Effects of phenolic compounds on the heat stability of milk and concentrated milk

1999 ◽  
Vol 66 (3) ◽  
pp. 399-407 ◽  
Author(s):  
JOHN E. O'CONNELL ◽  
PATRICK F. FOX

A methanol extract of green tea was fractionated on Sephadex LH-20. The compounds eluted were identified by thin layer chromatography as catechin–epicatechin, gallocatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate. When added to milk at 2·0 g/l, these polyphenols, apart from the catechin–epicatechin mixture, increased the heat stability of skim milk, particularly in the region of the minimum (pH 6·8–7·1). When added at 0·4 g/l, green tea polyphenols also increased the heat stability of concentrated milk. The effects of other phenolic compounds on the heat stability of milk were also examined. Chlorogenic acid, guaiacol, thymol, vanillin, butylene hydroxyanisole, propyl gallate and butylene hydroxytoluene did not affect the heat stability of milk or concentrated milk. Quinic acid markedly reduced the heat stability of skim milk. Pyrogallol, catechol, tannic acid, ellagic acid, phloroglucinol and gallate converted a type A heat coagulation time–pH profile to a type B profile. Ferulic acid and vanillic acid increased heat stability in the region of the maximum, with little effect on the minimum, and stability did not recover at pH values on the alkaline side of the minimum. Caffeic acid increased the heat stability of milk while the related non-phenolic compounds 2,5-dimethoxycinnamic acid and 3,4-dimethoxycinnamic acid had no effect.

2021 ◽  
Author(s):  
Li Wang ◽  
Xin Huang ◽  
Huijuan Jing ◽  
Xin Ye ◽  
Chao Jiang ◽  
...  

Epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) are the most abundant ester catechins of green tea polyphenols (GTPs) with numerous potential bioactivities, which have a wide application prospect in the...


1990 ◽  
Vol 57 (2) ◽  
pp. 213-226 ◽  
Author(s):  
Mary-Ann Augustin ◽  
Phillip T. Clarke

SummaryChanges in heat stability and Ca2+ activity of recombined concentrated milk (18% solids non-fat:8% fat) induced by the additions of 0·011–0·217 mol phosphate/kg skim milk solids (SMS), 0·022–0·217 mol citrate/kg SMS, 0·011–0·022 mol Ca/kg SMS and 0·016–0·067 mol EDTA/kg SMS were evaluated. Heat stability was assessed using an objective method which involved determination of viscosity after heating under controlled conditions. Low levels of added phosphate and citrate generally effected an acid shift of the viscosity–pH profile, while higher levels caused a broadening of the profile. Addition of CaCl2 at a level of 0·011 mol/kg SMS resulted in a narrowing of the viscosity–pH curve; additions of higher levels resulted in a non-heat stable recombined milk concentrate. EDTA also caused a narrowing of the viscosity–pH curve. The results highlight the importance of pH control for effective stabilization of recombined milk concentrates by additions of phosphate and citrate.


1978 ◽  
Vol 45 (1) ◽  
pp. 37-45 ◽  
Author(s):  
D. D. Muir ◽  
A. W. M. Sweetsur

SummaryA progressive change takes place in the heat stability of skim-milk during concentration. At the maximum in the coagulation time (CT)–pH profile of milk concentrated to over 20% of total solids (TS) the total N depletion curve changed from single- to 2-stage and CT became insensitive to the addition of urea. Furthermore, addition of β-lactoglobulin to skim-milk concentrates destabilized the heated milk whilst the opposite effect was observed in the presence of sulphydryl-group blocking agents. As a result of these observations, it has been suggested that the mechanism of coagulation in concentrated milk is similar to that which occurs within the minimum of the CT–pH profile of skim-milk at normal levels of TS.


2020 ◽  
Vol 11 (5) ◽  
pp. 4114-4122
Author(s):  
Susanne M. Henning ◽  
Piwen Wang ◽  
Ru-Po Lee ◽  
Amy Trang ◽  
George Husari ◽  
...  

