The Art and Science of Jaggery Making: A Review

Sugarcane (Saccharum officinarum) is a cash crop widely grown for commercial in the world. Besides sugar production, sugarcane is also used for the preparation of jaggery, khandsari. Sugarcane, the prime source of sugar in India, is cultivated in an area of about 5.15 million hectare with a production of about 383 million tonnes (2018-19). Sugar industry, the second largest agro-based industry in India sustains the livelihood of about 12.34 million farmers and farm workers. This industry is meeting about 40% of the total requirement of sweeteners and giving employment to 2.5 millions of people in rural areas with minimum capital investment (Anwar, 1999). Jaggery is an unrefined, non-centrifugal whole cane sugar consumed all over the world. It is a traditional Indian sweetener used in India much prior to arrival of modern sugar making technology. The color of jaggery varies from golden brown to dark brown but from market point of view light golden colored jaggery is very popular. Jaggery is a rich mixture of minerals and vitamins, thus it is the healthiest sugar from the group of sweeteners. The mineral contents in jaggery are approximately 50 times greater than refined sugar and 5 times more than brown sugar by Gopalan et al., (1991). Jaggery is a good source of energy (383 kcal/100 g) and has various medicinal values (Ghosh et al., 1998; Anonymus, 2014).
 
Jaggery market scenario
 
India has now become the largest producer and consumer of sugar with its production reaching up to 33 MMT for marketing year (MY) 2018-19. As the major producer of Jaggery, the country has recognized as one of the leading traders and exporters of Jaggery to the world. Uttar Pradesh and Maharashtra are the major sugar producing states and as far as Uttar Pradesh is concerned, it is said to be the largest state in sugarcane production in the country. Uttar Pradesh alone contributes to 42-44% of the country’s total sugarcane production and also occupies the top of the list in being the largest sugar producing state with around 107.19 lakh tonnes during the marketing year (MY) 2018-19. It was estimated that about 50% of total sugarcane produced in India is used to manufacture 8-10 million tons of jaggery (Madan et al., 2004).
 
India during the last couple of years has produced more than 300 MMT of sugarcane out of which, about 79.91% is utilized in producing white sugar, 11.29% in producing jaggery and khandsari, 8.80% as cane juice, seed cane for the next harvest etc. Sugar recovery for different states in India lies in the range of 8.89 to 11.26% on cane (MY 2018-19), whereas, recovery of jaggery (gur) ranges from 10-13% depending upon the variety of sugarcane, sugarcane quality, soil texture, irrigation facilities, time of cane crushing etc., (Mohan and Agarwal, 2020). The jaggery has a good demand in domestic and foreign market. The values of nominal protection coefficient and domestic resource cost of jaggery were observed less than unity, which shows that it is a good exportable product and has high export competitiveness (Banakar et al., 2012).
 
 Nutritional status and importance of jaggery
 
Jaggery, a product of sugarcane, is such a product which is rich in important minerals viz., magnesium-70-90 mg, potassium-10-56 mg, phosphorus-20-90 mg, sodium-19-30 mg, iron-10-13 mg, manganese-0.2-0.5 mg, zinc-0.2- 0.4 mg, copper-0.1-0.9 mg and chloride-5.3 mg per 100 g of jaggery), vitamins (viz., Vitamin A-3.8 mg, Vitamin B₁-0.01 mg, Vitamin B₂- 0.06 mg, Vitamin B₅-0.01 mg, Vitamin B₆-0.01 mg, Vitamin C-7.00 mg, Vitamin D₂-6.50 mg, Vitamin E-111.30 mg) and protein-280 mg per 100 g of jaggery, which can be made available to the masses to mitigate the problems of malnutrition and under nutrition. The micronutrients present in the jaggery possess antitoxic and anti-carcinogenic properties (Nath et al., 2015). The magnesium strengthens the nervous system, helps to relax our muscles, gives relief from fatigue and takes care of our blood vessels. The potassium and low amount of sodium present in jaggery maintain the acid balance in the body cells and also combat acids and acetone and control our blood pressure. Iron helps to prevent anaemia. It also helps to relieve tension and takes care of asthma, as it has anti-allergic properties. The moderate amount of calcium, phosphorous and zinc helps to maintain optimum health.
 
