| Thermal Stability of Ascorbic Acid and Ascorbic Acid Oxidase in African Cowpea Leaves ( Vigna unguiculata ) of Different Maturities. | |
| | |
MedLine Citation:
|
PMID: 21309563 Owner: NLM Status: Publisher |
Abstract/OtherAbstract:
|
Cowpea, an African leafy vegetable ( Vigna unguiculata ), contains a high level of vitamin C. The leaves harvested at 4-9 weeks are highly prone to vitamin C losses during handling and processing. Therefore, the purpose of this research was to study the effect of thermal treatment on the stability of ascorbic acid oxidase (AAO), total vitamin C content (l-ascorbic acid, l-AA), and dehydroascorbic acid (DHAA) and l-AA/DHAA ratio in cowpea leaves harvested at different maturities (4, 6, and 8 weeks old). The results showed that AAO activity, total vitamin C content, and l-AA/DHAA ratio in cowpea leaves increased with increasing maturity (up to 8 weeks). Eight-week-old leaves were the best source of total vitamin C and showed a high ratio of l-AA/DHAA (4:1). Thermal inactivation of AAO followed first-order reaction kinetics. Heating at temperatures above 90 °C for short times resulted in a complete AAO inactivation, resulting in a protective effect of l-AA toward enzyme-catalyzed oxidation. Total vitamin C in young leaves (harvested at 4 and 6 weeks) was predominantly in the form of DHAA, and therefore temperature treatment at 30-90 °C for 10 min decreased the total vitamin C content, whereas total vitamin C in 8-week-old cowpea leaves was more than 80% in the form of l-AA, so that a high retention of the total vitamin C can be obtained even after heating and/or reheating (30-90 °C for 10 min) before consumption. The results indicated that the stability of total vitamin C in situ was strongly dependent on the plant maturity stage and the processing conditions applied. |
| | |
Authors:
|
Michael Wawire; Indrawati Oey; Francis Mathooko; Charles Njoroge; Douglas Shitanda; Marc Hendrickx |
Related Documents
:
|
17598023 - An animal model assessment of common dye-induced allergic contact dermatitis. 2079653 - Transdermal oxymorphone formulation development and methods for evaluating flux and lag... 5432583 - Thyroid hormone control of erythrocyte 2,3-diphosphoglyceric acid concentrations. |
Publication Detail:
|
Type: JOURNAL ARTICLE Date: 2011-2-10 |
Journal Detail:
|
Title: Journal of agricultural and food chemistry Volume: - ISSN: 1520-5118 ISO Abbreviation: - Publication Date: 2011 Feb |
Date Detail:
|
Created Date: 2011-2-11 Completed Date: - Revised Date: - |
Medline Journal Info:
|
Nlm Unique ID: 0374755 Medline TA: J Agric Food Chem Country: - |
Other Details:
|
Languages: ENG Pagination: - Citation Subset: - |
Affiliation:
|
Department of Food Science and Technology, South Eastern University College , P.O. Box 170, Kitui 90200, Kenya. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Helical Encapsulation of Graphene Nanoribbon into Carbon Nanotube.
Next Document: Simple and Rapid Method for the Analysis of Phenolic Compounds in Beverages and Grains.