Etiket Arşivleri: Pectin

Chapter:1 Pectin

Chapter 1 Pectin

1-1  Structure and Terminology

1-2  Production

1-3  Characterization of pectin gel

1-4  Factors affecting gelation

1-5  Chemical properties

1-6  Pectic enzymes

1-7  Structure and mechanisms of gel formation

1-8  Application

1-1  Structure and Terminology

Pectin is heterogeneous complex polysaccharide

Its composition varies with the source and the conditions applied during isolation

All pectin molecules contain linear segments of (1à4)-linked a-D-galactopyranosyluronic acid with some of the carboxyl groups esterified with methanol.

Some of the hydroxyl groups of the galacturonosyl unit (O-2 and O-3) are esterified with acetic acid.

Pectin molecule with methyl esterified or nonesterified carboxyl groups

Amidated pectin has commercial importance

Terminology

Protopectin

Pectinic acids

Pectic acids

Pectins

Degree of esterification (DE) > 50

High-methoxyl pectins (HM-pectins)

High concentration of soluble solids, low pH

DE < 50

LM-pectins

Divalent cations

1-2  Production

1-2-1 Raw materials

Citrus peel (20-30%), apple pomace(10-15%)

Sugarbeet waste, sunflower heads, mango waste

Sugarbeet pectin is inferior to citrus or apple pectin

Presence of  acetate esterification

A relatively low molecular mass

Presence of large amount of neutral sugar side chain


Making Jams, Jellies and Fruit Preserves

Homemade jams, jellies and fruit preserves are a favorite treat in summer and all year long. Today we will discuss the basic steps and hints for delicious homemade treats from your garden or orchard.

Many of the points in today’s discussion come from the publication:

B2909 Making Jams, Jellies and Fruit Preserves

The season for summer fruits which can be deliciously preserved as jam or jelly isn’t far behind.

This publication will offer ideas for regular and low- or no-sugar jams and jellies.

Start with 4 basic ingredients:

Fruit gives each product its characteristic color and flavor.  Use at least some flavorful, just-ripe fruit in each recipe. You may also be able to use canned, frozen or dried fruit. Use canned or frozen fruits preserved without sugar. Thaw frozen fruit in the refrigerator before using. Cook dried fruit in water until tender and use to make jams and conserves.

Pectin is the natural plant substance (carbohydrate) that causes fruit to gel, and there are many options available now for pectin (more on that later).

Acid is essential in jellied fruit products for both gel formation and flavor.  The acid content varies among fruits, and is higher in under-ripe fruits.  For best quality, add bottled lemon juice to fully ripened, low-acid fruits according to tested recipes.

Sugar is another essential ingredient in jellied fruit products.  Added sugar preserves fruit, helps the gel form, and contributes to flavor.  Use the amount of sugar a recipe calls for, or the product will not form a gel. To make a low-sugar or no-sugar product, choose a pectin or research-tested recipe designed for this.  Sugar substitutes — also called artificial sweeteners — cannot replace sugar in regular recipes because the sugar is needed to form a gel.

Fruits such as apples, crabapples, currants, grapes and some plums contain enough natural pectin to form a gel; others require added pectin.  You can add pectin to any fruit to ensure a good gel, and there are several advantages for doing so:

You can use fully ripe, flavorful fruit

Cooking time is shorter so you retain more of the natural color and flavor of the fruit

You will have more jars on the shelf from the same amount of fruit.

Regular pectins work with sugar, fruit and acid to form a gel. Regular pectin comes in two types, liquid (such as Certo) and powdered (such as Sure-Jell). Liquid pectin is added to a hot pre-cooked mixture of sugar and fruit and cooked for 1 more minute; powdered pectin is cooked with fruit, then sugar is added and the mixture is cooked for 1 more minute. The two types of pectin are not interchangeable.

Low-methoxyl pectins are chemically different from regular pectins and can gel with little or no added sugar. The resulting gel will be softer, but this can be acceptable for those on a low-sugar or no-sugar diet. The product also tends to be less sweet, and to have a fruiter taste. Even commercial manufacturers are taking advantage of this type of gelling agent to produce high quality products.

No sugar refrigerator products may call for powdered gelatin as the gelling agent. Powdered gelatin is a protein, unlike pectin which is a carbohydrate. Gelatin must be treated carefully or the gel structure will break. So, do not freeze these jellies and do not can these products. Store them in the refrigerator.

