A Method for Determination of Tannins in Foods by Means of Immobilized Protein

Hoff, Johan E.; Singleton, K. I.

doi:10.1111/j.1365-2621.1977.tb08427.x

Cited by 152 publications

(79 citation statements)

References 12 publications

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“…The total phenolic content was determined by the FolinCiocalteu method, using gallic acid as the standard (Hoff and Singleton 1977;Muhammad 2006). Two grams of frozen tomato sample was homogenized in 100% methanol (20 ml).…”

Section: Total Phenolic Contentmentioning

confidence: 99%

Influence of Postharvest UV-C Hormesis on the Bioactive Components of Tomato during Post-treatment Handling

Jagadeesh

Charles

Gariépy

et al. 2009

Food Bioprocess Technol

104

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Mature green tomato fruit exposed to a predetermined hormetic dose of UV-C (3.7 kJ/m 2 ) and untreated fruit (control) were stored at 13°C and 95% relative humidity. After 10, 20, and 30 days of storage, fruits were randomly sampled and transferred to room temperature (23°C) for 7 and 14 days to allow ripening. Edible pericarp was excised from the equatorial region for subsequent analyses of the antioxidant components. Ascorbic acid and total phenolic contents were higher in the UVtreated tomatoes, but UV treatment significantly reduced the lycopene content of the tomatoes. The UV treatment did not affect significantly the antioxidant activity of the hydrophilic extract, expressed as Trolox equivalent. Both storage and ripening period were found to affect positively all the bioactive components of tomato evaluated in this study. The results suggest the possible existence of a window of opportunity for the development of practices based on storage temperature and duration to preserve the beneficial effects expected from UV-C hormesis and to circumvent its negative impact on lycopene synthesis.

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Section: Total Phenolic Contentmentioning

confidence: 99%

Influence of Postharvest UV-C Hormesis on the Bioactive Components of Tomato during Post-treatment Handling

Jagadeesh

Charles

Gariépy

et al. 2009

Food Bioprocess Technol

104

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“…Polyphenols were measured with the Folin-Ciocalteau reagent, according to the method of Hoff and Singleton [1966]. Gallnut tannic acid (Sigma Chemical Co., St. Louis, Mo., USA) was used as a standard.…”

Section: Chemical Assaysmentioning

confidence: 99%

Inhibition of Salivary Amylase by Black and Green Teas and Their Effects on the Intraoral Hydrolysis of Starch

Zhang¹,

Kashket²

1998

Caries Res

135

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Tea decoctions prepared from a number of black and green teas inhibited amylase in human saliva. Black teas gave higher levels of inhibition than green teas, and removal of tea tannins with gelatin led to the loss of inhibitory activity from all decoctions. Streptococcal amylase was similarly inhibited by tea decoctions. Fluoride was without effect on amylase. Since salivary amylase hydrolyzes food starch to low molecular weight fermentable carbohydrates, experiments were carried out to determine whether tea decoctions would interfere with the release of maltose in food particles that became entrapped on the dentition. Subjects consumed salted crackers and rinsed subsequently for 30 s with black or green tea decoctions, or water. Maltose release was reduced by up to about 70% after rinsing with the teas. Black tea decoction was significantly more effective than green tea, in agreement with the in vitro data. The observations supported the hypothesis that tea consumption can be effective in reducing the cariogenic potential of starch-containing foods such as crackers and cakes. Tea may reduce the tendency for these foods to serve as slow-release sources of fermentable carbohydrate.

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“…Total phenols concentration was measured according to Hoff and Singleton (1977). Fifty lL of the methanol extract was mixed with 100 lL Folin-Ciocalteu reagent, 850 lL of methanol and allowed to stand for 5 min at ambient temperature.…”

Section: Estimation Of Total Phenolsmentioning

confidence: 99%

Postharvest chitosan, gallic acid and chitosan gallate treatments effects on shelf life quality, antioxidant compounds, free radical scavenging capacity and enzymes activities of ‘Sukkari’ bananas

et al. 2017

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The effect of postharvest chitosan, gallic acid (GA) and chitosan gallate (CG) dipping treatments at different concentrations on quality parameters, antioxidant compounds, free radical scavenging capacity (FRSC) and enzymes activities of 'Sukkari' bananas were studied during storage (ripening) at 20 ± 2°C and 60-70% RH for 13 days. Weight loss and peel color index (the change from green to yellow) increased while, membrane stability index of peel tissues, pulp firmness and acidity decreased during storage. CG and GA treatments slowed down the changes in these parameters compared to control. Total soluble solids (TSS) concentration increased during storage and was lower at CG than other treatments. TSS/acid ratio increased during storage and showed higher value after storage than initial. This ratio was lower at 1% chitosan, 0.075% GA and CG treatments than control. Both vitamin C and total flavonoids concentrations decreased during storage and were not affected by the applied treatments. Total phenols concentration decreased during storage and was higher at acetic acid and the high rate of chitosan, GA and CG treatments than control. FRSC (DPPH IC 50 values) of fruit peel ranged from 2.54 to 4.19 lg phenolics concentration among the treatments. FRSC was not affected by the applied treatments but increased (lower IC 50 value) during shelf life. The possible relations of these biochemical changes with the activities of the enzymes a-amylase, xylanase, polygalacturonase, peroxidase and polyphenoloxidase were discussed. It is concluded that postharvest CG and GA treatments delayed ripening and maintained better quality parameters of 'Sukkari' bananas during 13 days of shelf life than control.

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A Method for Determination of Tannins in Foods by Means of Immobilized Protein

Cited by 152 publications

References 12 publications

Influence of Postharvest UV-C Hormesis on the Bioactive Components of Tomato during Post-treatment Handling

Influence of Postharvest UV-C Hormesis on the Bioactive Components of Tomato during Post-treatment Handling

Inhibition of Salivary Amylase by Black and Green Teas and Their Effects on the Intraoral Hydrolysis of Starch

Postharvest chitosan, gallic acid and chitosan gallate treatments effects on shelf life quality, antioxidant compounds, free radical scavenging capacity and enzymes activities of ‘Sukkari’ bananas

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