Thermal inactivation kinetics of Rabdosia serra (Maxim.) Hara leaf peroxidase and polyphenol oxidase and comparative evaluation of drying methods on leaf phenolic profile and bioactivities

Lin, Lianzhu; Lei, Fenfen; Sun, Da‐Wen; Dong, Yunhui; Yang, Bao; Zhao, Mouming

doi:10.1016/j.foodchem.2012.04.008

Cited by 45 publications

(30 citation statements)

References 23 publications

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“…Leaves showed no significant TPC change after blanched leaves underwent all drying treatments as a result of inactivation of both PPO and POD during blanching. Inactivation of oxidase enzymes by blanching was also observed in studies where blanched Rabdosia serra leaves showed loss of PPO and POD activity in all blanching temperatures across time (Lin et al, 2012), while blanched Morus alba leaves showed no change in TPC after oven-drying at 50 and 100 °C due to complete inactivation of PPO and POD (Tan et al, 2015). Inactivation of PPO and POD can be described based on first-order kinetic model and the determination coefficients (R 2 ) of both enzymes increased with increasing blanching temperature (Lin et al, 2012).…”

Section: Effects Of Drying and Blanching On Ppo And Pod Activitysupporting

confidence: 62%

“…Inactivation of oxidase enzymes by blanching was also observed in studies where blanched Rabdosia serra leaves showed loss of PPO and POD activity in all blanching temperatures across time (Lin et al, 2012), while blanched Morus alba leaves showed no change in TPC after oven-drying at 50 and 100 °C due to complete inactivation of PPO and POD (Tan et al, 2015). Inactivation of PPO and POD can be described based on first-order kinetic model and the determination coefficients (R 2 ) of both enzymes increased with increasing blanching temperature (Lin et al, 2012). The study showed that short blanching time at high temperature would ensure inactivation of PPO and POD and the retention of phenolic compounds in leaves (Lin et al, 2012).…”

Section: Effects Of Drying and Blanching On Ppo And Pod Activitysupporting

confidence: 62%

“…Inactivation of PPO and POD can be described based on first‐order kinetic model and the determination coefficients (R 2 ) of both enzymes increased with increasing blanching temperature (Lin et al, ). The study showed that short blanching time at high temperature would ensure inactivation of PPO and POD and the retention of phenolic compounds in leaves (Lin et al, ). Results from blanching P. americana leaves confirm the involvement of enzymatic degradation of phenolic compounds in the leaves and the short blanching time (1 min) was able to minimize phenolic compounds from leaching out into the boiling water with average leached TPC of only 5.6%.…”

Section: Resultsmentioning

confidence: 99%

“…Inactivation of PPO and POD can be described based on first-order kinetic model and the determination coefficients (R 2 ) of both enzymes increased with increasing blanching temperature (Lin et al, 2012). The study showed that short blanching time at high temperature would ensure inactivation of PPO and POD and the retention of phenolic compounds in leaves (Lin et al, 2012).…”

Section: Effects Of Drying and Blanching On Ppo And Pod Activitymentioning

confidence: 93%

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Drying effects on antioxidant activity, enzyme activity, and phytochemicals of avocado ( Persea americana ) leaves

Loh

Lim

2018

J Food Process Preserv

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In this study, avocado leaves were dried by five different drying treatments: oven‐drying at 50 and 100 °C, microwave‐drying, ambient air‐drying, and freeze‐drying. Investigation showed that oven‐drying and ambient air‐drying of leaves caused decrease in antioxidant properties while microwave‐drying and freeze‐drying preserved them. Polyphenol oxidase (PPO) and peroxidase (POD) activities decreased notably after drying in oven at 50 and 100°C, microwave, ambient air and blanching at 100°C. However, increase in PPO was observed in freeze‐dried leaves. Chlorogenic acid and rutin present in leaves showed varying decrease in drying processes except microwave‐drying, and freeze‐drying. Cellular antioxidant assay revealed reduced antioxidant activity in all drying treatments except for microwave‐drying. Factors that affected changes in antioxidant properties by various drying processes were identified and discussed. Microwave‐drying was considered to be the best drying method for avocado leaves as phenolic compounds were preserved and PPO and POD activities were deactivated. Practical applications Avocado leaves are used as herbal tea in traditional medicine and are reported to have medicinal properties such as antioxidant, anti‐viral, and anti‐inflammatory. Processing of fresh herbal tea leaves are required to preserve phenolic compounds and quality of the tea leaves. This study represents a comprehensive study on the effects of different drying treatments on the antioxidant activity using both in vitro and in vivo analysis and enzymatic changes of avocado leaves. The optimum drying condition found in this study will be beneficial to the tea processing industry.