Epigallocatechin gallate, epicatechin gallate (Green Tea Polyphenols – GTPs) and quercetin (Q) were taken up in prostate tissue after Q and GTP consumption. Our findings herein suggest a potential effect of Q on GTP metabolism.


2019 ◽  
Vol 15 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Satheesh Babu Natarajan ◽  
Suriyakala Perumal Chandran ◽  
Sahar Husain Khan ◽  
Packiyaraj Natarajan ◽  
Karthiyaraj Rengarajan

Background: Tea (Camellia sinensis, Theaceae) is the second most consumed beverage in the world. Green tea is the least processed and thus contain rich antioxidant level, and believed to have most of the health benefits. </p><p> Methods: We commenced to search bibliographic collection of peer reviewed research articles and review articles to meet the objective of this study. </p><p> Results: From this study, we found that the tea beverage contains catechins are believed to have a wide range of health benefits which includes neuroprotective, anti-inflammatory, antiulcer, antiviral, antibacterial, and anti-parasitic effects. The four major catechin compounds of green tea are epigallocatechin (EGC), epicatechin (EC), epigallocatechin gallate (EGCG), and epicatechin gallate (ECG), of which EGCG is the major constituent and representing 50-80% of the total catechin content. And also contain xanthine derivatives such as caffeine, theophylline, and theobromine, and the glutamide derivative theanine. It also contains many nutritional components, such as vitamin E, vitamin C, fluoride, and potassium. We sum up the various green tea phytoconstituents, extraction methods, and its medicinal applications. </p><p> Conclusion: In this review article, we have summarized the pharmacological importance of green tea catechin which includes antioxidant potential, anti-inflammatory, antimicrobial, anticancer, antidiabetic and cosmetic application.


2021 ◽  
Vol 12 (3) ◽  
pp. 1793-1797
Author(s):  
Priyanka Sirari ◽  
Jigisha Anand ◽  
Devvret ◽  
Ashish Thapliyal ◽  
Nishant Rai

Green tea is credited as one of the world’s healthiest drinks with enriched antioxidants. It is known for its multi-beneficial health benefits against diabetes, blood pressure, hypertension, gastro-intestinal upset and is bestowed with significant antimicrobial potential. There are previous scientific evidence highlighting the antifungal potential of green tea and has identified it as a potential inhibitor of non-albicans Candida species. Lansterol 14-α demethylase (Erg 11) or CYP51 protein belongs to the cytochrome P450 monooxygenase (CYP) superfamily. Erg 11 is involved in ergosterol biosynthesis and has a significant role in azole drug resistance in Candida glabrata. The present study attempted to identify the inhibitory potential of green tea phytocompounds against inhibition of Erg 11 in Candida glabrata using bioinformatics tool viz., autodock vina software. Out of 15 green tea phytocompounds investigated, the study identified, Rutin (-10.5 kcal) Kaempferitrin (-9.4kcal), Epigallocatechin gallate (-10kcal), Epicatechin gallate (-8.7kcal), and Coumaroylquinic acid (-8.6kcal) acid as the potent phytocompounds which showed significant molecular interaction with Erg 11 in Candida glabrata. In attribution to the constant emergence of azole-resistant isolates, this preliminary analysis therefore, indicated the potential of green tea phytocompounds against inhibition of non-albicans Candida specific candidiasis. However, further, in vitro antimicrobial efficacy of these phytocompounds, the dose regime, drug likeliness, and cytotoxic analysis are required to be investigated and validated.


2004 ◽  
Vol 48 (1) ◽  
pp. 69-74 ◽  
Author(s):  
Cristina Paveto ◽  
María C. Güida ◽  
Mónica I. Esteva ◽  
Virginia Martino ◽  
Jorge Coussio ◽  
...  

