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ACTION PLAN
Control of diseases
and physiological disorder in fresh-cut pineapple
using phenyllactic acid bio-compound
Implemented by Bui Kim Thuy & Nguyen Thi Lan Huong
Vietnam Institute of Agricultural Engineering
& Postharvest Technology
Presented by Nguyen Thi Lan Huong
Mekong Institute, Thailand, Nov.1, 2011
INTRODUCTION
Great potential for production of fruits and
vegetables in Vietnam
- The climate and soil: suitable for culturing tropical FAV
- In 1999: the government approved national project of
developing vegetables, fruits, flowers and bonsai in
period of 1999-2010.
2003: area reached 1.27 mil. hectares with
yield of 13.8 million tons.
In which, vegetables: 577,000 ha,
yield: 8.18 million tons
→ Annual average increase of over 13% in area and 2% in
yield.
Consumption demand
- Domestic consumption of fruit: ≈ 3.5 million/year,
 50 kg/head/year in urban and
 20-30 kg/head/year in rural areas
- Increase of using canned, dried fruits and vegetables
- Increase of demand for convenient products that
preserve their nutritional value,
retain a natural color, flavor and texture, and
contain fewer additives
(Jongen, 2002)
→ Fruit industry needs to diversify types of minimally
processed fruits
Fresh-cut fruits
Consumption with double digit growth
+
Demand for diversified forms of fruits
+
Most fruit is consumed at home
=
Great opportunity for
FRESH-CUT FRUIT
Fresh-cut fruits (cont.)
- Highly perishable products due to their intrinsic characteristics
and minimal processing
 Microbial growth,
 Sensorial attributes decays, and
 Loss of nutrients
(Ayala Zavala et al., 2008a).
- These drawbacks are caused by the steps in the minimal
processing like peeling and cutting which promote an increment in the metabolic rate, enzymatic
reactions, and release juice
(Rapisada et al., 2006).
- Chemical synthetic additives reduce decay rate, but chemical
residues could affect health and environmental pollution,
→ Need to develop alternative methods for controlling fresh cut
fruit decay
Phenyllactic acid (PLA)
C6H5CH2CHOH==COOH
 A novel antimicrobial compound with
broad inhibitory activity, higher
stability and safety
Gram(+) and gram(-) bacteria.
Mold, fungi (mycotoxigenic species)
Dieuleveus et al., 1998a, 1998b
 Anti-oxidant property
 Practical application as a novel
bio-preservative in the food industry.
 Intl. research on PLA: quite new
(since 1998)
 PLA was no toxicity on animals and
human health
(Oberdoester et al., 2000
)
RESULTS I: PATHOGEN INHIBITION
Inhibition activity of PLA against some
pathogens in vitro
 Antifungal activity of PLA against three fungal pathogens
Inhibitory conc.
Inhibitory diameter (D-d, mm)
(mg/ml)
A.flavus
A.niger
P.digitatum
10
0.0 ± 0.0
0.0 ± 0.0
2.3 ± 0.06
12.5
0.0 ± 0.0
0.0 ± 0.0
3.7 ± 0.03
20
2.2 ± 0.01
3.6 ± 0.02
5.5 ± 0.05
25
3.6 ± 0.03
4.1 ± 0.05
6.6 ± 0.04
40
5.4 ± 0.04
6.7 ± 0.04
7.7 ± 0.07
50
9.4 ± 0.02
10.3 ± 0.02
12.6 ± 0.02
 Antifungal activity of PLA against three fungal strains (cont.)
The inhibitory ability of PLA against 3 fungal strains
PLA 20 mg/ml inhibitable 50.1% of P.digitatum population, but 28.3 and
20.1% of A.niger and A.flavus,
PLA 50 mg/ml:
 Antibacteria activity
Inh. Conc.
