ORIGINAL PAPER

A comparative study on the effect of packaging materialand storage environment on shelf life of fresh bell-pepper

Nihar R. Sahoo • Lalit M. Bal • Uma S. Pal •

Dipika Sahoo

Received: 21 January 2014 / Accepted: 30 March 2014

� Springer Science+Business Media New York 2014

Abstract The effect of packaging materials [low density

polyethylene (LDPE), polypropylene (PP)] and storage

environment [modified atmospheric packaging (MAP)] on

shelf life enhancement of bell pepper in terms of quality

attributes such as physiological weight loss, ascorbic acid,

texture, surface colour and subjective quality analysis have

been studied at ambient and refrigerated condition. Dif-

ferent packaging techniques used for the experiment were

MAP with LDPE, MAP with PP, MAP in perforated LDPE

films, MAP in perforated PP films, shrink packaging with

bi-axially oriented PP (BOPP) film and vacuum packaging

with PP film. The in-pack bell pepper created a suitable

headspace environment with low O2 and high CO2 con-

centrations, which resulted in a better retention of freshness

of the vegetables and its marketability. Shrink packaging

with BOPP film could not yield better result under ambient

storage because of high water vapor transmission rate of

the film and consequently loss of turgidity of the vegeta-

bles. Among different packaging techniques and storage

conditions, MAP with PP film in refrigerated condition was

found to be the best followed by vacuum pack with PP film

in refrigerated condition and could be used to store for

20 days for bell pepper with maintenance of texture, col-

our, ascorbic acid and marketability. It is also inferred that

under ambient conditions, bell pepper could be stored for

4 days using ventilated LDPE and PP as MAP storage.

Further studies are needed to evaluate the sensory aspects,

as well as to microbiological evaluation to characterize the

fresh bell pepper during storage.

Keywords Bell pepper � Storage � Modified atmospheric

packaging � Physiological loss in weight

Introduction

Pepper is an important cash crop in India and the world’s

second most important solanaceous vegetable after tomato,

also known as bell pepper and locally known as simla

mirch [1]. Though it is low in saturated fat, cholesterol, and

sodium but it is rich in dietary fiber, Vitamin A, Vitamin C,

Potassium, Manganese, Thiamin, Riboflavin, Niacin and

Magnesium makes it nutritionally rich for maintaining

optimum health and weight loss programme [2]. However,

it has high rate of respiration and thus a shorter shelf-life at

room temperature due to various physiological factors

regulated by genetic mechanisms high susceptibility to

fungal diseases [3]. The major changes taking place during

its senescence include loss in weight due to moisture loss,

degradation of chlorophyll thus change in colour, loss of

turgidity and change in texture, loss of nutritional value

and reduction in marketability.

In recent days, there have been reports of different

methods of polymeric film packaging of fresh produces to

increase the shelf life. Polymeric film packaging in com-

bination with cool storage has been successful in delaying

N. R. Sahoo � U. S. Pal

Department of Agricultural Processing and Food Engineering,

Orissa University of Agriculture and Technology,

Bhubaneswar 751003, Odisha, India

L. M. Bal (&)

Post Harvest Process and Food Engineering, College of

Agriculture, Jawaharlal Nehru Agricultural University,

Tikamgarh 472001, Madhya Pradesh, India

e-mail: lalit.bal@gmail.com

D. Sahoo

Department of Horticulture, College of Agriculture,

Bhawanipatna, Orissa University of Agriculture and

Technology, Bhubaneswar 751003, Odisha, India

123

Food Measure

DOI 10.1007/s11694-014-9177-4

senescence, maintenance of physico-chemical constituents

and extending shelf life. However, the selection of an

appropriate packaging film and packaging techniques are

the important criteria for its storage life. Improper film

selection and packaging technique can lead to loss of

quality in a very short period [4].

Generally for highly respiring materials like vegetables,

micro-perforated films having high gas transmission rates

for O2 and CO2 can be used to extend their shelf life [5].

But the micro-perforated films are costly. On the other

hand, application of non-perforated continuous films could

create anaerobic atmosphere inside the package headspace

in a short period thus accelerating quality deterioration.

Taking these factors into account, the application of

ordinary readily available polymeric films with appropriate

perforations can be explored. Therefore, objective of the

present study was on the effect of packaging material and

storage environment on shelf life of fresh bell-pepper.

Materials and methods

Raw material and sample preparation

Fresh green mature bell pepper was procured after har-

vesting manually from the research farm, Orissa University

of Agriculture and Technology, Bhubaneswar. Immedi-

ately after harvest, samples were transported to the

experimental site in plastic crates. The vegetables were

washed thoroughly with tap water to remove field heat and

adhering soil particles on the surface. The samples were

sorted for uniform size and colour, and packed separately,

approximately about 500 g per each pack.