Forms of jaggery
 
Jaggery is basically available in three forms viz., solid (lumped), liquid and granular jaggery. Of this 80 per cent is in solid lump form while remaining 20 per cent constitute liquid and granular jaggery (Singh et al., 2011). The composition of these forms (Table 1) is reported by Said and Pradhan (2013).
 

 
Solid jaggery
 
To prepare solid jaggery the clarified sugarcane juice is boiled at its striking point temperature varying from 116 to 120°C and then filled in to the molds of different shapes and sizes. The moisture contents of solid jaggery lies in between 5.0% and 7.0% as per the Bureau of India Standard (Anonymous, 1990).  The liquid jaggery is semi liquid syrup made by boiling of sugarcane juice below striking point temperature varying from 105 to 108°C (Nevkar et al., 2008). It contains 30-36% water, 40-46% sucrose, 15-25% invert sugar and 0.30% calcium (Wandre and Hasabnis 1995).
 
Liquid jaggery
 
It is an intermediate product obtained during concentration of purified sugarcane juice during jaggery making and is semi liquid syrup like product. The quality of liquid jaggery largely depends upon quality and composition of cane juice, type of clarificants used and striking temperature at which concentrating juice is collected. For quality liquid jaggery, the juice concentrate is removed from boiling pan, when it reaches striking point temperature of 103-106°C depending upon the variety and agro-climatic zone. Chemical composition of typical liquid jaggery could be: water 30-36%, sucrose 40-60%, invert sugar 15-25%, calcium 0.30%, iron 8.5-10 mg/100 mg, phosphorus 05/100 mg, protein 0.10/100 mg and vitamin B 14/100 mg (Singh et al., 2013).
 
Granular or powder jaggery
 
The process of making granular jaggery is similar up to concentration. The concentrating slurry is rubbed with wooden scrapper, for formation of grains. The granular jaggery is then cooled and sieved. Less than 3 mm sized crystals are found to be better for quality granular jaggery. Raising of pH of cane juice with lime up to 6.0-6.2 and striking point temperature of 120°C was found to yield quality granular jaggery with high sucrose content of 88.6%, low moisture of 1.65%, with good colour, friability and crystallinity. Jaggery in the form of granules (sieved to about 3 mm), sun dried and moisture content reduced to less than 2% and packed in polyethylene polyester bags or polyethylene bottles, can be stored for longer time (more than two years), even during monsoon period with little changes in quality. Colour of jaggery powder can range from golden yellow to golden brown dark brown like dark chocolate. The colour is often dependent on base ingredient used to make jaggery powder. It is softer than sugar and also amorphous. This is because vitamins proteins and in gradient of cane are not removed. It is made up of predominantly sucrose mineral salts iron. Hence consumption of jaggery is recommended in case of iron deficiency anaemia. It contains longer chains of sucrose therefore it is digested slowly and energy release is also slow. Hence energy is provided for a longer period of time and it not harmful for the body.
 
Traditional jaggery manufacturing process
 
Mechanical and thermal energies are required to prepare jaggery using open earth pan furnace. Mechanical energy is required to crush the sugarcane to produce sugarcane juice, and thermal energy is required to heat the sugarcane juice to prepare jaggery in the furnace. Crushing the sugarcane will produce sugarcane juice and bagasse as a by-product. At the initial moment the moisture content in the bagasseis around 40-50% (Manohar Rao, 1977). The moisture content can be reduced to 8-10% by drying the bagasse in open area and then dry bagasse is used as a raw material to produce heat by combustion in the open earth furnace. It was observed that out of the total energy produced in the combustion process, around 45% is used for jaggery preparation and remaining is lost through flue gases, ash and furnace walls. Sugarcane juice used in preparation of jaggery in the open earth pan consists of three different stages.
 
