Автор конспекта:
Автор(ы): — Матвеева Ирина Георгиевна, Мартыненко Катя, Ершова Влада
Место работы, должность: —
МОУ "Гимназия №1", учитель английского языка
Регион: — Саратовская область
Характеристика конспекта:
Уровни образования: — среднее (полное) общее образование
Класс(ы): — 10 класс
Класс(ы): — 11 класс
Предмет(ы): — Английский язык
Целевая аудитория: — Учитель (преподаватель)
Тип ресурса: — дидактический материал
Краткое описание ресурса: —
Реферат Мороженое — наше любимое лакомство — выступление на школьной научно-практической конференции, 2010
Contents
1. Introduction
2. What’s this – ice-cream?
3. The History of ice-cream.
4. Ice Cream Flavours
5. Dietary.
6. Some Questions about the Possible Benefits or Harm of the Ice-cream
7. Conclusion.
8. Literature.
INTRODUCTION
We are actually school-leavers. This year we are going to finish our school and enter the university. As you know, we are learning in chemistry and biology class and we are going to study medicine at the university. That’s why we have made up our minds to dwell on the topic which is connected with our work and profession in future. We have decided to speak about the ice-cream.
There are practically no people all over the world, who dislike sweets or something sweet or even who has never tasted something sweet. And perhaps one of the most favourite delicacies in the world is the ice-cream. It is rather difficult to say how many flavours the ice-cream has. It can be of different colours and shapes. The main ingredient of the ice-cream can be either fruit or berry juice or milk. But nowadays the colour of the ice-cream often depends on the synthetic ingredients. Is it really safe and healthy to eat ice-cream? It is true to say that people of all ages and especially children can’t imagine their lives without ice-cream. In summer we need ice-cream like a drop of water. It’s a pity, but almost no one knows about the ice-cream actually. And we thought that it would be very interesting to speak about the creation of the ice-cream, the influence that the ice-cream has on people’s health. And it’s a good idea to know what our primary school pupils think about different sweet things. Taking everything into consideration we are determined to do the following:
-to speak about the history of creating the ice-cream
-to learn about the ingredients that the ice-cream usually consists of and make a research about their influence on the humans’ health
-to make a public opinion poll of pupils of our school to know how important different sweet things are for them.
What’s this – ice-cream?
Ice or ice-cream is a frozen dessert usually made from dairy products , such as milk and cream, and often combined with fruits or some other ingredients and flavours. Most kinds of ice-cream contain sugar, although some are made with other sweeteners . In some cases, synthetic fillings, flavours and colourants are used in addition to (or in replacement of) the natural ingredients. This mixture is stirred slowly while cooling to prevent large ice crystals from forming; the result is a smoothly textured ice-cream.
The meaning of the term ice cream varies from one country to another. Terms like frozen custard , frozen yogurt , sorbet , gelato and others are used to distinguish different varieties and styles. In some countries, like the USA, the term ice-cream applies only to a specific variety, and their governments regulate the commercial use of all these terms based on quantities of ingredients. In others, like Italy and Argentina, one word is used for all the variants. Alternatives made from soy milk , rice milk , and goat milk are available for those who are lactose intolerant or have an allergy to dairy protein , or in the case of soy and rice milk, for those who want to avoid animal products.
Before the development of modern refrigeration , ice cream was a luxury reserved for special occasions. Making it was quite labourious. Ice was cut from lakes and ponds during the winter and stored in holes in the ground, or in wood-frame or brick ice houses , insulated by straw. Many farmers and plantation owners, including U.S. Presidents George Washington and Thomas Jefferson , cut and stored ice in the winter for use in the summer. Frederic Tudor of Boston turned ice harvesting and shipping into big business, cutting ice in New England and shipping it around the world.
Ice cream was made by hand in a large bowl placed inside a tub filled with ice and salt. This was called the pot-freezer method. French confectioners refined the pot-freezer method, making ice-cream in a sorbetière (a covered pail with a handle attached to the lid). In the pot-freezer method, the temperature of the ingredients is reduced by the mixture of crushed ice and salt. The salt water is cooled by the ice, and the action of the salt on the ice causes it to (partially) melt, absorbing latent heat and bringing the mixture below the freezing point of pure water. The immersed container can also make better thermal contact with the salty water and ice mixture than it could with ice alone.
The hand-cranked churn, which also uses ice and salt for cooling, replaced the pot-freezer method. The exact origin of the hand-cranked freezer is unknown, but the first U.S. patent for one was #3254 issued to Nancy Johnson on September 9, 1843. The hand-cranked churn produced smoother ice-cream than the pot freezer and did it quicker. Many inventors patented improvements on Johnson's design.