Different packaging techniques used for the experiments

were modified atmospheric packaging (MAP) with low

density polyethylene (LDPE), MAP with polypropylene

(PP), MAP in perforated LDPE films, MAP in perforated

PP films, shrink packaging with bi-axially oriented PP

(BOPP) film and vacuum packaging with PP film. The

properties of these films used for packaging experiments

have been given in Table 1. Bag area of 10 cm 9 10 cm

was provided for each pack and perforations provided in

the LDPE and PP films were five holes of 0.3 mm diameter

in each side of the films. Sample packs were stored at

ambient (23–35 �C, 35–75 % RH) and chilled refrigerated

(4–6 �C, 45 % RH) conditions separately. The control

samples of 500 g each were kept unsealed under similar

environmental conditions of temperature and RH sepa-

rately. Three packages each from MAP storage treatments

of LDPE, ventilated LDPE, PP and ventilated PP were

taken out at 8 h storage interval for analysis of in-pack

head space concentration of O2 and CO2. The qualitative

analysis of the stored bell pepper packages (in triplicate)

was carried out in 2 days interval.

Physico-chemical analysis

Headspace gas evaluation

Changes in CO2 and O2 concentration of the headspaces of

the fresh-cut bell pepper packages during storage were

monitored with a check point O2/CO2 instrument (PBI

Dansensor, Denmark) at prespecified time [6]. The instru-

ment has ceramic solid state sensor for recording O2 and

infrared double wavelength sensor for recording CO2 by

means of a built-in pump and measuring gas was taken

from the suction probe or via enclosed needle. The accu-

racy of 0.1 % for O2 and 2 % for CO2 were in full range.

The calibration for the instrument was done with O2 and

CO2 air percentages. Parameters were expressed as DCO2

and DO2 percentage referred to initial values.

Physiological loss in weight (PLW)

The weight of each bell pepper package sample was

determined by weighing on the day after each period of

storage using a laboratory weighing balance having

0.0001 g accuracy. The PLW was calculated and expressed

in percentage based on initial weight of the samples. The

cumulative PLW was analyzed with respect to different

treatments.

Ascorbic acid

Ascorbic acid content of bell pepper sample was estimated

using standard procedure of titration method suggested by

Ranganna [7] based on the reduction of 2, 6-dichlorophenol

indophenol dye by ascorbic acid and can be expressed as

mg/100 g fresh weight.

Texture analysis

The texture of the stored bell peppers at regular intervals

were analysed by measuring the peak force from the

puncture test with a 2 mm probe using 50 kg load cell with

the help of a texture analyzer (TA-XT Plus, Stable Mi-

crosystems Ltd.).

Marketable quality evaluation

For assessing the marketable quality of the vegetable,

descriptive quality attributes were determined subjectively

by observing the level of visible mould growth, decay,

shriveling, smoothness and shine of the produce. The

N. R. Sahoo et al.

123

number of marketable vegetable (C80 %) was used as a

measure to calculate the percentage of marketable vege-

table during storage. Performance of the chamber was

evaluated in terms of shelf-life in number of days with

marketability C80 % [8, 9]. The fruits and vegetables were

stored in plastic crates inside the chamber and their shelf-

life was determined on the basis of an index of 20 %

spoilage or unmarketability.

Statistical analyses

The results obtained were subjected to analysis of variance

using SPSS 10.0 software. The means obtained from each

set were compared using the Duncan’s multiple range test

based on a complete randomized design (at 0.05 confidence

level).

Results and discussion

Headspace gases

The in-pack gaseous of O2 and CO2 concentrations for bell

pepper stored in different packages under ambient and

refrigerated condition are shown in Figs. 1 and 2, respec-

tively. The in-pack atmosphere of bell pepper attained

steady state levels of 9.4, 9.8, 9.0 and 9.2 % O2 and 3.3,

3.6, 3.9 and 4.1 % CO2 concentration level in-packs of

LDPE, ventilated LDPE, PP and ventilated PP, respectively

after 32 h of storage under refrigerated condition. Mano-

lopoulou et al. [10] made similar observation with MAP

storage of green bell pepper in polymeric films of LDPE-

60, MDPE-30 and PVC. In ambient storage of vegetables

in vacuum pack and shrink pack, initially there was no

head space gas, however after 4 and 8 days of storage there

was little gas accumulation and the samples spoiled

thereafter. So head space gas analysis was not done for

those samples. In case of refrigerated storage of vegetables,

vacuum was maintained in both vacuum pack and shrink

pack till 20 days of storage, so no head space gas analysis

was done.

