Effect of Methyl Ester Content on Heat Degradation of Chelator‐Soluble Carrot Pectin

Sajjaanantakul, Tanaboon; Buren, J. P. Van; Downing, Donald L.

doi:10.1111/j.1365-2621.1989.tb05972.x

Cited by 122 publications

(78 citation statements)

References 35 publications

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“…Changes in the cell wall compartment were fairly limited; this may be linked to the pH, which was close to that of maximum stability of pectins, 8,59 rather than to the intrinsic properties of the pear pectins, to the structure of the cell walls or to the presence of a high proportion of stone cells with their secondary cell walls (and high xylose content). The proportion of AIS, usually taken to be representative of the cell wall, actually increased early in the cooking.…”

Section: Discussionmentioning

confidence: 99%

Effects of conventional boiling on the polyphenols and cell walls of pears

Renard¹

2004

J Sci Food Agric

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Pears of the cultivar Gieser Wildeman were cooked for up to 24 h and changes in polyphenol and cell wall components were monitored. The main polyphenols were flavan-3-ols (epicatechin and its procyanidin oligomers), with an average degree of polymerisation of 6, and caffeoylquinic acid. Upon cooking, flavan-3-ols were retained in the pear tissue while the hydroxycinnamic acids were partially leached into the cooking water. After 1 h of cooking, 65% of the original flavan-3-ols and 40% of the original caffeoylquinic acid were still detectable in the pear tissue; the cooking water contained only 2% of the flavan-3-ols but 24% of the caffeoylquinic acid. Cell walls represented 23 g kg −1 of the fresh pear and were composed of cellulose, pectins and xylans. The pectic fractions was degraded during cooking while xylans and cellulose were not affected.

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Section: Discussionmentioning

confidence: 99%

Effects of conventional boiling on the polyphenols and cell walls of pears

Renard¹

2004

J Sci Food Agric

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“…177 Third, demethoxylation of pectin reduces its sensitivity to chemical b-eliminative depolymerisation, occurring during heating and associated with heat-induced softening of many fruits and vegetables. 87,178,179 Thus, a reduction in DM by PME stimulation through pretreatment has a second texture-conserving effect, reducing the vulnerability to thermal softening.…”

Section: Pme In Relation To Texture Of Plant-based Foodsmentioning

confidence: 98%

Pectin methylesterase and its proteinaceous inhibitor: a review

Jolie

Duvetter

Loey

et al. 2010

Carbohydrate Research

270

178

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“…Table 4 shows changes in the relative content of WSP during steaming show that the b-elimination reaction was involved in increasing the WSP content with increasing steaming time. It is known that the higher the methyl ester content, the greater the degradation of pectic substances by the b-elimination reaction (Sajjaanantakul et al, 1989). We reasoned that because of a decrease in esterification rates of pectic substances in tea leaves harvested during the fallwinter crop season, the degree of increase in the WSP content by steaming for that crop season was lower than for the first and second crop seasons.…”

Section: Determination Of the Degree Of Methylation (Dm) Of Pecticmentioning

confidence: 92%

Changes in the Content of Pectic Substances in Tea Leaves (Camellia sinensis L.) during Steam Processing of Green Tea

Hirono¹,

Uesugi²

2014

FSTR

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We examined the change in the content of pectic substances in tea leaves during the steaming of green tea. In four cultivars of tea leaves, water-soluble pectin (WSP) content increased with steaming time, whereas the dilute hydrochloric acid soluble pectin (HSP) content remained almost constant. A β-elimination reaction proceeds throughout the steaming process, so it was postulated that some water-insoluble forms of pectin in HSP convert to a water-soluble form via β-elimination degradation with increasing steaming time. When tea leaves were steamed, pectin fractions with a molecular weight of 1,100 × 10 3 were degraded from water-insoluble HSP and eluted as WSP.Additionally, as steaming time increased, the fraction of smaller molecular weight pectin increased.Keywords: pectic substances, green tea, steaming process IntroductionIt has been elucidated that the bitter or astringent taste of catechins and the umami taste of amino acids such as theanine are important factors in the taste of green tea (Nakagawa et al., 1981).The taste of green tea changes depending not only on the conditions used to brew the tea, but also on how the tea leaves are processed.When raw tea leaves are processed differently, the tea products differ in quality. As an example, fukamushi tea steamed for a longer time tastes less astringent than asamushi tea steamed for a shorter time. The amounts of several components, such as catechins and amino acids, have typically been considered to be indices of the quality of the tea. However, the amounts of these components do not change during the course of tea processing (Takayanagi and Anan, 1986). In contrast, the amount of water-soluble pectin (WSP) increases during the steaming process with increased steaming time (Takayanagi et al., 1987). It was therefore assumed that the increase in WSP masked the astringent taste of catechins, as fukamushi tea tastes less astringent (Horie and Kohata, 1999 et al., 1960). In this paper, we examined the change in the content of pectic substances in tea leaves during the steaming process by varying cultivars, harvesting time, and maturity of the tea leaves. Additionally, we investigated the extent of b-elimination degradation and the molecular weight distribution of WSP during the steaming process. from the first crop season were also plucked by their degree of maturity: younger, optimum, and over-matured. On average, the interval between these three levels of maturity was 2 days. About 100 g of plucked tea leaves (raw leaves) were immediately frozen and the rest were steamed. About 100 g of tea leaves were steamed for 30, 60, 120, and 300 s for the 'Yabukita' cultivar, and for 60 and 300 s for the other three cultivars. The steamed leaves were then frozen. All frozen tea leaves were lyophilized and powdered using a cyclone sample mill. was stirred and heated in a boiling water bath for 10 min. After cooling to room temperature, the optical density was measured at 548 nm in a spectrophotometer. Materials and Methods Preparation of tea leaves Preparation of al...

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Effect of Methyl Ester Content on Heat Degradation of Chelator‐Soluble Carrot Pectin

Cited by 122 publications

References 35 publications

Effects of conventional boiling on the polyphenols and cell walls of pears

Effects of conventional boiling on the polyphenols and cell walls of pears

Pectin methylesterase and its proteinaceous inhibitor: a review

Changes in the Content of Pectic Substances in Tea Leaves (Camellia sinensis L.) during Steam Processing of Green Tea

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