Fruits

Multiple Fruit

* Develop from a tight cluster of several flowers: Pineapples, figs * Each segment of the pineapple develops from the carpel of a separate flower

Simple Fruits

* Develop from one ovary in one flower * Fruits with a pit: cherries, peaches, apricots, coconuts, olives * Fruits with seeds in central core: apples, pears, tomatoes, bananas, grape, watermelon, pumpkin, squash * Citrus fruits * Grains such as corn, wheat, barley, rye * Nuts such as acorn and filbert * Legumes/peas

Fruit Spread - Preserves

* Made from whole fruit

Enzymatic Browning limiting by - Ultrafiltration

* Wine and fruit juices. Ultrafiltration is able to remove larger molecules like polyphenoloxidase, but not lower-molecular-weight components like polyphenols.

Enzymatic Browning cause

- Caused by exposure to air and bruising.

Fruit Preparation: Dry Heat and Moist Heat

- Dry-heat preparation •Baking: In skin •Broiling •Frying/sautéing •Preparing dried fruit - Moist-heat preparation •Stewing/poaching

Fruit Grading

Voluntary: US Fancy, US No 1, US No2, US No 3; most are fancy, lower grades for jams, preserves Selected based on individual evaluation factors, whether or not graded, the fruits peak season

Lycopenes

decreases the risk of prostrate and colon cancer

Fruits and vegetables are supposed to fill _______ of our plate when we eat.

half

Enzymatic Browning - To avoid flavor and quality loss, dehydration should not involve _______

heat

Enzymatic Browning limiting by - Blanching before freezing

inactivates the enzyme polyphenoloxidase (PPO)

Enzymatic Browning limiting by - Reduced pH <4

inhibits enzyme activity (lemon juice, vinegar)

Anthocyanins

reduces the growth of tumors and protects against cell damage

Fruit ZEST

§Contains aromatic oils that give a lot of flavor §Contains more flavor than fruit juice Organic is better because you want to minimize pesticide exposure

Fruit Flavor

§Flavor substances and volatile compounds tend to be lost during heating §Heat only for a very short time

Selection of Fruit

§Follow the season §Fruit ripened on the vine is much more aromatic that fruit grown in hothouses §Leave fruit out at room temperature until fully ripe; then refrigerate

Fruit Texture and when to consume:

§Fruits are best if consumed fresh because the texture changes during heating

Definition of Juice Names:

•100% juice - Juice or Juice blend > 50% juice - Juice drink (added water, sugar solution) >30-40% juice: Nectar >25% juice - -ade such as limeade/lemonade >10% juice - Juice Drink or juice cocktail 1% juice - Fruit punch Freshly squeezed - Not pasteurized, held refrigerated, food safety concerns Not from concentrate - Pasteurized after extraction From concentrate - Reconstituted and pasteurized

fruits as functional foods

•Antioxidants •Polyphenols (phenolics)

Fruit Preparation: Drying

•Cut fruits into thin slices after washing them. When drying small fruits like berries, leave them whole. •To prevent browning, fruit can be briefly (2 minutes) immersed in lemon water (4 parts water:1 part lemon juice). •Spread fruit on a lined baking sheet and put it in the oven. Allow to dry for 4-8 hours at your oven's lowest temperature setting.

Polyphenols

•Decrease risk of hypertension, heart disease, stroke, and dementia

Fruit Spread Ingredients

•Pectin (1%) •Sugar (60%) •Acid (pH: 2.8-3.4) •Fruit Pectin molecules form a network. They need a low pH to form the gel needed to make fruit spreads.

Fruit Preparation: Baking

•Performed in skin of fruit because skin protects against dehydration •To avoid explosion, peel a narrow strip of skin around the equator of the fruit •Microwave works well

Fruit Preparation: Poaching Fruit

•Simmering just below boiling point until fruit is tender •Leave lid on to retain volatile flavoring components •Well suited for apples, pears, peaches

Food additives in fruits

•Sulfites, sorbates, benzoates, and ascorbic acid

Enzymatic Browning limiting by - Treatment with supercritical carbon dioxide (SC-CO2)

•Supercritical carbon dioxide (fluid carbon dioxide at high pressure) treatment is mostly applied to destroying microorganisms but can also be applied for enzyme inactivation, especially for inactivation of PPO in shrimps, lobsters and potatoes. Inactivation of the enzyme is a result of a decrease in pH caused by production of carbonic acid from carbon dioxide.

Fruit Spread - Chutneys

•Thick sauces containing fruits and/or vegetables, sugar, vinegar, and spices •Side dish of the cuisines of the Indian subcontinent, but also popular in Great Britain (mango chutney) and the Caribbean Islands (mango and papaya chutney) •Can be made with fresh ingredients to be kept for only a few days, but is also produced commercially •Can be chunky or smooth, spicy to hot, sour or sweet •Sweeter versions can be served with bread or as an accompaniment for cheese •In India, chutneys are served at almost every meal, especially as relishes with curry

Enzymatic Browning limiting by - Ultrasonication

•Ultrasonication is an advanced method to inactivate enzymes. Ultrasonic sound waves are able to destroy large molecules by liberating highly reactive radicals from water. It is not yet applied on a large scale.

