Preparation and stability assessment of Perilla frutescens seed oil powder

Abstract

Objective: The present study deals with the preparation and stability assessment of Perilla frutescens seed oil powder (PSOP) by spray drying technique.Methods: Perilla oil emulsion was prepared with various combinations of emulsifiers and maltodextrin powder. The emulsion was dried in a spray dryer, and dried samples were packed and stored at 4, 25, and 40°C for 3 months. The changes in acid and peroxide value the fatty acid content of PSOP during storage were assessed. PSOP samples were subjected to scanning electron microscopic analysis to examine the size and shape of the particle.Results: About 9.52% of PSOP yield was obtained while 5% of whey protein was used as an emulsifier. The moisture content of the PSOP was 2.06 ± 0.23-3.08 ± 0.13%. The acid and peroxide values were increased from 1.49 ± 0.09 to 3.71 mg KOH/g of PSOP, 4.10-7.18 mEq/kg of PSOP, while stored in aluminum foil and kept at 40°C. About 39.97, 26.68, 24.78, and 7.47% of linolenic, oleic, linoleic, and palmitic acids were found in PSOP, respectively.Conclusion: The study revealed that spray-dried PSOP was stable when stored in the absence of light and air at low temperature. The spray-dried PSOP is the best candidate for pharmacological and food applications.

Full text

Vol 10, Issue 12, 2017
Online - 2455-3891
Print - 0974-2441
PREPARATION AND STABILITY ASSESSMENT OF PERILLA FRUTESCENS SEED OIL POWDER
CHAIYAVAT CHAIYASUT1, BHAGAVATHI SUNDARAM SIVAMARUTHI1*, NETNAPA MAKHAMRUEANG1,
PERIYANAINA KESIKA1, SASITHORN SIRILUN1, SARTJIN PEERAJAN2
1Faculty of Pharmacy, Innovation Center for Holistic Health, Nutraceuticals and Cosmeceuticals, Chiang Mai University, Chiang Mai 50200,
Thailand. 2Health Innovation Institute, Chiang Mai 50230, Thailand. Email: sivasgene@gmail.com
Received: 28 July 2017, Revised and Accepted: 18 September 2017
ABSTRACT
Objective: The present study deals with the preparation and stability assessment of Perilla frutescens seed oil powder (PSOP) by spray drying
technique.
Methods: Perilla oil emulsion was prepared with various combinations of emulsifiers and maltodextrin powder. The emulsion was dried in a spray
dryer, and dried samples were packed and stored at 4, 25, and 40°C for 3 months. The changes in acid and peroxide value the fatty acid content of PSOP
during storage were assessed. PSOP samples were subjected to scanning electron microscopic analysis to examine the size and shape of the particle.
Results: About 9.52% of PSOP yield was obtained while 5% of whey protein was used as an emulsifier. The moisture content of the PSOP was 2.06 ±
0.23-3.08 ± 0.13%. The acid and peroxide values were increased from 1.49 ± 0.09 to 3.71 mg KOH/g of PSOP, 4.10-7.18 mEq/kg of PSOP, while stored
in aluminum foil and kept at 40°C. About 39.97, 26.68, 24.78, and 7.47% of linolenic, oleic, linoleic, and palmitic acids were found in PSOP, respectively.
Conclusion: The study revealed that spray-dried PSOP was stable when stored in the absence of light and air at low temperature. The spray-dried
PSOP is the best candidate for pharmacological and food applications.
Keywords: Fatty acid, Perilla frutescens, Spray drying technique, Scanning electron microscopy.
INTRODUCTION
Perilla frutescens (L.) Britton is an annual herbaceous plant and used
as a traditional medicine in Asian countries for years. The perilla
seed (PS) and PS oil (PSO) are rich sources of phenolic compounds,
antioxidants, and polyunsaturated fatty acids (especially, α-linolenic
acid, linoleic acid, oleic acid, and palmitic acid). Several reports revealed
that the PS, PSO, and perilla leaves have antioxidant, antiallergic, anti-
inflammatory, anticancer, neuroprotective, and α-glucosidase inhibitory
properties [1-4]. PSO is commonly used to flavor the foods, and as
cooking oil (particularly in Korean cuisine), and in cleansing products.