(mg/ml)
10
12.5
20
25
40
50
Average inhibitory diameter (D-d, mm)
E.coli
S.typhi
V.cholerea
5.3 ± 0.07
8.6 ± 0.05
12.7 ± 0.02
16.3 ± 0.06
18.4 ± 0.05
24.6 ± 0.04
4.5 ± 0.03
6.3 ± 0.02
10.5 ± 0.04
14.3 ± 0.02
16.7 ± 0.06
20.3 ± 0.05
8.7 ± 0.06
11.3 ± 0.04
21.5 ± 0.02
26.0 ± 0.07
28.1 ± 0.04
31.3 ± 0.05
- Vibrio cholerae was the most sensitive, E.coli was the least sensitive
- These findings would be illustrated more clearly by calculating
percentage inhibition of tested population
Percentage inhibition (%)
 Antibacteria activity (cont’.)
120
100
80
60
E.coli
40
S.typhi
V.cholerea
20
0
6.25
10
12.5
20
25
30
40
PLA concentration (mg/ml)
→ PLA 25 mg/ml absolutely inhibited against V.cholerea
and S.typhi (100% of population) while PLA at this level
could inhibit 95.6% of E.coli population
Inhibition activity of PLA against some pathogens
in fresh-cut pineaple
 Total aerobic bacteria
→ Total aerobic bacteria at PLA 20 mg/ml and 25 mg/ml was the
lowest and lasted shelf-life of pineapple till 12 day storage.
RESULT II: PHYSIOLOGICAL CHANGES
 Color changes of fresh cut pineapple
- ∆E value was the highest in the control (increased from 0.0 up to 11.27
after 6 days), the lowest in the test treated by PLA 20 mg/ml (∆E was only
6.48 after 12 day storage)
→ fresh-cut pineapple treated with PLA could have the shelf-life longer
than non-treated one.
 Firmness of fresh cut pineapple
 Total acidity content
CONCLUSIONS
- In vitro study showed that PLA had a board antimicrobial
spectrum: controlled some harmful fungi, and pathogenic
bacteria
o 40-50 mg/ml can absolutely inhibit 100% population of A.niger,
A.flavus, and P.digitatum
o 25-30 mg/ml can absolutlely inhibit 100% of population of
E.coli, S.typhi, and V.cholerea
- In vivo study showed that PLA acts as a bio-preservative in fresh-cut
pineapple in minimal processing when it kept the quality of fresh-cut
pineapple for 12 days in cool temperature
→ PLA acts as a prospective bio-preservative compound applicable in
food industry
→ More experiments are being conducted to surely conclude about the
applicability of PLA
THANK YOU FOR YOUR ATTENTION!
ACTION PLAN
Expected
Outputs
Progress
Indicators
1. Decay
Optimal
Reduction phenyllactic
acid (PLA)
conc.
inhibiting the
development
of pathogenic
microbial
organisms
Decay rate
Activities
Duration
Inputs/R
esource
s
Budget
(USD)
Determine
3 month
the optimal
PLA conc. on:
- Bacteria:
E.coli,
Staphylococc
us
- Fungi/
molds:
Aspergillus
Penicillium
Finance
from the
State
project
1000
- Bui Kim Thuy
- Nguyen Thi
Lan Huong
- Colleges in
VIAEP
Evaluate the
rate of
samples was
spoiled
Finance
from the
State
project
1000
- Bui Kim Thuy
- Nguyen Thi
Lan Huong
- Colleges in
VIAEP
3 month
Responsible
Persons
ACTION PLAN (Con’t.)
Expected
Outputs
Progress
Indicator
s
Activities
Duration
Resource
s
Budget
(USD)
2. Decrease
Physiol.
changes
Browing
inhibition
Measure
Polyphenol
oxydase
activity by SM
Nutritional
factors of
fresh-cut
produce
Evaluate the
changes in
room and cool
temperature:
- Vitamin C
- Ethanol
- Sensory
quality: smell,
taste,
color,etc.
Responsible
Persons
3 months*
Finance
from the
State
project
1500
- Bui Kim Thuy
- Nguyen Thi
Lan Huong
- Colleges
3 months*
Finance
from the
State
project
2000
- Bui Kim Thuy
- Nguyen Thi
Lan Huong
- Colleges