Isolation and characterization of blackspot pigments from potato tubers

Stevens, Lucas H.; Davelaar, E.

doi:10.1016/0031-9422(96)00088-x

Cited by 27 publications

(29 citation statements)

References 18 publications

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“…Furthermore, little information on the structure of melanins is currently available. Nevertheless, UV-Vis, FT-IR, and solidstate nuclear magnetic resonance ( 13 C-NMR) spectroscopy, molecular mass determinations, elemental analysis and other chemical analyses have provided valuable information on the structure of melanins from various sources 1,16,32 . The presented study focused on the properties of melanin from apricot kernel skins (MAKS), which are currently waste products but have high melanin contents.…”

Section: Discussionmentioning

confidence: 99%

“…Melanin is also used for diverse purposes in the pharmaceutical 3,5 , cosmetic 6,7 , food 8 , electronics 9 , and other industries 10,11 , as it has strong antioxidant activities, anti-radiation functions, anti-virus functions, hepatoprotective effects, and photoconductivity. It can be obtained by chemical synthesis from tyrosine or its derivatives 12,13 , or extracted from either animals 14,15 or plants 16,17 . Some microorganisms also produce melanins 18 , with physical and chemical properties that include high molecular weight, insolubility in water 19 , aqueous acids and common organic solvents, decolourization by oxidizing agents (KMnO 4 , NaOCl, and H 2 O 2 ), metal ion chelating ability, and strong UV-Vis absorption.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of melanin extracted from apricot (Armeniaca sibirica) and its effect on hydrazine-induced rat hepatic injury

Li¹,

Li²,

Zhao³

2016

ScienceAsia

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ABSTRACT:Melanin is a complex, highly coloured natural antioxidant with potent biological activities and diverse applications. A potential source of melanin is the Siberian apricot (Armeniaca sibirica) whose kernel skin is currently a waste by-product. To explore its potential, melanin from apricot kernel skin was extracted. The molecular mass was determined by gel chromatography and its structure was examined by elemental analysis, UV-Vis, infrared, and solid-state nuclear magnetic resonance ( 13 C-NMR) spectroscopy. In addition, its protective effect against hydrazineinduced hepatic injury in rats was evaluated. The results showed that melanin has < 5% sulphur (S) content, indicating that it consists mostly of eumelanin. Its UV-Vis, infrared and 13 C-NMR spectra were very similar to those of synthetic melanin, although it had relatively high carboxylate, aliphatic, and phenol-skeleton content. Two distinct fractions (2.4 ± 0.12 and 0. ± 560.1 kDa) were detected. Injections of hydrazine at 65 mg/kg body-weight (b.wt.) doses resulted in significant (p < 0.01) increases in lipid peroxidation (malondialdehyde contents) in liver homogenates and serum alanine aminotransferase and aspartate aminotransferase activities (64%, 69%, and 98% increase relative to the controls, respectively). It also induced significant (p < 0.05 or 0.01) decreases in liver homogenate catalase, glutathione peroxidase, and superoxide dismutase activities and reduced glutathione content (48%, 28%, 7%, and 98% reduction, respectively). Administering melanin prior to hydrazine, at 10 mg/kg b.wt., strongly inhibited these changes and ameliorated histopathological hepatic injury. The results indicated that melanin alleviated hydrazine-induced liver injury by relieving oxidative stress, which may provide a novel protective strategy for protection against liver diseases.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Characterization of melanin extracted from apricot (Armeniaca sibirica) and its effect on hydrazine-induced rat hepatic injury

Li¹,

Li²,

Zhao³

2016

ScienceAsia

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“…Besides free tyrosine, other free amino acids seem to affect discoloration. For example, free cysteine in tubers can react with dopaquinone leading to phaeomelanin, a reddish brown compound (Stevens & Davelaar, 1996). Also Dean et al (1992) found higher amounts of phenylalanine in cultivars susceptible to discoloration.…”

Section: Introductionmentioning

confidence: 98%

“…By contrast, Kiattisak et al (1999) found that chlorogenic and cafeic acids can be a substrate for polyphenol oxidase. According to Stevens & Davelaar (1996) chlorogenic acid is one of the main substrates in tubers, although its low content does not allow good correlation with discoloration (Stevens & Davelaar, 1997). Besides free tyrosine, other free amino acids seem to affect discoloration.…”

Section: Introductionmentioning

confidence: 98%

“…Mulder (1949) found that discoloration of bruised potatoes results from oxidation of phenolic groups in the presence of polyphenol oxidase leading to the dark compound melanin. This enzyme has a wide substrate specificity (Stevens & Davelaar, 1996: Matheis, 1987. Vertreg (1968) and Mondy et al (1960) found a positive correlation between polyphenol oxidase and discoloration susceptibility, whilst Stark et al (1985) and Dean et al (1993) found a negative correlation, and Stevens & Davelaar (1997) found no correlation.…”

Section: Introductionmentioning

confidence: 99%

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Importance of chlorogenic acid on the oxidative potential of potato tubers of two German cultivars

2001

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SummaryTwo German cultivars differing in blackspot susceptibility were grown in pots in 1998 and 1999 under control and water stress conditions. Blackspot susceptibility of the tubers was defined as oxidative potential. The effect of free tyrosine, cysteine, phenylalanine, chlorogenic and ascorbic acid on the oxidative potential was analyzed. A high concentration of ascorbic acid led to a decrease in the oxidative potential after harvesting in 1998. No correlation was found between oxidative potential and free tyrosine, phenylalanine or cysteine, respectively. Chlorogenic acid content increased during storage and gave a significant correlation with discoloration, showing that it can have an effect on the oxidative potential of the tuber greater than previously thought. Supplementing freeze-dried potato samples with pure chlorogenic acid increased the oxidative potential. Oxidative potential seems to depend on a series of chemical compounds, and their content is affected by factors including annual variations, cultivar, water availability and storage.

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2014

Fruit and Vegetables

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Isolation and characterization of blackspot pigments from potato tubers

Cited by 27 publications

References 18 publications

Characterization of melanin extracted from apricot (Armeniaca sibirica) and its effect on hydrazine-induced rat hepatic injury

Characterization of melanin extracted from apricot (Armeniaca sibirica) and its effect on hydrazine-induced rat hepatic injury

Importance of chlorogenic acid on the oxidative potential of potato tubers of two German cultivars

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