In general, plant-based oils are vulnerable to isomerization and
oxidation during processing and storage due to the presence of
unsaturated fatty acids. Thus, the prevention of the degradation of the
bioactive components in the oil is important to maintain the quality of
the oil [5].
The conversion of oil into powder form by drying methods such as
freeze dry and spray dry is one of the ways to preserve and store the oil
efficiently. The spray drying of oil improved the handling and stabilizing
the essential fatty acids present in the oil and extends the storage/ shelf
life. Several spray-dried powders of emulsified oils; fats are used in food
industries [6].
The carrier matrixes (CM) were utilized in the spray drying process to
facilitate the powderization. Further, emulsification of oil is performed
in many cases before spray drying. The CM are selected based on the
stability, solubility, yield, and absorbency. The maltodextrin (MD),
lactose, cyclodextrin, starch, and modified starch are commonly served
as CM. The stability of dry emulsions with MD, lactose, and mannitol was
reported and revealed that it facilitates the crystalline [7]. The spray-
dried Myracrodruon urundeuva Allemão extract retain its bioactivities,
and author claimed that spray drying method provides an adequate
amount of dry powdered extract [8].
The storage conditions significantly affect the quality of the product.
The factors such as sunlight, temperature, oxygen content influence the
bioactivity, and quality of the spray-dried powders. In general, the rate
of degradation process is high in the foods with high unsaturated fatty
acids. Decomposition led the product to become unfeasible, and/or
affect the flavor, color, and nutritional value of the food [9].
PS and PSO are used in pharmacological preparation because of the
valuable nutraceutical property of perilla. Thus, the current study was
aimed to formulate and produce the PSO powder (PSOP) by the spray
drying method. Further, the present study explains about the stability
of PSOP while stored at different temperature and conditions for
3 months.
METHODS
Raw materials
The cold pressed perilla (P. frutescens [L.] Britton) seed oil (PSO) was
purchased from Energy Friend Ltd., Part. (Chiang Mai, Thailand) and
stored at 4°C until use. MD powder (with dextrose equivalent of 11.08)
was obtained from WGC Co., Ltd., Nakornpatom, Thailand, which is used
to increase the texture of the final product. Whey protein isolate (WPI)
was also obtained from WGC Co., Ltd. (Nakornpatom, Thailand). Emultec
908 (E908) was obtained from Siam Modified Starch Corporation Co.,
Ltd., Pathum Thani, Thailand.
Preparation of PSOP by spray drying method
The composition of the emulsion was PSO (30 and 40%) and MD (15
and 20%) and an emulsifier such as E908 (2% and 5 %) and WPI (2%
and 5%) (Table 1).
© 2017 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons.
org/licenses/by/4. 0/) DOI: http://dx.doi.org/10.22159/ajpcr.2017.v10i12.21672
Research Article

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Chaiyasut et al.
The ingredients of the emulsion were dissolved in deionized water
at 50°C. Then, it was mixed thoroughly using high shear laboratory
mixer (Silverson, L5M-A, Buckinghamshire, England) at 7000 rpm
for 3 minutes. The viscosity of the emulsion was measured using
Rheometer (Brookfield, R/S-CPS, Middleboro, MA). The emulsion was
dried in spray dryer (Lab Plant, Spray drier SD-04, North Yorkshire,
England) at 180°C (inlet temperature), and 90°C (outlet temperature)
with the inlet flow rate of 3 rpm. After that, the powder was cooled to
room temperature. The collected powders were preserved in several
storage conditions until use. The percentage of yield was calculated as
detailed previously [4].
