Changes in Phenolic Metabolites and Biological Activities of Pumpkin Leaves (Cucurbita moschata Duchesne ex Poir.) During Blanching

Pumpkin leaves (Cucurbita moschata Duchesne ex Poir.) are popularly consumed in Sub-Saharan Africa and Asia. Blanching the leaves before drying is a method of preservation during off-season. In this study, different blanching treatments and media are used to test the changes in non-targeted phenolic...

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Main Authors: Florence M. Mashitoa, Tinotenda Shoko, Jerry L. Shai, Retha M. Slabbert, Dharini Sivakumar
Format: Article
Language:English
Published: Frontiers Media S.A. 2021-03-01
Series:Frontiers in Nutrition
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fnut.2021.641939/full
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author Florence M. Mashitoa
Florence M. Mashitoa
Tinotenda Shoko
Jerry L. Shai
Retha M. Slabbert
Dharini Sivakumar
author_facet Florence M. Mashitoa
Florence M. Mashitoa
Tinotenda Shoko
Jerry L. Shai
Retha M. Slabbert
Dharini Sivakumar
author_sort Florence M. Mashitoa
collection DOAJ
description Pumpkin leaves (Cucurbita moschata Duchesne ex Poir.) are popularly consumed in Sub-Saharan Africa and Asia. Blanching the leaves before drying is a method of preservation during off-season. In this study, different blanching treatments and media are used to test the changes in non-targeted phenolic compounds, antioxidant capacity (FRAP and ABTS activity), in vitro α-glucosidase activity and cell cytotoxicity of pumpkin leaves. Steam blanching in plain water led to the highest retention of total phenolic content and reduced the loss of quercetin 3-glucoside 7-rhamnoside (Rutin), kaempferol 7-neohesperidoside, isoorientin 2″-O-rhamnoside, isorhamnetin-3-O-rutinoside, quercetin 3-galactoside, coumaroyl glucaric acid, isorhamnetin-3-galactoside-6″-rhamnoside, 2-caffeoylisocitric acid, quercetin 3-galactoside 7-rhamnoside by (3.04%), (7.37%), (10.65%), (10.97%), (14.88%), (16.1%), (16.73%), (18.88%), and (23.15%), respectively, and coumaroyl isocitrate increased by 14.92%. Candidate markers, 2-O-caffeoylglucaric acid, 2-(E)-O-feruloyl-D-galactaric acid, quercetin 3-galactoside 7-rhamnoside (rutin) and unidentified compounds ([(M-H) 677.28 and at RT 21.78] were responsible for the separation of the steam blanched samples in plain water from the other blanching treatments. Steam blanching in plain water increased the antioxidant capacity (FRAP and ABTS activity). There were no cytotoxic effect or inhibitory effect of α-glucosidase activity detected in the raw or blanched pumpkin leaves. Thus, this study recommends steam blanching in plain water for African cuisine, and confirms it is safe to consume pumpkin leaves frequently.
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spelling doaj.art-e4dba7fb553641ee83da32001a25b55a2022-12-21T22:23:39ZengFrontiers Media S.A.Frontiers in Nutrition2296-861X2021-03-01810.3389/fnut.2021.641939641939Changes in Phenolic Metabolites and Biological Activities of Pumpkin Leaves (Cucurbita moschata Duchesne ex Poir.) During BlanchingFlorence M. Mashitoa0Florence M. Mashitoa1Tinotenda Shoko2Jerry L. Shai3Retha M. Slabbert4Dharini Sivakumar5Phytochemical Food Network Research Group, Department of Crop Sciences, Tshwane University of Technology, Pretoria, South AfricaDepartment of Horticulture, Tshwane University of Technology, Pretoria, South AfricaPhytochemical Food Network Research Group, Department of Crop Sciences, Tshwane University of Technology, Pretoria, South AfricaDepartment of Biomedical Sciences, Tshwane University of Technology, Pretoria, South AfricaDepartment of Horticulture, Tshwane University of Technology, Pretoria, South AfricaPhytochemical Food Network Research Group, Department of Crop Sciences, Tshwane University of Technology, Pretoria, South AfricaPumpkin leaves (Cucurbita moschata Duchesne ex Poir.) are popularly consumed in Sub-Saharan Africa and Asia. Blanching the leaves before drying is a method of preservation during off-season. In this study, different blanching treatments and media are used to test the changes in non-targeted phenolic compounds, antioxidant capacity (FRAP and ABTS activity), in vitro α-glucosidase activity and cell cytotoxicity of pumpkin leaves. Steam blanching in plain water led to the highest retention of total phenolic content and reduced the loss of quercetin 3-glucoside 7-rhamnoside (Rutin), kaempferol 7-neohesperidoside, isoorientin 2″-O-rhamnoside, isorhamnetin-3-O-rutinoside, quercetin 3-galactoside, coumaroyl glucaric acid, isorhamnetin-3-galactoside-6″-rhamnoside, 2-caffeoylisocitric acid, quercetin 3-galactoside 7-rhamnoside by (3.04%), (7.37%), (10.65%), (10.97%), (14.88%), (16.1%), (16.73%), (18.88%), and (23.15%), respectively, and coumaroyl isocitrate increased by 14.92%. Candidate markers, 2-O-caffeoylglucaric acid, 2-(E)-O-feruloyl-D-galactaric acid, quercetin 3-galactoside 7-rhamnoside (rutin) and unidentified compounds ([(M-H) 677.28 and at RT 21.78] were responsible for the separation of the steam blanched samples in plain water from the other blanching treatments. Steam blanching in plain water increased the antioxidant capacity (FRAP and ABTS activity). There were no cytotoxic effect or inhibitory effect of α-glucosidase activity detected in the raw or blanched pumpkin leaves. Thus, this study recommends steam blanching in plain water for African cuisine, and confirms it is safe to consume pumpkin leaves frequently.https://www.frontiersin.org/articles/10.3389/fnut.2021.641939/fullleafy vegetablephytochemicalsantioxidant activitypost-harvest processingbioactivity
spellingShingle Florence M. Mashitoa
Florence M. Mashitoa
Tinotenda Shoko
Jerry L. Shai
Retha M. Slabbert
Dharini Sivakumar
Changes in Phenolic Metabolites and Biological Activities of Pumpkin Leaves (Cucurbita moschata Duchesne ex Poir.) During Blanching
Frontiers in Nutrition
leafy vegetable
phytochemicals
antioxidant activity
post-harvest processing
bioactivity
title Changes in Phenolic Metabolites and Biological Activities of Pumpkin Leaves (Cucurbita moschata Duchesne ex Poir.) During Blanching
title_full Changes in Phenolic Metabolites and Biological Activities of Pumpkin Leaves (Cucurbita moschata Duchesne ex Poir.) During Blanching
title_fullStr Changes in Phenolic Metabolites and Biological Activities of Pumpkin Leaves (Cucurbita moschata Duchesne ex Poir.) During Blanching
title_full_unstemmed Changes in Phenolic Metabolites and Biological Activities of Pumpkin Leaves (Cucurbita moschata Duchesne ex Poir.) During Blanching
title_short Changes in Phenolic Metabolites and Biological Activities of Pumpkin Leaves (Cucurbita moschata Duchesne ex Poir.) During Blanching
title_sort changes in phenolic metabolites and biological activities of pumpkin leaves cucurbita moschata duchesne ex poir during blanching
topic leafy vegetable
phytochemicals
antioxidant activity
post-harvest processing
bioactivity
url https://www.frontiersin.org/articles/10.3389/fnut.2021.641939/full
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