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Section: Effects Of Drying and Blanching On Ppo And Pod Activitysupporting

confidence: 62%

Section: Effects Of Drying and Blanching On Ppo And Pod Activitysupporting

confidence: 62%

Section: Resultsmentioning

confidence: 99%

Section: Effects Of Drying and Blanching On Ppo And Pod Activitymentioning

confidence: 93%

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Drying effects on antioxidant activity, enzyme activity, and phytochemicals of avocado ( Persea americana ) leaves

Loh

Lim

2018

J Food Process Preserv

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“…A higher content of gallic acid found in un-treated may be due to 2 main mechanisms; (1) hydrolyzed of tannin to tannic acid and gallic acid [44] and (2) these was no leaching effect into water particularly free, conjugated phenolics, when compared with blanching process [39,45]. He et al [46] reported that cinnamic acid seemed to be decreased in blanched extract due to oxidation of cinnamic acid structure to p-coumaric acid, which was similar to this result confirmed by HPLC profile.…”

Section: Contentmentioning

confidence: 99%

Influence of hot water blanching process on phenolic profile and antioxidant activity of Cinnamomum porrectum herbal tea

Saetan

Usawakesmanee²,

Siripongvutikorn³

2016

FFHD

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Background: Cinnamomum porrectum leaves, one kind of Cinnamomum family, has recently been used to produce a locally herbal tea. Although C. porrectum essential oil and aqueous extract have been reported to have some biological activities, including antioxidant, antimicrobial, and anti-inflammatory activities, there is no scientific data using the blanching process for the production of herbal tea. Therefore, this experiment aimed to study the effect of hot water blanching before drying process on microstructure, nutrition content of the tea powder, TPC, TFC, antioxidant activities of infusion, as well as the phenolic profile of the extract.Objective: To determine effect of hot water blanching process on nutritional value, microstructure, phenolic profile, and antioxidant activity of the C. porrectum herbal tea.Methods: The C. porrectum leaves were divided into 2 groups; control (un-treated) and blanched before dried for herbal tea processing. The fresh leaves and the powders of control and blanched leaves were checked for proximate composition and chlorophyll contents, in addition to color value. The powders were determined microstructure by SEM. The infusions were determined to have color value and total extractable phenolic and flavonoid contents, as well as antioxidant activities. The hydrolyzed extracts of freeze dried infusion were subjected to identify phenolic profile by HPLC. Results: The blanched tea powder yielded a percentage of fat and protein contents higher than untreated due to easier extraction because of the bigger pore size found in microstructure. Chlorophyll content of blanched was decreased compared with the control sample. However, it was found that blanching could greater maintain green color of both powder and infusion.Additionally, blanching helped increased TPC, TFC extractability, and antioxidant activities in all assays except metal chelating property. Based on retention time and peak profile determined by using HPLC, it was found that both control and treated extracts consisted of similar main phenolic and flavonoid compounds however, only kaempferol was found in un-treated. Moreover, hydrolyzed blanched extract showed a higher intensity of 2 unknown compounds than un-treated. Though un-treated provided a higher intensity of pyrogallol, gallic acid, and cinnamic acid, the blanched exhibited a higher intensity of caffeic acid, protocatechuic acid, p-coumaric acid, and rutin. Conclusion:Blanching before drying expanded pore size of dried leaves, increased yield extractability, maintained color value, chlorophylls and increased TPC and TFC which related to antioxidant activities. Blanched extract provided higher intensity of some phenolic compounds than un-treated.

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Assessment of microwave drying for rapid and convenient analysis of medicinal plants for quality assurance

Bala,

Dey,

Patra

et al. 2024

Phytochemical Analysis

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IntroductionThe safety and quality of many medicinally important herbs are compromised since farmers and small organizations are involved in the cultivation, aggregation, and primary processing of these herbs. Such organizations often lack adequate quality control facilities. To improve the safety and quality of herbal products, simple, rapid, and affordable quality control systems are required.ObjectivesThe aim of this study was to assess the suitability of microwave oven‐drying for moisture content (MC) determination and sample preparation of herbs in small organizations.MethodsMicrowave oven‐drying (720 W) and convective oven‐drying at 105°C for MC determination were compared. The effects of three different drying methods (microwave oven‐drying, low‐temperature convective drying, and freeze‐drying) on in vitro antioxidant and polyphenol oxidase (PPO) activity were determined, similarity analysis was conducted using HPLC signature spectra, and validation was performed with LC‐MS focusing on one herb.ResultsMicrowave oven‐drying at 720 W significantly reduced the drying time (from hours to minutes), whereas the spatial variation of temperature in convective ovens set at 105°C can cause about 10% underestimation of MC. Microwave oven‐drying showed similar macro‐properties like freeze‐drying and higher extractability (10%–20%) and in vitro antioxidant capacity (33%–66%) and lower PPO activity compared to low‐temperature convective drying. HPLC signature spectra revealed strong similarity of soluble components between freeze‐dried and microwave oven‐dried herbs. LC‐MS analysis demonstrated more common compounds between freeze‐dried and microwave oven‐dried Centella asiatica extracts, whereas convective tray‐dried samples had fewer compounds common with samples obtained by freeze‐drying or microwave oven‐drying.ConclusionsMicrowave oven‐drying is rapid (tens of min) and shows small batch‐to‐batch variation compared to oven‐drying at 105°C. The in vitro antioxidant assays and signature spectra can be used for assessing the source and purity or quality of a specific herb variety.

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Thermal inactivation kinetics of Rabdosia serra (Maxim.) Hara leaf peroxidase and polyphenol oxidase and comparative evaluation of drying methods on leaf phenolic profile and bioactivities

Cited by 45 publications

References 23 publications

Drying effects on antioxidant activity, enzyme activity, and phytochemicals of avocado ( Persea americana ) leaves

Drying effects on antioxidant activity, enzyme activity, and phytochemicals of avocado ( Persea americana ) leaves

Influence of hot water blanching process on phenolic profile and antioxidant activity of Cinnamomum porrectum herbal tea

Assessment of microwave drying for rapid and convenient analysis of medicinal plants for quality assurance

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