Physiological loss in weight (PLW)

The PLW% in case of bell pepper storage was maximum in

the ambient control which was 21.60 (±2.57) % (Fig. 3)

after 8th day followed by 12.57 (±2.34) % (Fig. 4) in

refrigerated control at the end of 20th day of storage.

Table 1 Properties of films used for packaging of bell pepper

Thickness

(l)

Density

(g/cm3)

Oxygen transmission

rate (cm3/m2/24 h)

Water vapor

transmission rate (g/

m2/24 h)

Tensile

strength (kg/

cm2)

Elongation

(%)

Refractive

index at

200 �C

Water

absorption

rate (%)

LDPE

film

25 0.910 6,400 04.50 165 600 – 0.9

PP

film

45 1.054 3,000 07.75 400 300 1.58 –

BOPP

film

23 0.901 4,500 18.00 300 – – –

Fig. 1 Changes in head space concentrations of O2 and CO2 for bell

pepper samples stored under ambient conditionFig. 2 Changes in head space concentrations of O2 and CO2 for bell

pepper samples stored under refrigerated condition

Study on the effect of packaging material and storage environment

123

Ambient shrink pack sample showed a PLW% of 4.53

(±0.56) after eighth day and refrigerated shrink pack

sample showed PLW% of 1.78 (±0.34), which were

significantly higher to all other types of packaging condi-

tions. PP film without perforation under refrigerated con-

dition could check the PLW% to 0.49 (±0.07) %, whereas

with perforation it was only 0.59 (±0.08) %. Vanndy et al.

[11] also found similar result in their study of MAP of fresh

chilli.

Ascorbic acid

The ascorbic acid content decreased with storage period

under all the packaging treatments and storage environ-

ments. But the decrease in ascorbic acid content was sig-

nificantly higher under ambient conditions (Fig. 5) as

compared to the refrigerated storage condition (Fig. 6). In

ambient control storage, the decrease in ascorbic acid was

observed to be maximum (9.6 %) from an initial value of

158.42 (±1.24)–143.26 (±1.57) mg/100 g at the end of 8th

day whereas in refrigerated control samples the decrease

(11.5 %) was to 140.20 (±1.59) mg/100 g at the end of 20th

days of storage. The retention of ascorbic acid was highest

with the vacuum packaging condition maintaining 155.03

(±2.57) mg/100 g followed by PP with ventilation main-

taining 153.66 (±2.37) mg/100 g at the end of 20 days

among all the packaging types under refrigerated storage

condition. This could be due to the fact that low temperature

retarded the ageing through reduced respiration rate and

other undesirable metabolic changes. High temperature is

known to increase enzymatic catalysis and leads to a

chemical and bio-chemical breakdown in vegetables [12].

Texture analysis

A decrease in the peak force required to puncture the bell

pepper samples was observed in all the packaging types

both under ambient and refrigerated storage conditions.

The decrease in peak force was from 1.32 (±0.34) to 1.19

Fig. 3 Changes in PLW% of bell pepper under ambient storage

Fig. 4 Changes in PLW% of bell pepper under refrigerated storage

Fig. 5 Change in ascorbic acid content of bell pepper under ambient

storage

Fig. 6 Change in ascorbic acid content of bell pepper under

refrigerated storage

N. R. Sahoo et al.

123

(±0.62) kgf in PP with ventilation in refrigerated storage,

whereas, from 1.32 (±0.34) to 0.80 (±0.37) kgf in samples

stored in LDPE with ventilation under ambient storage

after 8 days. The control sample showed a decrease of peak

force from 1.32 (±0.34) to 0.54 (±0.35) kgf at the end of

20th day under refrigerated storage. The decrease in

puncture force was gradual in all other samples stored in

different packaging types under refrigerated condition.

Samples stored in vacuum pack condition maintained the

best texture among all the refrigerated stored samples with

a value of 1.03 (±0.23) kgf at the 20th day (Table 2).

Marketable quality

Marketability quality of fruits and vegetables was subjec-

tively assessed by observing the level of visible mould

growth, rotting, shriveling or discolouring shown in

Figs. 7, 8, 9, 10, and 11. The percentage marketable bell

pepper subjected to storage in different packaging materi-

als and storage environment are shown in Table 3. The

highest marketability of bell pepper was obtained in PP

with perforations under refrigerated storage. The percent-

age marketability were found to be 86.53, 61.30, 78.44 and

62.35 % after 20 days of storage in PP with perforations,

LDPE with perforation, vacuum pack and shrink pack

samples, respectively under refrigerated storage. In ambi-

ent storage of bell pepper, the percentage marketability

started decreasing since fourth day onwards and after

8 days of ambient storage all the packaging type showed

almost 2/3 of vegetables unmarketable. Ponnachanna et al.

[13] found similar result with storage studies of tomato and

bell pepper using eco-friendly films.