ABSTRACT The trypanocidal action of green tea catechins against two different developmental stages of Trypanosoma cruzi is reported for the first time. This activity was assayed with the nonproliferative bloodstream trypomastigote and with the intracellular replicative amastigote parasite forms. An ethyl acetate fraction from Camellia sinensis green tea leaves, which contains most of the polyphenolic compounds and the maximal trypanocidal activity, was obtained by fractionation of the aqueous extract with organic solvents. The active compounds present in this extract were further purified by LH-20 column chromatography and were identified by high-performance liquid chromatography analysis with a photo diode array detector and gas chromatography coupled to mass spectroscopy. The following flavan-3-ols derivatives, known as catechins, were identified: catechin, epicatechin, gallocatechin, epigallocatechin, catechin gallate, epicatechin gallate, gallocatechin gallate, and epigallocatechin gallate. The purified compounds lysed more than 50% of the parasites present in the blood of infected BALB/c mice at concentrations as low as 0.12 to 85 pM. The most active compounds were gallocatechin gallate and epigallocatechin gallate, with minimal bactericidal concentrations that inhibited 50% of isolates tested of 0.12 and 0.53 pM, respectively. The number of amastigotes in infected Vero cells decreased by 50% in the presence of each of these compounds at 100 nM. The effects of the catechins on the recombinant T. cruzi arginine kinase, a key enzyme in the energy metabolism of the parasite, were assayed. The activity of this enzyme was inhibited by about 50% by nanomolar concentrations of catechin gallate or gallocatechin gallate, whereas the other members of the group were less effective. On the basis of these results, we suggest that these compounds could be used to sterilize blood and, eventually, as therapeutic agents for Chagas' disease.


Viruses ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2533
Author(s):  
Rackhyun Park ◽  
Minsu Jang ◽  
Yea-In Park ◽  
Yeonjeong Park ◽  
Woochul Jung ◽  
...  

The COVID-19 pandemic has resulted in a huge number of deaths from 2020 to 2021; however, effective antiviral drugs against SARS-CoV-2 are currently under development. Recent studies have demonstrated that green tea polyphenols, particularly EGCG, inhibit coronavirus enzymes as well as coronavirus replication in vitro. Herein, we examined the inhibitory effect of green tea polyphenols on coronavirus replication in a mouse model. We used epigallocatechin gallate (EGCG) and green tea polyphenols containing more than 60% catechin (GTP60) and human coronavirus OC43 (HCoV-OC43) as a surrogate for SARS-CoV-2. Scanning electron microscopy analysis results showed that HCoV-OC43 infection resulted in virion particle production in infected cells. EGCG and GTP60 treatment reduced coronavirus protein and virus production in the cells. Finally, EGCG- and GTP60-fed mice exhibited reduced levels of coronavirus RNA in mouse lungs. These results demonstrate that green tea polyphenol treatment is effective in decreasing the level of coronavirus in vivo.


Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1550
Author(s):  
Karin Sasagawa ◽  
Hisanori Domon ◽  
Rina Sakagami ◽  
Satoru Hirayama ◽  
Tomoki Maekawa ◽  
...  

Streptococcus pneumoniae is a causative pathogen of several human infectious diseases including community-acquired pneumonia. Pneumolysin (PLY), a pore-forming toxin, plays an important role in the pathogenesis of pneumococcal pneumonia. In recent years, the use of traditional natural substances for prevention has drawn attention because of the increasing antibacterial drug resistance of S. pneumoniae. According to some studies, green tea exhibits antibacterial and antitoxin activities. The polyphenols, namely the catechins epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC) are largely responsible for these activities. Although matcha green tea provides more polyphenols than green tea infusions, its relationship with pneumococcal pneumonia remains unclear. In this study, we found that treatment with 20 mg/mL matcha supernatant exhibited significant antibacterial activity against S. pneumoniae regardless of antimicrobial resistance. In addition, the matcha supernatant suppressed PLY-mediated hemolysis and cytolysis by inhibiting PLY oligomerization. Moreover, the matcha supernatant and catechins inhibited PLY-mediated neutrophil death and the release of neutrophil elastase. These findings suggest that matcha green tea reduces the virulence of S. pneumoniae in vitro and may be a promising agent for the treatment of pneumococcal infections.


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