HANDOUT - INTRODUCTION TO PHV - PART 1 AND 2 - 17.5.2018 (1)

Dương Thị Ngọc Diệp NLU, May 2018POST HARVEST TECHNOLOGY OF FRESH FRUITS AND VEGETABLES -Introduction-LEARNING OBJECTIVES At the end of the lesson, the learners are expected to: 1..

Dr Dương Thị Ngọc Diệp NLU, May 2018

POST HARVEST TECHNOLOGY OF

FRESH FRUITS AND VEGETABLES

-Introduction-LEARNING OBJECTIVES

At the end of the lesson, the learners are

expected to:

1 define post harvest technology;

2 determineits importance and

objectives;

3 explainthe causes of post harvest food

lossesand the prevention measures;

and

4 determinethe pre-harvest factors

affecting the post harvest life and quality

aspects.

and the Prevention Measures; and

4 Pre-Harvest FactorsAffecting the Post

Harvest Life and Quality Aspects

What is Post-Harvest Technology?

Post-harvest technologies constitute an

inter-disciplinary science and techniques applied to

agricultural commodities after harvest for the purpose

of preservation, conservation, quality

control/enhancement, processing,

packaging, storage, distribution, marketing,

Post-harvest technology stimulates

agricultural production by:

prevents post-harvest losses;

improves nutrition;

adds value to agricultural products;

opens new marketing opportunities; and

generates new jobs

What is Post-Harvest Technology?

Postharvest handling specifically

involves the movement and the

operations that commodities undergo

from harvest to the time immediately

before meal preparation

What is Post-Harvest Technology?

 Its main concern is to keep

commodities in an acceptable state

from harvest until it reaches the

consumer since most commodities

are transported in their perishable

Transportation

Distribution

 In addition, postharvest handling

aims to minimize losses at the least

possible cost.

 The existing postharvest

environment requires appropriate

technologies to maintain quality of

commodities

 Poor handling of agricultural

commodities can result in quality

What is Post-Harvest Technology?

The three main objectives of applying

postharvest technology to harvested fruits and

vegetables are:

1) to maintain quality (appearance, texture,

flavor and nutritive value)

2) to protect food safety, and

3) to reduce losses between harvest and

consumption.

Objectives of Post-Harvest Technology?

Vegetable and fruits products are

usually of high value (compared to

grains) and need to be handled

carefully in order to preserve that value

Vegetables and fruits are living

commodities and deteriorate in

quality very quickly

Why is the study of postharvest

physiology and technology so important?

 A lot of money and other resources is

invested in growing the crop

 To get the best price possible for the crop, it

must be looked after appropriately until it

reaches the consumer

 Vegetables and fruits are rich source of

vitamins, minerals, plant proteins and

medicinal substances - proper care helps

maintain nutritional and pharmacological

value.

Why is the study of postharvest

physiology and technology so important?

 Fresh fruits, vegetables, and flowers must be

in excellent condition and have excellent

quality if maximum shelf life is desired

 The best possible quality of any commodity

exists at the moment of harvest

 From that point on, quality cannot be

improved, only maintained.

 Remember that shelf life begins at harvest.

REMEMBER!!!

POST HARVEST LOSS???

This means that tenth to

one-half of all the land, inputs, and labor

used to produce the commodities goes

to waste

When expressed in monetary terms,

this could amount to millions of dollars

POST HARVEST LOSS???

Globally, food losses and postharvest

waste are estimated at 30 to 40% of

production

Losses of perishable foods such as fruits

and vegetables can be even higher during

the postharvest period, depending upon

the weather, access to storage or

distance from markets.

POST HARVEST LOSS???

Utilizing improved postharvest practices

often results in:

reduced food losses,

improved overall quality and food

The three main objectives of applying

postharvest technology to harvested fruits and

vegetables are:

 to maintain quality (appearance, texture,

flavor and nutritive value)

 to protect food safety, and

 to reduce losses (both physical and

in market value) between harvest and

consumption

 THE BASICS OF POSTHARVEST TECHNOLOGY

Objectives of Post-Harvest Technology?

Actual postharvest losses of selected

perishable crops

 Inadequate packaging materials further

add to the problem

VIETNAM

COMMON CAUSES OF POSTHARVEST LOSSES IN

VIETNAM

In general,

 minimizing rough handling,

 sorting to remove damaged and

diseased produce and

 effective temperature management

 will help considerably toward

maintaining a quality product and

Storage life will be enhanced if:

the temperature during the

postharvest period is kept as close to

the optimum as feasible for a given

commodity.

 The ideal temperature often depends on the

geographic origin of the product

 Tropical plants have evolved in warmer

climates and therefore cannot tolerate low

temperatures during storage Plants from

tropical origins must be stored above 12°C.

 This is in contrast to plants which have

evolved in temperate, cooler climates which

can be stored at 0°C

 EFFECT OF TEMPERATURE ON POSTHARVEST

EFFECT OF TEMPERATURE ON POSTHARVEST

The rapid cooling after harvest is so

important:

If the temperature is lowered and the

harvested products are put in refrigerated

storage, water and quality loss can be

reduced

Fresh produce is alive, living and breathing.