Acid is essential in jellied fruit products. Sometimes the acid comes from under-ripe fruit, and sometime it is added in the form of bottled lemon juice. Freshly squeezed lemon juice won’t necessarily work as well.

Added sugar preserves jellied fruit by inhibiting the growth of microbes, helps form the gel, and adds flavor too! Measure sugar carefully and do not reduce the amount in the recipe. Beet and cane sugar will work equally well.  Using brown sugar is not recommended because of the dark color it imparts to the finished product. Honey or light corn syrup can be used, but remember that liquid ingredients must be adjusted accordingly. These sweeteners will also impart a stronger flavor and color to jellied fruit products.

There are a wide variety of sugar substitutes available on the market. These can NOT substitute for sugar if using regular pectin, but can be used to add sweetness when making jams and jellies with low-methoxyl pectin. Sugar substitutes such as sucralose (Splenda) and saccharin (Sweet-n-Low) tend to hold up well during heating. Follow the manufacturer’s directions for using these products. Do not use aspartame (Equal or Nutrasweet) as the resulting product will be unsatisfactory.

Many consumers wonder why they need to water bath can jams and jellies, especially when the pectin packages that they buy in the store suggest that inverting the hot-filled jars is sufficient.  Well, there are several good reasons for water bath canning:

  • helps form of a good seal on a product

  • destroys yeast and mold which might be present on the rim or lid and thus increases shelf life (it’s really a pasteurization process)

  • is required for any item entered in a county fair competition

Because of their high sugar content, jams and jellies will not readily support the growth of microorganisms; and certainly not when they are sealed with a vacuum seal. But once the jars are opened, then microbial growth can begin. By putting jars through a water bath process, the jars are more likely to seal and to resist mold and yeast growth once opened.

Sometimes, regardless of how careful you are, jams and jellies refuse to set. Most any jellied fruit product makes great syrup, but sometimes jam or jelly is all that is acceptable. Consumers can try to re-make jams and jellies, although the resulting product will be darker in color and may have more of a cooked flavor.

In general, recooking of jams and jellies that don’t set will be most successful if:

  • You work in small batches

  • You carefully measure all ingredients

  • You add pectin to the product as you are re-cooking

See pages 14-15 of the Jams and Jellies publication for hints on successfully remaking Jams and Jellies.

Everyone who has answered questions about jams and jellies has been confronted with questions such as:

  • Why does the fruit float at the top of my jam? Fruit will have less of a tendency to float if it ‘soaks’ in sugar and if sufficient air is released; both not usually an option in the rapid cooking process when making jams with added pectin. So.. Consider stirring the cooked fruit/pectin/sugar mixture for 5 minutes off the stove before ladeling into jars. This will help fruit to settle throughout the product.

  • Is moldy jam safe to eat? If kept too long in the refrigerator, or on the counter, jam, jelly and other fruit products will eventually mold. Current USDA recommends are to discard all moldy product. Be sure to start with pre-sterilized jars and pre-treated lids. Be sure to include a water bath processing step as part of your process. And be sure that the water bath covers the top of the jars by at least 1 inch during processing.

  • Why is using paraffin not recommended? Paraffin does not form as tight a seal as water bath processing and is no longer recommended.


Pectins

Consists mainly of the partial methyl esters of polygalacturonic acid and their sodium, potassium, calcium and ammonium salts; obtained by extraction in an aqueous medium of appropriate edible plant material usually citrus fruits or apples; no organic precipitants shall be used other than methanol, ethanol and isopropanol; in some types a portion of the  methyl esters may have been converted to primary amides by treatment  with ammonia under alkaline conditions. Sulfur dioxide may be added as a  preservative.  The commercial product is normally diluted with sugars for standardization purposes. In addition to sugars, pectins may be mixed with suitable food-grade buffer salts required for pH control and desirable setting characteristics. The article of commerce may be further specified as to pH value, gel strength, viscosity, degree of esterification, and setting characteristics. C.A.S. number  9000-69-5 DESCRIPTION White, yellowish, light greyish or light brownish powder

Source

Pectin

Pectin „ Occurs in plant middle lamella „ Gel former, e.g., fruit jelly „From the Greek word meaning tto congeal „Pectin was discovered in 1790 by Vauquelin and later (1825) crudely characterized by Braconnot O Pectic Substance Nomenclature „Protopectin-high methyl ester content „Pectinic acid-intermediate methyl ester contentcontent, solublesoluble – Salts are pectinates „Pectin-intermediate methyl ester content, colloidal „Pectic Acid-little methyl ester content – Salts are pectates

