Jams, Jellies and Marmalades - Herbstreith & Fox

Jams, Jellies and Marmalades

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CONTENT

GENERAL INFORMATION

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RAW MATERIALS

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GELATION OF H&F PECTINS

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Pectin

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Gelling Mechanisms

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High Methylester Pectins ? Gelling Behaviour

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Low Methylester Pectins ? Gelling Behaviour

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Low Methylester, Amidated Pectins ? Gelling Behaviour

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SYNERESIS BEHAVIOUR

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THE STANDARDIZATION OF H&F PECTINS

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CLASSIC, COMBI AND AMID PECTINS AND THEIR APPLICATION

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PRODUCTION METHODS OF JAMS, JELLIES AND MARMALADES

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GENERAL CALCULATIONS AND DESIGN OF FORMULATIONS

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FOOD LEGISLATION Low-Calorie Products Dietetic Products

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INDIVIDUALITY IS OUR STRENGTH

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Jams, Jellies and Marmalades

General

Information

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Cooking jams, jellies and marmalades using fruits, sugar, pectin and edible acids is one of the oldest food preserving processes known to mankind and presents a way of making food stable by increasing the content in soluble solids. The shelf-life of the products gained by this method depends on the following criteria as regards their stability to microbial spoilage: Perfect hygienic operating conditions, such

as production units, filling and production system. Perfect hygienic raw materials and packaging materials. A high sugar content (min. 60% soluble solids in jams, jellies and marmalades), which causes a lowering of the free water by hydration. Sufficient pasteurization or chemical preservation of low-calorie fruit spreads, jams, jellies and marmalades (less than 60% soluble solids). A low pH-range (pH 2.6-3.2) when using high methylester pectins. Sufficient cooking time to achieve an inversion and exchange of sugar between the medium and fruits (otherwise the formation of low-sugar concentration zones may incur the risk of crystal formation or water exudation).

Cooking temperature: open system: 90-105?C (194-221?F) vacuum cooker: 65-80?C (149-176?F).

Head space sterilization of the glass jar after filling.

Turn the closed glass upside down. Capping under vacuum.

Raw

Materials

The quality criteria for jams and marmalades are decisively determined by the flavour, colour and consistency as well as state of preservation and distribution of fruits. These properties depend to a high degree on the raw materials used, with special importance given to the proper selection of suitable fruits. The characteristic nature of the finished product is further determined by the addition of sugars, pectin and edible acids.

The German Fruit Jams Regulation gives the following definition for the required condition of the raw materials:

Fruits: Fresh, sound, not spoiled fruit, containing all its essential constituents, after cleaning and removal of blemishes and sufficiently ripe. Chestnut for the purpose of the regulation is the fruit of the sweet chestnut tree (Castanca sativa). The term "fruits" is extended for the purpose of the regulation also to:

The edible parts of rhubarb stalks, ginger, e.g. parts of the ginger plant, tomatoes, cucumbers, melons, water melons, pumpkins, carrots and sweet potatoes.

Stone fruits and kernel fruits are generally processed without stones, pits and cores and in unpeeled condition, citrus fruits are generally peeled when processed, part of the peels is requently added.

Fresh fruits, for cost as well as seasonal reasons, are only used in smaller quantities for the manufacture of finished products. Thus, the largest amount of fruits for production purposes are either frozen, heated (canned) or preserved with sulphur dioxide.

The most important quality criteria for fruits used are: optimal state of ripeness full fruity flavour variety-specific colour no blemishes (no spots, no bruises) sufficient consistency (solidity of form) soluble solids content in agreement with

quality standards perfect hygienic condition of raw materials

and packaging

Fruit Pulp (pulp): The edible part of the whole fruit, peeled or cored if necessary, which may be whole, sliced or chopped.

Fruit Pur?e (pur?e): The edible part of the whole peeled or cored fruit, which has been reduced to pur?e by straining or a similar process.

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Fruit Juice: Products complying with the German Fruit Juice Regulation.

Aqueous Extracts of Fruits: Aqueous extracts of fruits which contain all water-soluble constituents of the fruits except technically unavoidable losses.