The general term for all the processes going

Temperature has a big effect on

the rate of metabolism of the

product

When the temperature of the

product rises, so too does the rate

of metabolism

EFFECT OF TEMPERATURE?

One of the main processes of metabolism

is respiration which is the process of

Temperature management for fresh

produce is the key to quality

Lowering the temperature as quickly as

possible after harvest will slow the rate of

metabolism and therefore extend the

EFFECT OF TEMPERATURE?

High temperatures accelerate ripening

and the speed at which rots develop

A 10 oC increase in temperature will

cause fruit and vegetables to

deteriorate twice as fast, as well as

encouraging disease organisms to grow

twice as fast as well.

EFFECT OF TEMPERATURE?

Major quality loss reactions

Microbiological Enzymic Chemical Physical

Growth or Hydrolytic Oxidative Mass transfer,

presence of reactions rancidity movement of

toxinogenic catalyzed by low MW

microorganisms lipases, components

protease…

Growth or Lypoxygenase Oxidative and Loss of

presence of reductive texture

infective discoloration

microorganisms Growth of Enzymic Non-enzymic Loss of flavors

spoilage browning browning Freeze-induced

Causes of post-harvest losses of fresh fruits and

vegetables:

 use of uncertified seeds

 excessive use of fertilizer,

 poor irrigation system

 poor harvesting practices,

 limited access to loan

 handling: poor transport and storage

 diseases and pests

Assessment of post harvest losses

• Producers are aware that quality of

produce is affected by:

– Delay weeding

– Water management

– Fertilizer & pesticide use

– Disease and pests

Assessment of PHV losses for leafy vegetable

F&V PRODUCTION IN VIETNAM

2017 - The Year of the Vegetable Industry !!!!

Disasters, severe diseases…

But, with the efforts, the whole agriculture industry in

2017 has achieved success beyond expectations,

especially in export, with export turnover estimated to

reach $ 3.5 billion, up to 40% over 2016,

Vegetables continue to affirm that agricultural products

will be the great power of Vietnam in the future.

F&V PRODUCTION IN VIETNAM

Updated data from the

General Department of

Customs showed that in

January 2018, the value of

vegetable and fruit exports

was $ 320 million, up by 37%

over the same period last

F&V PRODUCTION IN VIETNAM

 Vietnam’s F&V are mainly exported in the

form of fresh fruits, so the value added is

low and affected by technical barriers

such as plant quarantine, fruit quality

decreases rapidly, short shelf life due to

lack of skillful labor and advanced

preservation technology and food

hygiene and safety

F&V PRODUCTION IN VIETNAM

Exportation on: dragon fruit, products

from coconut, pomelo, longan

Processed products: puree, concentrated,

dried, frozen

China  America  Japan  Korea: 4

biggest markets of Viet Nam F&V.

F&V PRODUCTION IN VIETNAM

1 Post harvest loss of 20-25%

2 Small-scale production

3 Hand-operating

4 Behind-time technology

6 Wrong harvesting INDICATORS

 Different F & V needs

different handling technique

THANK YOU!

PROCESSING OF

FRUITS AND VEGETABLES

-

introduction-Dr Dương Thị Ngọc Diệp NLU, May 2018

1 Why fruit and vegetable processing?

- All fruits & vegetables lose their

quality at some rate after harvesting

The principal quality loss reactions are:

Processing of fruits and vegetables

is for:

1 Preservation: by slowing down the natural

processes of decay caused by microorganisms,

enzymes and other factors such as heat,

moisture and sunlight.

2 Food diversification: attractive and in demand

by consumers.

Table 1 Major quality loss reactions

Microbiological Enzymic Chemical Physical

Growth or Hydrolytic Oxidative Mass transfer,

presence of reactions rancidity movement of

toxinogenic catalyzed by low MW

microorganisms lipases, components

protease…

Growth or Lypoxygenase Oxidative and Loss of crispy

presence of reductive texture

infectous discoloration

microorganisms

Growth of Enzymic Non-enzymic Loss of flavors

spoilage browning browning Freeze-induced

Table 2 Consequences of quality loss

Nature of quality loss Consequence

Presence of toxin Hazard to the consumer

Presence of pathogenic microorganisms

Microbial spoilage Loss of food

Potential microbial hazard Inability to distribute &

Unacceptable rate of oxidation market product

Unacceptable change in texture

Development of rancidity Limitation of self life

Color change Increased packaging and

Flavor loss distribution cost

Texture change

2 Major fruit and vegetable processing techniques

Objective Factor Mode of achievement

Slowing down or Reduced water Drying and freeze-drying

inhibition of activity/raised Curing and salting

microbial growth osmoability Conserving with added sugars

Decreased oxygen Vacuum and nitrogen packaging

Acidification Addition of acids

Lactic or acetic fermentation

Alcoholic fermentation Brewing, vinification

Use of preservatives Addition of preservatives:

- Sulphite, nitrite

- Sorbate, benzoate …

- Antibiotics

Major fruit and vegetable processing techniques (cont.)

Objective Factor Mode of