Pectin–Chemical structure Some other sugars, mainly L-rhamnose, are also present O Pectin structure „ Other monosaccharides (L-rhamnose, L- arabinose, D-xylose) in the structure may limit the size of junctions zones that can bbe fformedd andd, ththus, att lleastt partitialllly determine ultimate gel strength O Carboxyl Substitution in Pectin „Degree of Methoxylation (DM) – Protopectin 16% – NormalNormal pectinpectin 8%8% – Low Methoxyl Pectin 2-4% „Degree of Esterification – Protopectin 100% – Normal Pectin 50% – Low Methoxyl Pectin 12.5-25%

High and low methoxyl pectins „If DE is greater than 50%, it is a high methoxyl pectin (HM pectin) „If the DE is less than 50%, it is a low methoxyl pectin (LM pectin) O Degree of amidation (DA) „ The DA value indicates the percentage of carboxyl groups that nave been converted to the amide form by ammonia processiing „Amidated LM pectins may have a DA of 15-25% „Amidated pectins are especially sensitive to Ca+2 (see W&B, Figure 13.5) O Types of pectins HM LM Amidated LM -COOCH3 -COOCH3 -COOCH3 ((>> 50%)50%) ((<< 50%)50%) ((<< 50%)50%) -COOH -COOH -COOH – + – + – + -COO Na -COO Na -COO Na -CONH2 (15-25%)

Pectic Substances and Gelation „ Normal Pectin – Gels in the presence of acid and sugar „ Low Methoxyyl Pectin – Doesn’t need sugar, but does need calcium ion „ Pectic Acid – Forms insoluble calcium pectate. This reaction is responsible for the firming effect seen in certain plant tissues, e.g., canned tomatoes O Pectin gels Atomic force microscopy image courtesy of Peter Cooke, ERRC, ARS, USDA O Chemistry of pectic substances Me O H O O O H O dilute acid O O O O O oror basebase O O H O O H H H dilute acid depolymerization high temperature

Commercial (Normal) Pectin „ Liquid or powdered „ Source — mostly lemon and lime peel (20-30% ppectin)). This is the higghest qqualityy. „ Some from apple pomace (10-15% pectin) „ Pectin grade = number of pounds of sugar that one pound of pectin can carry in a jelly O Pectin production „ Citrus peel is extracted at pH 1.5-3.0 and 60-100oC „Extract is filtered „Pectin is precipitated by addition of isopropanol O Commercial (Normal) Pectin „ Grade is influenced by DE and molecular weight „ Gel strength — measured by ridgelimeter (measures(measures %% sag)sag), penetrometerpenetrometer, InstronInstron, oror texture analyzer.

Low methoxyl pectin „Available commercially „Requires no sugar to gel „Reqquires calcium ion to ggel „Preparation Enzyme, acid, alkali – Pectin LM Pectin – Acid preparation is best, produces firmer gels – Enzyme preparation is inferior as demethylation is not random O Low methoxyl pectin „Range of pH for gel formation = 2.5-6.5 O Pectin uses „Principally used in jellies and jam „However, some is used in – Confections – Beverages – Acidified drinks „ See W&B, Table 13.2 for other uses of pectins

Jelly making „Need — pectin + acid + sugar „Pectin – 0.5-1.0% – If juice is low in pectin, may concentrate by boiling or add more as commercial pectin – Peach — poor gel, pectin contains acetyl groups – Citrus — forms a good gel O Jelly making „Acid – Contributes flavor – pH optimum is 3.2 – If juice is low in acid, add lemon juice O Jelly making „ Sugar – Preservative – Micororganisms cannot grow due to the jjelllly’’s hihighh osmotiic pressure – Optimum sugar concentration is about 65% soluble solids

Jelly making „ Sugar – This is reflected in the final cooking temperature (colligative properties) of 104.5o CC – During this cooking some of the sucrose is hydrolyzed to invert sugar which will discourage sugar crystallization in the jelly O Gel strength in normal pectin jellies Jelly strength Continuity of Rigidity of structure structure [Pectin] Optimum is Acidity [Sugar] about 1% Optimum is 3.2 Optimum 65% Low-hard gel Low-weak gel High-no gel High-crystals form O Setting times HM pectins DE Setting time Rapid set 72-75% 20-70 sec Medium set 68-71% — Slow set 62-68% 180-250 sec