Citrus Peels (peels): Cleaned citrus peels with or without endocarp.

Fruit Constituents: In fresh condition, fleshy-juicy fruits consist, as a rule, of 80-85% water. The main constituents, besides water, are carbohydrates, furthermore organic acids, polymer carbohydrates such as pectins and starches, nitrogenous compounds, minerals, vegetable phenols, flavours and vitamins.

The composition of the fruits underlies great deviations in dependence on type of fruit, degree of ripeness, conditions of cultivation and climate.

pH-value and titratable acid: pH and titratable acid are indicators for the quantity of organic acids and its salts contained in a fruit. Both factors affect gelation. In the production of jams with high methylester pectins, the pH-range is usually set at about 2.8-3.2 with citric acid, since this pH-range is very favourable in view to gelation, flavour and shelf-life;

Calcium content: Low methylester and amidated pectins gel in combination with calcium ions. Thus the fruit-owned calcium content is of great importance. Generally speaking, the insoluble parts of fruits are especially rich in calcium. However, the total calcium amount is not available to pectin, but only part of it, the so-called "free calcium". The remaining calcium ions, or "bound calcium", are solidly fixed to complexing agents.

Fruit varieties used in the production of jams, jellies and marmalades have to be especially selected for their:

fruit owned pectin content: The fruit owned pectin content is off less importance. Usually the cooking time does not suffice to let the pectin become soluble and with that be able to gel;

The following table gives a summary of the average pectin contents as well as contents in titratable acids and calcium ions and the mean pH-range of the most important fruits in jam manufacture.

Type of fruit

apples sweet cherries plums peaches apricots strawberries raspberries blackberries red currants gooseberries

1) mgCa2+/100g

7 17 14 8 16 26 40 44 29 29

Table 1: M: calculated as malic acid C: calculated as citric acid

1) + 2) pectin [%]

0.70 0.36 0.76 0.54 0.96 0.81 0.40 0.48 0.93 0.62

2) pH

3.2-3.5 3.4-3.7 3.1-3.4 3.4-3.8 3.6-3.8 3.2-3.5 3.1-3.6 3.3-3.6 3.0-3.1 2.7-3.1

2) titratable acid [%]

0.52 (M) 1.36 (M) 2.21 (M) 0.62 (M) 1.13 (M) 1.11 (C) 1.35 (C) 1.09 (C) 2.14 (C) 2.37 (C)

1) Souci-Fachmann-Kraut: Die Zusammensetzung der Lebensmittel, N?hrwert-Tabellen 1989/1990, Wissenschaftliche Verlagsgesellschaft mbH Stuttgart 1989 2) K. Herrmann: Obst, Obstdauerwaren und Obsterzeugnisse, Verlag Paul Parey 1966

Types of sugar: All sugars listed in the "German Regulation on Certain Sugars Destined for Human Consumption" (Zuckerarten-Verordnung vom 23.10.2003 [BGBl. I.S. 2096] in the actual edition) may also be used in solution and in any mixing ratio.

Sugars are one of the main constituents of jams, jellies and marmalades and influence the shelf-life of these products decisively through the soluble solids content. At the same time they provide taste, flavour, consistency and colouring.

For jam production, mostly refined sugar or white sugar (sucrose) is used. During cooking, sucrose is partially inverted. This intended chemical reaction (splitting of sucrose into glucose and fructose by binding water) is influenced by

the pH-value the temperature the time

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The formation of invert sugar prevents the crystallization of the sucrose in the finished product. On the other hand, a complete inversion of sucrose may lead to crystallization of the glucose in the product.

Jams and marmalades produced on vacuum cookers are, as a rule, only slightly inverted.

Liquid Sugar, Invert Liquid Sugar, Invert Sugar Syrup:

Liquid sugar is an aqueous solution of sucrose with a minimum of 62% soluble solids and a maximum amount of 3% invert sugar related to soluble solids (ss).

generated by the fructose. Sweet taste, flavour and aw-value in the finished product may be influenced by suitable combinations with other sugars.