Composition of Fruits

•Water (85%) •Very low fat and protein content •High in carbohydrates - mostly sugar •Organic acids - Decrease during ripening •High fiber content •Acidity of fruits •Pectic substances -Use of pectin by food industry -Pectin formation in ripening fruit -Pectic substances and juice cloudiness •Phenolic compounds -Enzymatic browning

Enzymatic Browning limiting by dehydration - Lowering Water Activity:

•by adding water-binding chemicals. The most commonly used substances are salt (sodium chloride), sucrose, and other sugars, glycerol, propylene glycol and syrups or honey.

•Fruit juices

100% Juice only - contains juice and no water, no added sugar * Fruit/vegetable juice processing by: - Extraction, clarification, deaeration, pasteurization, and concentration/ additions

What fruits are exceptions to low fat:

Avocado, coconut, olives

Storage Conditions for different Fruits:

Once fruit is ripe, store in refrigerator in plastic bag with holes punched into it, except for: - Bananas: room temperature - Cherries: single layer between paper towels, inside plastic bag - Citrus fruit: cool room temperature or refrigerated - Uncut pineapples: room temperature - Pomegranates: room temperature for a few days; refrigerate beyond a few days

Enzymatic Browning limiting by - Refrigeration or freezing:

at 7°C the activity of polyphenoloxidase is inhibited but not inactivated

Enzymatic Browning limiting of reaction by:

•Denature enzymes (blanching) •Reduce pH (acid) •Lower temperature •Coat fruits with sugar or water •Add antioxidants: ascorbic acid, sulfur dioxide, bisulfite

Aggregate Fruits

* Develop from the merger of several ovaries that were separate in a single flower: Blackberries, raspberries, blueberries, strawberries

Enzymatic Browning of Fruit

* Enzymes located in fruits cause enzymatic browning when fruit is exposed to air by cutting or by bruising that causes breaking of the cell. * Enzyme reaction of polyphenoloxidase with phenolic compounds turns fruit brown * Function of polyphenoloxidase: plays an important role in the resistance of plants to microbial and viral infections and to adverse climatic conditions * Brown compounds are called melanin * Melanin is safe to eat

Nuts

* Fruits but we eat the seeds rather than the fleshy part of the fruit

What is the difference between golden and brown raisins

* Golden raisins are treated with sulfur dioxide and therefore do not brown

Enzymatic Browning limiting by - High pressure treatment

* High pressure treatment also called High Pressure Processing (HPP) is a technique of food processing where food is subjected to elevated pressures (500-700 atmosphere) to achieve microbial and enzyme inactivation. •High pressure processing causes minimal changes in foods. Compared to thermal processing, HPP results in foods with fresher taste, and better appearance, texture and nutrition. High pressure processing without heat eliminates thermally induced cooked off-flavors. The technology is especially beneficial for heat-sensitive products, but still very expensive.

Enzymatic Browning limiting by - Irradiation

* Irradiation, or as it is sometimes called "cold pasteurization", is a process in which food is submitted to ionized radiation in order to kill bacteria and reduce the enzyme activity. Irradiation is often applied in meats, seafood, fruits, vegetables, and cereal grains for long-term preservation. •Several types of irradiation methods are used in food processing: gamma rays, X-rays and accelerated electrons (electron beams). •Disadvantages of radiation are loss of nutrients and (low) consumer acceptance. Irradiation is thus rarely used.

Phytochemicals = Plant Chemicals

* Some are responsible for color and other organoleptic properties, such as the deep purple of blueberries and the smell of garlic. * Include antioxidants •Vitamins A, C, and E are anti-inflammatory •Anthocyanin reduces the growth of tumors and protects against cell damage •Lycopene decreases the risk of prostrate and colon cancer * Polyphenols •Decrease risk of hypertension, heart disease, stroke, and dementia *Flavonoids *Flavones *Isoflavones *Catechins *Anthcyanindins *Isothiocyanates *Allylsulfides

Enzymatic Browning limiting by dehydration - Freeze-drying:

* moisture is removed by sublimation (the change from solid to gas). Products are frozen and slowly dehydrated under vacuum.

Storage

- Best in refrigerator to slow ripening process - If water content is high, it is best to eat fruits within 3 days of purchase - Decreased temperature and oxygen are used to transport fruits to stores. - To speed up ripening, fruits can be placed in a brown paper bag and left at room temperature. Fruit produces a gas called ethylene (oranges, tomatoes) that assists in the ripening process. -Most fruits taste better at room temperature and should be allow to warm up before serving.