Storage condition of PSOP
About 5 g of PSOP were packed into an aluminum foil bag (AFB) and
amber glass bottle (AGB). The packed samples were stored at different
temperatures (4°C, 25°C, and 40°C) for 3 months. During storage,
the samples were withdrawn every month to measure the acid and
peroxide values. The fatty acid content of the samples was analyzed
only at the month of 0 (severed as control) and 3.
Viscosity and moisture content analysis
The moisture content of PSOP was determined using a moisture
analyzer (MS-50, A&D, Tokyo, Japan) at 160°C. The viscosity of
emulsion was determined using cylindrical spindles by R/S Rheometer
(Brookfield, R/S-CPS, Middleboro, MA, USA).
Determination of acid and peroxide value
The acid and peroxide values of PSOP were determined according to
Sirilun et al. [4]. The acid and peroxide values were represented as mg
of potassium hydroxide equivalent per gram of PSOP (mg KOH/g of
PSOP), and milliequivalent of oxygen per kilogram of PSOP (mEq/Kg of
PSOP), respectively.
Quantification of individual fatty acid content
The individual fatty acid content was measured as described in
the previous report [4] and outsourced at Halal Science Center,
Chulalongkorn University, Bangkok, Thailand.
Scanning electron microscopy (SEM)
The surface structure of PSOP was observed by LV-SEM (JEOL, JSM-
5910LV, Tokyo, Japan). The PSOP was coated with a very thin layer of
gold using Sputter coater (SPI-Module, West Chester, PA), before the
microscopic examination.
Statistical analysis
All the experiments were performed in triplicates except fatty acid
analysis, and the results were represented as mean ± SD. The statistical
significance of the data was assessed by one-way ANOVA. Duncan’s
new multiple range test determined significant differences, at the 95%
confidential level (p<0.05) using statistical SPSS software version 17.0
(SPSS Inc., Chicago, USA).
RESULTS AND DISCUSSION
Preparation and evaluation of PSOP
The purchased PSO was clear and yellow (Fig. 1a). The total of 16
oil emulsion formulas was prepared with various combinations of
emulsifier, MD, and PSO. The viscosity of all the formulas was analyzed.
The viscosity of the emulsions was found to be varied from 0.25 ± 0.007
to 5.87 ± 0.1 Pa.s. The high viscosity of about 5.87 Pa.s was observed in
the recipe no. 14 (Fig. 2).
Relatively high viscous emulsions were not subjected to spray
drying process due to the nozzle pore size (high viscous samples
are not able to flow through the nozzle of the spray dryer). Thus,
recipe no. 1, 3, 4, 5, 7, 8, 9, 11, 12, and 15 were subjected to a
spray drying process to yield the powder. The representative PSOP
samples were shown in Fig. 1b. The surface structure of the PSOP
was microscopically analyzed (Fig, 3a-g) and found that the size of
PSOP was 30-44 nm (Fig. 3a).
The powder yield of PSOP was significantly affected by the emulsifier
and MD concentration. To the maximum of 9.52% yield of PSOP was
obtained in the recipe 8, in which 5% of whey protein was used as an
emulsifier (Table 2). The moisture content of the PSOP was ranging
between 2.06 ± 0.23 and 3.08 ± 0.13% (Table 2).
The acid value represents the triglyceride content in an oil sample,
which is an indicator of degradation and rancidity of oil. As per the Thai
Ministry of Public Health Notification (2000), the acceptable level of
acid value is less than 4 mg KOH/g of oil. The acid value of the PSOP was
analyzed and found that the recipe no. 15 has the acid value of about
4.38 ± 0.34 mg KOH/g of PSOP. While other recipes showed the acid
value within the acceptable range except recipe no. 11 and 15 (Table 2).