The first stage of process begins with supplying sensible heat (around 6% of total energy produced in the combustion process) required to raise the temperature of sugarcane juice from ambient to its boiling point. Measured quantity of additives like bendi, calcium carbonate and phosphoric acid (each at around 30-50 g/100 kg of sugarcane) will be added to the sugarcane juice to maintain the required pH in this stage (Ghosh et al., 1998). The second stage consists of removal of water from the sugarcane juice at its saturation/boiling temperature. The amount of heat supplied during this stage (around 39% of the total energy produced in the combustion process) is considered to be latent of vaporization required to convert water to steam. Floating residue known as molasses (around 3-5 kg/390 kg of sugarcane juice) is formed at this point and needs to be removed from the free surface. At the end of the second stage, the sugarcane juice will become rich in concentrated solids as the water is completely removed. In the last stage of jaggery preparation, the heat supplied (around 0.1% of the total energy produced) is utilized to increase the temperature of the sugarcane juice from its boiling point to striking point. The striking point is the temperature at which the sugarcane juice converts to a semi solid paste which slides on the pan surface instead of sticking to the pan. At this stage the sugarcane juice in semi-solid state is removed from the pan and cooled to room temperature to prepare the jaggery. The conventional process of jaggery preparation is represented in (Fig 1 and 2).
 

 

 
Exploration of new avenues in jaggery processing
 
While producing jaggery by traditional process, naturally occurring enzymes and other compounds in sugarcane juice react with each other due to uncontrolled heating and form many dark colored complex compounds. Secondly, due to high heat, sugars in juice caramelize and form dark colored compounds. Finally, excessive use of lime and leaching of iron from pans also result in dark color. Many jaggery producers use surplus sugarcane after supply to sugarcane factories for the production of jaggery. Such sugarcane is not always compliant with the production process and results in lower quality of jaggery.
 
There are several jaggery units which are on the verge of closure as a result of traditional technologies, low market price for jaggery in comparison to fair remunerative Price (FRP) /State Adviced Price (SAP) for sugarcane. Traditional process involves manual labor and involves long hours of production. The flue gas emanating from direct fire under the pan releases harmful chemicals in the boiling house which are hazardous and cause respiratory problems to workers.
 
With the advent of modernization and introduction of new technologies while quality of sugar has improved to a greater extend in order to cater to the sector specific requirements of the market, jaggery production is still confined to small scale cottage industry usually for local consumption, using traditional technologies necessitating measures to be taken for quality improvement (Shahi, 1999). With the passage of time although the jaggery industry has witnessed growth in many folds, but sadly there isnt any significant improvement in its performance, technical efficiency and recovery. Few reasons as to why old technologies are still in practice for jaggery manufacturing are:

(a) Lack of government policy support.
(b) Dis-organized micro and small scale sector.
(c) Lack of will and financial constrains to adopt new technologies.
(d) Poor education of craftsmen involved in jaggery processing.
 
Technological advancements in jaggery processing
 
Conventionally jaggery is produced by evaporation of water in open pan/s. Furnace is fired using bagasse, which is residue of sugarcane, obtained during juice extraction. Furnace heat utilization efficiency is very low, which is ~15% for single (Sharon et al., 2014), ~30% for two (Anwar, 2010), and 50 to 60% for four pans (Shiralkar et al., 2014). It also depends on number of parameters like sizes of pan, furnace and chimney, flue gas flow patterns, orientation and air inlets, bagasse firing practices, etc. In addition to this, these units are mainly designed and developed through past experiences. Saving of bagasse gives additional revenues to the farmers. Chemicals like lime, phosphoric acid and hydros powder are used by jaggery makers to clarify juice (Singh et al., 2013; Sardeshpande et al., 2010; Bhardwaj and Singh, 2013). Traces of these chemicals in the jaggery are harmful for human health. This problem was overcome by the use of two pan; three or four-pan could be used so as to consume maximum thermal energy of the hot flue gasses. Several research is being carried out to enhance the performance of jaggery plant. The research study includes the use of juice pre-heaters, energy boosters, economizers, heat pump based freeze concentration system of sugarcane juice etc. Among all the above mentioned suggestions, the use of multiple pan plant with heat pump based freeze concentration system of sugarcane juice seems to be a promising approach for efficient jaggery production. These key issues are addressed by Energy Efficient Freeze Pre-concentration Process.
 
