Inhibitory Effect of Different Essential Oils on Aspergillus Niger of

Postharvest Grape

Yongdong Xie

1,4

, Jiawen Zhu

, Hanyang Liu

, Huashan Lian

and Ji Liu

4,*

Chengdu Agricultural Science and Technology Center, Chengdu 610213, China

Research Institute of Animal Husbandry, Chengdu Academy of Agriculture and Forestry Sciences,

Chengdu 611130, China

School of Agriculture and Horticulture, Chengdu Agricultural College, Chengdu 611130, China

Research Institute of Agricultural Products Processing and Storage, Chengdu Academy of Agriculture and Forestry

Sciences, Chengdu 611130, China

Keywords: Grape, Aspergillus Niger, Essential Oil, Colony Diameter.

Abstract:

Aspergillus Niger is the main pathogen causing grape smut disease. A vitro assay was conducted to screen

out the essential oils with better inhibitory effect on grape A. Niger. The results showed that among 31

essential oils, nine essential oils at 1000 μL/L can kill A. Niger. Reduced the concentration of these nine

essential oils to 500 μL/L, only basil and oregano essential oils had continuous antifungal effect on A. Niger.

But if the concentration of basil and oregano essential oils reduced to 250 μL/L, the antifungal effect was

weakened. Therefore, in order to maintain continuous antifungal effect, the concentration of essential oils

should more than 250 μL/L.

1 INTRODUCTION

Grapes are berry fruits that mainly distributed in

temperate and subtropical regions. Although grape

industry is developing rapidly and grape production

is increasing day by day, table grapes are still the most

important part of Chinese grape industry (Meng,

2017). Grape fruits are easily infected by pathogenic

fungus during postharvest storage due to their high-

water content and thin peel, which strongly affects the

edible taste and nutritional value of grapes (Guerra,

2016). If the fungus is not inhibited and preserved in

time, it will not only cause significant economic

losses, but also seriously restrict the development of

the grape industry (Xu, 2007).

Aspergillus niger is a dominant pathogen at high

temperature after harvesting fresh table grapes. They

can cause smut disease, often infecting grapes

through wounds. After grape fruit infected A. niger, it

will lead to grape corruption, dehydration, and

reduced nutritional value (Xu, 2007). For the

consideration of environmental protection and human

health, in recent years, natural preservatives extracted

from animals and plants have emerged in endlessly,

and plant extracts have been used in the preservation

of fruits and vegetables (Tanapichatsakul, 2020).

Singh found that most aromatic essential oil aqueous

emulsions with a concentration of 0.1-10 μg/g can

inhibit the growth of decay-causing fungus and food-

borne pathogenic fungus to a certain extent on the

immersion processing of fruit and vegetables. (Singh,

2002). However, effective concentration and side

effect should be considered before large-scale

application of plant essential oils.

In this study, the essential oils with inhibitory

effect on A. Niger of postharvest grape were screened

from 31 kinds of plant essential oils through in vitro

tests, and their concentration was gradually reduced

to determine the minimum concentration, which

provided ideas for the postharvest preservation of

grapes.

2 MATERIALS AND METHODS

2.1 Materials

Essential oils were provided by Ji'an Guoguang Spice

Oil Co., Ltd. (Ji'an, Jiangxi, China). Potato dextrose

agar (PDA) and potato dextrose broth (PDB) medium

were provided by Shanghai Bio-way technology Co.,

Xie, Y., Zhu, J., Liu, H., Lian, H. and Liu, J.

Inhibitory Effect of Different Essential Oils on Aspergillus Niger of Postharvest Grape.

DOI: 10.5220/0012012500003633

In Proceedings of the 4th International Conference on Biotechnology and Biomedicine (ICBB 2022), pages 31-34

ISBN: 978-989-758-637-8

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

Ltd. (Shanghai, China). A. Niger was isolated from

the mature grapes.

2.2 Methods

2.2.1 Propagation of A. Niger

The isolated and purified A. niger from tables grapes

was inoculated on the PDA medium and cultured at

26°C for 48h. The mycelium was picked to a conical

flask containing 50 mL PDB liquid medium with an

inoculating loop, and cultured at 26°C for 48h.

2.2.2 Preparation of Essential Oil Medium

and Determination of Colony Diameter

The stock solution of 31 kinds of plant essential oils

was diluted with 5% Tween solution, mixed with the

medium according to the required concentration,

poured into a petri dish, and repeated three times for

each essential oil. After the medium was solidified, a

puncher was used to punch out 0.7 cm stipe from the

prepared fungus-containing medium, and inoculated

them on the medium containing different essential

oils, and the medium without any essential oil but

inoculated with A. Niger was used as control (CK).

Then, all the inoculated culture dishes were placed in

a constant temperature incubator at 26 °C, and the

diameter of the colony was measured every 24h using

a millimeter scale.

2.3 Statistical Analysis

Statistical analyses were conducted using SPSS 20.0

statistical software (IBM Corporation, Armonk, New

York, USA). The data was analyzed using one-way

analysis of variance (ANOVA) followed by the least

significant difference (LSD) test applied at 5%

significance level.

