The Control of Postharvest Soft Rot Caused by <i>Rhizopus stolonifer</i> on Kokei No. 14 Organic Sweet Potato Roots by Carvacrol, Thymol, and Thyme Oil

Soft rotting caused by <i>Rhizopus stolonifer</i> is one of the most important postharvest decays in Kokei No. 14 organic sweet potato roots. While various methods have been explored for controlling this pathogen, there remains a need for effective, safe, and applicable alternatives, par...

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Main Authors: Guangwei Wu, Chenqi Fan, Xueqian Zang, Bei Wang, Yanli Chen, Jingjing Kou, Guopeng Zhu
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/14/7/1273
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author Guangwei Wu
Chenqi Fan
Xueqian Zang
Bei Wang
Yanli Chen
Jingjing Kou
Guopeng Zhu
author_facet Guangwei Wu
Chenqi Fan
Xueqian Zang
Bei Wang
Yanli Chen
Jingjing Kou
Guopeng Zhu
author_sort Guangwei Wu
collection DOAJ
description Soft rotting caused by <i>Rhizopus stolonifer</i> is one of the most important postharvest decays in Kokei No. 14 organic sweet potato roots. While various methods have been explored for controlling this pathogen, there remains a need for effective, safe, and applicable alternatives, particularly using essential oils (EOs). This study evaluated the efficacy of EOs, specifically carvacrol, thymol, and thyme oil, in controlling <i>Rhizopus</i> soft rot. We conducted both in vitro and in vivo tests to assess their effects on fungal mycelial growth, spore germination, and the incidence and severity of soft rot in sweet potatoes, along with quality evaluations of the roots. The results indicated that the vapor phase of carvacrol, thymol, and thyme oil was more effective than the contact phase in inhibiting fungal growth and spore germination. In vivo tests revealed that all three EOs significantly reduced the incidence and severity of soft rot, with thymol and thyme oil at 300 mg/L, and carvacrol at 500 mg/L being the most effective. Quality assessments showed minimal impact on properties such as firmness, weight loss, color, starch, carotenoids, and flavonoids, although residual odors increased. GC/MS analysis confirmed that thyme oil contained high levels of both thymol and carvacrol, along with other antimicrobial compounds, suggesting that the cumulative activity of these volatile compounds enhanced their bacteriostatic effects. Thyme oil demonstrated greater efficacy in reducing soft rot development compared to its individual components, making it a promising biofumigant for controlling postharvest diseases in Kokei No. 14 organic sweet potato roots. These findings emphasized the potential for using thyme oil as a safe and effective approach to managing postharvest decay.
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spelling doaj-art-67c031cc914048b5a39e5a4407f459022025-08-20T02:09:19ZengMDPI AGFoods2304-81582025-04-01147127310.3390/foods14071273The Control of Postharvest Soft Rot Caused by <i>Rhizopus stolonifer</i> on Kokei No. 14 Organic Sweet Potato Roots by Carvacrol, Thymol, and Thyme OilGuangwei Wu0Chenqi Fan1Xueqian Zang2Bei Wang3Yanli Chen4Jingjing Kou5Guopeng Zhu6School of Breeding and Multiplication, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya 572025, ChinaSchool of Breeding and Multiplication, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya 572025, ChinaSchool of Breeding and Multiplication, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya 572025, ChinaSchool of Breeding and Multiplication, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya 572025, ChinaSchool of Breeding and Multiplication, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya 572025, ChinaSchool of Breeding and Multiplication, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya 572025, ChinaSchool of Breeding and Multiplication, Sanya Institute of Breeding and Multiplication, Hainan University, Sanya 572025, ChinaSoft rotting caused by <i>Rhizopus stolonifer</i> is one of the most important postharvest decays in Kokei No. 14 organic sweet potato roots. While various methods have been explored for controlling this pathogen, there remains a need for effective, safe, and applicable alternatives, particularly using essential oils (EOs). This study evaluated the efficacy of EOs, specifically carvacrol, thymol, and thyme oil, in controlling <i>Rhizopus</i> soft rot. We conducted both in vitro and in vivo tests to assess their effects on fungal mycelial growth, spore germination, and the incidence and severity of soft rot in sweet potatoes, along with quality evaluations of the roots. The results indicated that the vapor phase of carvacrol, thymol, and thyme oil was more effective than the contact phase in inhibiting fungal growth and spore germination. In vivo tests revealed that all three EOs significantly reduced the incidence and severity of soft rot, with thymol and thyme oil at 300 mg/L, and carvacrol at 500 mg/L being the most effective. Quality assessments showed minimal impact on properties such as firmness, weight loss, color, starch, carotenoids, and flavonoids, although residual odors increased. GC/MS analysis confirmed that thyme oil contained high levels of both thymol and carvacrol, along with other antimicrobial compounds, suggesting that the cumulative activity of these volatile compounds enhanced their bacteriostatic effects. Thyme oil demonstrated greater efficacy in reducing soft rot development compared to its individual components, making it a promising biofumigant for controlling postharvest diseases in Kokei No. 14 organic sweet potato roots. These findings emphasized the potential for using thyme oil as a safe and effective approach to managing postharvest decay.https://www.mdpi.com/2304-8158/14/7/1273Kokei No. 14 sweet potato (<i>Ipomoea batatas [L.]. Lam</i>.)organic<i>Rhizopus stolonifer</i> (<i>R. stolonifer</i>)essential oils (EOs)carvacrolthymol
spellingShingle Guangwei Wu
Chenqi Fan
Xueqian Zang
Bei Wang
Yanli Chen
Jingjing Kou
Guopeng Zhu
The Control of Postharvest Soft Rot Caused by <i>Rhizopus stolonifer</i> on Kokei No. 14 Organic Sweet Potato Roots by Carvacrol, Thymol, and Thyme Oil
Foods
Kokei No. 14 sweet potato (<i>Ipomoea batatas [L.]. Lam</i>.)
organic
<i>Rhizopus stolonifer</i> (<i>R. stolonifer</i>)
essential oils (EOs)
carvacrol
thymol
title The Control of Postharvest Soft Rot Caused by <i>Rhizopus stolonifer</i> on Kokei No. 14 Organic Sweet Potato Roots by Carvacrol, Thymol, and Thyme Oil
title_full The Control of Postharvest Soft Rot Caused by <i>Rhizopus stolonifer</i> on Kokei No. 14 Organic Sweet Potato Roots by Carvacrol, Thymol, and Thyme Oil
title_fullStr The Control of Postharvest Soft Rot Caused by <i>Rhizopus stolonifer</i> on Kokei No. 14 Organic Sweet Potato Roots by Carvacrol, Thymol, and Thyme Oil
title_full_unstemmed The Control of Postharvest Soft Rot Caused by <i>Rhizopus stolonifer</i> on Kokei No. 14 Organic Sweet Potato Roots by Carvacrol, Thymol, and Thyme Oil
title_short The Control of Postharvest Soft Rot Caused by <i>Rhizopus stolonifer</i> on Kokei No. 14 Organic Sweet Potato Roots by Carvacrol, Thymol, and Thyme Oil
title_sort control of postharvest soft rot caused by i rhizopus stolonifer i on kokei no 14 organic sweet potato roots by carvacrol thymol and thyme oil
topic Kokei No. 14 sweet potato (<i>Ipomoea batatas [L.]. Lam</i>.)
organic
<i>Rhizopus stolonifer</i> (<i>R. stolonifer</i>)
essential oils (EOs)
carvacrol
thymol
url https://www.mdpi.com/2304-8158/14/7/1273
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