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 HuongVietnam 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

C6H5CH2CHOH==COOH

Phenyllactic acid (PLA)

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 pathogensInhibitory conc.

(mg/ml)Inhibitory diameter (D-d, mm)

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

The inhibitory ability of PLA against 3 fungal strains

Antifungal activity of PLA against three fungal strains (cont.)

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)

Average inhibitory diameter (D-d, mm)

E.coli S.typhi V.cholerea

10 5.3 ± 0.07 4.5 ± 0.03 8.7 ± 0.06

12.5 8.6 ± 0.05 6.3 ± 0.02 11.3 ± 0.04

20 12.7 ± 0.02 10.5 ± 0.04 21.5 ± 0.02

25 16.3 ± 0.06 14.3 ± 0.02 26.0 ± 0.07

40 18.4 ± 0.05 16.7 ± 0.06 28.1 ± 0.04

50 24.6 ± 0.04 20.3 ± 0.05 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

Antibacteria activity (cont’.)

0

20

40

60

80

100

120

6.25 10 12.5 20 25 30 40

PLA concentration (mg/ml)

Pe

rce

nta

ge

inh

ibit

ion

(%

)

E.coli

S.typhi

V.cholerea

→ 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

- 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

CONCLUSIONS

THANK YOU FOR YOUR ATTENTION!

Expected Outputs

Progress Indicators

Activities Duration Inputs/Resourc

es

Budget (USD)

Responsible Persons

1. Decay Reduction

Optimal phenyllactic acid (PLA) conc. inhibiting the development of pathogenic microbial organisms

Determine the optimal PLA conc. on:- Bacteria: E.coli, Staphylococcus- Fungi/ molds: Aspergillus Penicillium

3 month Finance from the State project

1000 - Bui Kim Thuy- Nguyen Thi Lan Huong

- Colleges in VIAEP

Decay rate Evaluate the rate of samples was spoiled

3 month Finance from the State project

1000 - Bui Kim Thuy- Nguyen Thi Lan Huong- Colleges in VIAEP

ACTION PLAN

Expected Outputs

Progress Indicator

s

Activities Duration Resources

Budget (USD)

Responsible Persons

2. Decrease Physiol. changes

Browing inhibition

Measure Polyphenol oxydase activity by SM

3 months* Finance from the State project

1500 - Bui Kim Thuy- Nguyen Thi Lan Huong

- Colleges

Nutritional factors of fresh-cut produce

Evaluate the changes in room and cool temperature:- Vitamin C

- Ethanol - Sensory quality: smell, taste, color,etc.

3 months* Finance from the State project

2000 - Bui Kim Thuy- Nguyen Thi Lan Huong

- Colleges

ACTION PLAN (Con’t.)