3 TEST RESULTS AND

DISCUSSIONS

3.1 Inhibitory Effect of Different

Essential Oils on Grape A. Niger

Table 1 showed that after culturing for 72 hours, the

colony diameter in the control is the largest, and

except for the three essential oil treatments, the

colony diameters in the other essential oil treatments

were significantly lower than those in the control.

Among the 31 essential oils, the colonies treated with

9 essential oils did not grow, and the diameter of the

colonies was only the diameter of the stipe. It may be

that 1000 μL/L of these 9 essential oils had killed A.

Niger, which can be used for follow-up research.

Table 1: Effects of different essential oils at 1000 μL/L on colony growth of A. Niger at 72h.

Essential oil Colony Diameter (cm) Essential oil Colony Diameter (cm)

5.68±0.34a Tea tree 5.21±0.45ab

Lemon 5.16±0.27ab Gin

5.05±0.46ab

Zanthoxylu

5.09±0.19b Folium eucalypti 4.82±0.29b

Rhizoma calami 4.84±0.37bc Perilla leaf 4.75±0.29bc

Artemisiae argyi 4.46±0.45c Rhubarb 4.45±0.32c

ristica fra

rans 4.32±0.31c Fructus fors

thiae 4.15±0.32c

Rhizoma atractylodis 4.06±0.22c

Chamomile 4.07±0.31c

hatherum

racile 3.96±0.18

Clausena lansium 3.82±0.27

Rhizoma Coptidis 3.48±0.26de Tangerine Peel 3.52±0.26de

Rosemar

3.19±0.27ef Mentha 3.25±0.18ef

Lavende

2.82±0.16f Pogostemon cablin 2.83±0.16f

ilawoo

1.73±0.06

me 0.70±0.00h

Citronella 0.70±0.00h Clove 0.70±0.00h

Ore

ano 0.70±0.00h Cinnamon 0.70±0.00h

Asarum 0.70±0.00h Basil 0.70±0.00h

Garlic 0.70±0.00h litsea cubeba 0.70±0.00h

ICBB 2022 - International Conference on Biotechnology and Biomedicine

Different lowercase letters within a column

indicate significant differences based on one-way

analysis of variance and the least significant

difference test (95% confidence level). The same as

below.

3.2 500 μL/L of 9 Essential Oils for

Continuous Inhibition on Grape A.

Niger

Table 2 showed that when the concentration of

essential oil was reduced to 500 μL/L, Cinnamon

essential oil lost its antifungal effect. Although the

five essential oils, citronella, clove, garlic, asarum

and basil had a certain antifungal effect, their colonies

had begun to grow. However, two essential oils, litsea

cubeba and oregano, still had good antifungal effects,

and the colony diameter had always been only the

diameter of the stipe, which were available for further

research.

Table 2: Effects of 9 essential oils at 500 μL/L on continuous colony growth of A. Niger.

Essential oil

Colony Diameter (cm)

24h 48h 72h

CK 1.51±0.14a 3.16±0.18a 4.69±0.35a

Cinnamon 1.14±0.08b 2.16±0.15b 4.08±0.29a

Citronella 0.70±0.00d 1.27±0.03e 2.16±0.11c

Clove 0.94±0.01c 1.38±0.06d 1.64±0.08d

Garlic 0.95±0.02c 1.66±0.09c 2.08±0.12c

Asarum 0.92±0.03c 1.67±0.06c 2.68±0.11b

Basil 0.70±0.00d 0.82±0.01f 0.91±0.02e

Litsea cubeba 0.70±0.00d 0.70±0.00g 0.70±0.00f

Ore

ano 0.70±0.00

0.70±0.00

0.70±0.00f

3.3 250μL/L of Basil and Oregano

Essential Oil for Continuous

Inhibition on A. Niger

It can be seen from table 3 that although the colony

diameters of basil and oregano essential oils were

significantly lower than those of the control in each

period, A. Niger had begun to grow, indicating that

250 μL/L of these two essential oils had lost their

continuous antifungal effect.

Table 3: Effects of 250 μL/L basil and oregano essential oil on colony growth of grape A. Niger.

Essential oil

Colony Diameter (cm)

24h 48h 72h

1.78±0.10a 2.96±0.13a 5.46±0.35a

Basil 1.36±0.04b 2.36±0.08b 4.67±0.26b

Oregano 1.02±0.01c 1.89±0.05c 3.35±0.18c

Inhibitory Effect of Different Essential Oils on Aspergillus Niger of Postharvest Grape

4 CONCLUSION

Based on the results presented above, the conclusions

are obtained as below:

(1) Most essential oils at high concentration have

antifungal effect on table grape A. Niger, but its

antifungal effect decreased with the decrease of

essential oil concentration.

(2) In vitro assay, basil and oregano essential oil

has good continuous antifungal effect on grape A.

Niger, but its concentration should be higher than 250

μL/L.

ACKNOWLEDGMENTS

This work was supported by Local Financial Funds of

National Agriculture Science and Technology Center,

Chengdu (NASC2020AR05) and Sichuan Science

and Technology Program (2021JDRC0134).

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