Table 1: The composition of the emulsions
Recipe Composition (%)
Water PSO MD Emulsifier
E908 Whey protein
1 53 30 15 2 -
2 50 30 15 5 -
3 53 30 15 - 2
4 50 30 15 - 5
5 48 30 20 2 -
6 45 30 20 5 -
7 48 30 20 - 2
8 45 30 20 - 5
9 43 40 15 2 -
10 40 40 15 5 -
11 43 40 15 - 2
12 40 40 15 - 5
13 38 40 20 2 -
14 35 40 20 5 -
15 38 40 20 - 2
16 35 40 20 - 5
E908: Emultec 908, MD: Maltodextrin, PSO: Perilla seed oil
Table 2: The yield, moisture content, acid value, and peroxide value of PSOP
Recipe Yield (%) Moisture content (%) Acid value (mg KOH/g PSOP) Peroxide value (mEq/kg PSOP)
1 3.61c±0.16 3.08d±0.13 1.56a±0.12 4.10a±0.08
3 3.55c±0.08 2.65c±0.10 1.70a±0.16 4.55bc±0.15
4 6.06d±0.10 2.50bc±0.15 1.46a±0.12 4.70c±0.09
5 1.75a±0.35 2.80cd±0.25 2.20b±0.05 4.46bc±0.08
7 2.41b±0.12 2.26ab±0.16 1.57a±0.23 4.79c±0.11
8 9.52e±0.70 2.50bc±0.24 1.49a±0.09 4.35ab±0.35
9 1.64a±0.37 2.06a±0.23 2.56bc±0.37 4.35ab±0.16
11 3.14c±0.11 2.63c±0.12 4.30d±0.40 5.14d±0.10
12 1.25a±0.24 2.61bc±0.21 2.75c±0.17 5.23d±0.07
15 3.48c±0.12 2.47bc±0.24 4.38d±0.34 6.37e±0.33
a-eIndicates the significant difference between the values. PSOP: Perilla frutescens seed oil powder

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Chaiyasut et al.
Likely, peroxide values are used as an indicator of oxidation of the oil. As
per the Thai Ministry of Public Health Notification (2000), the standard
level of peroxide is <10 mEq/kg of oil. The prepared PSOP has fallen in
the safe range of peroxide value (Table 2).
Stability study
The PSOP prepared from the recipe no. 8 was selected for stability study
since it yielded high powdered oil. The PSOP samples were stored at different
temperature and in different storage containers. The changes in the acid and
peroxide values were assessed at 0, 1, 2, and 3 months of storage, whereas
fatty acid content was assessed at 0, 1, and 3 months of storage.
The initial acid value (control) of PSOP was 1.49 ± 0.09 mg KOH/g of
PSOP. The results indicated that when the storage time increased,
the acid value also increased in the samples. To the maximum of
3.71 mg KOH/g of PSOP acid value was observed in the samples that
are stored in aluminum foil and kept at 40°C (Fig. 4a). The increase in
the acid value is possibly due to the high temperature which affects the
glycerol and free fatty acids in oil powder. Moreover, aluminum foil is
porous enough for the oxygen passage [5]. The samples stored in amber
bottles showed relatively low acid values.
The peroxide values are directly related to the autoxidation of oil,
especially occurred in the oil enriched with unsaturated fatty acid.
Moreover, the unsaturation levels were assessed by iodine/peroxide
values. The presence of iodine and oxidation leads to rancidity. The
initial peroxide value (control) of PSOP was 4.10 mEq/kg of PSOP.
Similar to acid value, the maximum of 7.18 mEq/kg of PSOP peroxide
value was observed in the samples that are stored in aluminum foil and
kept at 40°C. The samples stored in amber bottles showed relatively
low peroxide values (Fig. 4b).
Alpha-linolenic acid, oleic acid, linoleic acid, and palmitic acid are the
major of fatty acids present in PSO [4]. The PSOP has 39.97, 26.68,
24.78, and 7.47% of linolenic acid, oleic acid, linoleic acid, and palmitic
acid, respectively. The influence of storage temperature and container
on the fatty acid composition of PSOP was assessed (Table 3), and the
results revealed that the fatty acid content was not significantly affected
during storage when compared to that of the control.
