Many food ingredients are preserved with the help of sugar. In that, most of the people are addicted to Jam, jelly & marmalades. These kinds of products are sold in higher range compared to others. Because snacks item like bread are spread with this sugar products. Some people are addicted to this as their morning breakfast. The condiment aisle at the grocery store, you will find rows & rows of colourful spreads named as jam/jelly/marmalades. In this article, we discussed about the full details of jam, jelly & marmalades.
Jam is the product, prepared from the fruit juice/pulp/juice concentrate obtained from ripe, fresh, frozen, or dehydrated form of fruits and they are boiled with nutritive sweeteners such as sugar, dextrose or liquid sugar until it attains its consistency. It has an original fruit flavour with free from burnt smell or any other objectionable flavours & crystallization. In some cases, it contains little piece of fruit pieces. It is also called as “Fruit Jam” or “Fruit cheese”.
There are various flavours of jam are available in market. In that some are single flavour and some of them are mixed flavour jams. Examples are citrus fruits like lemon & orange are mixed to produce a jam, in this both contain acid as well as pectin. So, they are easily bind. Some of the most popular combination of mixed fruit jams are pineapple & paw paw, orange & banana and apple & plum.
Specific requirements of jam –
Total soluble solids – 65 %
Fruit content – 45 % (for strawberry & raspberry, it’s about 25%)
Relative humidity – 80 %
Characteristics of jam –
There are some special characteristics are needed for the jam to attain its consistency & other organoleptic properties. In some jams are made with a chunky texture for that, small amount of fruit pieces is added before 5 mins of finishing. In this product, water is used in bulk range with little amount of fibrous matter along with seeds. They are listed below:
Pectin is added in the range of 1 % based on the weight of the jam. It provides the proper structure to the jam. For citrus fruit jam, there is no need of pectin. Because, citrus fruit itself contain a pectin substance.
Example: – Low pectin fruits (Apricots, berries & peaches), they need natural pectin sources or use commercially available pectin.
Sugar added in the jam should be in correct proportion and they are based on the amount of pectin content in our chosen fruit. If there is any change in that, it will affect the characteristics of jam and it turned into sticky or gummy. In initial stage of preparation, the sugar is about 20 parts for 10 parts of fruit.
After the processing, at the stage of finishing, the sugar in the range of about 30- 40 %. Majorly invert sugar & glucose is used to resist the crystallization effects.
The Acid used for the jam influences the settling consistency of jam and inversion of sugar. The basic supplements of acids such as tartaric acid, malic acid or citric acid. Normally, the good jam contains the pH range of about 3.3, it might be varying depend on the fruits used for jam.
Example: – The pH of apple and plum jam contain 3.2-3.5.
Preparation of jam –
Shelf life of Jam –
Jam, which is prepared by home itself and it kept in a refrigeration condition. It can withstand up to one month. But they are processed under controlled condition in the industrial level, it might be good for a year in certain suitable cooling / dry place.
The Rigid cousin of jam is known as jelly, it has smooth, gelatinous layer. But it is prepared from fruit juice after staining to remove all the solid matters, to get a transparent & jiggly texture. The structure of jelly is transparent and sparkles, quivers but does not flow when removed from its mold. It should be tender enough to cut easily and is so firm that angles produced retain their shape.
Specific Requirements –
Total soluble solid – 65 %
Fruit juice content- 45 %
Total acidity – 0.5 to 0.75 (not exceed 1)
Sugar – 60 to 65 %
Water – 33 to 38
Rheology of Jelly –
The Rheology of the jelly is mainly based on the acidity content.
Theory of Jelly formulation –
There are 3 theories used for the jelly formulation and they are discussed below:
- Fibril theory
- Spencer’s theory
- Olsen’s theory
When sugar is added to pectin solution, it destabilizes the pectin-water equilibrium and pectin conglomerates forming a network of fibrils through the jelly. The network of fibrils holds the sugar solution in the interfibrillar
The firmness of network depends on
(a) the concentration of sugar,
The fibrils of pectin become tough in presence of acids. Small amount of acid gives a weak fibrillar structure. Large amount of acid tends to hydrolyze pectin; the fibrils lose elasticity, and the jelly becomes syrupy.
Sugar acts as a precipitating agent; the presence of acid helps it. Greater the quantity of acid, lower is the sugar requirement.
Sugar acts as a dehydrating agent which disturbs the equilibrium existing between water and pectin. The negative charge on pectin is reduced with help of hydrogen-ion-concentration. Pectin precipitates and coalesces in the form of a fine network of insoluble fibers, provided sugar is present in sufficient concentration. As the system reaches equilibrium, the jelly strength becomes the maximum.
Preparation of Jelly –
Shelf life of Jelly –
The shelf-life of the jelly can be determined with the help of sugar added in the process along with that the type of fruit chosen for the jelly preparation. Because some fruits contain more moisture, that kind of fruits are quickly spoilage due to the microbial growth. Once open form of jelly is good for a month, while kept in a refrigeration condition. Otherwise, it should withstand for about three to six months.
Defects occurs in jelly processing –
There are various defects are identified during the jelly processing. These defects are caused due to some mishandling or alter in the ratio of necessary requirements.
- Crystals in jelly – Due to excess of sugar/ acid
- Tough texture – Sugar ration is too low
- Cloudy appearance – Imperfect straining
- Failure to form gel – Insufficient amount of pectin / too much of water
A fruit preserve should be clear and transparent nature without any sticky texture, fruit peel also includes during the boiling water until it turns soft. After that, additional sweeteners are added with resulted as light gelatinous texture along with chunks of rind. It is a refined form of jam & jelly. Popular marmalades are combination citrus, orange-peach, orange-pear, ginger-pear, pear-pineapple and grape.
Specific requirements –
Total soluble solid – 65 %
Fruit content – 45 %
Peel – 5 %
Preparation of marmalades –
Shelf- life of marmalades –
The shelf life is similar to that of the jelly. It should be withstanding one month under the refrigeration condition.
Difference in jam, jelly & marmalades –
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