Jaggery making using freeze pre-concentration of sugarcane juice
 
In this process, water is selectively freezed and separated from juice to form ice and concentrated juice. Freezing point of juice changes from -1.5 to -4.6°C (Mathlouthi and Reiser, 1995) for 20 to 40° Brix. During this initial 63% water removal, bagasse is saved and that can be recycled in field for composting. Concentrated juice is obtained at low temperature. This juice is further concentrated using steam jacketed pan with vegetative clarificants. Altogether, it improves colour of jaggery from dark brown to golden yellow which has higher market value.
 
The number of open pan/s used for concentrating juice depends on severity of bagasse use. Some cane varieties are sugar rich while some are fibre rich. Single pan jaggery making with sugarcane having low fibre and high sugar content may require additional fuel other than bagasse. This issue was addressed by increasing number of pan for preheating and concentration. Two, three and four pan furnaces are reported in literature. It shows that furnace heat utilization efficiency increases with number of pans. Initial investment also increases with increase in number of operators. Quality of jaggery is still being questioned, as chemical clarificants are used to enhance colour of juice and hence colour of jaggery. Organic sugarcane cultivation and crushing same sugarcane for organic jaggery making using only vegetative clarificant showing huge potential in Indian market as well as for export. India exported 3,41,155.34 MT of jaggery and confectionery products to the world for the worth of Rs. 1,633.22 crores/ 227.90 USD Millions during the year 2019-20 (APEDA, 2020). This huge opportunity can be met by continuous and automated operation of small jaggery units. It will offer addition employment and help to improve status of debt ridden sugarcane farmers. These issues are addressed by energy efficient freeze pre-concentration of sugarcane juice using a reversible heat pump.
 
Advantages of fpcs are as follows
 
•  Low specific power consumption 9 to 11 kWhe/m3 water removal.
•  Saving of bagasse upto 77% of produced bagasse. It gives additional revenue to farmers.
•  Reduction in area required for jaggery making unit by 60%.
•  Quality of jaggery gets improved. Colour of jaggery gets without using chemicals.
• Reduction in pan size, which is required for boiling of concentrated juice.
• Operation of system is also possible using solar photo-voltaic cells.
•  Automated operation reduces number of workers required to handle boiling process.
 
Storage and packaging
 
The storage life of jaggery is mainly depends upon the atmospheric humidity and temperature.  The major problem associated with jaggery storage is the presence of inverts of sugars and mineral salts, which being hygroscopic in nature, absorb moisture particularly during the moonsoon season when the ambient humidity is high leads to spoilage of the jaggery materials. It was estimated that during monsoon season more than 10% of total jaggery produced in India of value 0.6 million US $ is lost annually (Mandal et al., 2006). For good consistency, the humidity content of jaggery should not exceed 6 per cent and should be kept at 43-61 per cent relative humidity. The storage of jaggery is a significant function for its preservation under adverse environmental conditions. Jaggery production begins in the month of September/October in India and continues until March/April and is processed for the rest of the year. It has been estimated that every year between one third and one half of the total output of jaggery is stored (Kumar et al., 2012).  The pretreatment with nitric oxide of sugar cane juice provides better colour and sucrose amount, which helps increase the shelf life of jaggery (Hussain et al., 2012).