Setting times „Rapid set pectins are used in jams where quick gelling is desired to prevent flotation of the fruit „ Slow set pectins are used in jellies to provide time for bubbles to escape „High methoxyl pectin gels can not usually be melted and reformed O Theory of normal pectin gel formation A pectin junction zone Hydrogen bonds O Pectin junction zones O OH O O CH3 H OH H OH HO H O H H O O H H OH OH H OH H H OH H H OH H H O O H H O H O H H O CH 33 HH OOHH HH OO OO O OH H O O H O CH H OH HO O 3 H O H O H H O O H OH H OH H OH H H H H OH H HO O H H O O H H OH CH H OH CH O O 3 O O 3 H OH

Theory of low methoxyl pectin gel formation CCallciium iion Ionic bonds O LMP junction zones H CH O OH 3 H O H OH O O H O H O H H O O H OH H OH H OH H H H H OH H HO O H H O O H H OH H OH O O- O O- H OH 2+ Ca 2+ Ca – O O – O O H OH H OH HO H O H H O O H H OH OH H OHH H OHH H OH H H O O H H O H O H H O CH 3 H OH H O O O O CH 3 O Theory of low methoxyl pectin gel formation – pH needs to be higher (3.2-4.0) because only carboxylate (COO-) groups can participate in these types of ionic bonds

Methyl ester content and gelling ability 2 + a C h t i ww l e g o t y t i l i b A 0 20 40 60 80 100 DE O Characteristics and uses of low methoxyl pectin gels – These gels can be melted and reformed repeatedly – No sugar is needed to form the gel, hence thesethese typestypes ofof pectinspectins areare usedused inin dieteticdietetic products. In practice, a small amount of sugar is left in the dietetic products as a tenderizer/texturizer. When included in these preparations, the resulting jellies are not as brittle as they would be in the absence of the sugar. O Uses of low methoxyl pectin gels „Fat mimetic – From Hercules, this is a LM pectin gelled with Ca+2 and microparticulated (particle sizesize << 11 μμm)m) – Trade name is Slendid

