FST 403:FRIUTS AND FST 403:FRIUTS AND VEGETABLE VEGETABLE

TECHNOLOGYTECHNOLOGYFIRST SEMESTER: FIRST SEMESTER:

20111/201220111/2012

FST 403:FRIUTS AND FST 403:FRIUTS AND VEGETABLE VEGETABLE

TECHNOLOGYTECHNOLOGYFIRST SEMESTER: FIRST SEMESTER:

20111/201220111/2012Lecturer: Prof. F.O.HenshawLecturer: Prof. F.O.Henshaw

E-mail:henofcpc@yahoo.comE-mail:henofcpc@yahoo.com :fohenshaw@unaab.edu.ng:fohenshaw@unaab.edu.ng

Mobile phone: +234 8034056311Mobile phone: +234 8034056311

COURSE OBJECTIVES• FST 403: A compulsory core course for the B.Sc

Food Science and Technology programme• At the end of the course students should have:

– Acquired an understanding of the nature and properties of the food commodity class, Fruits and vegetables

– Acquired an understanding of the post harvest physiological changes in fruits and vegetables

– Been exposed to various processing and preservation technologies appropriate for fruit and vegetables

– Acquired the required skills in post harvest handling and storage of different fruits and vegetables

– Developed critical thinking in relating post harvest handling to quality of fresh and processed fruits and vegetable products

COURSE OUTLINE1 Classification of Fruits and Vegetable2 Structure of Fruits and Vegetables3 Chemical Composition4 Post harvest Physiology5 Storage of fresh fruits and vegetable

*Controlled Atmosphere*Modified Atmosphere

6 Pretreatment methods: Blanching,sulphiting

7 Preservation TechnologiesFreezingCanningDehydration

sun dryingmechanical drying

Osmo dehydration8 Fruit and Vegetable Products

Fruit juice and DrinksFruit leather

9 Sugar Preservesjam, jellies and marmalade

10 Fermented vegetablesPickles,

COURSE REQUIREMENTS

• 75% attendance of Lecturescondition to qualify to seat for

final examination.Distribution of course grade

Take home assignment 10% In Class Quiz 20% Final Examination 70%

CLASSIFICATION• FRUITS: Botanically, are mature

ovaries and seed bearing parts of plants

• Include: grains, legumes, nutsCucumbers, olives , mangoes,

peppers, tomatoes, citrus, bananasgrapes, strawberry, pineapple,

• The course however does not include fruits of the grass family such as Cereals, nor the Legumes and nuts

• The succulent, high moisture and generally sweet fruits and consumed raw as dessert rather than main meals.

• Vegetables: are all other parts of plant which are edible

• Include; roots, stems, tubers , leaves etc

• These are generally consumed, processed in one form or the other and part of main meal.

• This course does not include the starchy roots and tubers

• This class of commodity (Fruits and Vegetable) have the following characteristics:

high moisture contenthighly perishable

• Post harvest changes in Fruits and vegetable can be desirable e.g Ripening of fruits, which leads to changes necessary for optimum eating quality, colour change, taste and flavour development

Structure of Fruits and vegetables

• Fruits and Vegetables are made of Simple and Complex cells– Simple cells

• Dermal tissue• Parenchyma tissueDermal tissue is the single layer outside

surface of leaves, stem, roots, etc

• Parenchyma tissue form majority of the plant tissue and is where the basic molecular activity take place:

• Synthesis– Storage of carbohydrate

(Photosynthesis) occur.