In Europe and early America, ice cream was made and sold by small businesses, mostly confectioners and caterers. Jacob Fussell of Baltimore , Maryland was the first to manufacture ice-cream on a large scale. Fussell bought fresh dairy products from farmers in York County, Pennsylvania, and sold them in Baltimore. An unstable demand for his dairy products often left him with a surplus of cream, which he made into ice-cream. He built his first ice-cream factory in Seven Valleys, Pennsylvania, in 1851. Two years later, he moved his factory to Baltimore. Later, he opened factories in several other cities and taught the business to others, who operated their own plants. Mass production reduced the cost of ice-cream and added to its popularity.
The most common method for producing ice-cream at home is to use an ice cream maker , in modern times generally an electrical device that churns the ice cream mixture while cooled inside a household freezer, or using a solution of pre-frozen salt and water, which gradually melts while the ice-cream freezes. Some more expensive models have an inbuilt freezing element. A newer method of making home-made ice-cream is to add liquid nitrogen to the mixture while stirring it using a spoon or spatula. Some ice-cream recipes call for making custard, folding in whipped cream, and immediately freezing the mixture.
The History of ice-cream.
Ancient civilizations have served ice for cold foods for thousands of years. The BBC reports that a frozen mixture of milk and rice was invented in China around 200 BC, and in 618-97 AD, King Tang of Shang had 94 men who made a frozen dish of buffalo milk, flour, and camphor . The Roman Emperor Nero (37–68) had ice brought from the mountains and combined with fruit toppings. These were some early chilled delicacies.
Ancient Persians mastered the technique of storing ice inside giant naturally-cooled refrigerators known as yakhchals . These structures kept ice brought in from the winter, or from nearby mountains, well into the summer. They worked by using tall windcatchers that kept the sub-level storage space at frigid temperatures.
In 400 BC, Persians invented a special chilled pudding-like dish, made of rose water and vermicelli which was served to royalty during summers. The ice was mixed with saffron , fruits, and various other flavours. The treat, widely made in Iran today, is called "faloodeh ", and is made from starch (usually wheat), spun in a sieve-like machine which produces threads or drops of the batter, which are boiled in water. The mix is then frozen, and mixed with rose water and lemons, before serving.
Ice cream was the favourite dessert for the Caliphs of Baghdad. Arabs were the first to utilise milk as a major ingredient in its production, sweeten the ice-cream with sugar rather than fruit juices , as well as perfect ways for its commercial production. As early as the 10th century, ice-cream was widespread amongst many of the Arab world's major cities such as Baghdad, Damascus and Cairo. Their version of ice-cream was produced from milk or cream and often some yoghurt similar to Ancient Greek recipes, flavoured with rosewater as well as dried fruits and nuts. It is believed that this was based on older Ancient Arab , Mesopotamian , Greek or Roman recipes, which were probably the first and precursors to Persian faloodeh .
In 62 AD, the Roman emperor Nero sent slaves to the Apennine mountains to collect snow to be flavoured with honey and nuts.
Maguelonne Toussaint-Samat asserts in her History of Food, "the Chinese may be credited with inventing a device to make sorbets and ice-cream. They poured a mixture of snow and saltpetre over the exteriors of containers filled with syrup, for, in the same way as salt raises the boiling-point of water, it lowers the freezing-point to below zero." (Toussaint does not provide historical documentation for this.)But in the age of Emperor Yingzong , Song Dynasty (960-1279) of China, there is a poem named "詠冰酪" (literally Ode to the ice cheese), written by poet Yang Wanli . There is also a saying , in the Yuan Dynasty , the Kublai Khan enjoy ice-cream a lot and keep it a royal secret, then Marco Polo came to China and brought the technique to Italy .
In the sixteenth century, the Mughal emperors used relays of horsemen to bring ice from the Hindu Kush to Delhi where it was used in fruit sorbets.
When Italian duchess Catherine de' Medici married the duc d’Orléans in 1533, she is said to have brought with her Italian chefs who had recipes for flavoured ices or sorbets and introduced them in France. One hundred years later, Charles I of England was supposedly so impressed by the "frozen snow" that he offered his own ice-cream maker a lifetime pension in return for keeping the formula secret, so that ice-cream could be a royal prerogative . There is, however, no historical evidence to support these legends, which first appeared during the 19th century.
The first recipe for flavoured ices in French appears in 1674, in Nicholas Lemery’s Recueil de curiositéz rares et nouvelles de plus admirables effets de la nature. Recipes for sorbetti saw publication in the 1694 edition of Antonio Latini's Lo Scalco alla Moderna (The Modern Steward). Recipes for flavoured ices begin to appear in François Massialot's Nouvelle Instruction pour les Confitures, les Liqueurs, et les Fruits starting with the 1692 edition. Massialot's recipes result in a coarse, pebbly texture. However, Latini claims that the results of his recipes should have the fine consistency of sugar and snow.