9/23/2008 O Labeling „Both HM and LM pectin may be labeled pectin

E400 – E495

Number Name Comments
E400 Alginic
acid
thickener
and vegetable gum, derived from seaweed; used in custard mix, cordial,
flavoured milk, ice blocks, thickened cream and yoghurt; no known adverse
effects in small quantities, large quantities can inhibit the absorption of
some nutrients
E401 Sodium
alginate
see 400
E402 Potassium
alginate
see 400
E403 Ammonium
alginate
see 400
E404 Calcium
alginate
see 400
E405 Propylene
glycol alginate
thickener
and vegetable gum, derived from petroleum; see separate entry
E406 Agar thickener
and vegetable gum derived from red seaweed; sometimes used as a laxative,
found in manufactured meats and ice cream
E407 Carrageenan
a fibre
extracted from seaweed, it has recently been linked with cancer because it
may become contaminated when ethylene oxide is added to an inferior product,
this results in ethylene chlorohydrins forming, a highly carcinogenic compound;
linked to toxic hazards, including ulcers and cancer; the most serious
concerns relate to degraded carrageen, which is not a permitted additive;
however, native carrageen an, which is used, may become degraded in the gut
E410 Locust
bean gum
derived
from Carob or Locust bean tree Ceratonia siliqua; used in lollies,
cordials, essences, some flour products, dressings, fruit juice drinks;
frequently used as a caffeine-free chocolate substitute; may lower
cholesterol levels
E412 Guar
gum
derived
from the seeds of Cyamoposis tetragonolobus of Indian origin; fed to
cattle in the US; can cause nausea, flatulence and cramps, may reduced
cholesterol levels
E413 Tragacanth
resin
form the tree Astragalus gummifer; used in foods, drugs including nasal
solutions, elixirs and tablets; also used as a binder in cosmetics; possible
contact allergy
E414 Acacia derived
from the sap of Acacia Sengal; easily broken down by the human
digestive system; possible allergen, soothes irritations of mucous membranes
E415 Xanthan
gum
derived
from the fermentation of corn sugar with a bacterium
E416 Karaya
gum
derived
from the tree Sterculia urens; often used in conjunction with Carob (E
410), in ice cream, custard and sweets, as a filler for its capability to
multiply its volume by 100 times with the addition of water; possible
allergen
E417 Tara
gum
derived
from the Tara bush, Caesalpinia Spinosa is indigenous to Ecuador and
Peru and is grown in Kenya
E420 Sorbitol
artificial
sweetener and humectants; derived from glucose, either obtained from berries
or synthesised; used in lollies, dried fruit, pastries, confectionary, low
calorie foods, pharmaceutical syrups and ophthalmic preparations and is the
seventh most widely used preservative in cosmetics; not permitted in foods
for infants and young children, can cause gastric disturbance
E421 Mannitol
artificial
sweetener and humectants; derived from seaweed or the manna ash tree;
possible allergen, not permitted in infant foods due to its ability to cause
diarrhoea and kidney dysfunction, also may cause nausea, vomiting; typical
products are low calorie foods
E422# Glycerol
humectants
and sweetener; oily colourless alcohol; derived by decomposition of natural
fats with alkalis; usually as a by-product of soap making using animal fat or
vegetable oil; can be obtained from petroleum products sometimes synthesised
from propylene or fermented from sugar; used in flexible coatings on sausages
and cheeses, also in crystallised and dried fruit, liqueurs and vodka.
“Glycerine has been shown to protect against DNA damage induced by
tumour promoters, ultraviolet lights and radiation, presumably via free
radical scavenging”; large quantities can cause headaches, thirst,
nausea and high blood sugar levels. Typical products are liquors,
confectionary, dried fruit, low calorie foods
E430# ? ?
E431# Polyoxyethylene
stearate
?
E432# Polysorbate
20
avoid it,
banned in some countries
E433# Polysorbate
80
emulsifiers
derived from animal fatty acids; used as synthetic flavourings, surfactants,
defoaming agents and dough conditioners; may increase the absorption of
fat-soluble substances
E434# Polysorbate
40
avoid it,
banned in some countries
E435# Polysorbate
60
see 433
E436# Polysorbate
120
see 433
E440(a) Pectin naturally
occurring in the skins of apples; used to thicken jams, jellies and sauces;
large quantities may cause temporary flatulence or intestinal discomfort
E440(b) Amidated
pectin
no
known adverse effects
E441# Gelatine
possible
allergen, may contain 220, asthmatics and people allergic to sulphites
beware!
E442 Ammonium
phosphatides
no
known adverse effects
E450 Diphosphates
High
intakes may upset the calcium/phosphate equilibrium
E460 Cellulose
anti-caking
agent; no adverse effects known
E461 Methyl
cellulose
can
cause flatulence, distension, intestinal obstruction
E463 Hydroxypropyl
cellulose
avoid it,
banned in some countries
E464 Hydroxypropyl
methyl cellulose
no
known adverse effects
E4120 Ethyl
methyl cellulose
no
known adverse effects
E466 Carboxy
methyl cellulose, Sodium carboxy methyl cellulose
no
known adverse effects
E469 Sodium
caseinate
no
known adverse effects
E470# Fatty
acids salts
avoid it,
banned in some countries
E471# Mono
& di glycerides of fatty acids
no
known adverse effects
E472# Fatty
acid esters of glycerides
no
known adverse effects
E473# Sucrose
esters of fatty acids
no
known adverse effects
E474# Sucroglycerides
avoid it,
banned in some countries
E475# Polyglycerol
esters of fatty acids
no
known adverse effects
E476# Polyglycerol
polyricinoleate
no
known adverse effects
E477# Propylene
glycol esters of fatty acids
derived
from petroleum; no known adverse effects
E478# ? ?
E479(b)# Thermally
oxidized soya bean oil interacted with mono- and diglycerides of fatty acids
?
E480 Dioctyl
sodium sulphosuccinate
awaiting
results of studies
E481# Sodium
stearoyl-2-lactylate
no
known adverse effects
E482# Calcium
stearoyl-2-lactylate
no
known adverse effects
E483# Stearyl
tartrate
avoid it,
banned in some countries
E491# Sorbitan
monos tearate
no
known adverse effects
E492# Sorbitan
tristearate
may
increase the absorption of fat-soluble substances
E493# Sorbitan
monolaurate
avoid it,
banned in some countries
E494# Sorbitan
mono-oleate
avoid it,
banned in some countries
E495# Sorbitan
monopalmitate
avoid it,
banned in some countries