action, which is linked to reduced cancer risk (Nishibe, 1997). The antioxidant properties of enzymes such as superoxide dismutase (SOD), peroxidase (POX), and catalase (CAT) were studied in particular. According to the results of the aforementioned investigation, V. rosea is a suitable plant for salt-affected locations, and we may acquire plants with increased antioxidant and therapeutic properties (Jayakumar et al., 2010). Kumar et al. (2012) investigated the antioxidant properties of V. rosea. They determined that the habitat's heat would have a direct influence on antioxidant capacity, allowing them to see that the superoxide dismutase and polyphenol oxidase enzymes, in contrast to catalase, had more antioxidant properties whenever the temperature rose. (Kumar et al., 2012). The investigation was guided by a methanolic extract of the leaves. Rasool et al. conducted numerous in vitro antioxidant experiments in 2011 to investigate the influence of the solution on the extract and overall anti-radical capability of various V. rosea extracts. The extraction and fractionation were shown to be an excellent source of antioxidants in the studies. The shoots of V. rosea demonstrated excellent antioxidant potential in a 100% methanolic extract and a portion of 100% ethyl acetate (Rasool et al., 2011).
Development of carbazole-bearing pyridopyrimidine-substituted urea/thiourea as polyphenol oxidase inhibitors: synthesis, biochemistry, and theoretical studies
Published in Archives of Physiology and Biochemistry, 2019
Arleta Rifati Nixha, Adem Ergun, Nahit Gencer, Oktay Arslan, Mustafa Arslan
Polyphenol oxidase (PPO, EC 1.14.18.1) is a copper-containing oxidoreductase enzyme which catalyses the o-hydroxylation of monophenols to o-diphenols, and also shows further catalytical oxidation of o-dihydroxyphenols to o-quinones (Mayer 2006). PPO enzyme that exists widely in all kinds of fruits and vegetables are one of the most crucial enzymes in plants (Yang et al.2000, Nunez-Delicado et al.2007, Mishra et al.2012). The enzyme is one of the main reasons for the browning reactions in plants and decreased food quality. During the reactions, the melanin-like brown-coloured pigment would occur with oxygen (Madinez and Whitaker 1995), and the browning which reduces the quality, taste, and flavour of vegetables and fruits causes more than 50% of nutrient loss in tropical fruits (Mayer 2006). A significant group is constituted by compounds structurally analogous to phenolic substrate, which usually shows competitive inhibition concerning this substrate, despite varying enzyme source and substrate used (Yan et al.2009). The development of safe and effective tyrosinase inhibitors is essential in industries such as cosmetic, agricultural, and medical. However, there have been only a few compounds such as kojic acid, arbutin, tropolone, and 1-phenyl 2-thiourea used as therapeutic agents and cosmetic products (Thanigaimalai et al.2010, Karatas et al.2014).
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).
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).
Related Knowledge Centers
- Benzene
- Catechol
- Enzyme
- Hydroxylation
- Phenols
- Food Browning
- Hydroxy Group
- Phenol
- Redox
- 1,2-Benzoquinone