NUTS

- Hard, dry, single-seeded fruit, partially or totally enclosed in a husk that remain with the fruit as it ripens

•Superfruits (marketing term)

- Scientific evidence suggesting potential health benefits - Term used to generate consumer demand - Exceptional health benefits - not a scientific term not approved by the FDA - eat variety of fruits: -Goji and acai -Blueberry -Cranberry -Pomegranate

Fruit Spread - Butters

- Thick, smooth fruit preserves -Less sweet than jams/jellies -Do not keep well

Storing olives

-Leftovers from OPEN can: stored in original brine, covered with breathable plastic wrap, refrigerated •Should NOT be stored in airtight container -Leftovers from open jar: can be stored in airtight container

Storing canned fruit

-Store in dry place under 70°F

Fruit Ripening Changes:

1) Color •pH, metal salts, ethylene gas 2) Texture •Conversion of protopectin to pectin •Degradation of cellulose and hemicellulose •Denaturation of cell-membrane proteins 3) Flavor •Zest

2 Types of fiber in fruits:

1) Insoluble fiber: Apple, banana, avocado, guava (very high), dried fruits 2) Soluble fiber: fruits

7 types of fruit spreads

1) Preserves 2) Jams 3) Conserves 4) Jellies 5) Marmalades 6) Butters 7) Chutneys

3 Classifications of Fruits

1) Simple fruit 2) Aggregate fruit 3) Multiple fruit

5 Steps in the Fruit Ripening process:

1.Decrease in green color and increase in yellow-orange or blue-red color. Change in color: Breakdown of chlorophyll with a color change to end fruit color of yellow or orange-red. 2.Softening of the flesh: Breakdown of protopectin to pectin. => Enzymes break down protopectin in the cell walls and between cells, making pectin. => In overripe fruits, pectin is converted to pectic acid (Undesirable). Only pectin has gelling ability. 3.Development of pleasant flavor/odor. With many fruits, fragrance is the best indicator of ripeness (pears, melons, peaches, pineapples). 4.Increase in sugar content and decrease in starch content. When unripe, fruit is more starchy and some are eaten as a vegetable vs fruit. Example is a green banana or Plantanes. 5.Decrease in organic acids that make the fruit tart => Least acidic fruits like bananas and cucumbers become more bland => Oxalic acid in rhubarb, citric acid in citrus fruits and tomatoes, malic acid in apples, pears, strawberries, peaches and cherries. When NOT RIPE you can tell the difference in the

Fruits you should pick or buy ripe and ready-to-eat (NON-CLIMACTERIC):

Apples, cherries, grapefruit, grapes, oranges, pineapple, strawberries, tangerines and watermelon.

Fruits that Continue to Ripen (CLIMACTERIC):

Apricots, bananas, cantaloupe, kiwi, nectarines, peaches, pears, plantains and plums

Climacteric v. non-climacteric fruits

Climacteric - Continue to ripen after harvested Non-climacteric - best ripened before harvest

Enzymatic Browning Limiting and Dehydration

Dehydration is caused by the removing water molecules from the product. The PPO enzyme needs sufficient water to be active. By drying the enzyme is inhibited, but not destroyed. •To avoid flavor and quality loss, dehydration should not involve heat.

This is used to achieve the optimal COLOR in oranges and tomatoes

Ethylene Gas - putting fruit into a brown paper bag helps them to ripen more quickly - Food industry will use ethylene gas to speed up ripening and have color change from green to bright orange in oranges

Enzymatic Browning limiting by - Addition of inhibitors

Inhibitions can act in three ways: 1) Inactivation towards the enzyme (acting directly on the enzyme) 2) Inactivation towards substrate (removing the substrate like oxygen or phenolic compounds) 3) Inactivation towards the product (changing the product composition) •Large amount of inhibitors are applied in food processing depending on the type of product and process. The most important inhibitors are shown in table 3 on slide.

Enzymatic Browning limiting by - Covering with sugar or water:

Limits exposure to oxygen

•Processed fruits

Loses Vitamins when processed. -Canned -Frozen - never same texture once frozen -Dried - Price should be no more than 5 x the price of fresh fruit

Fruit Spread - Conserves

Made from a mixture of fruits and nuts/raisins •Usually contains at least some citrus

Fruit Spread - Jellies

Made from fruit juice

Fruit Spread - Jams

Made from ground or mashed fruit

Fruit Spread - Marmalades

Made from juice with slices of fruit/fruit rind, esp. citrus

What is Fruit?

Many vegetables are technically fruits. According to the classification, fruits are seed-bearing parts of a plant or from from a plant flower. They include cucumbers, tomatoes, squash, green beans, and okra. Since some vegetables are technically fruits, it is obvious that not all fruits are sweet. The seed bearing parts of a plant are fleshy and pulpy. Often, they are juicy, usually sweet with a fragrant odor. Rhubarb is technically not a fruit but a vegetable, but it is treated as a fruit due to its flavor.

Speed up the ripening of fruits such as peaches, pears, and plums:

Put them in a ripening bowl or in a loosely closed brown paper bag at room temperature. Plastic bags don't work for ripening.