The good storage performance of vegetables in terms of

marketability in PP with perforation in refrigerated storage

Table 2 Effect of packaging

material and storage

environment on texture of bell

pepper

Figures in parenthesis are

standard deviation. Values in

the same rows followed by

different superscript letters (a–f)

are significant different

(p \ 0.05)

Packaging materials Texture ðkgf)Storage period ðdays)

0 4 8 12 16 20

Ambient

Control 1.32a (0.34) 0.66b (0.13) 0.43c (0.09) – – –

LDPE 1.32a (0.34) 0.87b (0.15) 0.61c (0.15) – – –

LDPE with pin

holes

1.32a (0.34) 0.94b (0.37) 0.75c (0.31) – – –

Polypropylene 1.32a (0.34) 0.89b (0.23) 0.74c (0.29) – – –

PP with pin holes 1.32a (0.34) 0.97b (0.41) 0.80bc (0.37) – – –

Vacuum pack 1.32a (0.34) 0.95b (0.33) 0.87c (0.19) – – –

Shrink pack 1.32a (0.34) 0.88b (0.39) 0.72c (0.41) – – –

Refrigerated

Control 1.32a (0.34) 0.97b (0.31) 0.83cd (0.51) 0.77d

(0.56)

0.61e

(0.47)

0.54f

(0.35)

LDPE 1.32a (0.34) 1.26b (0.73) 1.22b (0.37) 1.15bc

(0.33)

0.92c

(0.24)

0.87de

(0.44)

LDPE with pin

holes

1.32a (0.34) 1.19b (0.52) 1.07bc (0.29) 0.98cd

(0.38)

0.89e

(0.43)

0.84e

(0.36)

Polypropylene 1.32a (0.34) 1.21b (0.62) 1.14bc (0.34) 1.06d

(0.24)

0.96de

(0.37)

0.91e

(0.52)

PP with pin holes 1.32a (0.34) 1.26bc (0.49) 1.19d (0.62) 1.12de

(0.19)

1.09e

(0.52)

1.01ef

(0.49)

Vacuum pack 1.32a (0.34) 1.30a (0.38) 1.25ab (0.27) 1.19bc

(0.41)

1.11c

(0.34)

1.03de

(0.27)

Shrink pack 1.32a (0.34) 1.29a (0.51) 1.20bc (0.35) 1.16c

(0.63)

1.04de

(0.37)

0.98f

(0.22)

Fig. 7 Samples in LDPE film with hole after 8 days

Study on the effect of packaging material and storage environment

123

could be attributed to the fact that low temperature storage

along with modified atmosphere retarded the senescence.

No significant variation could be observed among pack-

aging material under ambient condition.

Conclusions

The in-pack bell pepper created a suitable headspace

environment with low O2 and high CO2 concentrations,

which resulted in a better retention of freshness of the

vegetables and its marketability. Shrink packaging with

BOPP film could not yield better result under both ambient

and refrigerated storage because of high water vapor

transmission rate of the film and consequently loss of tur-

gidity of the vegetables. Among different packaging tech-

niques and storage conditions, MAP with perforated PP

film in refrigerated condition was found to be the best

followed by vacuum pack with PP film in refrigerated

condition. It could be inferred that perforated PP film

packages could be used to store bell pepper for 20 days

under MAP refrigerated condition with maintenance of

texture, colour, ascorbic acid and marketability in com-

parison to 4 days in ambient condition.

Fig. 8 Samples in PP film without hole after 8 days

Fig. 9 Samples in PP film with hole after 20 days

Fig. 10 Samples in vacuum pack in PP film without hole after

20 days

Fig. 11 Samples in control after 8 days

Table 3 Effect of packaging material and storage environment on

percent marketability of bell pepper

Packaging materials Marketability (%)Storage period ðdays)

0 4 8 12 16 20

Ambient

Control 100 72.31 21.50 – – –

LDPE 100 81.25 32.93 – – –

LDPE with pin holes 100 85.33 45.17 – – –

Polypropylene 100 83.72 48.36 – – –

PP with pin holes 100 86.91 50.03 – – –

Vacuum pack 100 85.17 47.62 – – –

Shrink pack 100 79.39 38.11 – – –

Refrigerated

Control 100 75.06 53.41 42.95 30.33 20.50

LDPE 100 81.44 76.30 71.03 66.22 52.05

LDPE with pin holes 100 100 100 93.34 78.52 61.30

Polypropylene 100 85.50 78.93 76.38 68.19 55.72

PP with pin holes 100 100 100 96.17 90.09 86.53

Vacuum pack 100 100 100 94.34 82.93 78.44

Shrink pack 100 92.38 85.78 71.06 68.43 62.35

N. R. Sahoo et al.

123

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