CHEMISTRY AND MANUFACTURING TECHNOLOGY OF MOLASSES FROM
SUGARCANE BY PRODUCT
Molasses
is the dark, sweet, syrupy byproduct made during the extraction of sugars from sugarcane and sugar beets. The word molasses
comes from the Portuguese word melaco, which is a superlative from Greek
meli. The quality of molasses depends on the maturity of the sugar cane or
sugar beet, the amount of sugar extracted, and the method of extraction. Sweet
sorghum syrup is known in some parts of the United States as molasses, though
it is not true molasses. In Nepal it is called chaku and is used in the
preparation of various newari condiments like the yomari. Molasses can vary in
color, sweetness, and nutritional content depending on the variety or how much
sugar has been extracted.
Chemistry of Molasses
Molasses is made up of residual ingredients of the processed
sugar cane as well as traces from used additives in different proportions, depending
on whether the sugar production method is used. Based on usage the following
ingredients are viewed as the main quality determiners. The sugar content of
sugar cane is typically termed as sucrose or total sugar, the dry matter as
Brix or it is displayed as water / drymatter.
The quality of non-standardized cane molasses can vary
within the following benchmarks:
Sucrose
|
25 to 39%
|
Invert
|
12 to 19%
|
Brix
|
77 to 86%
|
Ash
|
8 to 14%
|
Raw protein
|
4 to 6%
|
Depending on usage, this commodity is traded in different
forms. For fermenting purposes mainly based on analysis or sample report with a
price setting pro – rata calculation of the sugar content.
For raw material purposes in the compound feed sector and according
to customers demand there are different standardized trading norms as follows:
Sugarcane molasses:
|
min.47 %
total sugar, max. 28 % water or
min.45 %
total sugar, max. 30 % water,
|
How Molasses is Made
During the sugar making process, juice extracted from
sugarcane or sugar beets is boiled down until the sugars crystallize and
precipitate out. The syrup left over after crystallization is referred to as
molasses. Typically, sugar cane juice undergoes three cycles of boiling and crystallization
to extract as much sugar as possible. With each successive cycle, the left over
molasses contains less sugar.
Molasses Varieties
- Light Molasses: This is the syrup left over after the first boiling cycle of sugarcane juice. This molasses is the lightest in color, has the highest sugar content, and the least viscous texture.
- Dark Molasses: Dark molasses is the byproduct of the second boiling cycle of sugarcane. This molasses is darker and more viscous than light molasses, contains less sugar and has a slight bitter tinge to its taste.
- Black Strap Molasses: This is the final byproduct of the third boiling cycle in the sugar making process. This variety of molasses contains the least sugar and has the highest concentration of vitamins and minerals. Black strap molasses has a very dark color and is extremely viscous in texture. Because this type of molasses is highly concentrated, it has a deep, spicy flavor. Blackstrap molasses is a source of calcium, magnesium, potassium, and iron; one tablespoon provides up to 20% of the daily value of each of those nutrients. Blackstrap has long been sold as a health supplement. It is also used in the manufacture of ethyl alcohol for industry and as an ingredient in cattle feed.
- Sorghum Molasses: Although a similar process is used to make sorghum molasses, it is not considered a true molasses because it is not made from sugarcane or sugar beets. Sorghum is a grass cultivated for animal feed, ethanol, and alcoholic beverages, among other things. Sugar can be extracted from sorghum in the same way as sugarcane and the resulting syrup is simply referred to as “sorghum molasses.”
Sulfured Vs Unsulfured Molasses
Sulfured molasses refers to molasses
that has been treated with sulfur dioxide as a preservative. Generally, only
young sugarcane requires this treatment. Therefore, molasses made from mature
sugarcane is often unsulfured. Unsulfured molasses may have a lighter, cleaner
sugar flavor.
The Manufacturing Process
Whether the base is sugar cane, the sugar extraction and refining process of which molasses is a byproduct is a circular path of washing and heating the cane with hot water.
1. Washing and cutting
The
sugar cane stalks are loaded onto conveyer belts and subjected to hot water
sprays to remove dirt and other field debris. Then, they are passed under
rotating knife blades that cut the stalk into short pieces or shreds.
2. Extracting the sugar juice
In
the sugar cane processing plant, extraction can be accomplished in one of two
ways: diffusion or milling. By the diffusion method, the cut stalks are
dissolved in hot water or lime juice. In the milling process, the stalks are
passed under several successive heavy rollers, which squeeze the juice out of
the cane pulps. Water is sprayed throughout the process to facilitate the
dissolving of the juice.