Ice Cream Flavours
Most ice cream is purchased by the consumer on basis of flavour and ingredients. There are many different flavours of ice cream manufactured, and to some extent limited only by imagination. Vanilla accounts for 30% of the ice cream consumed. This is partly because it is used in so many products, like milkshakes, sundaes, banana splits, in addition to being consumed with pies, desserts, etc.
US Ice Cream Consumption by Flavour, 2006
Percentage of volume
1. Vanilla 30.2
2. Chocolate 10.0
3. Chocolate Chip 5.7
4. Butter Pecan 4.0
5. Strawberry 3.7
6. Neapolitan 3.0
7. Cookies and cream 2.6
8. Rocky Road 1.9
9. Cookie Dough 1.5
10. Cherry Vanilla 0.9
11. Coffee 0.7
Ingredients are added to ice cream in four ways during the manufacturing process:
Mix Tank: for liquid flavours, colours, fruit purees, flavored syrup bases anything that will be homogeneously distributed in the frozen ice cream.
Variegating Pump: for ribbons, swirls, ripples, revels
Ingredient Feeder: for particulates — fruits, nuts, candy pieces, cookies, etc., some complex flavours may utilize 2 feeders
Shaker table: for large inclusions
Generally, the delicate, mild flavours are easily blended and tend not to become objectionable at high concentrations, while harsh flavours are usually objectionable even in low concentrations. Therefore, delicate flavours are preferable to harsh flavours, but in any case a flavour should only be intense enough to be easily recognized.
Flavouring materials may be:
1. Natural
2. Artificial or imitation
3. Blends of the two
Vanilla
Vanilla is without exception the most popular flavour for Ice Cream in North America. The dairy industry uses half of the total imported vanilla to North America. It is a very important ice cream ingredient, not only in vanilla ice cream, but in many other flavours where it is used as a flavour enhancer, e.g. chocolate much improved by presence of vanilla. Vanilla comes from a plant belonging to the orchid family called Vanilla planifolia. There are several varieties of vanilla beans among which are Bourbon, Tahitian, Mexican. Bourbon beans are used to produce best vanilla extracts. Vanilla can be and is produced synthetically to a large extent.
Vanilla flavouring is available in liquid form as:
• Natural Vanilla
• Natural and artificial (reinforced Vanilla with Vanillin)
• Artificial Vanilla (vanillin)
Some vanillin actually improves flavour over pure vanilla extract but too much vanillin results in harsh flavours.
The choicest of ice creams can be made only with the best of flavouring materials. A good vanilla enhances the flavour of good dairy products in ice cream. It does not mask it.
Chocolate and Cocoa
The cacao bean is the fruit of the tree Theobroma cacao, (Cacao, food of the gods) which grows in tropical regions such as Mexico, Central America, South America, West Indies, African West Coast. The word cocoa is a corruption of the native word cacao. The beans are embedded in pods on the tree, 20-30 beans per pod. When ripe, the pods are cut from the trees, and after drying, the beans are removed from the pods and allowed to ferment, 10 days (microbiological and enzymatic fermentation). Beans then are washed, dried, sorted, graded and shipped.
At the processing plant, beans are roasted, seed coat removed — called the nib. The nib is ground, friction melts the fat and the nibs flow from the grinding as a liquid, known as chocolate liquor.
Liquor:
55% fat, 17% carbohydrate, 11% protein, 6% tannins and many other compounds (bitter chocolate — baking).
Cocoa butter:
fat removed from chocolate liquor, narrow melting range 30 to 36° C
Cocoa:
after the cocoa butter is pressed from the chocolate liquor, the remaining press cake is now material for cocoa manufacture
The amount of fat remaining determines the cocoa grade:
• medium fat (Breakfast) cocoa 20-24% fat
• low fat 10-12% fat
Cocoa powder can also be alkalized, which reduces acidity/astringency and darkens the colour. Slightly alkalized cocoa is usually preferred in ice cream because it gives a deeper colour but the choice depends upon:
• consumer preference
• desired color (Blackshire cocoa may be used to darken color)
• strength of flavour
• fat content
There are many types of chocolate that differ in the amounts of chocolate liquor, cocoa butter, sugar, milk, other ingredients, and vanilla.
Imitation chocolate
• replacing some or all of the cocoa fat with other vegetable fats. Improved coating properties, resistance to melting
White chocolate
• cocoa butter, MSNF, sugar, no cocoa or liquor
A good chocolate ice cream will be made if the cocoa and/or chocolate liquor is added to the vat and homogenized with the rest of the mix. Chocolate mixes have a tendency to become excessively viscous so stabilizer content and homogenizing pressure need to be adjusted.
