Sidel Confirms Benefits of PET for Soy Milk
09 Feb 2016 --- The Sidel Liquid Package Interaction (LPI) Center of Excellence recently completed extensive research proving the compatibility of PET packaging for sensitive beverages such as soy milk.
Health benefits
High in protein and iron, and low in fat and sodium it contains no lactose, the natural sugar found in cow’s milk, making it much easier to digest. The growth of the popularity of soy milk is partly due to its health benefits, as well as an increase in consumer demand for alternatives to traditional dairy products. Soy contains polyphenols, the natural antioxidant chemicals found in all plants, which have been linked to protection against the development of cancers, cardiovascular diseases and diabetes. The polyphenol group in soy milk notably includes isoflavones, which have natural estrogen-like properties that can help prevent menopause symptoms, as well as some chronic diseases.
Production and packaging
Many beverage producers are keen to develop new soy milk products to meet consumer demands for this health-promoting beverage. However, packaging soy milk presents a number of challenges. The soy bean is a low acid food, and as such a good host for the breeding of bacteria. Soy milk production needs to ensure product integrity during its shelf life. At the same time, the high levels of nutrients and minerals need to be retained. This makes quality control and food safety critical through- out the entire production and packaging process.
While glass and carton are the most popular packaging types for soy milk accounting for over 99% of all soy milk product packaging, there is a growing interest in PET because of the design flexibility and consumer convenience it offers. For this reason, Sidel’s Liquid Package Interaction scientists have been working to test the compatibility and potential reactions of soy milk products when packaged in PET bottles.
Their studies evaluated the performance of long shelf life soy milk aseptically filled in three types of container: glass, virgin PET and PET with an oxygen barrier. Much of the research took place in a reduced-scale filling plant and at Sidel laboratories using ultra-high temperature (UHT) processed soy milk.
The tests were handled in three different storage conditions in terms of temperature and light: standard conditions -400 lux at 20°C, 21% O2-, and in two different accelerated conditions –0 lux at 20°C, 75% O2 and -10,000 lux at 20°C and 21% O2-. These extreme light and oxygen storage conditions aged the product and provided faster results on product stability.
Extensive testing
Many different parameters were evaluated including packaging permeability, oxygen consumption, color changes, aroma changes and nutritional component stability. A number of external partners including universities and laboratories were also involved. The research culminated in the release of over 3,000 analyses on soy milk, all of which help beverage producers find the right packaging type for their product and recipe.
Results
The results clearly showed that PET gives soy milk beverage producers the long-term high levels of food safety and quality they need, alongside all the advantages of product differentiation that PET offers. However, to prolong soy milk shelf life and avoid oxygen impact, a PET bottle with an oxygen barrier is recommended. Although various alternatives are available on the market, Sidel experts have recommend the most relevant packaging solution for each individual product depending on its specifications, shelf life and storage conditions.
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