کد مقاله کد نشریه سال انتشار مقاله انگلیسی ترجمه فارسی نسخه تمام متن
8881767 1624949 2018 12 صفحه PDF سفارش دهید دانلود رایگان
عنوان انگلیسی مقاله ISI
Pinking of lettuce
ترجمه فارسی عنوان
پاستوریزه
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موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم زراعت و اصلاح نباتات
چکیده انگلیسی
The mid-ribs of whole and processed (i.e., fresh-cut) lettuce can develop a pink discoloration that reduces consumer acceptance. Both biotic and abiotic stresses stimulate the phenylpropanoid pathway in lettuce to produce a number of o-diphenol compounds. Caffeic acid, an intermediate in this pathway, usually reacts with quinic or tartaric acid to form the o-diphenols chlorogenic and isochlorogenic acids, or caffeoltartaric and dicaffeoltartaric acids, respectively. The concentration of these higher molecular weight o-diphenols is usually low in unstressed lettuce, but they can accumulates to levels that can produce tissue discoloration after the tissue has been stressed (e.g., wounded). The constitutive enzyme polyphenol oxidase (PPO) converts o-diphenols into reactive o-quinones. Diversion of caffeic acid from the phenylpropanoid pathway by reaction with PPO produces caffeic acid o-quinone that is pinkish in color, while PPO activity on the accumulated higher molecular weight o-diphenols (e.g., chlorogenic acid) produces o-quinones that are brownish in color. Some of these higher molecular weight o-diphenols (e.g., chlorogenic acid) can act as antioxidants and reduce the formation of pink o-quinone from the action of PPO on caffeic acid. The interplay among the phenylpropanoid pathway, the accumulation and sequestering of the phenolic compounds produced, the activity of PPO, the mixing and reaction of the o-diphenols with PPO, and the reaction of the o-quinones produced can account for the variability in pinking in lettuce.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Postharvest Biology and Technology - Volume 145, November 2018, Pages 41-52
نویسندگان
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