Fruit Ice Cream
Fruit for Ice Cream is available in the following forms:
• Fresh Fruit
• Raw Frozen Fruit
• Open Kettle Processed Fruit
• Aseptically Processed Fruit
Advantages of processed fruits:
1. Purchasing year round supply: problems of procurement and storage transferred to fruit processor
2. Availability: blending of sources from around the world in RTU form, no thawing, straining, etc.
3. Quality control: processor adjusts for quality variations
4. Ice Cream quality: fruit won't freeze in ice cream, usually free of debris, straw, pits.
5. Microbial Safety
6. Convenience
Fruit feeders are used with continuous freezers to add the fruit pieces, while any fruit juice is added directly to the mix. Fruit is usually added at about 15-25% by weight.
Nuts in Ice Cream
Nuts are usually added at about 10% by wt. Commonly used are walnuts, pecans, filberts, almonds and pistachios. Brazil nuts and cashews have been tried without much success.
Quality Control of Nutmeats for Ice Cream
1. Extraneous and Foreign Material:
Requires extensive cleaning, Colour Sorter, Destoner, X-rays, Aerator, Hand-Picking, Screening
2. Microbiological Testing:
Aflatoxin contamination can be a hazard with Peanuts, Pistachios, Brazils. All nutmeats should receive random testing for: Standard Plate Count, Coliform, E. Coli, Yeast and Mold, Salmonella.
3. Bacteria Control:
Nuts must be processed in a clean sanitary premise following good manufacturing practices. Nuts should be either oil roasted or heat treated to reduce any bacteria.
4. Sizing:
Some nutmeats require chopping to achieve a uniform size in order to fit through the fruit feeder, i.e.: Pecans, Almonds, Peanuts, Filberts
5. Storage Nutmeats should be stored at 34-38° F to maintain freshness and reduce problems with rancidity.
Colour in Ice Cream
Ice cream should have a delicate, attractive colour that suggests or is closely associated with its flavour. Almost all ice creams are slightly coloured to give them the shade of the natural product 15% fruit produces only a slight effect on colour. However, most suppliers, would include some colour in the fruit to save the processor time i.e. solid pack strawberries include colour. Most colours are of synthetic origin, must be approved, purchased in liquid or dry form. Solutions can easily become contaminated and therefore must be fresh.
Colours are used in ice cream to create appeal. If used to excess they indicate cheapness. The choice of shade is dictated by flavour, i.e. red for strawberry, light green for mint, purple for grape, etc.
Dietary.
Ice cream may have the following composition:
• More than 10% milk fat and usually between 10% and as high as 16% fat in some premium ice creams:
• 9 to 12% milk solids-not-fat: this component, also known as the serum solids, contains the proteins (caseins and whey proteins) and carbohydrates (lactose) found in milk:
• 12 to 16% sweeteners: usually a combination of sucrose and glucose-based corn syrup sweeteners:
• 0.2 to 0.5% stabilizers and emulsifiers:
• 55% to 64% water which comes from the milk or other ingredients.
These compositions are percentage by weight. Since ice-cream can contain as much as half air by volume, these numbers may be reduced by as much as half if cited by volume. In terms of dietary considerations, however, the percentages by weight are more relevant.
Even the low fat products have high caloric content: Ben and Jerry's No Fat Vanilla Fudge contains 150 calories per half cup due to its high sugar content.
Some Questions about the Possible Benefits or Harm of the Ice-cream
How does ice-cream influence our body?
About 15or 20 minutes after you eat the ice-cream you are physically cooled thanks to the contact with the ice-cream, as the heat of your body is transferred to the ice-cream. However, as the digestive process goes on, the body temperature increases as the body works to digest and absorb the nutrients from the ice-cream, as well as to store the calories. The body will physiologically respond to energy (i.e., heat) loss by increasing blood flow to the “cool region” and bring the temperature back up to a physiological body temperature.
Will lots of ice cream make you put on lots of weight or won’t ?
It depends on your caloric intake. If you're burning off the ice-cream that you have eaten then you won't gain weight but if you eat about 2000 calories a day and then 300-500 calories worth of ice cream you'll gain weight over time.
Conclusion.
We have told you about the most favourite delicacies in the world for people of all ages. We have spoken about the history of creation of the ice-cream, about different kinds of ice-cream in many countries of the world, about the ingredients (natural and synthetic), which the ice-cream has, about the influence, that the ice-cream has on the people’s health.
Having discussed everything, that was mentioned above we have come to the following conclusion:
Literature
Ice-cream.
What is it?
Ershova Vlada, Martynenko Ekaterina
11 B form
Supervisor: Matveeva I.G.
Saratov
2010
Файлы: ice-cream 2.doc
Размер файла: 74240 байт.