After 3 months of storage, the PSOP was subjected to microscopic
observation. The particle size of the PSOP was not significantly affected
(Fig. 3), which indicated that the tested storage conditions caused no
damage in the structure and size of the perilla oil powder.
Hui-Juan et al. [10] reported that more than 30% embedding rate
was achieved by preparing PSOP using cross-linked esterified porous
starch. This powdering method also extended the time for lipid
peroxidation in PSOP when compared to that of the PSO. Dachuan
et al. [11] reported that the 95% embedding efficiency was attained by
preparing PSOP with MD and soybean isolate through emulsification
and spray drying method at optimum conditions. Kha et al. [5] reported
the stability of microencapsulated GAC oil powder at different storage
conditions and proved that the encapsulated GAC oil powder is stable
when stored at low temperatures particularly in the absence of air and
light. In the present study, PSOP was prepared by emulsification and
spray drying method, and analysis of the stability of PSOP at different
storage conditions suggested that storage of PSOP in airtight AGB at
4°C, prevent the oxidation, and preserve the nutritional value of PSOP.
CONCLUSION
The present study employed emulsification and the spray drying
technique to produce PSOP. The yield of the PSOP was too low to
further proceed to industrial level production. However, the desirable
qualities of the PSO, especially nutritional values, are preserved by
powderization process. The storage and stability study revealed that
Fig. 2: The viscosity of emulsions. The values are represented as
mean ± standard deviation
Fig. 3: Scanning electron microscopic pictures of PSOP stored
at different conditions for 3 months. The images were taken at
200× and 1000× magnifications. (a) Control at 0 month, (b) PSOP
stored in aluminum foil bag at 4°C, (c) stored in aluminum foil
bag at 25°C, (d) stored in aluminum foil bag at 40°C, (e) stored in
amber glass bottle at 4°C, (f) stored in amber glass bottle at 25°C,
and (g) stored in amber glass bottle at 40°C
d
c
g
b
f
a
e
Fig. 1: Perilla seed oil (a) and perilla seed oil powder (b)
b
a

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Chaiyasut et al.
spray-dried PSOP was stable, especially when stored in the absence of
light and air at low temperature. Further, investigation on the carrier
and emulsifier is required to improve the yield of PSOP. The spray-dried
PSOP is the best candidate for pharmacological and food applications.
ACKNOWLEDGMENT
Authors gratefully acknowledge the Chiang Mai University grant (CMU-
grant) for the financial support. Authors also acknowledge the Faculty
Table 3: Fatty acid content of PSOP stored at various storage conditions for 3 months. Control samples were analyzed for fatty acid
content immediately after the preparation of PSOP
Storage condition Representative fatty acids (%)
Duration Packaging Temp(°C) Linolenic acid Oleic acid Linoleic acid Palmitic acid
Control (0 h) 39.97 26.68 24.78 7.47
After 1 month Stored in aluminum foil bag 4 38.57 25.48 26.19 7.41
25 38.35 25.64 25.65 7.61
40 36.48 23.99 29.24 7.13
After 3 months Stored in amber glass bottle 4 38.44 25.36 25.47 7.51
25 38.79 25.85 24.62 7.75
40 38.56 25.96 24.70 7.68
PSOP: Perilla frutescens seed oil powder
of Pharmacy and Chiang Mai University, Thailand, for the support and
instrumentation facilities.
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Fig. 4: The acid (a) and peroxide (b) values of PSOP stored at
different conditions. F4: Stored in aluminum foil at 4°C, F25:
Stored in aluminum foil at 25°C, F40: Stored in aluminum foil at
40°C, G4: Stored in amber glass bottle at 4°C, G25: Stored in amber
glass bottle at 25°C, and G40: Stored in amber glass bottle at 40°C
b
a