Starch-Saccharification Products: Glucose Syrup, Dextrose:

Glucose syrup is a starch degradation product and contains glucose, maltose, dextrine and fructose. Glucose syrup is less sweet than sucrose and inhibits crystallization of glucose and sucrose in the finished product. Its addition improves the texture (smoother consistency of the finished product). Dried glucose syrup may also be used instead of glucose syrup.

Invert liquid sugar is an aqueous solution of sucrose, partially inverted in hydrolysis, in which the amount of invert sugar does not preponderate and the following criteria are given: a minimum of 62% soluble solids and no less than 3% but no more than 50% invert sugar related to soluble solids.

Invert sugar syrup is an aqueous solution of sucrose partially inverted in hydrolysis, which is dominated in its composition by the amount of invert sugar present and which meets the following criteria: a minimum of 62% soluble solids and more than 50% invert sugar related to soluble solids.

These sugar solutions are characteristic for their relatively low viscosity, temperature tolerance and the fact, that they do not crystallize even at a low temperature. They affect the microbiological stability of the product positively owing to the higher osmotic pressures

Glucose syrups may be of different composition depending on the various possible methods employed in large-scale productions. The production, however, always starts with a partial starch hydrolysis. The application of the enzyme glucose isomerase has greatly extended the range of available glucose syrups. This enzyme causes the conversion of part of the glucose into fructose. The glucose syrups produced in this way have higher fructose volumes and thus greater sweetening power as starter syrups. Depending on the fructose share, these syrups are called glucose-fructose-syrup resp. fructoseglucose-syrup. Thus high fructose-glucosesyrups with approx. 42% fructose and 52% glucose related to soluble solids are, for example, used in production.

Dextrose is made by starch hydrolysis. It is of practically no importance in jam manufacture, since dextrose tends to crystallize and lends a dull and mat appearance to the products.

Sugar Substitutes:

Sugar substitutes form a group of substances which may be used to substitute sucrose in food products. Similar to sugars they provide

When high dosages (more than 20g per person and day) are consumed, polyols may sometimes

food with "bulk" or "body" and a physiological calorific value. Their sweetening power is comparable to sucrose or less.

Comparison of the sweetening power of sugar substitutes in relation to sucrose

The following sugar substitutes are of importance: Fructose (fruit sugar) is a monosaccharide which is naturally present in practically all fruits. Its relevance as a sugar substitute consists in its insulin independent metabolism and digestion, which makes it suitable for dietetic food products for diabetics. The calorific value of fructose is determined at 17KJ/g (or 4kcal/g), equal to sucrose or glucose. The sweetening power of fructose is higher than that of sucrose. Fruit sugar is normally traded as fruit sugar syrup with 70% ss.

fructose sorbitol mannitol isomalt maltitol lactitol xylitol

1.10-1.30 * 0.63 *

0.50-0.60 * 0.45 *

0.65-0.68 * 0.30-0.35 *

0.00 *

Table 2: * the figures indicate the factor by which the sugar substitute in question tastes sweeter than sucrose. from: S??ungsmittel im ?berblick (a summary of sweeteners), Gordian 88/4, p. 72ff.

have a laxative effect. Sweeteners:

Polyols or sugar alcohols form the main group of sugar substitutes. The physiological benefit

Sweeteners are natural or synthetic compounds which have no or, compared to their sweetening power, only a negligible calorific value.

of these sugar substitutes is their suitability for diabetics (insulin independent metabolism) as well as their partially anti-cariogenic effect and lower calorific value.

Their sweetening power is by far greater than that of sucrose.

Comparison of the sweetening power of sweeteners in relation to sucrose

For all sugar alcohols a uniform physiological calorific value of 10kJ/7g is fixed.

acesulfame-k aspartame

130-200 * 200-250 *

cyclamate

30-40 *

saccharine

450-500 *

sucralose

approx. 600 *

Table 3: * the figures indicate the factor by which the sugar replacer in question tastes sweeter than sucrose. from: S??ungsmittel im ?berblick (a summary of sweeteners), Gordian 88/4, p. 72ff. resp. Handbuch S??ungsmittel, Behr's Verlag

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Jams, Jellies and Marmalades

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