Studies on storage stability and quality attributes of jamun (Syzygium cumini L.) jam under different packaging materials
A 2025–26 study conducted at G D Goenka University evaluated seven packaging materials for jamun jam stored over 150 days, revealing that multilayer pouches (T7) provided superior retention of physicochemical, nutritional, and sensory quality compared to other options, while HDPE jars (T3) resulted in the most significant deterioration.
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Fruit preserves have long been a way to extend the fleeting life of a harvest, turning seasonal abundance into a year-round treat. However, once a jar of jam is sealed, a slow chemical battle begins inside. Sugars can break down, vitamins can fade, and the vibrant colors and sharp flavors that define a good preserve can dull over time. The container holding the fruit plays a critical role in this process. Just as a shield protects a soldier from the elements, packaging acts as a barrier against oxygen, light, and moisture, all of which can accelerate spoilage. For a fruit like the jamun, also known as the Indian blackberry, which is prized for its deep purple hue and rich nutritional profile, finding the right container is essential to keeping its quality intact. Researchers in India recently set out to test which of several common packaging materials could best preserve the taste, color, and health benefits of jamun jam over a period of five months.
The study took place in a laboratory at G D Goenka University in Haryana, where scientists prepared batches of jamun jam using ripe fruits from the local market. They cooked the fruit pulp with sugar and citric acid until it reached the proper thickness and sweetness, then filled the hot jam into seven different types of containers. These included a standard glass jar, which served as the control, alongside various plastic jars made from PET, HDPE, and PP, a Tetra Pack pouch, an aluminum can, and a multilayer pouch. The filled containers were sealed and stored at normal room temperature. Over the course of 150 days, the researchers checked the jam at regular intervals to see how its chemical makeup and taste changed. They measured things like the total amount of dissolved solids, the acidity, the levels of vitamin C, and the content of anthocyanins, which are the pigments that give the jam its dark color and antioxidant properties. They also asked a panel of judges to taste the jam and rate its overall appeal.
As the months passed, the jam in every container began to change, but the speed and severity of these changes depended entirely on the material holding it. In all the jars, the total amount of dissolved solids and the sugar content slowly increased, while the acidity dropped and the pH level rose, making the jam slightly less tart. The vitamins and colorful pigments also began to fade. However, the multilayer pouch proved to be the most effective guardian of quality. After 150 days, the jam inside this pouch retained the highest levels of vitamin C, anthocyanins, and other beneficial compounds. It also maintained the best balance of acidity and sugar, resulting in a product that still tasted fresh and vibrant. The judges gave this sample the highest overall score, noting that it had changed the least from its original state.
The aluminum can performed as a strong second choice, keeping the jam's quality very close to that of the multilayer pouch. It successfully slowed down the loss of nutrients and color, keeping the product stable for the entire storage period. In stark contrast, the jam stored in the HDPE plastic jar deteriorated the most. By the end of the five months, this sample had lost the most vitamin C and color, and its acidity had dropped significantly. The judges rated this sample the lowest, describing it as having the poorest flavor and appearance. The glass jar and other plastic containers fell somewhere in between these two extremes, showing moderate levels of change.
The findings suggest that the multilayer pouch offers a superior way to store jamun jam, protecting it from the chemical reactions that cause spoilage. While the aluminum can is also a reliable option, the HDPE jar proved to be the least suitable for long-term storage of this specific fruit product. The researchers concluded that choosing the right packaging is not just about convenience or cost, but is a decisive factor in how long a food product remains safe, nutritious, and enjoyable. For producers looking to extend the shelf life of jamun jam without compromising its quality, the multilayer pouch emerged as the most effective solution, ensuring that the fruit's unique flavor and health benefits are preserved for up to 150 days.
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