3. Clarifying the juice
The
extracted juice is clarified by adding milk of lime and carbon dioxide. The juice
is piped into a decanter, heated and mixed with lime. The juice passes through
carbon filters, producing a mud-like substance called carb juice, this mud is
pumped through a heater and then to a clarifying machine. Here the mud settles
to the bottom and the clear juice is piped to yet another heater and treated again
with carbon dioxide. Once again the mud is filtered out, leaving a pale yellow
liquid called thin juice.
4. Evaporating and concentrating the syrup
The
juice is pumped into an evaporator that boils the juice until the water
dissipates and the syrup remains. The syrup is concentrated through several
stages of vacuum boiling, a low temperature boil to avoid scorching the syrup.
Eventually, the sugar crystallizes out of the syrup, creating a substance
called massecuite. The massecuite is poured into a centrifuge to further
separate the raw sugar crystals from the syrup. In the centrifuge, the sugar
crystals fall away from the syrup that is being spun at a significant force.
This remaining syrup is molasses, and it is forced out through holes in the
centrifuge.
5. Storage and boffling
The
molasses is piped to large storage tanks. It is then pumped, as needed, to the
bottling machine where pre-measured amounts of molasses are poured into bottles
moving along a conveyer belt.
Byproducts/Waste
In addition to molasses, which is itself a byproduct
of the processing of sugar cane, there are several others materials that are
used for other purposes. After pressing the juice out of the cane stalks, the
dry stalk residue, called bagasse, are used as fuel in the plant. Beet pulp is
used in the processing of pet foods. Cane wax, which is extracted from the dry
residue, is used in the manufacture of cosmetics, polish, and paper coatings.
Uses for Molasses
- Baked Goods: In the United States, molasses is a common sweetener and flavoring in many baked goods such as gingerbread, Boston brown bread, and shoofly pie. Molasses is also responsible for the classic, sweet, rich flavor of baked beans.
- Alcohol: Molasses is the sugar used to make rum. Rum is therefore common in regions of the world where sugarcane or sugar beets are heavily cultivated because of the abundance of molasses. Molasses is also sometimes used to brew dark ales like stout.
- Brown Sugar: Molasses is responsible for the dark, rich flavor and texture of brown sugar. Brown sugar is produced by combining refined white sugar with approximately 5% molasses.
- Tobacco: Molasses is added to some tobacco products for flavor. Tobacco flavored with molasses is particularly popular in the Middle East for use in hookahs.
Nonculinary uses
Because of its unusual properties, molasses has
several uses beyond that of a straightforward food additive.
Other food and consumption derivatives
- Molasses can be used as the base material for fermentation into rum.
- Molasses is commonly used in dark brewed beverages such as stout and very heavy dark ales.
- Molasses is added to some brands of tobacco used for smoking through a Middle Eastern water pipe (e.g., hookah, shisha, narghile, etc.). It is mixed into the tobacco with glycerine and flavorings; sometimes it is used with honey and other syrups or fully substituted by them. Brands that use molasses include Mazaya, Al-Fakher, Nakhla, Tangiers and Salloum.
- Blackstrap molasses may also be used as an iron supplement for those who cannot tolerate the constipation associated with other iron supplementation.
- Molasses is used as an additive in livestock feeds.
- Molasses is used in fishing groundbait.
Chemical
- Molasses can be used as the carbon source for in situ remediation of chlorinated hydrocarbons.
- Molasses is blended with magnesium chloride and used for de-icing.
- In Australia, molasses is fermented to produce ethanol for use as an alternative fuel in motor vehicles.
Industrial
- Molasses can be used as a chelating agent to remove rust where a rusted part stays a few weeks in a mixture of 1 part molasses and 10 parts water.
- Molasses can be used as a minor component of mortar for brickwork.
- Ink rollers on printing presses were originally cast using a mixture of molasses and glue.
Soil
- Molasses can be added to the soil of almost any plant to promote microbial activity.
Hydroponic
- Molasses contains the disaccharide sucrose. This sugar does not substitute as a flowering enhancer in hydroponic gardening. Other substitute "sugar boosters" for hydroponics contain deoxyribose, lyxose, ribose, xylulose, and xylose. These simple and complex carbohydrates are the main components of cellular reproduction, and deliver an immediately usable form of energy to the plant, which would normally rely on a soil-type organic medium for beneficial microbial activity
Nutritional information
Each tablespoon of molasses (20 g) contains 58 kcal, 14.95 g of carbohydrates, and 11.1 g of sugar divided amongst:- Sucrose: 5.88 g
- Glucose: 2.38 g
- Fructose: 2.56 g
Reference:
Presented and prepered by:
Md. Rafiqul Islam Shuvo
B.Sc.Ag.(Hons.) , PSTU
MS in Horticulture, BAU
www-agricultureinfo.blogspot.com
shuvo_ag10@yahoo.com
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