Sugarcane Syrup/Juice Preservation: Methods & Challenges – The Catalysts Group

Sugarcane Syrup/Juice Preservation: Methods & Challenges

India produces large quantities of sugarcane in the country (approximately 271 MT) every year, mainly for developing sweetening agents like sugar & jaggery and a small proportion is used for various other purposes. Sugarcane juice is commonly used as a delicious drink in both urban and rural areas. Sugarcane juice of 100 ml contains 40 kcal of energy, 10 mg of iron and six µg of carotene. It is rich in enzymes and has many medicinal properties. Sugarcane juice is a great preventive and healing source for sore throat, cold and flu. It has a low glycaemic index which keeps the body healthy. Even diabetics can enjoy this one sweet drink without fear. This is because it does not contain simple sugars. It also hydrates the body quickly when exposed to prolonged heat and physical activity; and is an excellent substitute for aerated drinks. Sugarcane juice refreshes and energizes the body instantly as it is rich in carbohydrates.

Sugarcane juice or syrup is available fresh across the country, however preservation of the same is a challenge. Storage of sugarcane syrup at room temperature causes it to turn dark brown with significant sedimentation. In general, sugarcane juice is spoiled quickly due to the presence of simple sugars. Very shortly after the harvest of sugarcane crop, endogenous invertase enzyme is activated and accentuates deterioration. The organisms convert sucrose into polysaccharides, such as dextran. Apart from the loss of sucrose, the presence of dextran even in very small amount creates a problem of filtration, clarification, crystallization and alters the shape of sugar crystals, thereby affecting the quality of sugar

Extensive work and research has been done in the field of preservation of sugarcane juice & syrup, given its extensive benefits & uses in the consumer & industrial market.Various methods are employed for preservation and bottling of sugarcane syrup to enhance its shelf-life. Earlier conventional processes which chiefly involved evaporation by heating presented two major drawbacks. It consumes a huge amount of energy and, heating the syrup also decomposes the sugar and other substances resulting in low-quality and dark-coloured juice/syrup.

  1. To tackle this, a new method of making syrup without heating the juice is employed, using a low-energy-consuming reverse osmosis process. TNAU developed a technique for preserving the sugarcane juice in which bottles can preserve the juice for a period up to six months. The process involves peeling, crushing, filtration, pasteurization and bottling. Sodium Benzoate @ 125 ppm is added as preservative. Preservation of sugarcane juice by pasteurization of the juice at 70 degrees Celsius for 10 min and adding citric acid ( 40mg/100ml), ascorbic acid(40mg/100ml) and potassium metabisulphite (150 ppm) is used. The sugarcane juice beverage having citric acid and potassium metabisulphite showed minimum changes in sensory qualities during storage.
  1. Attempts have been made to preserve the sugarcane juice extensively. Most of the methods involved blanching of stems, juice extraction, pasteurization followed by addition of ascorbic and / or citric acid and preservatives such as potassium metabisulphite, sulphur dioxide. The juice was added with ginger or lemon to improve the taste.
  1. Another similar method, with slight variations involves, using a combination of gamma radiation (5 kGy) with eligible preservatives and storage temperature (10 °C) could preserve raw sugarcane juice for more than a month. The preservatives used were citric acid (0.3%), sodium benzoate (0.015%), potassium sorbate (0.025%), and sucrose (10%). Process extended the shelf life to 15 days at ambient temperature (26 ± 2 °C) and 35 days at 10 °C. The microbial load was below the detectable limit within this period. The biochemicals like phenolics and flavonoids were not found to be affected by addition of these preservatives. The antioxidant activities including free radical scavenging activity, nitrite scavenging activity, and reducing power were also not significantly affected. The sensory evaluation scores showed that the juice with this combination treatment was highly acceptable.
  1. Another method is attempted using herbal agents for preservation of sugarcane juice & syrup. Sugarcane varieties Isd 34, Isd 35, Isd 36, Isd 37 and Isd 38 were used for collection of juice and juices were collected in the months of September, October, November, December, January, February and March. Juices collected in the month of December, January showed the highest shelf-life due to the presence of lower reducing sugar and highest percentage of sucrose.

Scientists & Industrial Experts have studied various preservation technologies such as pasteurization, pulsed electric field, ultrasound, microwave, and high‐pressure processing to secure enzymatic reactions and microbial growth in fresh sugarcane juice/syrup. In present times, the food industry is more concerned with the product shelf‐life longevity and safety for which chemical preservatives are extensively added. These chemical preservatives are artificially synthesized, for example, sodium and potassium salts of lactic acid, benzoic acid, and sodium diacetate and the like. Most of these chemical preservatives are expensive and pose health problems as they are carcinogenic and cause digestive and respiratory problems.

In the contemporary markets, the health‐conscious consumer, food manufacturers expect natural, safe, and environment-friendly preservatives that are less expensive, more nutritious, and can be easily obtained. However despite the chemical and non-chemical preservatives, catalysts, the challenges remain in the preservation of sugarcane syrup & juice as there are no particular technologies that can ensure preservation without compromise in the taste, colour and sensory attributes. Sugarcane syrup still remains one of the most difficult syrups/juices to preserve and extend its shelf-life despite worldwide research and investment into it.