The researchers used various conventional and enhanced methods to increase the shelf life of jaggery. Studies on the handling, packaging and solar drying of jaggery under various environmental conditions have been addressed in this document. For jaggery storage, which varies from region to region, usually earthen pot, wood box and metal drums are used. Jaggery is stored in the shape of a heap in some areas and filled with cane garbage, bagasse, wheat straw, cottonseed, furnace ash, palmyra leaf mat, rice husk, etc. to protect it from direct contact with moist air (Rai and Paul, 2007). The first national seminar on jaggery manufacturing, its quality and storage was organized in 1985 at Indian Institute of Sugarcane Research, Lucknow (Baboo and Ghosh, 1985). The prepared jaggery, can be kept at low temperature for up to eight months (Uppal and Sharma, 2002).  Jaggery can be stored without any physical changes for duration of 20 months at a temperature range of 7-9°C (Uppal, 2002).  Excessive use of sulfite as a clarifier can impact jaggery colour during storage (Perez-Gago et al., 2002). Excessive microbial growths during jaggery storage are very harmful to human body (Singh et al., 2009). The shape and sizes of jaggery particles also affect the storage life time of jaggery powder. Jaggery powder of coarse grade (0.5-0.708 mm) was found to be more suitable than medium (0.351-0.420 mm) and fine (0.211-0.296 mm) in 100 gauge polyethylene bags for a period of six months in terms of its chemical properties and organoleptic properties (Unde et al., 2011). An improved drying cum-storage bin (100 kg capacity) and a six-ton capacity godown were built by IISR, which was found suitable for almost all regions in India (Anwar, 1999).  In the jaggery cum storage bin, the change in quality characteristics during storage such as moisture content, colour, sucrose and sugar reduction was found to be more successful than the open pan and polyethylene bag for a period of six months (Chand et al., 2011).  Jaggery storage in the IISR bin was also found to be more effective under hilly climatic conditions than the polythene bag and open storage. For a longer time than jute bags, the PET film with 100% nitrogen can be used to store jiggery (Chand et al., 2014). The storage of jaggery in drying cum storage bin with edible coating of whey protein was found to be good as compared to uncoated jaggery. Patil and Anekar (2014) observed the storage of jaggery in a pre sterilized PET bottle at refrigeration temperature (7°C) was found more efficient than at room temperature (27°C) and high temperature (37°C). Mishra et al., (2016) utilized the carboxy methyl cellulose and whey protein to maintain the moisture content of jaggery or storage of jaggery for some time. Shweta et al., (2019) suggested that solid jaggery can be kept for more than one year at low temperature.  Quality and colour are the significant characteristics that decide the acceptability of customers towards jaggery. In the case of jaggery stored at low temperatures, the consistency and colour of solid jaggery stored at room temperature are good and appropriate.  The various studies carried out on storage and packaging of jaggery is listed in (Table 2 and Table 3) respectively.
 

 

The thermal and overall efficiencies of the production plants for jaggery are very limited, depending on the number of variables. Design and construction specifications of the plant, bagasse combustion, the use of hot flue gas thermal energy and the draught produced by the furnace are some of the major factors that need due attention. All these parameters are directly related to the efficiencies of the plant that makes jaggery. The researchers also face major challenges with low juice recovery quality, low productivity and elevated operating time of conventional jaggery plants. In order to solve this problem, two-pan, three-pan and four-pan plants are used to absorb hot flue gases with optimum thermal capacity. The use of multi-pan plants with a heat pump based freeze concentration system is found to be a good approach for the efficient production of jaggery from sugarcane juice from the available literature on improvements for the production of jaggery production plants.
 
Jaggery storage is also a major concern. In order to preserve the quality of jaggery, the conventional storage methods such as earthen pot, wooden box and metal drum, etc. are not very successful. Edible coating, PET film, drying cum storage bin, low temperature storage, PET film with 100 % nitrogen is used as packaging materials for keeping quality of jaggery.  The storage of jaggery in the whey coated drying cum storage bin is most efficient in maintaining the consistency of jaggery for a longer time. Some of the researchers’ current research activities are improving the efficiency of heat utilization, preheating of juice, using the freeze concentration technique, automating various processes and maintaining the consistency of jaggery for a longer period under all environmental conditions. In short, the key challenge before the researchers is the optimization of jaggery manufacturing processes, improvement in conventional jaggery manufacturing plants and preservation of jaggery.

The scientists/researchers have to work more effectively in the production and storage of jaggery to meet these challenges in the future.  To make the jaggery manufacturing process eco-friendly, the government and researchers should encourage the farmers to use solar energy in heating sugarcane juice.