Insight into prevention of enzymatic browning and increase of antioxidant potential of crepe rubber with ethephon stimulation

Attanayake, AP; Karunanayake, L.; Nilmini, A. H. R. L

doi:10.4038/jrrisl.v95i0.1836

Cited by 4 publications

(5 citation statements)

References 2 publications

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“…It was also reported that polyphenols, proteins, and carotenoids are the coloring constituents in NR latex [17]. The concentration of polyphenols, proteins, and carotenoids in the NR latex were 2 × 10 −2 , 1, and 3 × 10 −5 (w/w), respectively, and their contribution to the total absorptivity in the yellow-brown region were 2.3, 0.1, and 0.01%, respectively [18]. After processing the NR latex into the dry rubber, the residual color substances continue to be oxidized by heat to generate a variety of yellow oxides; the value of the color index with the clones and processing parameters are very different.…”

Section: Composition and Biosynthesis Of Color Substancesmentioning

confidence: 85%

“…Ethephon treated 1-3% samples showed significantly low Lovibond color index (lighter color), and overdosage may lead to discoloration. Lighter-colored rubber is also obtained by adding glutathione at the latex stage to replace the toxic bleach [18]. The first is to obtain high-quality white NR latex from the control source.…”

Section: Biologically Controlled Methodsmentioning

confidence: 99%

“…Therefore, thiol concentration above a critical level allows permanent protection against enzymatic browning [39]. However, this level may often be dependent on the physiological condition of the tree [18].…”

Section: Effect Of Ethephon Stimulation On Polyphenols Contentmentioning

confidence: 99%

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Discoloration Mechanisms of Natural Rubber and Its Control

Fang

Heping

et al. 2022

Polymers

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Color is an important indicator for evaluating the quality of natural rubber (NR). Light-colored standard rubbers are widely used in high-grade products and have high economic value. This paper first introduces the history and test standards of the standard light-colored rubber. The origin of color deepening in NR processing, color substances, and its biosynthetic pathway are reviewed. Then, the discoloration mechanism of NR is studied from the perspectives of enzymatic browning (caused by polyphenol oxidase and polyphenols) and non-enzymatic browning (including Maillard reaction and lipid oxidation). Finally, the strategies to control the discoloration of NR will be described.

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Section: Composition and Biosynthesis Of Color Substancesmentioning

confidence: 85%

Section: Biologically Controlled Methodsmentioning

confidence: 99%

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Discoloration Mechanisms of Natural Rubber and Its Control

Fang

Heping

et al. 2022

Polymers

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“…[ 12 ] The prevention of enzymatic browning in NR by stimulation Hevea tree with optimum concentration of ethephon has been reported. [ 13 ] The ethephon increased the content of thiol of the latex which acted as antioxidant by reacting with phenolic compound to form colorless products. A decrease of PPO activity in latexes at the first tapping after stimulation has been reported.…”

Section: Introductionmentioning

confidence: 99%

Physical decoloration in the concentration process of natural rubber

2021

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Natural rubber (NR) latex contains many components, especially non-rubber components, which can affect the color of products made from it. There is a growing demand in NR products which are lightly colored or color filled. One way to reduce the yellow color of NR is to remove non-rubber components, for example, lipids and proteins, from NR. This study focused on several NR latex decoloration techniques, including controlling centrifugation speed and time as well as percentage of total solid content (% TSC) of field latex. It was found that the best condition to reduce yellow color was centrifugation of the field latex containing less than 35% TSC at 12,000 rpm for 30 min. In addition, decoloration of NR latex was very effective by washing the centrifuged latex at least twice. Other factors, such as storage time and drying conditions, promoted coloration of NR due to the oxidation of the non-rubbers.

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“…According to the Sakdapipanich, 2022 the polyphenol react with oxygen in the presence of polyphenol oxidase. When these quinines react with amino acids and proteins, colourants will form (Attanayake et al, 2015). It has been shown that the fractionation process of the latexm obtained from the RRISL 203 clone yields white colour crepe rubber compared to the widely used clones in Sri Lanka.…”

Section: Introductionmentioning

confidence: 99%

Study of raw rubber and dynamic properties of RRISL 203 genotype using rubber process analyzer

Attanayake

Weerasinghe

2021

J Rubber Res Inst Sri Lanka

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Quality raw materials are essential for a sustainable rubber product industry. RRISL has introduced RRISL 203 clones as a solution for demand in high-yielding, and disease-resistant clones with vigorous growth. The objective of the present study is to study the raw rubber and rheological properties to find the suitability to produce advanced rubber products. Un-fractioned-unbleached crepe rubber manufactured using latex from the clone was collected from three crepe rubber factories in three different areas in Sri Lanka. RRIC 121, which is the most popular clone in Sri Lanka was selected as the control. Studies carried out on the raw rubber properties of these rubbers revealed that RRISL 203 clone recorded the highest Plasticity number as well as the highest Mooney viscosity among clones available in Sri Lanka. Further, this clone possesses relatively higher Plasticity Retention Index, nitrogen, and gel content with a significantly higher Mooney relaxation rate which leads to high elasticity. A frequency sweep test carried out using RPA (Rubber Process Analyzer) revealed that RRISL 203 possesses linear polymer with a low degree of branching while having a high molecular weight and broader molecular weight distribution. The overall results revealed that rubber obtained from the new clone leads could be used to produce rubber products with high strength and elastic properties. RRISL 203 clone showed moderate raw rubber properties with the highest Mooney viscosity value. Hence, the associated mastication energy requirement would be higher than that of RRIC 121.

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Insight into prevention of enzymatic browning and increase of antioxidant potential of crepe rubber with ethephon stimulation

Cited by 4 publications

References 2 publications

Discoloration Mechanisms of Natural Rubber and Its Control

Discoloration Mechanisms of Natural Rubber and Its Control

Physical decoloration in the concentration process of natural rubber

Study of raw rubber and dynamic properties of RRISL 203 genotype using rubber process analyzer

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