Chemical composition

• Water• Carbohydrates• Organic acid• Fiber• Pigments• Vitamins• Minerals• Pectic substances

Food

Carbohydrate

Protein Fat Ash Water

Cereals

wheat flour, white 73.9 10.5 1.9 1.7 12

rice, milled, white 78.9 6.7 0.7 0.7 13

maize, whole grain 72.9 9.5 4.3 1.3 12

Earth vegetables

potatoes, white 18.9 2.0 0.1 1.0 78

sweet potatoes 27.3 1.3 0.4 1.0 70

Vegetables          

carrots 9.1 1.1 0.2 1.0 88.6

radishes 4.2 1.1 0.1 0.9 93.7

asparagus 4.1 2.1 0.2 0.7 92.9

beans, snap, green 7.6 2.4 0.2 0.7 89.1

peas, fresh 17.0 6.7 0.4 0.9 75.0

lettuce 2.8 1.3 0.2 0.9 94.8

Fruit

banana 24.0 1.3 0.4 0.8 73.5

orange 11.3 0.9 0.2 0.5 87.1

apple 15.0 0.3 0.4 0.3 84.0

strawberries 8.3 0.8 0.5 0.5

• Phytochemicals: non nutrient plant chemicals

• Beneficial in disease prevention• Subject of Scientific research on

effects on human health

Structure of chlorophyll

• Chlorophyll –green pigment in plant found in the chloroplast, it is responsible for photosynthesis

• Fat soluble• Structurally a porphyrin ring containing

magnesium at the center• Displacement of magnesium from the

center leads to irreversible pigment change

• Change to a gray-green called pheophytin

• conversion to pheophytin is favoured by acid Phbut does not occur easily under alkaline condition

• Other factors that can cause colour change;– Heat of cooking– Change in pH– Minerals ( zinc and copper)

Carotenoids– Red, orange, and yellow pigments in fruits

and vegetables– Occur in chloroplast along with

chlorophyll,where the chlorophyll dominates– Also in chromoplasts without chlorophyll

• Carotenoids are responsible or the colour of tomatoes, peppers, citrus , carrots.

• E.g beta –carotene- orange colour, structurally an unsaturated hydrocarbon, the conjugated double bonds are responsible for the colour

• Beta-carotene is a precursor of vitamin A (retinol), cleaved by enzyme in the intestinal mucosa to yeild vitamin A

• Lycopene- red-orange colour of tomatoes and water melon,

• Xanthophylls: yellow orange colour• Derivatives of carotene• Reponsible for colour of yellow maize

(cryptoxanthin)• Are vitamin A precursor • Carotenoids are fairly stable , resistant

to to heat, pH changes, water leaching since they are fat soluble

carotenoids may undergo autoxidation due to large nos of double bonds

• Can lead to off-flavour• Antioxidants are usually applied to

prevent oxidative changes

Structure of carotenoids

• Flavonoids:- group of compounds, pigments and colour precursors– Water soluble– E.g; Anthocyanins: red, blue-red,

purple pigments such as in blueberries, cherries, raspberries, plums and grapes

– structrally

Structure of Anthocyanin

Structure of e.gs of Anthoxanthin

Harvesting, handling and Postharvest

changes• Different harvest regimes for Fruits and

vegetables• Appropriate maturity stage required for

optimum quality• Respiration continue after harvest i.e

taking in O2 and giving off CO2, heat and moisture

• mechanical damage during harvesting hastens respiration rate and spoilage

• Ripening: major post harvest change in fruits

• Ripening pattern vary , 2 categories– Climacteric ripen

after harvest– Non Climacteric

ripen before harvest

Climacteric

Non-Climacteric

ApplesBananaMangoPeachPlumPawpawavocado

CitrusCherryPineapplemelonstrawberry

• Ripening involves biochemical changes

• Enzymic, hormonal • Leading to colour changes, flavour

development and optimum eating quality

• Storage of fresh produce must seek to control post harvest changes

• Controlled storage conditions ca extend the shelf life of produce– Modified atmosphere packaging:

Principle is to replace the internal atmosphere of fresh produce by flushing with nitrogen or carbon dioxide and this will lead to extension of shelf life

• After flushing the material is sealed in a package to prevent oxygen entry

• Normal air composition (78%, Nitrogen; 20% oxygen and 0.03% carbon dioxide) is modififed within the package to:– Reduces respiration– Retards growth of aerobic organisms

• Controlled atmosphere storage: • Principle is similar to MA storage

involve modification of the gas composition. Reducing oxygen and increasing carbon dioxide in the store

• Combined with low temperature.